Skip to main content

Full text of "IC Datasheet: RC-22 RCA Receiving Tube Manual Jul63"

See other formats


Series  RC-22 


RADIO  CORPORATION  OF  AMERICA 

ELECTRONIC  COMPONENTS  AND  DEVICES  •  HARRISON,  N  J 


Contents 


Page 

Electrons,  Electrodes,  and  Electron  Tubes   ....  3 

Electrons,  Cathodes,  Generic  Tube  Types,  Diodes,  Triodes,  Tetrodes, 
Pentodes,  Beam  Power  Tubes,  Multi-Electrode  and  Multi-Unit  Types, 
Receiving  Tube  Structure,  Television  Picture  Tubes 

Electron  Tube  Characteristics    .  12 

Electron  Tube  Applications        .    .  \ 14 

Amplification,  Rectification,  Detection,  Autoni^atic  Volume  or  Gain 
Control,  Tuning  Indication  with  Electron-Ray  Tubes,  Oscillation,  De- 
flection Circuits,  Frequency  Conversion,  Automatic  Frequency  Control 

Electron  Tube  Installation    .........  58 

Filament  and  Heater  Power  Supply,  Heater-to-Cathode  Connection, 
Plate  Voltage  Supply,  Grid  Voltage  Supply,  Screen-Grid  Voltage  Supply, 
Shielding,  Dress  of  Circuit  Leads,  Filters,  Output-Coupling  Devices, 
High-Fidelity  Systems,  High- Voltage  Considerations  for  Television 
Picture  Tubes,  Picture-Tube  Safety  Considerations 

Interpretation  of  Tube  Data                                 .  69 

Application  Guide  for  RCA  Receiving  Tubes  ....  75 

Technical  Data  for  RCA  Tube  Types   83 

Picture-Tube  Characteristics  Chart   484 

Electron  Tube  Testing   487 

Resistance-Coupled  Amplifiers   491 

Outlines                                                            .  500 

Circuits   .504 

Index    536 

Reading  List   544 


Information  furnished  by  RCA  is  believed  to  be  accurate  and  reliable.  However,  no  responsibility  is 
assumed  by  RCA  for  its  use;  nor  for  any  infringements  of  patents  or  other  rights  of  third  parties  which 
may  result  from  its  use.  No  license  is  granted  by  implication  or  otherwise  under  any  patent  or  patent 
rights  of  RCA. 


Copyright  1963  by  Radio  Corporation  of  America  (All  Rights  Reserved) 


V  Trade  Mark(s)  Registered 
'@    Marca(s)  Registrada(s) 


7-63 

Printed  in  U.  S.  A. 


RCA 

Receiving  Tube  Manual 


THIS  MANUAL,  like  its  preceding  editions,  has 
been  prepared  to  assist  those  who  work  or  experi- 
ment with  home-entertainment-type  electron  tubes 
and  circuits.  It  will  be  found  valuable  by  engineers, 
service  technicians,  educators,  experimenters,  radio 
amateurs,  hobbyists,  students,  and  many  others 
technically  interested  in  electron  tubes. 

The  material  in  this  edition  has  been  augmented 
and  revised  to  include  the  recent  technological 
advances  in  the  electronics  field.  Many  tube  types 
widely  used  in  the  design  of  new  electronic  equip- 
ment only  a  few  years  ago  are  now  chiefly  of  interest 
for  renewal  purposes.  Consequently,  in  the  Tube 
Types  Section,  information  on  many  older  types  is 
limited  to  basic  essential  data ;  information  on  newer 
and  more  important  types  is  given  in  greater  detail. 


RADIO  CORPORATION  OF  AMERICA 

Electronic  Components  and  Devices  Harrison,  N.  J. 


2 


Electrons,  Electrodes, 
and  Electron  Tubes 


The  electron  tube  is  a  marvelous 
device.  It  makes  possible  the  performing 
of  operations,  amazing  in  conception, 
with  a  precision  and  a  certainty  that  are 
astounding.  It  is  an  exceedingly  sensi- 
tive and  accurate  instrument— the  prod- 
uct of  coordinated  efforts  of  engineers 
and  craftsmen.  Its  construction  requires 
materials  from  every  corner  of  the  earth. 
Its  use  is  world-wide.  Its  future  possi- 
bilities, even  in  the  light  of  present-day 
accomplishments,  are  but  dimly  fore- 
seen, for  each  development  opens  new 
fields  of  design  and  application. 

The  importance  of  the  electron  tube 
lies  in  its  ability  to  control  almost  in- 
stantly the  flight  of  the  millions  of  elec- 
trons supplied  by  the  cathode.  It  accom- 
plishes this  control  with  a  minimum  of 
energy.  Because  it  is  almost  instantane- 
ous in  its  action,  the  electron  tube  can 
operate  efficiently  and  accurately  at 
electrical  frequencies  much  higher  than 
those  attainable  with  rotating  machines. 

Electrons 

All  matter  exists  in  the  solid,  liquid, 
or  gaseous  state.  These  three  forms  con- 
sist entirely  of  minute  divisions  known 
as  molecules,  which,  in  turn,  are  com- 
posed of  atoms.  Atoms  have  a  nucleus 
which  is  a  positive  charge  of  electricity, 
around  which  revolve  tiny  charges  of 
negative  electricity  known  as  electrons. 
Scientists  have  estimated  that  electrons 
weigh  only  1/30-billion,  billion,  billion, 
billionths  of  an  ounce,  and  that  they 
may  travel  at  speeds  of  thousands  of 
miles  per  second. 

Electron  movement  may  be  accele- 
rated by  the  addition  of  energy.  Heat  is 
one  form  of  energy  which  can  be  con- 
veniently used  to  speed  up  the  electron. 
For  example,  if  the  temperature  of  a 
metal  is  gradually  raised,  the  electrons 
in  the  metal  gain  velocity.  When  the 
metal  becomes  hot  enough,  some  elec- 
trons may  acquire  sufficient  speed  to 


break  away  from  the  surface  of  the 
metal.  This  action,  which  is  accelerated 
when  the  metal  is  heated  in  a  vacuum, 
is  utilized  in  most  electron  tubes  to 
produce  the  necessary  electron  supply. 

An  electron  tube  consists  of  a  cath- 
ode, which  supplies  electrons,  and  one  or 
more  additional  electrodes,  which  con- 
trol and  collect  these  electrons,  mounted 
in  an  evacuated  envelope.  The  envelope 
may  be  made  of  glass,  metal,  ceramic,  or 
a  combination  of  these  materials. 

Cathodes 

A  cathode  is  an  essential  part  of  an 
electron  tube  because  it  supplies  the 
electrons  necessary  for  tube  operation. 
When  energy  in  some  form  is  applied  to 
the  cathode,  electrons  are  released.  Heat 
is  the  forifi  of%nergy  generally  used.The 
method  of  heating  the  cathode  may  be 
used  to  distinguish  between  the  different 
forms  of  cathodes.  For  example,  a  di- 
rectly heated  cathode,  or  filament-cath- 
ode, is  a  wire  heated  by  the  passage  of 
an  electric  current.  An  indirectly  heated 
cathode,  or  heater-cathode,  consists  of  a 
filament,  or  heater,  enclosed  in  a  metal 
sleeve.  The  sleeve  carries  the  electron- 
emitting  material  on  its  outside  surface 
and  is  heated  by  radiation  and  conduc- 
tion from  the  heater. 

A  filament,  or  directly  heated  cath- 
ode, such  as  that  shown  in  Fig.  1  may 
be  further  classified  by  identifying  the 
filament  or  electron-emitting  material. 
The  materials  in  regular  use  are  tung- 
sten, thoriated  tungsten,  and  metals 
which  have  been  coated  with  alkaline- 
earth  oxides.  Tungsten  filaments  are 
made  from  the  pure  metal.  Because  they 
must  operate  at  high  temperatures  (a 
dazzling  white)  to  emit  suflScient  elec- 
trons, a  relatively  large  amount  of  fila- 
ment power  is  required. 

Thoriated-tungsten  filaments  are 
made  from  tungsten  impregnated  with 
thorium  oxide.  Due  to  the  presence  of 


3 


RCA  Receiving  Tube  Manual 


thorium,  theie  filaments  liberate  elec- 
trons at  a  more  moderate  temperature 
of  about  1700°C  (a  bright  yellow)  and 
are,  therefore,  much  more  economical  of 
filament  power  than  are  pure  tungsten 
filaments. 

Alkaline  earths  are  usually  applied 
as  a  coating  on  a  nickel-alloy  wire  or 
ribbon.  This  coating,  which  is  dried  in  a 
relatively  thick  layer  on  the  filament, 
requires  only  a  relatively  low  tempera- 
ture of  about  700-750°C  (a  dull  red)  to 
produce  a  copious  supply  of  electrons. 
Coated  filaments  operate  very  eflficiently 
and  require  relatively  little  filament 
power.  However,  each  of  these  cathode 
materials  has  special  advantages  which 
determine  the  choice  for  a  particular 
application. 


Fig.  1  Fig.  2 


Directly  heated  filament-cathodes 
require  comparatively  little  heating 
power.  They  are  used  in  almost  all  of 
the  tube  types  designed  for  battery  op- 
eration because  it  is,  of  course,  desirable 
to  impose  as  small  a  drain  as  possible  on 
the  batteries.  Examples  of  battery-oper- 
ated filament  types  are  the  1R5,  1U4, 
1U5,  and  3V4.  AC-operated  types  hav- 
ing directly  heated  filament-cathodes 
include  the  2A3  and  5Y3GT. 

An  indirectly  heated  cathode,  or 
heater-cathode,  consists  of  a  thin  metal 
sleeve  coated  with  electron-emitting  ma- 
terial such  as  alkaline-earth  oxides.  The 
emissive  surface  of  the  cathode  is  main- 
tained at  the  required  temperature  (ap- 
proximately 1050°K)  by  resistance-heat- 
ing of  a  tungsten  or  tungsten-alloy  wire 
which  is  placed  inside  the  cathode  sleeve 
and  electrically  insulated  from  it,  as 
shown  in  Fig.  2.  The  heater  is  used  only 
for  the  purpose  of  heating  the  cathode 
sleeve  and  sleeve  coating  to  an  electron- 
emitting  temperature.  Useful  emission 
does  not  take  place  from  the  heater  wire. 


A  new  dark  heater  insulating  coat- 
ing developed  by  RCA  has  better  heat 
transfer  than  earlier  aluminum-oxide 
coatings,  and  makes  it  possible  to  operate 
heaters  at  lower  temperatures  for  given 
power  inputs.  Because  the  tensile 
strength  of  the  heater  wire  increases  at 
the  lower  operating  temperatures,  tubes 
using  dark  heaters  have  increased  re- 
liability, stability,  and  life. 

The  heater-cathode  construction  is 
well  adapted  for  use  in  electron  tubes  in- 
tended for  operation  from  ac  power  lines 
and  from  storage  batteries.  The  use  of 
separate  parts  for  emitter  and  heater 
functions,  the  electrical  insulation  of  the 
heater  from  the  emitter,  and  the  shield- 
ing effect  of  the  sleeve  may  all  be  utilized 
in  the  design  of  the  tube  to  minimize  the 
introduction  of  hum  from  the  ac  heater 
supply  and  to  minimize  electrical  inter- 
ference which  might  enter  the  tube  cir- 
cuit through  the  heater-supply  line. 
From  the  viewpoint  of  circuit  design, 
the  heater-cathode  construction  offers 
advantages  in  connection  flexibility  be- 
cause of  the  electrical  separation  of  the 
heater  from  the  cathode. 

Another  advantage  of  the  heater- 
cathode  construction  is  that  it  makes 
practical  the  design  of  a  rectifier  tube 
having  close  spacing  between  its  cathode 
and  plate,  and  of  an  amplifier  tube  hav- 
ing close  spacing  between  its  cathode 
and  grid.  In  a  close-spaced  rectifier  tube, 
the  voltage  drop  in  the  tube  is  low,  and, 
therefore,  the  regulation  is  improved.  In 
an  amplifier  tube,  the  close  spacing  in- 
creases the  gain  obtainable  from  the 
tube.  Because  of  the  advantages  of  the 
heater-cathode  construction,  almost  all 
present-day  receiving  tubes  designed  for 
ac  operation  have  heater-cathodes. 

Generic  Tube  Types 

Electrons  are  of  no  value  in  an  elec- 
tron tube  unless  they  can  be  put  to 
work.  Therefore,  a  tube  is  designed  with 
the  parts  necessary  to  utilize  electrons 
as  well  as  those  required  to  produce 
them.  These  parts  consist  of  a  cathode 
and  one  or  more  supplementary  elec- 
trodes. The  electrodes  are  enclosed  in  an 
evacuated  envelope  having  the  neces- 
sary connections  brought  out  through 
air-tight  seals.  The  air  is  removed  from 
the  envelope  to  allow  free  movement  of 


4 


Electrons,  Electrodes,  and  Electron  Tubes 


the  electrons  and  to  prevent  injury  to 
the  emitting  surface  of  the  cathode. 

When  the  cathode  is  heated,  elec- 
trons leave  the  cathode  surface  and  form 
an  invisible  cloud  in  the  space  around  it. 
Any  positive  electric  potential  within 
the  evacuated  envelope  offers  a  strong 
attraction  to  the  electrons  (unlike  elec- 
tric charges  attract;  like  charges  repel). 
Such  a  positive  electric  potential  can  be 
supplied  by  an  anode  (positive  elec- 
trode) located  within  the  tube  in  prox- 
imity to  the  cathode. 

Diodes 

The  simplest  form  of  electron  tube 
contains  two  electrodes,  a  cathode  and 
an  anode  (plate),  and  is  often  called  a 
diode,  the  family  name  for  a  two-elec- 
trode tube.  In  a  diode,  the  positive  po- 
tential is  suppUed  by  a  suitable  electrical 
source  connected  between  the  plate 
terminal  and  a  cathode  terminal,  as 
shown  in  Fig.  3.  Under  the  influence  of 


[OUTPUT 


Fig.  3 

the  positive  plate  potential,  electrons 
flow  from  the  cathode  to  the  plate  and 
return  through  the  external  plate-bat- 
tery circuit  to  the  cathode,  thus  com- 
pleting the  circuit.  This  flow  of  electrons 
is  known  as  the  plate  current. 

If  a  negative  potential  is  applied  to 
the  plate,  the  free  electrons  in  the  space 
surrounding  the  cathode  will  be  forced 
back  to  the  cathode  and  no  plate  cur- 
rent will  flow.  If  an  alternating  voltage 
is  applied  to  the  plate,  the  plate  is  alter- 
nately made  positive  and  negative.  Be- 
cause plate  current  flows  only  during  the 
time  when  the  plate  is  positive,  current 
flows  through  the  tube  in  only  one  direc- 
tion and  is  said  to  be  rectified.  Fig.  4 
shows  the  rectified  output  current  pro- 
duced by  an  alternating  input  voltage. 

Diode  rectifiers  are  used  in  ac  re- 
ceivers to  convert  the  ac  supply  voltage 
to  do  voltage  for  the  electrodes  of  the 


other  tubes  in  the  receiver.  Rectifier 
tubes  having  only  one  plate  and  one 
cathode,  such  as  the  35W4,  are  called 
half-wave  rectifiers,  because  current 
can  flow  only  during  one-half  of  the 
alternating-current  cycle.  When  two 
plates  and  one  or  more  cathodes  are 


:\  ALTERNATING 
1    VOLTAGE  INPUT 


Fig.  4 

used  in  the  same  tube,  current  may  be 
obtained  on  both  halves  of  the  ac  cycle. 
The  6X4,  5Y3GT,  and  5U4GB  are  ex- 
amples of  this  type  and  are  called 
full-wave  rectifiers. 

Not  all  of  the  electrons  emitted  by 
the  cathode  reach  the  plate.  Some  return 
to  the  cathode  while  others  remain  in 
the  space  between  the  cathode  and  plate 
for  a  brief  period  to  produce  an  effect 
known  as  space  charge.  This  charge  has 
a  repelling  action  on  other  electrons 
which  leave  the  cathode  surface  and  im- 
pedes their  passage  to  the  plate.  The  ex- 
tent of  this  action  and  the  amount  of 
space  charge  depend  on  the  cathode 
temperature,  the  distance  between  the 
cathode  and  the  plate,  and  the  plate 
potential.  The  higher  the  plate  potential, 
the  less  is  the  tendency  for  electrons  to 
remain  in  the  space-charge  region  and 
repel  other  electrons.  This  effect  may  be 
noted  by  applying  increasingly  higher 
plate  voltages  to  a  tube  operating  at  a 
fixed  heater  or  filament  voltage.  Under 
these  conditions,  the  maximum  number 
of  available  electrons  is  fixed,  but  in- 
creasingly higher  plate  voltages  will 
succeed  in  attracting  a  greater  propor- 
tion of  the  free  electrons. 

Beyond  a  certain  plate  voltage, 
however,  additional  plate  voltage  has 
little  effect  in  increasing  the  plate  cur- 
rent because  all  of  the  electrons  emitted 


5 


RCA  Receiving  Tube  Manual 


by  the  cathode  are  already  being  drawn 
to  the  plate.  This  maximum  current, 
illustrated  in  Fig.  5,  is  called  saturation 
current.  Because  it  is  an  indication  of 
the  total  number  of  electrons  emitted,  it 
is  also  known  as  emission  current  or 
simply  emission. 

Although  tubes  are  sometimes  tested 
by  measurement  of  their  emission  cur- 
rent, it  is  generally  not  advisable  to 
measure  the  full  value  of  emission  be- 
cause this  value  would  be  sufficiently 
large  to  cause  change  in  the  tube's  char- 
acteristics or  even  to  damage  the  tube. 
Consequently,  while  the  test  value  of 
emission  current  is  somewhat  larger  than 


Sati 

rati 

)n  P 

)int 

PLATE  VOLTAGE — 


Fig.  6 

the  maximum  current  which  will  be  re- 
quired from  the  cathode  in  the  use  of  the 
tube,  it  is  ordinarily  less  than  the  full 
emission  current.  The  emission  test, 
therefore,  is  used  to  indicate  whether 
the  cathode  can  supply  a  sufficient  num- 
ber of  electrons  for  satisfactory  opera- 
tion of  the  tube. 

If  space  charge  were  not  present  to 
repel  electrons  coming  from  the  cathode, 
the  same  plate  current  could  be  produced 
at  a  lower  plate  voltage.  One  way  to 
make  the  effect  of  space  charge  small  is 
to  make  the  distance  between  plate  and 
cathode  small.  This  method  is  used  in 
rectifier  types  having  heater-cathodes, 
such  as  the  6V4GA  and  the  6AX5GT. 
In  these  types  the  radial  distance  be- 
tween cathode  and  plate  is  only  about 
two  hundredths  of  an  inch. 

Another  method  of  reducing  space- 
charge  effect  is  utilized  in  mercury- 
vapor  rectifier  tubes.  When  such  tubes 
are  operated,  a  small  amount  of  mercury 
contained  in  the  tube  is  partially  vapor- 
ized, filling  the  space  inside  the  bulb 
with  mercury  atoms.  These  atoms  are 


bombarded  by  electrons  on  their  way  to 
the  plate.  If  the  electrons  are  moving  at 
a  sufficiently  high  speed,  the  collisions 
tear  off  electrons  from  the  mercury 
atoms.  The  mercury  atom  is  then  said 
to  be  "ionized,"  i.e.,  it  has  lost  one  or 
more  electrons  and,  therefore,  has  a 
positive  charge.  Ionization  is  evidenced 
by  a  bluish-green  glow  between  the 
cathode  and  plate.  When  ionization  oc- 
curs, the  space  charge  is  neutralized  by 
the  positive  mercury  atoms  so  that  in- 
creased numbers  of  electrons  are  made 
available.  Mercury-vapor  tubes  are  used 
primarily  for  power  rectifiers. 

lonic-heated-cathode  rectifiers 
depend  on  gas  ionization  for  their  opera- 
tion. These  tubes  are  of  the  full-wave 
design  and  contain  two  anodes  and  a 
coated  cathode  sealed  in  a  bulb  contain- 
ing a  reduced  pressure  of  inert  gas.  The 
cathode  in  each  of  these  types  becomes 
hot  during  tube  operation,  but  the  heat- 
ing effect  is  caused  by  bombardment  of 
the  cathode  by  ions  within  the  tube 
rather  than  by  heater  or  filament  cur- 
rent from  an  external  source. 

The  internal  structure  of  an  ionic- 
heated  -cathode  tube  is  designed  so  that 
when  sufficient  voltage  is  applied  to  the 
tube,  ionization  of  the  gas  occurs  be- 
tween the  anode  which  is  instantaneously 
positive  and  the  cathode.  Under  normal 
operating  voltages,  ionization  does  not 
take  place  between  the  anode  that  is 
negative  and  the  cathode  so  that  the 
requirements  for  rectification  are  satis- 
fied. The  initial  small  flow  of  current 
through  the  tube  is  sufficient  to  raise  the 
cathode  temperature  quickly  to  incan- 
descence whereupon  the  cathode  emits 
electrons.The  voltage  drop  in  such  tubes 
is  slightly  higher  than  that  of  the  usual 
hot-cathode  gas  rectifiers  because  energy 
is  taken  from  the  ionization  discharge  to 
keep  the  cathode  at  operating  tempera- 
ture. Proper  operation  of  these  rectifiers 
requires  a  minimum  flow  of  load  current 
at  all  times  in  order  to  maintain  the 
cathode  at  the  temperature  required  to 
supply  sufficient  emission. 

Triodes 

When  a  third  electrode,  called  the 
grid,  is  placed  between  the  cathode  and 
plate,  the  tube  is  known  as  a  triode,  the 
family  name  for  a  three-electrode  tube. 


6 


Electrons,  Electrodes,  and  Electron  Tubes 


The  grid  usually  consists  of  relatively 
fine  wire  wound  on  two  support  rods 
(siderods)  and  extending  the  length  of 
the  cathode.  The  spacing  between  turns 
of  wire  is  large  compared  with  the  size  of 
the  wire  so  that  the  passage  of  electrons 
from  cathode  to  plate  is  practically  un- 
obstructed by  the  grid.  In  some  types,  a 
frame  grid  is  used.  The  frame  consists 
of  two  siderods  supported  by  four  metal 
straps.  Extremely  fine  lateral  wire  (di- 
ameter of  0.5  mil  or  less)  is  wound  under 
tension  around  the  frame.  This  type  of 
grid  permits  the  use  of  closer  spacings 
between  grid  wires  and  between  tube 
electrodes,  and  thus  improves  tube  per- 
formance. 

The  purpose  of  the  grid  is  to  control 
the  flow  of  plate  current.  When  a  tube 
is  used  as  an  amplifier,  a  negative  dc  volt- 
age is  usually  applied  to  the  grid.  Under 
this  condition  the  grid  does  not  draw  ap- 
preciable current. 

The  number  of  electrons  attracted 
to  the  plate  depends  on  the  combined 
effect  of  the  grid  and  plate  polarities,  as 
shown  in  Fig.  6.  When  the  plate  is  posi- 
tive, as  is  normal,  and  the  dc  grid  volt- 
age is  made  more  and  more  negative,  the 
plate  is  less  able  to  attract  electrons  to  it 
and  plate  current  decreases.  When  the 


ELECTRON 
FLOW 


OUTPUT 


Fig.  6 

grid  is  made  less  and  less  negative  (more 
and  more  positive),  the  plate  more  read- 
ily attracts  electrons  to  it  and  plate  cur- 
rent increases.  Hence,  when  the  voltage 
on  the  grid  is  varied  in  accordance  with 
a  signal,  the  plate  current  varies  with 
the  signal.  Because  a  small  voltage  ap- 
plied to  the  grid  can  control  a  compara- 
tively large  amount  of  plate  current,  the 
signal  is  amplified  by  the  tube.  Typical 
three-electrode  tube  types  are  the  6C4 
and  6AF4A. 

The  grid,  plate,  and  cathode  of  a 
triode  form  an  electrostatic  system,  each 


electrode  acting  as  one  plate  of  a  small 
capacitor.  The  capacitances  are  those 
existing  between  grid  and  plate,  plate 
and  cathode,  and  grid  and  cathode. 
These  capacitances  are  known  as  inter- 
electrode  capacitances.  Generally,  the 
capacitance  between  grid  and  plate  is  of 
the  most  importance.  In  high-gain  radio- 
frequency  amplifier  circuits,  this  capaci- 
tance may  act  to  produce  undesired 
coupling  between  the  input  circuit,  the 
circuit  between  grid  and  cathode,  and 
the  output  circuit,  the  circuit  between 
plate  and  cathode.  This  coupling  is  un- 
desirable in  an  amplifier  because  it  may 
cause  instability  and  unsatisfactory  per- 
formance. 

Tetrodes 

The  capacitance  between  grid  and 
plate  can  be  made  small  by  mounting  an 
additional  electrode,  called  the  screen 
grid  (grid  No.  2),  in  the  tube.  With  the 
addition  of  the  grid  No.2,  the  tube  has 
four  electrodes  and  is,  accordingly,  called 
a  tetrode.  The  screen  grid  or  grid  No.2 
is  mounted  between  the  grid  No.l  (con- 
trol grid)  and  the  plate,  as  shown  in  Fig. 
7,  and  acts  as  an  electrostatic  shield  be- 
tween them,  thus  reducing  the  grid-to- 
plate  capacitance.  The  effectiveness  of 


Fig.  7 


this  shielding  action  is  increased  by  a 
bypass  capacitor  connected  between 
screen  grid  and  cathode.  By  means  of  the 
screen  grid  and  this  bypass  capacitor, 
the  grid-plate  capacitance  of  a  tetrode  is 
made  very  small.  In  practice,  the  grid- 
plate  capacitance  is  reduced  from  sev- 
eral picofarads  (pf)  for  a  triode  to  0.01 
pf  or  less  for  a  screen-grid  tube. 

The  screen  grid  has  another  desir- 
able effect  in  that  it  makes  plate  current 
practically  independent  of  plate  voltage 
over  a  certain  range.  The  screen  grid  is 
operated  at  a  positive  voltage  and. 


7 


RCA  Receiving  Tube  Manual 


therefore,  attracts  electrons  from  the 
cathode.  However,  because  of  the  com- 
paratively large  space  between  wires  of 
the  screen  grid,  most  of  the  electrons 
drawn  to  the  screen  grid  pass  through  it 
to  the  plate.  Hence  the  screen  grid  sup- 
plies an  electrostatic  force  pulling  elec- 
trons from  the  cathode  to  the  plate.  At 
the  same  time  the  screen  grid  shields  the 
electrons  between  cathode  and  screen 
grid  from  the  plate  so  that  the  plate  ex- 
erts very  little  electrostatic  force  on 
electrons  near  the  cathode. 

So  long  as  the  plate  voltage  is  higher 
than  the  screen-grid  voltage,  plate  cur- 
rent in  a  screen-grid  tube  depends  to  a 
great  degree  on  the  screen-grid  voltage 
and  very  little  on  the  plate  voltage.  The 
fact  that  plate  current  in  a  screen-grid 
tube  is  largely  independent  of  plate  volt- 
age makes  it  possible  to  obtain  much 
higher  amplification  with  a  tetrode  than 
with  a  triode.  The  low  grid-plate  capaci- 
tance makes  it  possible  to  obtain  this 
high  amplification  without  plate-to-grid 
feedback  and  resultant  instability.  In 
receiving-tube  applications,  the  tetrode 
has  been  replaced  to  a  considerable  de- 
gree by  the  pentode. 

Pentodes 

In  all  electron  tubes,  electrons  strik- 
ing the  plate  may,  if  moving  at  sufficient 
speed,  dislodge  other  electrons.  In  two- 
and  three-electrode  types,  these  dis- 
lodged electrons  usually  do  not  cause 
trouble  because  no  positive  electrode 
other  than  the  plate  itself  is  present  to 
attract  them.  These  electrons,  therefore, 
are  drawn  back  to  the  plate.  Emission 
caused  by  bombardment  of  an  electrode 
by  electrons  from  the  cathode  is  called 
secondary  emission  because  the  effect  is 
secondary  to  the  original  cathode  emis- 
sion. 

In  the  case  of  screen-grid  tubes,  the 
proximity  of  the  positive  screen  grid  to 
the  plate  offers  a  strong  attraction  to 
these  secondary  electrons  and  particu- 
larly so  if  the  plate  voltage  swings  lower 
than  the  screen-grid  voltage.  This  effect 
lowers  the  plate  current  and  limits  the 
useful  plate-voltage  swing  for  tetrodes. 

The  effects  of  secondary  emission 
are  minimized  when  a  fifth  electrode  is 
placed  within  the  tube  between  the 
screen  grid  and  plate.This  fifth  electrode 
is  known  as  the  suppressor  grid  (grid 

8 


No.3)  and  is  usually  connected  to  the 
cathode,  as  shown  in  Fig.  8.  Because  of 
its  negative  potential  with  respect  to  the 
plate,  the  suppressor  grid  retards  the 
flight  of  secondary  electrons  and  diverts 
them  back  to  the  plate. 


SUPPRESSOR 
GRID  — 


Fig.  8 


The  family  name  for  a  five-electrode 
tube  is  "pentode".  In  power-output 
pentodes,  the  suppressor  grid  makes  pos- 
sible higher  power  output  with  lower 
grid-driving  voltage;  in  radio-frequency 
amplifier  pentodes  the  suppressor  grid 
makes  possible  high  voltage  amplifica- 
tion at  moderate  values  of  plate  voltage. 
These  desirable  features  result  from  the 
fact  that  the  plate-voltage  swing  can  be 
made  very  large.  In  fact,  the  plate  volt- 
age may  be  as  low  as,  or  lower  than,  the 
screen-grid  voltage  without  serious  loss 
in  signal-gain  capability.  Representative 
pentodes  used  for  power  amplification 
are  the  3V4  and  6K6GT;  representative 
pentodes  used  for  voltage  amplification 
are  the  1U4,  6AU6A,  6BA6,  and  5879. 

Beam  Power  Tubes 

A  beam  power  tube  is  a  tetrode  or 
pentode  in  which  directed  electron  beams 
are  used  to  increase  substantially  the 
power-handling  capability  of  the  tube. 
Such  a  tube  contains  a  cathode,  a  con- 
trol grid  (grid  No.l),  a  screen  grid  (grid 
No.2),  a  plate,  and,  optionally,  a  sup- 
pressor grid  (grid  No.3).  When  a  beam 
power  tube  is  designed  without  an  ac- 
tual suppressor  grid,  the  electrodes  are 
so  spaced  that  secondary  emission  from 
the  plate  is  suppressed  by  space-charge 
effects  between  screen  grid  and  plate. 
The  space  charge  is  produced  by  the 
slowing  up  of  electrons  traveling  from  a 
high-potential  screen  grid  to  a  lower- 
potential  plate.  In  this  low-velocity  re- 
gion, the  space  charge  produced  is  suffi- 


Electrons,  Electrodes,  and  Electron  Tubes 


cient  to  repel  secondary  electrons  emit- 
ted from  the  plate  and  to  cause  them  to 
return  to  the  plate. 

Beam  power  tubes  of  this  design 
employ  beam-confining  electrodes  at 
cathode  potential  to  assist  in  producing 
the  desired  beam  effects  and  to  prevent 
stray  electrons  from  the  plate  from  re- 
turning to  the  screen  grid  outside  of  the 
beam.  A  feature  of  a  beam  power  tube 
is  its  low  screen-grid  current.  The  screen 
grid  and  the  control  grid  are  spiral  wires 
wound  so  that  each  turn  of  the  screen 
grid  is  shaded  from  the  cathode  by  a 
grid  turn.  This  alignment  of  the  screen 
grid  and  control  grid  causes  the  electrons 
to  travel  in  sheets  between  the  turns  of 
the  screen  grid  so  that  very  few  of  them 
strike  the  screen  grid.  Because  of  the 
effective  suppressor  action  provided  by 
space  charge  and  because  of  the  low  cur- 
rent drawn  by  the  screen  grid,  the  beam 
power  tube  has  the  advantages  of  high 
power  output,  high  power  sensitivity, 
and  high  efficiency. 

Fig.  9  shows  the  structure  of  a  beam 
power  tube  employing  space-charge  sup- 
pression and  illustrates  how  the  electrons 


are  confined  to  beams.  The  beam  condi- 
tion illustrated  is  that  for  a  plate  po- 
tential less  than  the  screen-grid  poten- 
tial. The  high-density  space-charge  re- 
gion is  indicated  by  the  heavily  dashed 
lines  in  the  beam.  Note  that  the  edges  of 
the  beam-confining  electrodes  coincide 
with  the  dashed  portion  of  the  beam.  In 
this  way  the  space-charge  potential  re- 
gion is  extended  beyond  the  beam 
boundaries  and  stray  secondary  electrons 
are  prevented  from  returning  to  the 


screen  grid  outside  of  the  beam.  The^ 
space-charge  effect  may  also  be  obtained 
by  use  of  an  actual  suppressor  grid.  Ex- 
amples of  beam  power  tubes  are  6AQ5A, 
6L6GB,  6V6GT,  and  50C5. 

Multi-Electrode  and 
Multi-Unit  Tubes 

Early  in  the  history  of  tube  develop- 
ment and  application,  tubes  were  de- 
signed for  general  service;  that  is,  a 
single  tube  type— a  triode— was  used  as 
a  radio-frequency  amplifier,  an  inter- 
mediate-frequency amplifier,  an  audio- 
frequency amplifier,  an  oscillator,  or  a 
detector.  Obviously,  with  this  diversity 
of  application,  one  tube  did  not  meet  all 
requirements  to  the  best  advantage. 

Later  and  present  trends  of  tube  de- 
sign are  the  development  of  "specialty" 
types.  These  types  are  intended  either  to 
give  optimum  performance  in  a  particu- 
lar application  or  to  combine  in  one  bulb 
functions  which  formerly  required  two 
or  more  tubes.  The  first  class  of  tubes  in- 
cludes such  examples  of  specialty  types 
as  the  6CB6  and  6BY6.  Types  of  this 
class  generally  require  more  than  three 
electrodes  to  obtain  the  desired  special 
characteristics  and  may  be  broadly 
classed  as  multi-electrode  types.  The 
6BY6  is  an  especially  interesting  type  in 
this  class.  This  tube  has  an  unusually 
large  number  of  electrodes,  namely 
seven,  exclusive  of  the  heater.  Plate  cur- 
rent in  the  tube  is  varied  at  two  different 
frequencies  at  the  same  time.  The  tube 
is  designed  primarily  for  use  as  a  com- 
bined sync  separator  and  sync  clipper  in 
television  receivers. 

The  second  class  includes  multi- 
unit  tubes  such  as  the  twin-diode  triodes 
6BF6  and  6AV6,  as  well  as  triode-pen- 
todes  such  as  the  6U8A  and  6X8.  This 
class  also  includes  class  A  twin  triodes 
such  as  the  6CG7  and  12AX7,  and  types 
such  as  the  6CM7  containing  dissimilar 
triode  units  used  primarily  as  combined 
vertical  oscillators  and  vertical  deflec- 
tion amplifiers  in  television  receivers. 
Full-wave  rectifiers  are  also  multi-unit 
types. 

A  third  class  of  tubes  combines  fea-^ 
tures  of  each  of  the  other  two  classes. 
Typical  of  this  third  class  are  the  penta- 
grid-converter  types  1R5,  6BE6,  and 
6SA7.  These  tubes  are  similar  to  the 


9 


RCA  Receiving  Tube  Manual 


multi-electrode  types  in  that  they  have 
seven  electrodes,  all  of  which  affect  the 
electron  stream;  and  they  are  similar  to 
the  multi-unit  tubes  in  that  they  per- 
form simultaneously  the  double  function 
of  oscillator  and  mixer  in  superhetero- 
dyne receivers. 

Receiving  Tube  Structure 

Receiving  tubes  generally  utilize  a 
glass  or  metal  envelope  and  abase.  Orig- 
inally, the  base  was  made  of  metal  or 
molded  phenolic  material.  Types  hav- 
ing a  glass  envelope  and  a  molded  phen- 
olic base  include  the  "octal"  types  such 
as  the  5U4GB  and  the  6SN7GTB. 
Types  having  a  metal  envelope  and 
molded  phenolic  octal  base  include  the 
6AC7  and  the  6AG7.  Many  modern  types 
utilize  integral  glass  bases.  Present-day 
conventional  tube  designs  utilizing  glass 
envelopes  and  integral  glass  bases  in- 
clude the  seven-pin  and  nine-pin  mini- 
ature types,  the  nine-pin  novar  and  neo- 
noval  types,  and  the  twelve-pin duodecar 
types.  Examples  of  the  seven-pin  mini- 
ature types  are  the  6AU6A  and  6BN6. 
Examples  of  the  nine-pin  miniature  types 
are  the  12 AU7A  and  6E A8.  Examples  of 
the  novar  types  are  the  6BH3  and  7868. 
The  nine-pin  base  for  the  novar  types 
has  a  relatively  large  pin-circle  diameter 
and  long  pins  to  insure  firm  retention  of 
the  tube  in  its  socket. 

The  nuvistor  concept  provided  a 
new  approach  to  electron  tube  design. 


Nuvistor  tubes  utilize  a  light-weight  can- 
tilever-supported cyUndrical  electrode 
structure  housed  in  a  ceramic-metal  en- 
velope (see  page  2  for  cutaway  view). 
These  tubes  combine  new  materials,  proc- 
esses, and  fabrication  techniques.  Ex- 
amples of  the  nuvistor  are  the  2CW4 
and  the  6CW4. 

Television  Picture  Tubes 

The  picture  tube,  or  kinescope,  is  a 
multi-electrode  tube  used  principally  in 
television  receivers  for  picture  display. 
It  consists  essentially  of  an  electron  gun, 
a  glass  or  metal-and-glass  envelope  and 
face-plate  combination,  and  a  fluores- 
cent screen. 

The  electron  gun  includes  a  cathode 
for  the  production  of  free  electrons,  one 
or  more  control  electrodes  for  acceler- 
ating the  electrons  in  the  beam,  and, 
optionally,  a  device  for  "trapping"  un- 
wanted ions  out  of  the  electron  beam. 

Focusing  of  the  beam  is  accom- 
plished either  electromagnetically  by 
means  of  a  focusing  coil  placed  on  the 
neck  of  the  tube,  or  electrostatically,  as 
shown  in  Fig.  10,  by  means  of  a  focusing 
electrode  (grid  No.  4)  within  the  enve- 
lope of  the  tube.  The  screen  is  a  white- 
fluorescing  phosphor  P4  of  either  the 
silicate  or  the  sulfide  type. 

Deflection  of  the  beam  is  accom- 
plished either  electrostatically  by  means 
of  deflecting  electrodes  within  the  enve- 
lope of  the  tube,  or  electromagnetically 


DEFLECTING 
YOKE 


GLASS  NECK 
SECTION 


-CENTERlislG  MAGNET! 

t 

REFERENCE  LINE— »J 
Fig.  10 


10 


Electrons,  Electrodes,  and  Electron  Tubes 


by  means  of  a  deflecting  yoke  placed  on 
the  neck  of  the  tube.  Fig.  10  shows  the 
structure  of  the  gun  section  of  a  pic- 
ture tube  and  illustrates  how  the  elec- 
tron beam  is  formed  and  how  the  beam 
is  deflected  by  means  of  an  electromag- 
netic deflecting  yoke.  In  this  type  of 
tube,  ions  in  the  beam  are  prevented 
from  damaging  the  fluorescent  screen  by 
an  aluminum  film  on  the  gun  side  of  the 
screen.  This  film  not  only  "traps"  un- 
wanted ions,  but  also  improves  picture 
contrast.  In  many  types  of  non-alumi- 
nized  tubes,  ions  are  separated  from  the 
electron  beam  by  means  of  a  tilted-gun 
and  ion-trap-magnet  arrangement. 

Color  television  picture  tubes  are 
similar  to  black-and-white  picture  tubes, 
but  differ  in  three  major  ways.  (1)  The 
light-emitting  screen  is  made  up  of  trios 
of  phosphor  dots  deposited  in  an  inter- 
laced pattern.  Each  dot  of  a  trio  is  capa- 
ble of  emitting  light  in  one  of  the  three 
primary  colors  (red,  green,  or  blue).  (2) 
A  shadow  mask  mounted  near  the  screen 
of  the  tube  contains  over  300,000  aper- 
tures, one  for  each  of  the  phosphor  dot 
trios.  This  mask  provides  color  separa- 
tion by  shadowing  two  of  the  three 
phosphor  dots  of  each  trio.  (3)  Three 
closely  spaced  electron  guns,  built  as  a 
unit,  provide  separate  beams  for  excita- 
tion of  the  three  different  color-phos- 
phor-dot arrays.  Thus  it  is  possible  to 
control  the  brightness  of  each  of  the  three 
colors  independently  of  the  other  two. 


The  three  electron  guns  are  mounted 
with  their  axes  tilted  toward  the  central 
axis  of  the  envelope,  and  are  spaced  120 
degrees  with  respect  to  each  other.  The 
focusing  electrodes  of  the  three  guns  are 
interconnected  internally,  and  their  po- 
tential is  adjusted  to  cause  the  separate 
beams  to  focus  at  the  phosphor-dot 
screen.  All  three  beams  must  be  made 
to  converge  at  the  screen  while  they  are 
simultaneously  being  deflected,  Con- 
vergence is  accomplished  by  the  action 
of  static  and  dynamic  magnetic  fields 
set  up  by  the  radial-converging  magnet 
assembly  mounted  on  the  neck  of  the 
tube.  These  fields  are  coupled  into  the 
radial-converging  pole  pieces  within  the 
tube.  Another  pair  of  pole  pieces  in  the 
tube  is  activated  by  the  lateral-converg- 
ing magnet  also  mounted  on  the  neck 
of  the  tube.  These  pole  pieces  permit 
lateral  shift  in  position  of  the  blue  beam 
in  opposition  to  the  lateral  shift  of  the 
green  and  red  beams. 

A  purifying  magnet  is  used  with 
color  picture  tubes  to  provide  a  mag- 
netic field,  adjustable  in  magnitude  and 
direction,  to  effect  register  over  the  en- 
tire area  of  the  screen.  A  magnetic  shield 
is  used  to  minimize  the  effects  of  the 
earth's  magnetic  field. 

Deflection  of  the  three  beams  is  ac- 
complished simultaneously  by  a  deflect- 
ing yoke  consisting  of  four  electromag- 
netic coils  similar  to  the  deflecting  yoke 
used  for  black-and-white  picture  tubes. 


11 


Electron  Tube 
Characteristics 


The  term  "characteristics"  is  used 
to  identify  the  distinguishing  electrical 
features  and  values  of  an  electron  tube. 
These  values  may  be  shown  in  curve 
form  or  they  may  be  tabulated.  When 
the  characteristics  values  are  given  in 
curve  form,  the  curves  may  be  used  for 
the  determination  of  tube  performance 
and  the  calculation  of  additional  tube 
factors. 

Tube  characteristics  are  obtained 
from  electrical  measurements  of  a  tube 
in  various  circuits  under  certain  definite 
conditions  of  voltages.  Characteristics 
may  be  further  described  by  denoting 
the  conditions  of  measurements.  For  ex- 
ample Static  Characteristics  are  the  val- 
ues obtained  with  different  dc  potentials 
applied  to  the  tube  electrodes,  while  Dy- 
namic Characteristics  are  the  values  ob- 
tained with  an  ac  voltage  on  a  control 
grid  under  various  conditions  of  dc  po- 
tentials on  the  electrodes.  The  dynamic 
characteristics,  therefore,  are  indicative 
of  the  performance  capabilities  of  a  tube 
under  actual  working  conditions. 

Static  characteristics  may  be  shown 
by  plate  characteristics  curves  and  trans- 
fer (mutual)  characteristics  curves.These 
curves  present  the  same  information, 
but  in  two  different  forms  to  increase  its 
usefulness.  The  plate  characteristic 
curve  is  obtained  by  varying  plate  volt- 
age and  measuring  plate  current  for  dif- 
ferent grid  bias  voltages,  while  the  trans- 
fer-characteristic curve  is  obtained  by 
varying  grid  bias  voltage  and  measuring 
plate  current  for  different  plate  voltages. 
A  plate-characteristic  family  of  curves  is 
illustrated  by  Fig.  11.  Fig.  12  gives  the 
transfer-characteristic  family  of  curves 
for  the  same  tube. 

Dynamic  characteristics  include 
amplification  factor,  plate  resistance, 
control-grid— plate  transconductance, 
and  certain  detector  characteristics,  and 
may  be  shown  in  curve  form  for  varia- 
tions in  tube  operating  conditions. 

The  amplification  factor,  or  is 
the  ratio  of  the  change  in  plate  voltage 


to  a  change  in  control-electrode  voltage 
in  the  opposite  direction,  under  the  con- 
dition that  the  plate  current  remains  un- 
changed and  that  all  other  electrode 
voltages  are  maintained  constant.  For 
example,  if,  when  the  plate  voltage  is 


/ 

'V 

<» 

/ 1 

Q 

/  1 

)  5 

0  1 

}0  \i 

>0  2( 

)0  2S 

PLATE  VOLTS 

Fig.  11 

made  1  volt  more  positive,  the  control- 
electrode  (grid-No.  1)  voltage  must  be 
made  0.1  volt  more  negative  to  hold 
plate  current  unchanged,  the  amplifica- 
tion factor  is  1  divided  by  0.1,  or  10.  In 
other  words,  a  small  voltage  variation  in 
the  grid  circuit  of  a  tube  has  the  same 
effect  on  the  plate  current  as  a  large 


-20 
GRID  VOLTS 

Fig.  12 

plate- voltage  change— the  latter  equal 
to  the  product  of  the  grid-voltage  change 
and  amplification  factor.  The  il  of  a  tube 
is  often  useful  for  calculating  stage  gain. 
This  use  is  discussed  in  the  ELECTRON 
TUBE  APPLICATIONS  SECTION. 

Plate  resistance  (rp)  of  an  electron 
tube  is  the  resistance  of  the  path  between 
cathode  and  plate  to  the  flow  of  alter- 
nating current.  It  is  the  quotient  of  a 


12 


Electron  Tube  Characteristics 


small  change  in  plate  voltage  divided  by 
the  corresponding  change  in  plate  cur- 
rent and  is  expressed  in  ohms,  the  unit 
of  resistance.  Thus,  if  a  change  of  0.1 
milliampere  (0.0001  ampere)  is  produced 
by  a  plate  voltage  variation  of  1  volt, 
the  plate  resistance  is  1  divided  by 
0.0001,  or  10000  ohms. 

Control-grid — plate  transconduct- 
ance,  or  simply  transconductance  (gm), 
is  a  factor  which  combines  in  one  term 
the  amplification  factor  and  the  plate 
resistance,  and  is  the  quotient  of  the 
first  divided  by  the  second.  This  term 
has  also  been  known  as  mutual  conduct- 
ance. Transconductance  may  be  more 
strictly  defined  as  the  quotient  of  a  small 
change  in  plate  current  (amperes)  di- 
vided by  the  small  change  in  the  control- 
grid  voltage  producing  it,  under  the  con- 
dition that  all  other  voltages  remain  un- 
changed. Thus,  if  a  grid-voltage  change 
of  0.5  volt  causes  a  plate-current  change 
of  1  milliampere  (0.001  ampere),  with 
all  other  voltages  constant,  the  trans- 
conductance is  0.001  divided  by  0.5,  or 
0.002  mho.  A  "mho"  is  the  unit  of  con- 
ductance and  was  named  by  spelling 
ohm  backwards.  For  convenience,  a 
millionth  of  a  mho,  or  a  micromho 
(/tmho),is  used  to  express  transconduct- 
ance. Thus,  in  the  example,  0.002  mho 


is  2000  micromhos. 

Conversion  transconductance  (ge) 
is  a  characteristic  associated  with  the 
mixer  (first  detector)  function  of  tubes 
and  may  be  defined  as  the  quotient  of 
the  intermediate-frequency  (if)  current 
in  the  primary  of  the  if  transformer  di- 
vided by  the  applied  radio-frequency 
(rf)  voltage  producing  it;  or  more  pre- 
cisely, it  is  the  limiting  value  of  this 
quotient  as  the  rf  voltage  and  if  current 
approach  zero.  When  the  performance 
of  a  frequency  converter  is  determined, 
conversion  transconductance  is  used  in 
the  same  way  as  control-grid— plate 
transconductance  is  used  in  single-fre- 
quency amplifier  computations. 

The  plate  efficiency  of  a  power  am- 
plifier tube  is  the  ratio  of  the  ac  power 
output  (Po)  to  the  product  of  the  aver- 
age dc  plate  voltage  (Eb)  and  dc  plate 
current  (lb)  at  full  signal,  or 

Plate  eflSciency  Po  watts  

(%)        ""Eb  volts  X  lb  amperes^ 

The  power  sensitivity  of  a  tube  is 
the  ratio  of  the  power  output  to  the 
square  of  the  input  signal  voltage  (Em) 
and  is  expressed  in  mhos  as  follows: 

„  /  .  X  Po  watts 
Power  sensitivity  (mhog)  =   


13 


Electron  Tube 
Applications 


The  diversified  applications  of  an 
electron  receiving  tube  have,  within  the 
scope  of  this  section,  been  treated  under 
seven  headings.  These  are:  Amplifica- 
tion, Rectification,  Detection,  Auto- 
matic Volume  or  Gain  Control,  Oscilla- 
tion, Frequency  Conversion,  and  Au- 
tomatic Frequency  Control.  Although 
these  operations  may  take  place  at  either 
radio  or  audio  frequencies  and  may  in- 
volve the  use  of  different  circuits  and 
different  supplemental  parts,  the  gen- 
eral considerations  of  each  kind  of  oper- 
ation are  basic. 

Amplification 

The  amplifying  action  of  an  electron 
tube  was  mentioned  under  Triodes  in 
the  section  on  ELECTRONS,  ELEC- 
TRODES, and  ELECTRON  TUBES. 
This  action  can  be  utilized  in  electronic 
circuits  in  a  number  of  ways,  depending 
upon  the  results  desired.  Four  classes  of 
amplifier  service  recognized  by  engineers 
are  covered  by  definitions  standardized 
by  the  Institute  of  Radio  Engineers. 
This  classification  depends  primarily  on 
the  fraction  of  input  cycle  during  which 
plate  current  is  expected  to  flow  under 
rated  full-load  conditions.  The  classes 
are  class  A,  class  AB,  class  B,  and  class 
C.  The  term  "cutoff  bias"  used  in  these 
definitions  is  the  value  of  grid  bias  at 
which  plate  current  is  very  small. 

Classes  of  Service 

A  class  A  amplifier  is  an  amplifier 
in  which  the  grid  bias  and  alternating 
grid  voltages  are  such  that  plate  current 
in  a  specific  tube  fiows  at  all  times. 

A  class  AB  amplifier  is  an  ampli- 
fier in  which  the  grid  bias  and  alter- 
nating grid  voltages  are  such  that  plate 
current  in  a  specific  tube  flows  for  ap- 
preciably more  than  half  but  less  than 
the  entire  electrical  cycle. 

A  class  B  amplifier  is  an  amplifier 
in  which  the  grid  bias  is  approximately 
equal  to  the  cutoff  value,  so  that  the 
plate  current  is  approximately  zero 
when  no  exciting  grid  voltage  is  applied, 


and  so  that  plate  current  in  a  specific 
tube  flows  for  approximately  one-half 
of  each  cycle  when  an  alternating  grid 
voltage  is  applied. 

A  class  C  amplifier  is  an  amplifier 
in  which  the  grid  bias  is  appreciably 
greater  than  the  cutoff  value,  so  that  the 
plate  current  in  each  tube  is  zero  when 
no  alternating  grid  voltage  is  applied, 
and  so  that  plate  current  flows  in  a 
specific  tube  for  appreciably  less  than 
one-half  of  each  cycle  when  an  alter- 
nating grid  voltage  is  applied. 

The  suffix  1  may  be  added  to  the  letter 
or  letters  of  the  class  identification  to 
denote  that  grid  current  does  not  flow 
during  any  part  of  the  input  cycle.  The 
suffix  2  may  be  used  to  denote  that  grid 
current  flows  during  part  of  the  cycle. 

For  radio-frequency  (rf)  amplifiers 
which  operate  into  a  selective  tuned  cir- 
cuit, as  in  radio  transmitter  applications, 
or  under  requirements  where  distortion 
is  not  an  important  factor,  any  of  the 
above  classes  of  amplifiers  may  be  used, 
either  with  a  single  tube  or  a  push-pull 
stage.  For  audio-frequency  (af)  ampli- 
fiers in  which  distortion  is  an  important 
factor,  only  class  A  amplifiers  permit 
single-tube  operation.  In  this  case,  oper- 
ating conditions  are  usually  chosen  so 
that  distortion  is  kept  below  the  conven- 
tional 5  per  cent  for  triodes  and  the  con- 
ventional 7  to  10  per  cent  for  tetrodes  or 
pentodes.  Distortion  can  be  reduced  be- 
low these  figures  by  means  of  special  cir- 
cuit arrangements  such  as  that  discussed 
under  inverse  feedback.  With  class  A 
amplifiers,  reduced  distortion  with  im- 
proved power  performance  can  be  ob- 
tained by  using  a  push-pull  stage  for 
audio  service.  With  class  AB  and  class  B 
amplifiers,  a  balanced  stage  using  two 
tubes  is  required  for  audio  service. 

Class  A  Voltage  Amplifiers 

As  a  class  A  voltage  amplifier,  an 
electron  tube  is  used  to  reproduce  grid- 
voltage  variations  across  an  impedance 
or  a  resistance  in  the  plate  circuit.  These 


14 


Electron  Tube  Applications 


variations  are  essentially  of  the  same 
form  as  the  input  signal  voltage  im- 
pressed on  the  grid,  but  their  amplitude 
is  increased.  This  increase  is  accom- 
plished by  operation  of  the  tube  at  a 
suitable  grid  bias  so  that  the  applied 
grid  input  voltage  produces  plate-cur- 
rent variations  proportional  to  the  signal 
swings.  Because  the  voltage  variation 
obtained  in  the  plate  circuit  is  much 
larger  than  that  required  to  swing  the 
grid,  amphfication  of  the  signal  is  ob- 
tained. 

Fig.  13  gives  a  graphical  illustration 
of  this  method  of  amplification  and 


OUTPUT   SIGNAL  (O) 


-GRID  VOLTS 


Fig.  13 

shows,  by  means  of  the  grid- voltage  vs. 
plate-current  characteristics  curve,  the 
effect  of  an  input  signal  (S)  applied  to 
the  grid  of  a  tube.  The  output  signal  (0) 
is  the  resulting  amplified  plate-current 
variation. 

The  plate  current  flowing  through 
the  load  resistance  (R)  of  Fig.  14  causes 
a  voltage  drop  which  varies  directly 
with  the  plate  current.  The  ratio  of  this 
voltage  variation  produced  in  the  load 
resistance  to  the  input  signal  voltage  is 
the  voltage  amplification,  or  gain,  pro- 
vided by  the  tube.  The  voltage  ampli- 
fication due  to  the  tube  is  expressed  by 
the  following  convenient  formulas: 


Voltage  amplification 


gm  X  rp  X  Rl 
1000000  X  (rp+  Rl) 
where  /*  is  the  amplification  factor  of 
the  tube,  Rl  is  the  load  resistance  in 
ohms,  Tp  is  the  plate  resistance  in  ohms, 
and  gm  is  the  transconductance  in 
micromhos. 

From  the  first  formula,  it  can  be 
seen  that  the  gain  actually  obtainable 


LOAD 
RCSISTANCe  < 

,  OUTPUT 
R  5  VOLTACB 


Fig.  14 

from  the  tube  is  less  than  the  tube  am- 
plification factor  but  that  the  gain  ap- 
proaches the  amplification  factor  when 
the  load  resistance  is  large  compared  to 
the  tube  plate  resistance.  Fig.  15 
shows  graphically  how  the  gain  ap- 
proaches the  amplification  factor  of  the 
tube  as  the  load  resistance  is  increased. 
From  the  curve  it  can  be  seen  that  a 
high  value  of  load  resistance  should  be 
used  to  obtain  high  gain  in  a  voltage 
amplifier. 

In  a  resistance-coupled  amplifier, 
the  load  resistance  of  the  tube  is  approx- 
imately equal  to  the  resistance  of  the 
plate  resistor  in  parallel  with  the  grid 
resistor  of  the  following  stage.  Hence,  to 
obtain  a  large  value  of  load  resistance,  it 
is  necessary  to  use  a  plate  resistor  and  a 
grid  resistor  of  large  resistance.  How- 
ever, the  plate  resistor  should  not  be  too 
large  because  the  flow  of  plate  current 
through  the  plate  resistor  produces  a 
voltage  drop  which  reduces  the  plate 
voltage  applied  to  the  tube.  If  the  plate 
resistor  is  too  large,  this  drop  will  be  too 


VOLTAGE  AMPLIFICATION  vs.LOAD  RESISTANCE 
FOR  THEORETICAL   TRIOOE  HAVING*. 
PLATE    RESISTANCE  =  10000  OHMS 
AMPLIFICATION  FACTOR=IO 
TRANSCONDUCTANCE  =1000  MICROMHOS 


100000  200000  300000  400000 

LOAD    RESl'=^TANCE  -OHMS 


Fig.  15 


15 


RCA  Receiving  Tube  Manual 


large,  the  plate  voltage  on  the  tube  will 
be  too  small,  and  the  voltage  output  of 
the  tube  will  be  too  small.  Also,  the  grid 
resistor  of  the  following  stage  should  not 
be  too  large,  the  actual  maximum  value 
being  dependent  on  the  particular  tube 
type.  This  precaution  is  necessary  be- 
cause all  tubes  contain  minute  amounts 
of  residual  gas  which  cause  a  minute 
flow  of  current  through  the  grid  resistor. 
If  the  grid  resistor  is  too  large,  the  posi- 
tive bias  developed  by  the  flow  of  this 
current  through  the  resistor  decreases 
the  normal  negative  bias  and  produces 
an  increase  in  the  plate  current.  This  in- 
creased current  may  overheat  the  tube 
and  cause  liberation  of  more  gas  which, 
in  turn,  will  cause  further  decrease  in 
bias.  The  action  is  cumulative  and  re- 
sults in  a  runaway  condition  which  can 
destroy  the  tube. 

A  higher  value  of  grid  resistance  is 
permissible  when  cathode-resistor  bias 
is  used  than  when  fixed  bias  is  used. 
When  cathode-resistor  bias  is  used,  a 
loss  in  bias  due  to  gas  or  grid-emission 
effects  is  almost  completely  offset  by  an 
increase  in  bias  due  to  the  voltage  drop 
across  the  cathode  resistor.  Typical  val- 
ues of  plate  resistor  and  grid  resistor  for 
tube  types  used  in  resistance-coupled 
circuits,  and  the  values  of  gain  obtain- 
able, are  shown  in  the  RESISTANCE- 
COUPLED  AMPLIFIER  SECTION. 

The  input  impedance  of  an  electron 
tube  (that  is,  the  impedance  between 
grid  and  cathode)  consists  of  (1)  a  reac- 
tive component  due  to  the  capacitance 
between  grid  and  cathode,  (2)  a  resistive 
component  resulting  from  the  time  of 
transit  of  electrons  between  cathode  and 
grid,  and  (3)  a  resistive  component  de- 
veloped by  the  part  of  the  cathode  lead 
inductance  which  is  common  to  both  the 
input  and  output  circuits.  Components 
(2)  and  (3)  are  dependent  on  the  fre- 
quency of  the  incoming  signal.  The  in- 
put impedance  is  very  high  at  audio 
frequencies  when  a  tube  is  operated  with 
its  grid  biased  negative.  In  a  class  Ai  or 
ABi  transformer-coupled  audio  ampli- 
fier, therefore,  the  loading  imposed  by 
the  grid  on  the  input  transformer  is 
negligible.  As  a  result,  the  secondary 
impedance  of  a  class  Ai  or  class  ABi  in- 
put transformer  can  be  made  very  high 
because  the  choice  is  not  limited  by  the 


input  impedance  of  the  tube;  however, 
transformer  design  considerations  may 
limit  the  choice. 

At  the  higher  radio  frequencies,  the 
input  impedance  may  become  very  low 
even  when  the  grid  is  negative,  due  to 
the  finite  time  of  passage  of  electrons  be- 
tween cathode  and  grid  and  to  the  ap- 
preciable lead  reactance.This  impedance 
drops  very  rapidly  as  the  frequency  is 
raised,  and  increases  input-circuit  load- 
ing. In  fact,  the  input  impedance  may 
become  low  enough  at  very  high  radio 
frequencies  to  affect  appreciably  the 
gain  and  selectivity  of  a  preceding  stage. 
Tubes  such  as  the  "acorn"  and  "pencil" 
types  and  the  high-frequency  miniatures 
have  been  developed  to  have  low  input 
capacitances,  low  electron-transit  time, 
and  low  lead  inductance  so  that  their 
input  impedance  is  high  even  at  the 
ultra-high  radio  frequencies.  Input 
admittance  is  the  reciprocal  of  input 
impedance. 

A  remote-cutoflf  amplifier  tube  is 
a  modified  construction  of  a  pentode  or 
a  tetrode  type  designed  to  reduce  modu- 
lation-distortion and  cross-modulation 
in  radio-frequency  stages.  Cross-modu- 
lation is  the  effect  produced  in  a  radio 
or  television  receiver  by  an  interfering 
station  "riding  through"  on  the  carrier 
of  the  station  to  which  the  receiver  is 
tuned.  Modulation-distortion  is  a  dis- 
tortion of  the  modulated  carrier  and  ap- 
pears as  audio-frequency  distortion  in 
the  output.  This  effect  is  produced  by 
a  radio-frequency  amplifier  stage  opera- 
ting on  an  excessively  curved  character- 
istic when  the  grid  bias  has  been  increased 
to  reduce  volume.  The  offending  stage 
for  cross-modulation  is  usually  the  first 
radio-frequency  amplifier, while  for  mod- 
ulation-distortion the  cause  is  usually 
the  last  intermediate-frequency  stage. 
The  characteristics  of  remote-cutoff 
types  are  such  as  to  enable  them  to 
handle  both  large  and  small  input  sig- 
nals with  minimum  distortion  over  a 
wide  range  of  signal  strength. 

Fig.  16  illustrates  the  construction 
of  the  grid  No.l  (control  grid)  in  a  re- 
mote-cutoff tube.  The  remote-cutoff  ac- 
tion is  due  to  the  structure  of  the  grid 
which  provides  a  variation  in  amplifica- 
tion factor  with  change  in  grid  bias.  The 
grid  No.l  is  wound  with  open  spacing  at 


16 


Electron  Tube  Applications 


the  middle  and  with  close  spacing  at  the 
ends.  When  weak  signals  and  low  grid 
bias  are  applied  to  the  tube,  the  effect  of 
the  non-uniform  turn  spacing  of  the  grid 
on  cathode  emission  and  tube  character- 
istics is  essent'ally  the  same  as  for  uni- 
form spacing.  As  the  grid  bias  is  made 
more  negative  to  handle  larger  input 


CATHODEv  PLATE 


SUPPRESSOR     GRID  SCREEM 
GRID  GRID 

Fig.  16 

signals,  the  electron  flow  from  the  sec- 
tions of  the  cathode  enclosed  by  the  ends 
of  the  grid  is  cut  off.  The  plate  current 
and  other  tube  characteristics  are  then 
dependent  on  the  electron  flow  through 
the  open  section  of  the  grid.  This  action 
changes  the  gain  of  the  tube  so  that 
large  signals  may  be  handled  with  mini- 
mum distortion  due  to  cross-modulation 
and  modulation-distortion. 

Fig.  17  shows  a  typical  plate-cur- 
rent vs.  grid-voltage  curve  for  a  remote- 
cutoff  type  compared  with  the  curve  for 
a  type  having  a  uniformly  spaced  grid. 
It  will  be  noted  that  while  the  curves  are 
similar  at  small  grid-bias  voltages,  the 
plate  current  of  the  remote-cutoff  tube 
drops  quite  slowly  with  large  values  of 
bias  voltage.  This  slow  change  makes  it 


NEGATIVE  GRID  VOLTS  0 


Fig.  17 

possible  for  the  tube  to  handle  large  sig- 
nals satisfactorily.  Because  remote-cutoff 
types  can  accommodate  large  and  small 
signals,  they  are  particularly  suitable  for 
use  in  sets  having  automatic  volume 
control.  Remote-cutoff  tubes  also  are 
known  as  variable-mu  types. 


Class  A  Power  Amplifiers 

As  a  class  A  power  amplifier,  an 
electron  tube  is  used  in  the  output  stage 
of  a  radio  or  television  receiver  to  supply 
a  relatively  large  amount  of  power  to 
the  loudspeaker.  For  this  application, 
large  power  output  is  of  more  impor- 
tance than  high  voltage  amplification; 
therefore,  gain  possibilities  are  sacrificed 
in  the  design  of  power  tubes  to  obtain 
power-handling  capability. 

Triodes,  pentodes,  and  beam  power 
tubes  designed  for  power  ampHfier  serv- 
ice have  certain  inherent  features  for 
each  structure.  Power  tubes  of  the  triode 
type  for  class  A  service  are  characterized 
by  low  power  sensitivity,  low  plate- 
power  efficiency,  and  low  distortion. 
Power  tubes  of  the  pentode  type  are 
characterized  by  high  power  sensitivity, 
high  plate-power  efficiency  and,  usually, 
somewhat  higher  distortion  than  class  A 
triodes.  Beam  power  tubes  have  higher 


9*      B-      AC  riUAMCNT 


Fig.  18 

power  sensitivity  and  efficiency  than> 
triode  or  conventional  pentode  types. 

A  class  A  power  amplifier  is  also 
used  as  a  driver  to  supply  power  to  a 
class  AB2  or  a  class  B  stage.  It  is  usually 
advisable  to  use  a  triode,  rather  than  a 
pentode,  in  a  driver  stage  because  of  the' 
lower  plate  impedance  of  the  triode. 

Power  tubes  connected  in  either 
parallel  or  push-pull  may  be  employed 
as  class  A  amplifiers  to  obtain  increased 
output.The  parallel  connection  (Fig.  18) 
provides  twice  the  output  of  a  single* 
tube  with  the  same  value  of  grid-signal 
voltage.  With  this  connection,  the  effec- 
tive transconductance  of  the  stage  is 
doubled,  and  the  effective  plate  resist- 
ance and  the  load  resistance  required 
are  halved  as  compared  with  singles- 
tube  values. 

The  push-pull  connection  (Fig.  19),, 
although  it  requires  twice  the  grid-signaB 


17 


RCA  Receiving  Tube  Manual 


voltage,  provides  increased  power  and 
has  other  important  advantages  over 
single-tube  operation.  Distortion  caused 
iby  even-order  harmonics  and  hum  caused 


Fig.  19 


by  plate-voltage-supply  fluctuations  are 
either  eliminated  or  decidedly  reduced 
through  cancellation.  Because  distortion 
for  push-pull  operation  is  less  than  for 
single-tube  operation,  appreciably  more 
than  twice  single-tube  output  can  be  ob- 
tained with  triodes  by  decreasing  the 
load  resistance  for  the  stage  to  a  value 
approaching  the  load  resistance  for  a 
single  tube. 

For  either  parallel  or  push-pull 
class  A  operation  of  two  tubes,  all  elec- 
trode currents  are  doubled  while  all  dc 
electrode  voltages  remain  the  same  as 
for  single-tube  operation.  If  a  cathode 
resistor  is  used,  its  value  should  be  about 
one-half  that  for  a  single  tube.  If  oscilla- 
tions occur  with  either  type  of  connec- 
tion, they  can  often  be  eliminated  by  the 
use  of  a  non-inductive  resistor  of  ap- 
proximately 100  ohms  connected  in 
series  with  each  grid  at  the  socket 
terminal. 

Operation  of  power  tubes  so  that 


Power- Output  Calculations 

Calculation  of  the  power  output  of 
a  triode  used  as  a  class  A  amplifier  with 
either  an  output  transformer  or  a  choke 
having  low  dc  resistance  can  be  made 
without  serious  error  from  the  plate 
family  of  curves  by  assuming  a  resist- 
ance load.  The  proper  plate  current, 
grid  bias,  optimum  load  resistance,  and 
per-cent  second-harmonic  distortion  can 
also  be  determined.  The  calculations  are 
made  graphically  and  are  illustrated  in 
Fig.  20  for  given  conditions.  The  pro- 
cedure is  as  follows: 

(1)  Locate  the  zero-signal  bias  point 
P  by  determining  the  zero-signal  bias 
Eco  from  the  formula: 

Zero-signal  bias  (Eco)  =»  -(0.68  X  Eb)/^ 

where  Eb  is  the  chosen  value  in  volts  of 
dc  plate  voltage  at  which  the  tube  is  to 
be  operated,  and  ju  is  the  amplification 
factor  of  the  tube.  This  quantity  is 
shown  as  negative  to  indicate  that  a 
negative  bias  is  used. 

(2)  Locate  the  value  of  zero-signal 
plate  current,  lo,  corresponding  to  point 
P. 

(3)  Locate  the  point  2Io,  which  is 
twice  the  value  of  lo  and  corresponds  to 
the  v^alue  of  the  maximum-signal  plate 
current  Imax- 

(4)  Locate  the  point  X  on  the  dc 
bias  curve  at  zero  volts,  Ec  =  0,  corre- 
sponding to  the  value  of  I  max. 

(5)  Draw  a  straight  line  X  Y  through 
X  and  P. 

Line  XY  is  known  as  the  load  re- 
sistance line.  Its  slope  corresponds  to 


PLATE  VOLTS 
Fig.  20 


the  grids  run  positive  is  inadvisable  the  value  of  the  load  resistance.The  load 

•except  under  conditions  such  as  those  resistance  in  ohms  is  equal  to  (Emax- 

discussed  in  this  section  for  class  AB  Emi  i)  divided  by  (Imax  -  Imin),  where  E 

;and  class  B  amplifiers.  is  in  volts  and  I  is  in  amperes. 


18 


Electron  Tube  Applications 


I 


It  should  be  noted  that  in  the  case 
of  filament  types  of  tubes,  the  calcula- 
tions are  given  on  the  basis  of  a  dc- 
operated  filament.  When  the  filament  is 
ac-operated,  the  calculated  value  of  dc 
bias  should  be  increased  by  approxi- 
mately one-half  the  filament  voltage 
rating  of  the  tube. 

The  value  of  zero-signal  plate  cur- 
rent lo  should  be  used  to  determine  the 
plate  dissipation,  an  important  factor 
influencing  tube  life.  In  a  class  A  ampli- 
fier under  zero-signal  conditions,  the 
plate  dissipation  is  equal  to  the  power 
input,  i.e.,  the  product  of  the  dc  plate 
voltage  Eo  and  the  zero-signal  dc  plate 
current  I©.  If  it  is  found  that  the  plate- 
dissipation  rating  of  the  tube  is  exceeded 
with  the  zero-signal  bias  Eco  calculated 
above,  it  will  be  necessary  to  increase 
the  bias  by  a  sufficient  amount  so  that 
the  actual  plate  dissipation  does  not  ex- 
ceed the  rating  before  proceeding  further 
with  the  remaining  calculations. 

For  power-output  calculations,  it  is 
assumed  that  the  peak  alternating  grid 
voltage  is  sufficient  (1)  to  swing  the  grid 
from  the  zero-signal  bias  value  Eco  to 
zero  bias  (Ec  =  0)  on  the  positive  swing 
and  (2)  to  swing  the  grid  to  a  value 
twice  the  zero-signal  bias  value  on  the 
negative  swing.  During  the  negative 
swing,  the  plate  voltage  and  plate  cur- 
rent reach  values  of  Emax  and  Imin,*  dur- 
ing the  positive  swing,  they  reach  values 
of  Emin  and  Imax.  Becauso  power  is  the 
product  of  voltage  and  current,  the 
power  output  Po  as  shown  by  a  watt- 
meter is  given  by 


Po- 


,  (Imax  -  Imin)  X  (Emax  -  Emln) 
8 


where  E  is  in  volts,  I  is  in  amperes,  and 
Po  is  in  watts. 

In  the  output  of  power  amplifier 
triodes,  some  distortion  is  present.  This 
distortion  is  due  predominantly  to  sec- 
ond harmonics  in  single-tube  amplifiers. 
The  percentage  of  second-harmonic  dis- 
tortion may  be  calculated  by  the  follow- 
ing formula: 

Imax+  Imin 


%  distortion  < 


-X  100 


Imax  -  Imin 

where  lo  is  the  zero-signal  plate  current 
in  amperes.  If  the  distortion  is  excessive, 
the  load  resistance  should  be  increased 
or,  occasionally,  decreased  slightly  and 


the  calculations  repeated. 

Example:  Determine  the  load  re- 
sistance, power  output,  and  distortion 
of  a  triode  having  an  amplification  fac- 
tor of  4.2,  a  plate-dissipation  rating  of 
15  watts,  and  plate  characteristics  curves 
as  shown  in  Fig.  20.  The  tube  is  to  be 
operated  at  250  volts  on  the  plate. 

Procedure:  For  a  first  approxima- 
tion, determine  the  operating  point  P" 
from  the  zero-signal  bias  formula,  Ecq  == 
-(0.68  X  250)  /4.2  =  -40.5  volts.  From 
the  curve  for  this  voltage,  it  is  found 
that  the  zero-signal  plate  current  lo  at  a. 
plate  voltage  of  250  volts  is  0.08  ampere- 
and,  therefore,  the  plate-dissipation  rat- 
ing is  exceeded  (0.08  X  250  =  20  watts). 
Consequently,  it  is  necessary  to  reduce- 
the  zero-signal  plate  current  to  0.06  am- 
pere at  250  volts.  The  grid  bias  is  now 
seen  to  be  -43.5  volts.  Note  that  the^ 
curve  was  taken  with  a  dc  filament  sup- 
ply; if  the  filament  is  to  be  operated  oni 
an  ac  supply,  the  bias  must  be  increased 
by  about  one-half  the  filament  voltage, 
or  to  -45  volts,  and  the  circuit  returns, 
made  to  the  mid-point  of  the  filament 
circuit. 

Point  X  can  now  be  determined.. 
Point  X  is  at  the  intersection  of  the  dc 
bias  curve  at  zero  volts  with  Imax,  where- 
Imax  =  2Io  =  2  X  0.06  =  0.12  ampere. 
Line  XY  is  drawn  through  points  P  and 
X.  Emax,  Emin,  and  Imin  are  then  found 
from  the  curves.  Substituting  these  val- 
ues in  the  power-output  formula,  we- 
obtain 

Po  -  (0-12 -0.012)  X  (365- 105^  _  3 

The  resistance  represented  by  load 
line  XY  is 

(365  -  105) 
(0.12  -  0.012)  ' 

When  the  values  from  the  curves, 
are  substituted  in  the  distortion  f  ormula,„ 
we  obtain 

0.12  +  0.012 


-  -  2410  ohms 


2 


■  -  0.06 


%  distortion  -  0.12  -  0.012  ^  "  ^'^^ 
It  is  customary  to  select  the  load 
resistance  so  that  the  distortion  does  not 
exceed  five  per  cent.  When  the  method 
shown  is  used  to  determine  the  slope  of 
the  load  resistance  line,  the  second-har- 
monic distortion  generally  does  not  ex- 
ceed five  per  cent.  In  the  example,  how- 
ever, the  distortion  is  excessive  and  it  is^ 
desirable,  therefore,  to  use  a  slightly 

19 


RCA  Receiving  Tube  Manual 


Mgher  load  resistance.  A  load  resistance 
of  2500  ohms  will  give  a  distortion  of 
about  4.9  per  cent.  The  power  output  is 
reduced  only  slightly  to  3.5  watts. 

Operating  conditions  for  triodes  in 
push-pull  depend  on  the  type  of  opera- 
tion desired.  Under  class  A  conditions, 
distortion,  power  output,  and  efficiency 
are  all  relatively  low.  The  operating  bias 
can  be  anywhere  between  that  specified 
for  single-tube  operation  and  that  equal 
to  one-half  the  grid-bias  voltage  required 
to  produce  plate-current  cutoff  at  a 
plate  voltage  of  1.4Eo  where  Eo  is  the 
operating  plate  voltage.  Higher  bias  than 
this  value  requires  higher  grid-signal 
voltage  and  results  in  class  ABi  opera- 
tion which  is  discussed  later. 

The  method  for  calculating  maxi- 
5mum  power  output  for  triodes  in  push- 
pnli  class  A  operation  is  as  follows: 
Erect  a  vertical  line  at  0.6  Eo  (see  Fig. 
:21),  intersecting  the  Ec=0  curve  at  the 


RCA-2A3 
Zf-2.b  VOLTS  DC 


plate  dissipation  rating  of  the  tube  is  15 
watts.  Then,  for  class  A  operation,  the 
operating  bias  can  be  equal  to,  but  not 
more  than,  one-half  the  grid  bias  for  cut- 
off with  a  plate  voltage  of  1.4  X  300  =  420 
volts.  (Since  cutoff  bias  is  approximately 
-115  volts  at  a  plate  voltage  of  420  volts, 
one-half  of  this  value  is  -57.5  volts  bias.) 
At  this  bias,  the  plate  current  is  found 
from  the  plate  family  to  be  0.054  am- 
pere and,  therefore,  the  plate  dissipation 
is  0.054  X  300  or  16.2  watts.  Since  -57.5 
volts  is  the  limit  of  bias  for  class  A  oper- 
ation of  these  tubes  at  a  plate  voltage  of 
300  volts,  the  dissipation  cannot  be  re- 
duced by  increasing  the  bias  and  it, 
therefore,  becomes  necessary  to  reduce 
the  plate  voltage. 

If  the  plate  voltage  is  reduced  to 
250  volts,  the  bias  will  be  found  to  be 
-43.5  volts.  For  this  value,  the  plate  cur- 
rent is  0.06  ampere,  and  the  plate  dissi- 
pation is  15  watts.  Then,  following  the 


250  300 
PLATE  VOLTS 
Fig.  21 

point  Imax.  Then,  Imax  is  determined 
from  the  curve  for  use  in  the  formula 


Po  =-  (Imax  X  Eo)/5 

If  Imax  is  expressed  in  amperes  and  Eo 
lin  volts,  power  output  is  in  watts. 

The  method  for  determining  the 
iproper  load  resistance  for  triodes  in 
push-pull  is  as  follows:  Draw  a  load  line 
through  Imax  on  the  zero-bias  curve  and 
through  the  Eo  point  on  the  zero-current 
axis.  Four  times  the  resistance  repre- 
sented by  this  load  line  is  the  plate-to- 
plate  load  (Rpp)  for  two  triodes  in  a 
class  A  push-pull  amplifier.  Expressed 
as  a  formula, 

Rpp  =  4  X  (Eo  -  0.6Eo)/Imax 

where  Eo  is  expressed  in  volts,  imax  in 
amperes,  and  Rpp  in  ohms. 

Example:  Assume  that  the  plate 
voltage  (Eo)  is  to  be  300  volts,  and  the 

20 


method  for  calculating  power  output, 
erect  a  vertical  line  at  O.6E0  =  150  volts. 
The  intersection  of  the  line  with  the 
curve  Ec  =  0  IS  imax  or  0.2  ampere. When 
this  value  is  substituted  in  the  power 
formula,  the  power  output  is  (0.2  X  250) 
/5  =  10  watts.  The  load  resistance  is  de- 
termined from  the  load  formula:  Plate- 
to-plate  load  (Rpp)  =  4  X  (250  -  150) 
/0.2  =  2000  ohms. 

Power  output  for  a  pentode  or  a 
beam  power  tube  as  a  class  A  amplifier 
can  be  calculated  in  much  the  same  way 
as  for  triodes.  The  calculations  can  be 
made  graphically  from  a  special  plate 
family  of  curves,  as  illustrated  in  Fig.  22. 

From  a  point  A  at  or  just  below  the 
knee  of  the  zero-bias  curve,  draw  arbi- 
trarily selected  load  lines  to  intersect  the 
zero-plate-current  axis.  These  lines 
should  be  on  both  sides  of  the  operating 


Electron  Tube  Applications 


point  P  whose  position  is  determined  by 
the  desired  operating  plate  voltage,  Eo, 
and  one-half  the  maximum-signal  plate 
current.  Along  any  load  line,  say  AAi, 
measure  the  distance  AOi.  On  the  same 
line,  lay  off  an  equal  distance,  OiAi.  For 
optimum  operation,  the  change  in  bias 
from  A  to  Oi  should  be  nearly  equal  to 
the  change  in  bias  from  Oi  to  Ai.  If  this 
condition  can  not  be  met  with  one  line, 


%  total  (2nd  and  3rd)  harmonic  distortion  — 
V(%2nd)2  +  (%3rd)=' 

Conversion  Factors 

Operating  conditions  for  voltage 
values  other  than  those  shown  in  the 
published  data  can  be  obtained  by  the 
use  of  the  nomograph  shown  in  Fig.  23 
when  all  electrode  voltages  are  changed 
simultaneously  in  the  same  ratio.  The 


as  is  the  case  for  the  line  first  chosen, 
then  another  should  be  chosen.  When 
the  most  satisfactory  line  has  been  se- 
lected, its  resistance  may  be  determined 
by  the  following  formula: 


Load  resistance  (Rl)  ' 


Emax  - 
I  max  - 


Emln 
Imin 


The  value  of  Rl  may  then  be  sub- 
stituted in  the  following  formula  for 
calculating  power  output. 

Po=,  [Imax  -  Imin  +  1.41  (Ix  -  Iy)1  ^  Rl 
32 

In  both  of  these  formulas,  I  is  in 
amperes,  E  is  in  volts,  Rl  is  in  ohms, 
and  Po  is  in  watts.  Ix  and  ly  are  the  cur- 
rent values  on  the  load  line  at  bias  volt- 
ages of  Eci=V-  0.707V=  0.293V  and 
Eci=V  -h  0.707V=  1.707V,  respectively. 

Calculations  for  distortion  may  be 
made  by  means  of  the  following  formu- 
las. The  terms  used  have  already  been 
defined. 


%  2nd-harmonic  distortion  => 
Imax  +  Imin  -  2  Ip 
Imax  -  Imin  +  1.41  (Ix  -  ly) 

%  3rd-harmonic  distortion  => 

Imax  -  Imin  -  1.41  (Ix  -  ly) 
Imax  -  Imin  +  1.41  (Ix  -  ly) 


X  100 


X  100 


nomograph  includes  conversion  factors 
for  current  (Fi),  power  output  (Fp), 
plate  resistance  or  load  resistance  (Fr), 
and  transconductance  (Fgm)  for  voltage 
ratios  between  0.5  and  2.0.  These  factors 
are  expressed  as  functions  of  the  ratio 
between  the  desired  or  new  voltage  for 
any  electrode  (Edes)  and  the  published 
or  original  value  of  that  voltage  (Epub). 
The  relations  shown  are  applicable  to 
triodes  and  multigrid  tubes  in  all  classes 
of  service. 

To  use  the  nomograph,  simply  place 
a  straight-edge  across  the  page  so  that 
it  intersects  the  scales  for  Edes  and  Epub 
at  the  desired  values.  The  desired  con- 
version factor  may  then  be  read  directly 
or  estimated  at  the  point  where  the 
straight-edge  intersects  the  Fi,  Fp  Fr,  or 
Fgm  scale. 

For  example,  suppose  it  is  desired 
to  operate  two  6L6GB's  in  class  Aipush- 
pull,  fixed  bias,  with  a  plate  voltage  of 
200  volts.  The  nearest  published  oper- 
ating conditions  for  this  class  of  service 
are  for  a  plate  voltage  of  250  volts.  The 
operating  conditions  for  the  new  plate 
voltage  can  be  determined  as  follows: 

The  voltage  conversion  factor,  F©, 

21 


RCA  Receiving  Tube  Manual 


is  equal  to  200/250  or  0.8.  The  dashed 
lines  on  the  nomograph  of  Fig.  23  indi- 
cate that  for  this  voltage  ratio  Fi  is  ap- 
proximately 0.72,  Fp  is  approximately 


Because  contact-potential  effects  become 
noticeable  only  at  very  small  dc  grid- 
No.  1  (bias)  voltages,  they  are  generally 
negligible  in  power  tubes.  Secondary 


Fr 


Fgm 


Edes 

20  T- 

18: 

16 
14- 
12- 

10- 
9  + 
8- 
7-- 
«  6-- 


Epub 


1.30  -  - 

I  -  0.75 


0.70 


1.0- 
0.9- 
0.8  + 

0.7  + 
0.6 

0.5 


Edes 
-J- 20 

: '® 

-£l6 
--I4 
--I2 
10 

::9 

--8 

--7 


-72 
--I.8 


-^1.0 

Fi??.  23 


r6.o 

2.8  —  5.5 

2.4H"^-* 
--4.0 
2.2- 

2.0- 
1.9- 
1.8- 
1.7- 
1.6 -- 


1.5 
il.4 
\  1.3- 
■  1.2 


-2.0 
~(.8  ■ 

-1.6  I 

•1.4 


-1.0 

-  0.9 

-  0.8 
-f-  0.7 

-0.6 
-»-0.6 


a34- 


1.0 

--0.9  ; 

-  0.8  \ 

0.7  ' 
< 

0.6  ' 


-7  0.2 
0.18 


0.57,  Fr  is  1.12,  and  Fgm  is  approxi- 
mately 0.892.  These  factors  may  be  ap- 
plied directly  to  operating  values  shown 
in  the  tube  data,  or  to  values  calculated 
by  the  methods  described  previously. 

Because  this  method  for  conversion 
of  characteristics  is  necessarily  an  ap- 
proximation, the  accuracy  of  the  nomo- 
graph decreases  progressively  as  the 
ratio  Edes/Epub  departs  from  unity.  In 
general,  results  are  substantially  correct 
when  the  value  of  the  ratio  Edes/Epub  is 
between  0.7  and  1.5.  Beyond  these  lim- 
its, the  accuracy  decreases  rapidly,  and 
the  results  obtained  must  be  considered 
rough  approximations. 

The  nomograph  does  not  take  into 
consideration  the  effects  of  contact  po- 
tential or  secondary  emission  in  tubes. 

22 


emission  may  occur  in  conventional  tet- 
rodes, however,  if  the  plate  voltage 
swings  below  the  grid-No.2  voltage. 
Consequently,  the  conversion  factors 
shown  in  the  nomograph  apply  to  such 
tubes  only  when  the  plate  voltage  is 
greater  than  the  grid-No.2  voltage.  Be- 
cause secondary  emission  may  also  oc- 
cur in  certain  beam  power  tubes  at  very 
low  values  of  plate  current  and  plate 
voltage,  the  conversion  factors  shown  in 
the  nomograph  do  not  apply  when  these 
tubes  are  operated  under  such  conditions. 

C/ass  A6  Power  Amplifiers 

A  class  AB  power  amplifier  em- 
ploys two  tubes  connected  in  push-pull 
with  a  higher  negative  grid  bias  than  is 


Electron  Tube  Applications 


used  in  a  class  A  stage.  With  this  higher 
negative  bias,  the  plate  and  screen-grid 
voltages  can  usually  be  made  higher 
than  for  class  A  amplifiers  because  the 
increased  negative  bias  holds  plate  cur- 
rent within  the  limit  of  the  tube  plate- 
dissipation  rating.  As  a  result  of  these 
higher  voltages,  more  power  output  can 
be  obtained  from  class  AB  operation. 

Class  AB  amplifiers  are  subdivided 
into  class  ABi  and  class  AB2.  In  class 
ABi  there  is  no  flow  of  grid  current. That 
is,  the  peak  signal  voltage  applied  to  each 
grid  is  not  greater  than  the  negative 
grid-bias  voltage.  The  grids  therefore 
are  not  driven  to  a  positive  potential 
and  do  not  draw  current.  In  class  AB2, 
the  peak  signal  voltage  is  greater  than 
the  bias  so  that  the  grids  are  driven 
positive  and  draw  current. 

Because  of  the  flow  of  grid  current 
in  a  class  AB2  stage  there  is  a  loss  of 


Fip:.  24 

power  in  the  grid  circuit.  The  sum  of 
this  loss  and  the  loss  in  the  input  trans- 
former is  the  total  driving  power  re- 
quired by  the  grid  circuit.  The  driver 
stage  should  be  capable  of  a  power  out- 
put considerably  larger  than  this  re- 
quired power  in  order  that  distortion 
introduced  in  the  grid  circuit  be  kept 
low.  The  input  transformer  used  in  a 
class  AB2  amplifier  usually  has  a  step- 
down  turns  ratio. 

Because  of  the  large  fluctuations  of 
plate  current  in  a  class  AB2  stage,  it  is 
important  that  the  plate  power  supply 
should  have  good  regulation.  Otherwise 
the  fluctuations  in  plate  current  cause 


fluctuations  in  the  voltage  output  of  the 
power  supply,  with  the  result  that  power 
output  is  decreased  and  distortion  is  in- 
creased. To  obtain  satisfactory  regula- 
tion it  is  usually  advisable  to  use  a  low- 
drop  rectifier,  such  as  the  5V4GA,  with  a 
choke-input  filter.  In  all  cases,  the  resist- 
ance of  the  filter  choke  and  power  trans- 
formers should  be  as  low  as  possible. 

Class  AB\  Power  Amplifiers 

In  class  ABi  push-pull  amplifier 
service  using  triodes,  the  operating  con- 
ditions may  be  determined  graphically 
by  means  of  the  plate  family  if  Eo,  the 
desired  operating  plate  voltage,  is  given. 
In  this  service,  the  dynamic  load  line 
does  not  pass  through  the  operating 
point  P  as  in  the  case  of  the  single-tube 
amplifier,  but  through  the  point  D  in 
Fig.  24.  Its  position  is  not  affected  by 
the  operating  grid  bias  provided  the 


0 

Fig.  25 

plate-to-plate  load  resistance  remains 
constant. 

Under  these  conditions,  grid  bias 
has  no  appreciable  effect  on  the  power 
output.  Grid  bias  cannot  be  neglected, 
however,  since  it  is  used  to  find  the  zero- 
signal  plate  current  and,  from  it,  the 
zero-signal  plate  dissipation.  Because 
the  grid  bias  is  higher  in  class  ABi  than 
in  class  A  service  for  the  same  plate  volt- 
age, a  higher  signal  voltage  may  be  used 
without  grid  current  being  drawn  and, 
therefore,  higher  power  output  is  ob- 
tained than  in  class  A  service. 

In  general,  for  any  load  line  through 
point  D,  Fig.  24,  the  plate-to-plate  load 


23 


RCA  Receiving  Tube  Manual 


resistance  in  ohms  of  a  push-pull  ampli- 
fier is  Rpp=4Eo/I',  where  I'  is  the  plate 
current  value  in  amperes  at  which  the 
load  line  as  projected  intersects  the  plate 
current  axis,  and  Eq  is  in  volts.  This 
formula  is  another  form  of  the  one 
given  under  push-pull  class  A  amplifiers, 
Rpp  =  4(Eo  -  0.6Eo)/Imax,  but  is  more 
general.  Power  output  =  (Imax/\/2  Y  X 
Rpp/4,  where  Imax  is  the  peak  plate  cur- 
rent at  zero  grid  volts  for  the  load  chosen. 
This  formula  simplified  is  (Imax)^  X  Rpp/ 
8.  The  maximum-signal  average  plate 
current  is  2Imax/7r  or  0.636  J-maxj  the 
maximum-signal  average  power  input  is 
0.636  Imax  X  Eo. 

It  is  desirable  to  simplify  these 
formulas  for  a  first  approximation.  This 
simplification  can  be  made  if  it  is  as- 
sumed that  the  peak  plate  current,  -i-maxj 
occurs  at  the  point  of  the  zero-bias  curve 
corresponding  approximately  to  0.6  Eo, 
the  condition  for  maximum  power  out- 
put. The  simplified  formulas  are: 

Po  (ior  two  tubes)      (Imax  X  Eo)/5 
Rpp  »=  1.6Eo/Imax 

where  Eo  is  in  volts,  Imax  is  in  amperes, 
Rpp  is  in  ohms,  and  Po  is  in  watts. 

It  may  be  found  during  subsequent 
calculations  that  the  distortion  or  the 
plate  dissipation  is  excessive  for  this  ap- 
proximation; in  that  case,  a  different 
load  resistance  must  be  selected  using 
the  first  approximation  as  a  guide  and 
the  process  repeated  to  obtain  satisfac- 
tory operating  conditions. 

Example:  Fig.  24  illustrates  the 
application  of  this  method  to  a  pair  of 
2A3's  operated  at  Eo=300  volts.  Each 
tube  has  a  plate-dissipation  rating  of  15 
watts.  Tne  method  is  to  erect  a  vertical 
line  at  O.6E0,  or  at  180  volts,  which 
intersects  the  Ec=0  curve  at  the  point 
Imax=0.26  ampere.  Using  the  simplified 
formulas,  we  obtain 

Rpp  =  (1.6  X  300)/0.26  =  1845  ohms 
Po  =  (0.26  X  300)/5  »  15.6  watts 

At  this  point,  it  is  well  to  determine 
the  plate  dissipation  and  to  compare  it 
with  the  maximum  rated  value.  From 
the  average  plate  current  formula  (0.636 
Imax)  mentioned  previously,  the  maxi- 
mum-signal average  plate  current  is 
0.166  ampere.  The  product  of  this  cur- 
rent and  the  operating  plate  voltage  is 
49.8  watts,  the  average  input  to  the  two 
tubes.  From  this  value,  subtract  the 


power  output  of  15.6  watts  to  obtain  the 
total  dissipation  for  both  tubes  which  is 
34.2  watts.  Half  of  this  value,  17  watts, 
is  in  excess  of  the  15-watt  rating  of  the 
tube  and  it  is  necessary,  therefore,  to  as- 
sume another  and  higher  load  resistance 
so  that  the  plate-dissipation  rating  will 
not  be  exceeded. 

It  will  be  found  that  at  an  operating 
plate  voltage  of  300  volts  the  2A3's  re- 
quire a  plate-to-plate  load  resistance  of 
3000  ohms.  From  the  formula  for  Rpp, 
the  value  of  F  is  found  to  be  0.4  ampere. 
The  load  line  for  the  3000-ohm  load  re- 
sistance is  then  represented  by  a  straight 
line  from  the  point  V=  0.4  ampere  on  the 
plate-current  ordinate  to  the  point  Eo= 
300  volts  on  the  plate- volt  age  abscissa. 
At  the  intersection  of  the  load  line  with 
the  zero-bias  curve,  the  peak  plate  cur- 
rent, Imax,  can  be  read  at  0.2  ampere. 

Then      Po  -  (imax/  V2  )2  X  Rpp/4 
(0.2/1.41)2  X  3000/4 
■"is  watts 

Proceeding  as  in  the  first  approximation, 
we  find  that  the  maximum-signal  aver- 
age plate  current,  0.636Imax,  is  0.127 
ampere,  and  the  maximum-signal  aver- 
age power  input  is  38.1  watts.  This  input 
minus  the  power  output  is  38.1  -  15= 
23.1  watts.  This  value  is  the  dissipation 
for  two  tubes;  the  value  per  tube  is  11.6 
watts,  a  value  well  within  the  rating  of 
this  tube  type. 

The  operating  bias  and  the  zero- 
signal  plate  current  may  now  be  found 
by  use  of  a  curve  which  is  derived  from 
the  plate  family  and  the  load  fine.  Fig. 
25  is  a  curve  of  instantaneous  values  of 
plate  current  and  dc  grid-bias  voltages 
taken  from  Fig.  24.  Values  of  grid  bias 
are  read  from  each  of  the  grid-bias 
curves  of  Fig.  24  along  the  load  line  and 
are  transferred  to  Fig.  25  to  produce  the 
curved  line  from  A  to  C.  A  tangent  to 
this  curve,  starting  at  A,  is  drawn  to 
intersect  the  grid-voltage  abscissa.  The 
point  of  intersection,  B,  is  the  operating 
grid  bias  for  fixed-bias  operation.  In  the 
example,  the  bias  is  -60  volts.  Refer 
back  to  the  plate  family  at  the  operating 
conditions  of  plate  volts=300  and  grid 
bias=  -60  volts;  the  zero-signal  plate 
current  per  tube  is  seen  to  be  0.04 
ampere. 

This  procedure  locates  the  operating 
point  for  each  tube  at  P.  The  plate  cur- 


24 


Electron  Tube  Applications 


rent  must  be  doubled,  of  course,  to  ob- 
tain the  zero-signal  plate  current  for 
both  tubes.  Under  maximum-signal  con- 
ditions, the  signal  voltage  swings  from 
zero-signal  bias  voltage  to  zero  bias  for 
each  tube  on  alternate  half  cycles.  Hence, 
in  the  example,  the  peak  af  signal  volt- 
age per  tube  is  60  volts,  or  the  grid-to- 
grid  value  is  120  volts. 

As  in  the  case  of  the  push-pull  class 
A  amplifier,  the  second-harmonic  distor- 
tion in  a  class  ABi  amplifier  using  triodes 
is  very  small  and  is  largely  canceled  by 
virtue  of  the  push-pull  connection.Third- 
harmonic  distortion,  however,  which 
may  be  larger  than  permissible,  can  be 
found  by  means  of  composite  character- 
istic curves.  A  complete  family  of  curves 
can  be  plotted,  but  for  the  present  pur- 
pose only  the  one  corresponding  to  a 
grid  bias  of  one-half  the  peak  grid-volt- 
age swing  is  needed.  In  the  example,  the 
peak  grid  voltage  per  tube  is  60  volts, 
and  the  half  value  is  30  volts.  The  com- 
posite curve,  since  it  is  nearly  a  straight 
line,  can  be  constructed  with  only  two 
points  (see  Fig.  24).  These  two  points 
are  obtained  from  deviations  above  and 
below  the  operating  grid  and  plate 
voltages. 

In  order  to  find  the  curve  for  a  bias 
of  -30  volts,  we  have  assumed  a  devia- 
tion of  30  volts  from  the  operating  grid 
voltage  of  -60  volts.  Next  assume  a  de- 
viation from  the  operating  plate  voltage 
of,  say,  40  volts.  Then  at  300  -  40  =  260 
volts,  erect  a  vertical  line  to  intersect 
the  (-60)  -  (-30)  =  -30-volt  bias  curve 
and  read  the  plate  current  at  this  inter- 
section, which  is  0.167  ampere;  likewise, 
at  the  intersection  of  a  vertical  line  at 
300  +  40  =  340  volts  and  the  (-60)  + 
(-30)  =  -90-volt  bias  curve,  read  the 
plate  current.  In  this  example,  the  plate 
current  is  estimated  to  be  0.002  ampere. 
The  difference  of  0.165  ampere  between 
these  two  currents  determines  the  point 
E  on  the  300  -  40  =  260-volt  vertical. 
Similarly,  another  point  F  on  the  same 
composite  curve  is  found  by  assuming 
the  same  grid-bias  deviation  but  a  larger 
plate-voltage  deviation,  say,  100  volts. 

We  now  have  points  at  260  volts 
and  0.165  ampere  (E),  and  at  200  volts 
and  0.045  ampere  (F).  A  straight  line 
through  these  points  is  the  composite 
curve  for  a  bias  of  -30  volts,  shown  as  a 


long-short  dash  line  in  Fig.  24.  At  the 
intersection  of  the  composite  curve  and 
the  load  line,  G,  the  instantaneous  com- 
posite plate  current  at  the  point  of  one- 
half  the  peak  signal  swing  is  determined. 
This  current  value,  designated  lo.s  and 
the  peak  plate  current,  Imax,  are  used  in 
the  following  formula  to  find  peak  value 
of  the  third-harmonic  component  of  the 
plate  current. 

Ih,  -  (2Io.i  -  Imax)/3 

In  the  example,  where  lo.s  is  0.097  am- 
pere and  Imax  is  0.2  ampere,  Ihs  =  (2X 
0.097-0.2)/3=  (0.194-0.2)/3=  -0.006/ 
3=  -0.002  ampere.  (The  fact  that  Ihs  is 
negative  indicates  that  the  phase  rela- 
tion of  the  fundamental  (first-harmonic) 
and  third-harmonic  components  of  the 
plate  current  is  such  as  to  result  in  a 
slightly  peaked  wave  form.  Ins  is  posi- 
tive in  some  cases,  indicating  a  flatten- 
ing of  the  wave  form.) 

The  peak  value  of  the  fundamental 
or  first-harmonic  component  of  the  plate 
current  is  found  by  the  following 
formula: 

Ihi=  2/3  X  (Imax +Io.i) 

In  the  example,  Ihi  =  2/3  X  (0.2  -h 
0.097)  =  0.198  ampere.  Thus,  the  per- 
centage of  third-harmonic  distortion  is 
(Ihs/Ihi)  X  100  =  (0.002/0.198)  X  100- 
1  per  cent  approx. 

Class  A62  Power  Amplifiers 

A  class  AB2  amplifier  employs  two 
tubes  connected  in  push-pull  as  in  the 
case  of  class  ABi  amplifiers.  It  differs  in 
that  it  is  biased  so  that  plate  current 
flows  for  somewhat  more  than  half  the 
electrical  cycle  but  less  than  the  full 
cycle,  the  peak  signal  voltage  is  greater 
than  the  dc  bias  voltage,  grid  current  is 
drawn,  and  consequently,  power  is  con- 
sumed in  the  grid  circuit.  These  condi- 
tions permit  high  power  output  to  be 
obtained  without  excessive  plate  dissi- 
pation. 

The  sum  of  the  power  used  in  the 
grid  circuit  and  the  losses  in  the  input 
transformer  is  the  total  driving  power 
required  by  the  grid  circuit.  The  driver 
stage  should  be  capable  of  a  power  out- 
put considerably  larger  than  this  re- 
quired power  in  order  that  distortion 
introduced  in  the  grid  circuit  be  kept 
low.  In  addition,  the  internal  impedance 
of  the  driver  stage  as  reflected  into  or  as 


25 


RCA  Receiving  Tube  Manual 


effective  in  the  grid  circuit  of  the  power 
stage  should  always  be  as  low  as  possible 
in  order  that  distortion  may  be  kept 
low.  The  input  transformer  used  in  a 
class  AB2  stage  usually  has  a  step-down 
ratio  adjusted  for  this  condition. 

Load  resistance,  plate  dissipation, 
power  output,  and  distortion  determina- 
tions are  similar  to  those  for  class  ABi. 
These  quantities  are  interdependent 
with  peak  grid-voltage  swing  and  driv- 
ing power;  a  satisfactory  set  of  operating 
conditions  involves  a  series  of  approxi- 
mations. The  load  resistance  and  signal 
swing  are  limited  by  the  permissible  grid 
current  and  power,  and  the  distortion. 
If  the  load  resistance  is  too  high  or  the 
signal  swing  is  excessive,  the  plate-dissi- 
pation rating  will  be  exceeded,  distortion 
will  be  high,  and  the  driving  power  will 
be  unnecessarily  high. 

Class  B  Power  Amplifiers 
A  class  B  amplifier  employs  two 
tubes  connected  in  push-pull,  so  biased 
that  plate  current  is  almost  zero  when 
no  signal  voltage  is  applied  to  the  grids. 
Because  of  this  low  value  of  no-signal 
plate  current,  class  B  amplification  has 
the  same  advantage  as  class  AB2,  i.e., 
large  power  output  can  be  obtained 
without  excessive  plate  dissipation.  Class 
B  operation  differs  from  class  AB2  in 
that  plate  current  is  cut  off  for  a  larger 
portion  of  the  negative  grid  swing,  and 
the  signal  swing  is  usually  larger  than  in 
class  AB2  operation. 

Because  certain  triodes  used  as  class 
B  amplifiers  are  designed  to  operate  very 
close  to  zero  bias,  the  grid  of  each  tube 
is  at  a  positive  potential  during  all  or 
most  of  the  positive  half-cycle  of  its 
signal  swing.  In  this  type  of  triode  opera- 
tion, considerable  grid  current  is  drawn 
and  there  is  a  loss  of  power  in  the  grid 
circuit.  This  condition  imposes  the  same 
requirement  in  the  driver  stage  as  in  a 
class  AB2  stage;  i.e.,  the  driver  should 
be  capable  of  delivering  considerably 
more  power  output  than  the  power  re- 
quired for  the  grid  circuit  of  the  class  B 
amplifier  so  that  distortion  will  be  low. 
Similarly,  the  interstage  transformer  be- 
tween the  driver  and  the  class  B  stage 
usually  has  a  step-down  turns  ratio.  Be- 
cause of  the  high  dissipations  involved  in 
class  B  operation  at  zero  bias,  it  is  not 


feasible  to  use  tetrodes  or  pentodes  in 
this  type  of  class  B  operation. 

Determination  of  load  resistance, 
plate  dissipation,  power  output,  and  dis- 
tortion is  similar  to  that  for  a  class  ABa 
stage. 

Power  amplifier  tubes  designed  for 
class  A  operation  can  be  used  in  class  ABs 
and  class  B  service  under  suitable  oper- 
ating conditions. There  are  several  tube 
types  designed  especially  for  class  B  serv- 
ice. The  characteristic  common  to  all  of 
these  types  is  a  high  amplification  fac- 
tor. With  a  high  amplification  factor, 
plate  current  is  small  even  when  the  grid 
bias  is  zero.  These  tubes,  therefore,  can 
be  operated  in  class  B  service  at  a  bias 
of  zero  volts  so  that  no  bias  supply  is  re- 
quired. A  number  of  class  B  amplifier 
tubes  consist  of  two  triode  units  mounted 
in  one  tube.  The  two  units  can  be  con- 
nected in  push-pull  so  that  only  one 
tube  is  required  for  a  class  B  stage.  An 
example  of  a  twin  triode  used  in  class  B 
service  is  the  6N7. 

High-Fidelity  Amplifiers 

Several  high-fidelity  amplifiers  are 
shown  in  the  CIRCUITS  SECTION. 
The  performance  capabiHties  of  such 
amplifiers  are  usually  given  in  terms  of 
frequency  response,  total  harmonic  dis- 
tortion, maximum  power  output,  and 
noise  level. 

To  provide  high-fidelity  reproduc- 
tion of  audio  program  material,  an  am- 
pUfier  should  have  a  frequency  response 
which  does  not  vary  more  than  Idb  over 
the  entire  audio  spectrum.  General 
practice  is  to  design  the  amplifier  so  that 
its  frequency  response  is  flat  within  1  db 
from  a  frequency  below  the  lowest  to  be 
reproduced  to  one  well  above  the  upper 
limit  of  the  audible  region. 

Harmonic  distortion  and  intermod- 
ulation  distortion  produce  changes  in 
program  material  which  may  have  ad- 
verse effects  on  the  quality  of  the  repro- 
duced sound.  Harmonic  distortion 
causes  a  change  in  the  character  of  an 
individual  tone  by  the  introduction  of 
harmonics  which  were  not  originally 
present  in  the  program  material.  For 
high-fidelity  reproduction,  total  har- 
monic distortion  (expressed  as  a  percent- 
age of  the  output  power)  should  not  be 
greater  than  about  1  per  cent  at  the  de- 


26 


Electron  Tube  Applications 


sired  listening  level.  Types  such  as  the 
6973,  7027A  and  7868  are  designed  to 
provide  extremely  low  harmonic  distor- 
tion in  suitably  designed  push-pull  am- 
plifier circuits. 

Intermodulation  distortion  is  a 
change  in  the  waveform  of  an  individual 
tone  as  a  result  of  interaction  with  an- 
other tone  present  at  the  same  time  in  the 
program  material.  This  type  of  distor- 
tion not  only  alters  the  character  of  the 
modulated  tone,  but  may  also  result  in 
the  generation  of  spurious  signals  at 
frequencies  equal  to  the  sum  and  differ- 
ence of  the  interacting  frequencies.  Inter- 
modulation distortion  should  be  less  than 
2  per  cent  at  the  desired  listening  level. 
In  general,  any  amplifier  which  has  low 
intermodulation  distortion  will  have  very 
low  harmonic  distortion. 

The  maximum  power  output  which 
a  high-fidelity  amplifier  should  deliver 
depends  upon  a  complex  relation  of  sev- 
eral factors,  including  the  size  and  acous- 
tical characteristics  of  the  listening  area, 
the  desired  listening  level,  and  the  ef- 
ficiency of  the  loudspeaker  system.  Prac- 
tically, however,  it  is  possible  to  deter- 
mine amplifier  requirements  in  terms  of 
room  size  and  loudspeaker  efficiency. 

The  acoustic  power  required  to  re- 
produce the  loudest  passages  of  orches- 
tral music  at  concert-hall  level  in  the 
average-size  living  room  is  about  0.4 
watt.  Because  high-fidelity  loudspeakers 
of  the  type  generally  available  for  home 
use  have  an  efficiency  of  only  about  5 
per  cent,  the  output  stage  of  the  ampli- 
fier should  therefore  be  able  to  deliver  a 
power  output  of  at  least  8  watts.  Be- 
cause many  wide-range  loudspeaker  sys- 
tems, particularly  those  using  frequency- 
divider  networks,  have  efficiencies  of  less 
than  5  per  cent,  output  tubes  used  with 
such  systems  must  have  correspondingly 
larger  power  outputs.  The  6973,  7027A, 
7189,  and  7868  can  provide  ample  out- 
put for  most  systems  when  used  in  suit- 
able push-pull  circuits. 

The  noise  level  of  a  high-fidelity 
amplifier  determines  the  range  of  volume 
the  amplifier  is  able  to  reproduce,  i.e., 
the  difference  (usually  expressed  in  dec- 
ibels) between  the  loudest  and  softest 
sounds  in  program  material.  Because 
the  greatest  volume  range  utilized  in 
electrical  program  material  at  the  present 


time  is  about  60  db,  the  noise  level  of  a 
high-fidelity  amplifier  should  be  at  least 
60  db  below  the  signal  level  at  the  desired 
listening  level. 

Cathode-Drive  Circuits 

The  preceding  text  has  discussed 
the  use  of  tubes  in  the  conventional 
grid-drive  type  of  amplifier— that  is, 
where  the  cathode  is  common  to  both 
the  input  and  output  circuits.  Tubes 
may  also  be  employed  as  amplifiers  in 
circuit  arrangements  which  utilize  the 
grid  or  plate  as  the  common  terminal. 
Probably  the  most  important  of  these 
amplifiers  are  the  cathode-drive  circuit, 
which  is  discussed  below,  and  the  cath- 
ode-follower circuit,  which  will  be  dis- 
cussed later  in  connection  with  inverse 
feedback. 

A  typical  cathode-drive  circuit  is 
shown  in  Fig.  26.  The  load  is  placed  in 


Fig.  26 

the  plate  circuit  and  the  output  voltage 
is  taken  off  between  the  plate  and  ground 
as  in  the  grid-drive  method  of  operation. 
The  grid  is  grounded,  and  the  input 
voltage  is  applied  across  an  appropriate 
impedance  in  the  cathode  circuit.  The 
cathode-drive  circuit  is  particularly  use- 
ful for  vhf  and  uhf  applications,  in  which 
it  is  necessary  to  obtain  the  low-noise 
performance  usually  associated  with  a 
triode,  but  where  a  conventional  grid- 
drive  circuit  would  be  unstable  because 
of  feedback  through  the  grid-to-plate 
capacitance  of  the  tube.  In  the  cathode- 
drive  circuit,  the  grounded  grid  serves 
as  a  capacitive  shield  between  plate  and 
cathode  and  permits  stable  operation  at 
frequencies  higher  than  those  in  which 
conventional  circuits  can  be  used. 

The  input  impedance  of  a  cathode- 
drive  circuit  is  approximately  equal  to 
1/gm  when  the  load  resistance  is  small 
compared  to  the  rp  of  the  tube.  A  certain 


27 


RCA  Receiving  Tube  Manual 


amount  of  power  is  required,  therefore, 
to  drive  such  a  circuit.  However,  in  the 
type  of  service  in  which  cathode-drive 
circuits  are  normally  used,  the  advan- 
tages of  the  grounded-grid  connection 
usually  outweigh  this  disadvantage. 

Inverse  Feedback 

An  inverse-feedback  circuit,  some- 
times called  a  degenerative  circuit,  is 
one  in  which  a  portion  of  the  output 
voltage  of  a  tube  is  applied  to  the  input 
of  the  same  or  a  preceding  tube  in  oppo- 
site phase  to  the  signal  applied  to  the 
tube.Two  important  advantages  of  feed- 
back are:  (1)  reduced  distortion  from 
each  stage  included  in  the  feedback  cir- 
cuit and  (2)  reduction  in  the  variations 
in  gain  due  to  changes  in  line  voltage, 
possible  differences  between  tubes  of  the 
same  type,  or  variations  in  the  values  of 
circuit  constants  included  in  the  feed- 
back circuit. 

Inverse  feedback  is  used  in  audio 
amplifiers  to  reduce  distortion  in  the 
output  stage  where  the  load  impedance 
on  the  tube  is  a  loudspeaker.  Because 
the  impedance  of  a  loudspeaker  is  not 
constant  for  all  audio  frequencies,  the 
load  impedance  on  the  output  tube  varies 
with  frequency.  When  the  output  tube 
is  a  pentode  or  beam  power  tube  having 
high  plate  resistance,  this  variation  in 
plate  load  impedance  can,  if  not  cor- 
rected, produce  considerable  frequency 
distortion.  Such  frequency  distortion 
can  be  reduced  by  means  of  inverse 
feedback.  Inverse-feedback  circuits  are 
of  the  con  slant- voltage  type  and  the 
constant-current  type. 


The  application  of  the  constant- 
voltage  type  of  inverse  feedback  to  a 
power  output  stage  using  a  single  beam 
power  tube  is  illustrated  by  Fig.  27.  In 
this  circuit,  Ri,  Rs,  and  C  are  connected 
as  a  voltage  divider  across  the  output  of 


Fig.  27 

the  tube.  The  secondary  of  the  grid- 
input  transformer  is  returned  to  a  point 
on  this  voltage  divider.  Capacitor  C 
blocks  the  dc  plate  voltage  from  the 
grid.  However,  a  portion  of  the  tube's 
af  output  voltage,  approximately  equal 
to  the  output  voltage  multiplied  by  the 
fraction  Ra/CRi  +  R2),  is  applied  to  the 
grid.  This  voltage  lowers  the  source  im- 
pedance of  the  circuit  and  a  decrease  in 
distortion  results  which  is  explained  in 
the  curves  of  Fig.  28. 

Consider  first  the  amplifier  without 
the  use  of  inverse  feedback.  Suppose 
that  when  a  signal  voltage  es  is  applied 
to  the  grid  the  af  plate  current  i'p  has  an 
irregularity  in  its  positive  half-cycle. 
This  irregularity  represents  a  departure 
from  the  waveform  of  the  input  signal 
and  is,  therefore,  distortion.  For  this 
plate-current  waveform,  the  af  plate 


Fig.  28 


28 


Electron  Tube  Applications 


voltage  has  a  waveform  shown  by  e'p. 
The  plate-voltage  waveform  is  inverted 
compared  to  the  plate-current  wave- 
form because  a  plate-current  increase 
produces  an  increase  in  the  drop  across 
the  plate  load.  The  voltage  at  the  plate 
is  the  difference  between  the  drop  across 
the  load  and  the  supply  voltage;  thus, 
when  plate  current  goes  up,  plate  volt- 
age goes  down;  when  plate  current  goes 
down,  plate  voltage  goes  up. 

Now  suppose  that  inverse  feedback 
is  applied  to  the  amplifier.  The  voltage 
fed  back  to  the  grid  has  the  same  wave- 
form and  phase  as  the  plate  voltage,  but 
is  smaller  in  magnitude.  Hence,  with  a 
plate  voltage  of  waveform  shown  by 
e'p,  the  feedback  voltage  appearing  on 
the  grid  is  as  shown  by  e'gf.  This  voltage 
applied  to  the  grid  produces  a  compo- 
nent of  plate  current  i'pf.  It  is  evident 
that  the  irregularity  in  the  waveform  of 
this  component  of  plate  current  would 
act  to  cancel  the  original  irregularity 
and  thus  reduce  distortion. 

After  inverse  feedback  has  been  ap- 
plied, the  relations  are  as  shown  in  the 
curve  for  ip.  The  dotted  curve  shown  by 
i'pf  is  the  component  of  plate  current 
due  to  the  feedback  voltage  on  the  grid. 
The  dotted  curve  shown  by  i'p  is  the 
component  of  plate  current  due  to  the 
signal  voltage  on  the  grid.  The  algebraic 
sum  of  these  two  components  gives  the 
resultant  plate  current  shown  by  the 
solid  curve  of  ip.  Since  i'p  is  the  plate 
current  that  would  flow  without  inverse 
feedback,  it  can  be  seen  that  the  appli- 
cation of  inverse  feedback  has  reduced 
the  irregularity  in  the  output  current. 
In  this  manner  inverse  feedback  acts  to 
correct  any  component  of  plate  current 
that  does  not  correspond  to  the  input 
signal  voltage,  and  thus  reduces  dis- 
tortion. 

From  the  curve  for  ip,  it  can  be  seen 
that,  besides  reducing  distortion,  inverse 
feedback  also  reduces  the  amplitude  of 
the  output  current.  Consequently,  when 
inverse  feedback  is  applied  to  an  ampli- 
fier there  is  a  decrease  in  gain  or  power 
sensitivity  as  well  as  a  decrease  in  dis- 
tortion. Hence,  the  application  of  in- 
verse feedback  to  an  amplifier  requires 
that  more  driving  voltage  be  applied  to 
obtain  full  power  output,  but  this  out- 
put is  obtained  with  less  distortion. 


Inverse  feedback  may  also  be  ap- 
plied to  resistance-coupled  stages  as 
shown  in  Fig.  29.  The  circuit  is  conven- 
tional except  that  a  feedback  resistor, 
R3,  is  connected  between  the  plates  of 
tubes  Ti  and  Tj.  The  output  signal  volt- 
age of  Ti  and  a  portion  of  the  output 
signal  voltage  of  T2  appears  across  Rj. 
Because  the  distortion  generated  in  the 
plate  circuit  of  Tj  is  applied  to  its  grid 
out  of  phase  with  the  input  signal,  the 
distortion  in  the  output  of  Ta  is  com- 
paratively low.  With  sufficient  inverse 
feedback  of  the  constant-voltage  type 
in  a  power-output  stage,  it  is  not  neces- 
sary to  employ  a  network  of  resistance 
and  capacitance  in  the  output  circuit  to 
reduce  response  at  high  audio  frequen- 
cies. Inverse-feedback  circuits  can  also 
be  applied  to  push-pull  class  A  and  class 
ABi  amplifiers. 

Constant-current  inverse  feedback 
is  usually  obtained  by  omitting  the  by- 
pass capacitor  across  a  cathode  resistor. 


C-     B-,C+  B-f 
Fig.  29 


This  method  decreases  the  gain  and  the 
distortion  but  increases  the  source  im- 
pedance of  the  circuit.  Consequently, 
the  output  voltage  rises  at  the  resonant 
frequency  of  the  loudspeaker  and  ac- 
centuates hangover  effects. 

Inverse  feedback  is  not  generally 
applied  to  a  triode  power  amplifier,  such 
as  the  2A3,  because  the  variation  in 
speaker  impedance  with  frequency  does 
not  produce  much  distortion  in  a  triode 
stage  having  low  plate  resistance.  It  is 
sometimes  applied  in  a  pentode  stage 
but  is  not  always  convenient.  As  has 
been  shown,  when  inverse  feedback  is 
used  in  an  amplifier,  the  driving  voltage 
must  be  increased  in  order  to  give  full 
power  output.  When  inverse  feedback  is 
used  with  a  pentode,  the  total  driving 
voltage  required  for  full  power  output 
may  be  inconveniently  large,  although 
still  less  than  that  required  for  a  triode. 
Because  a  beam  power  tube  gives  full 


29 


RCA  Receiving  Tube  Manual 


power  output  on  a  comparatively  small 
driving  voltage,  inverse  feedback  is 
especially  applicable  to  beam  power 
tubes.  By  means  of  inverse  feedback, 
the  high  efficiency  and  high  power  out- 
put of  beam  power  tubes  can  be  com- 
bined with  freedom  from  the  effects  of 
varying  speaker  impedance. 

Cathode-Follower  Ckcuifs 
Another  important  application  of 
inverse  feedback  is  in  the  cathode-fol- 
lower circuit,  an  example  of  which  is 
given  in  Fig.  30.  In  this  application,  the 
load  has  been  transferred  from  the  plate 
circuit  to  the  cathode  circuit  of  the  tube. 


Fig.  30 

The  input  voltage  is  applied  between 
the  grid  and  ground  and  the  output  volt- 
age is  obtained  between  the  cathode  and 
ground.The  voltage  amplification  (V.A.) 
of  this  circuit  is  always  less  than  unity 
and  may  be  expressed  by  the  following 
convenient  formulas. 
For  a  triode: 

mX  Rl 


V.  A.= 


rp  +  lRLX(M  +  l)l 


gm  X  Rl 


For  a  pentode: 

V.  A.-;^  ^(g^><  j^j^) 

In  these  formulas,  /u  is  the  amplifi- 
cation factor,  Rl  is  the  load  resistance 
in  ohms,  rp  is  the  plate  resistance  in 
ohms,  and  gm  is  the  transconductance 
in  mhos. 

The  use  of  the  cathode  follower  per- 
mits the  design  of  circuits  which  have 
high  input  resistance  and  high  output 
voltage.  The  output  impedance  is  quite 
low  and  very  low  distortion  may  be  ob- 
tained. Cathode-follower  circuits  may 
be  used  for  power  amplifiers  or  as  im- 
pedance transformers  designed  either  to 
match  a  transmission  line  or  to  produce 
a  relatively  high  output  voltage  at  a  low 
impedance  level. 

In  a  power  amplifier  which  is  trans- 
former coupled  to  the  load,  the  same 

30 


output  power  can  be  obtained  from  the 
tube  as  would  be  obtained  in  a  conven- 
tional grid-drive  type  of  amplifier.  The 
output  impedance  is  very  low  and  pro- 
vides excellent  damping  to  the  load, 
with  the  result  that  very  low  distortion 
can  be  obtained.  The  peak-to-peak  sig- 
nal voltage,  however,  approaches  13^ 
times  the  plate  supply  voltage  if  maxi- 
mum power  output  is  required  from  the 
tube.  Some  problems  may  be  encoun- 
tered, therefore,  in  the  design  of  an  ade- 
quate driver  stage  for  a  cathode-follower 
output  system. 

When  a  cathode-follower  circuit  is 
used  as  an  impedance  transformer,  the 
load  is  usually  a  simple  resistance  in  the 
cathode  circuit  of  the  tube.  With  rela- 
tively low  values  of  cathode  resistor,  the 
circuit  may  be  designed  to  supply  sig- 
nificant amounts  of  power  and  to  match 
the  impedance  of  the  device  to  a  trans- 
mission line.  With  somewhat  higher  val- 
ues of  cathode  resistor,  the  circuit  may 
be  used  to  lower  the  output  impedance 
sufficiently  to  permit  the  transmission 
of  audio  signals  along  a  line  in  which  ap- 
preciable capacitance  is  present. 

The  cathode  follower  may  also  be 
used  as  an  isolation  device  to  provide 
extremely  high  input  resistance  and  low 
input  capacitance  as  might  be  required 
in  the  probe  of  an  oscilloscope  or  vacu- 
um-tube voltmeter.  Such  circuits  can  be 
designed  to  provide  effective  impedance 
transformation  with  no  significant  loss 
of  voltage. 

Selection  of  a  suitable  tube  and  its 
operating  conditions  for  use  in  a  cath- 
ode-follower circuit  having  a  specified 
output  impedance  (Zo)  can  be  made,  in 
most  practical  cases,  by  the  use  of  the 
following  formula  to  determine  the  ap- 
proximate value  of  the  required  tube 
transconductance. 


Required  gm  (/ttmhos) 


1,000,000 
Zo  (ohms) 


Once  the  required  transconductance 
is  obtained,  a  suitable  tube  and  its  oper- 
ating conditions  may  be  determined 
from  the  technical  data  given  in  the 
TUBE  TYPES  SECTION.  The  tube 
selected  should  have  a  value  of  trans- 
conductance slightly  lower  than  that 
obtained  from  the  above  expression  to 
allow  for  the  shunting  effect  of  the  cath- 
ode load  resistance.  The  conversion 


Electron  Tube  Applications 


nomograph  given  in  Fig.  23  may  be 
used  for  calculation  of  operating  condi- 
tions for  values  of  transconductance  not 
included  in  the  tabulated  data.  After 
the  operating  conditions  have  been  de- 
termined, the  approximate  value  of  the 
required  cathode  load  resistance  may  be 
calculated  from  the  following  formulas. 
For  triode: 

ZoXrp 


Cathode  Rl= 


rp-lZoX(l  +  M)l 


Zo 


For  pentode: 

Cathode  Rl=-i      ,     ^  rr  \ 
1  —  (gm  X  Zo) 

Resistance  and  impedance  values  are  in 
ohms;  transconductance  values  are  in 
mhos. 

If  the  value  of  the  cathode  load  re- 
sistance calculated  to  give  the  required 
output  impedance  does  not  give  the  re- 
quired operating  bias,  the  basic  cathode- 
follower  circuit  can  be  modified  in  a 
number  of  ways.  Two  of  the  more  com- 
mon modifications  are  given  in  Figs. 
31  and  32. 

In  Fig.  31  the  bias  is  increased  by 
adding  a  bypassed  resistance  between 
the  cathode  and  the  unbypassed  load 
resistance  and  returning  the  grid  to  the 
low  end  of  the  load  resistance.  In  Fig.  32 
the  bias  is  reduced  by  adding  a  bypassed 
resistance  between  the  cathode  and  the 
unbypassed  load  resistance  but,  in  this 
case,  the  grid  is  returned  to  the  junction 
of  the  two  cathode  resistors  so  that  the 
bias  voltage  is  only  the  dc  voltage  drop 
across  the  added  resistance.  The  size  of 


Fig.  31 

the  bypass  capacitor  should  be  large 
enough  so  that  it  has  negligible  reactance 
at  the  lowest  frequency  to  be  handled. 
In  both  cases  the  B-supply  should  be  in- 
creased to  make  up  for  the  voltage  taken 
for  biasing. 

Example:  Select  a  suitable  tube 


and  determine  the  operating  conditions 
and  circuit  components  for  a  cathode- 
follower  circuit  having  an  output  im- 
pedance that  will  match  a  500-ohm 
transmission  line.  Procedure:  First,  de- 
termine the  approximate  transconduc- 
tance required. 

1,000,000 


Required  gm  = 


-«  2000/imhos 


A  survey  of  the  tubes  that  have  a 
transconductance  in  this  order  of  mag- 
nitude shows  that  type  12AX7  is  among 


Fig.  32 

the  tubes  to  be  considered.  Referring  to 
the  characteristics  given  in  the  technical 
data  section  for  one  triode  unit  of  high- 
mu  twin  triode  12AX7,  we  find  that  for 
a  plate  voltage  of  250  volts  and  a  bias  of 
-2  volts,  the  transconductance  is  1600 
micromhos,  the  plate  resistance  is  62500 
ohms,  the  amplification  factor  is  100, 
and  the  plate  current  is  0.0012  ampere. 
When  these  values  are  used  in  the  ex- 
pression for  determining  the  cathode 
load  resistance,  we  obtain 


Cathode  Rl- 


500  X  62500 


62500-500X(100+1) 


-2600  ohms 


The  voltage  across  this  resistor  for 
a  plate  current  of  0.0012  ampere  is 
2600  X  0.0012  =  3.12  volts.  Because  the 
required  bias  voltage  is  only  -2  volts, 
the  circuit  arrangement  given  in  Fig.  32 
is  employed.  The  bias  is  furnished  by  a 
resistance  that  will  have  a  voltage  drop 
of  2  volts  when  it  carries  a  current  of 
0.0012  ampere.  The  required  bias  resist- 
ance, therefore,  is  2/0.0012  =  1670 
ohms.  If  60  cycles  per  second  is  the  low- 
est frequency  to  be  passed,  20  micro- 
farads is  a  suitable  value  for  the  bypass 
capacitor.  The  B-supply,  of  course,  is  in- 
creased by  the  voltage  drop  across  the 
cathode  resistance  which,  in  this  exam- 

31 


RCA  Receiving  Tube  Manual 


pie,  is  approximately  5  volts.  The  B- 
supply,  therefore,  is  250  +  5  =  255  volts. 

Because  it  is  desirable  to  eliminate, 
if  possible,  the  bias  resistor  and  bypass 
capacitor,  it  is  worthwhile  to  try  other 
tubes  and  other  operating  conditions  to 
obtain  a  value  of  cathode  load  resistance 
which  will  also  provide  the  required  bias. 
If  the  triode  section  of  twin  diode — 
high-mu  triode  6AT6  is  operated  under 
the  conditions  given  in  the  technical 
data  section  with  a  plate  voltage  of  100 
volts  and  a  bias  of  -1  volt,  it  will  have 
an  amplification  factor  of  70,  a  plate 
resistance  of  54000  ohms,  a  transcon- 
ductance  of  1300  micromhos,  and  a  plate 
current  of  0.0008  ampere.  Then, 

The  bias  voltage  obtained  across 
this  resistance  is  1460  X  0.0008  =  1.17 
volts.  Since  this  value  is  for  all  practical 
purposes  close  enough  to  the  required 
bias,  no  additional  bias  resistance  will 
be  required  and  the  grid  may  be  returned 
directly  to  ground.  There  is  no  need  to 
adjust  the  B-supply  voltage  to  make  up 
for  the  drop  in  the  cathode  resistor.  The 
voltage  amplification  (V.A.)  for  the 
cathode-follower  circuit  utilizing  the 
triode  section  of  type  6AT6  is 

VA  70  X  1460 

"  54000  +  1460  X  (70  +  1)  " 

For  applications  in  which  the  cath- 
ode follower  is  used  to  isolate  two  cir- 
cuits—for example,  when  it  is  used  be- 
tween a  circuit  being  tested  and  the 
input  stage  of  an  oscilloscope  or  a  vacu- 
um-tube voltmeter— voltage  output  and 
not  impedance  matching  is  the  primary 
consideration.  In  such  applications  it  is 
desirable  to  use  a  relatively  high  value 
of  cathode  load  resistance,  such  as  50,000 
ohms,  in  order  to  get  the  maximum  volt- 
age output.  In  order  to  obtain  proper 
bias,  a  circuit  such  as  that  of  Fig.  32 
should  be  used.  With  a  high  value  of 
cathode  resistance,  the  voltage  amplifi- 
cation will  approximate  unity. 

Corrective  Filters 

A  corrective  filter  can  be  used  to 
improve  the  frequency  characteristic  of 
an  output  stage  using  a  beam  power 
tube  or  a  pentode  when  inverse  feedback 
is  not  applicable.  The  filter  consists  of  a 
resistor  and  a  capacitor  connected  in 


series  across  the  primary  of  the  output 
transformer.  Connected  in  this  way,  the 
filter  is  in  parallel  with  the  plate  load 
impedance  reflected  from  the  voice-coil 
by  the  output  transformer.  The  magni- 
tude of  this  reflected  impedance  increases 
with  increasing  frequency  in  the  middle 
and  upper  audio  range.  The  impedance 
of  the  filter,  however,  decreases  with  in- 
creasing frequency.  It  follows  that  by 
use  of  the  proper  values  for  the  resist- 
ance and  the  capacitance  in  the  filter, 
the  effective  load  impedance  on  the  out- 
put tubes  can  be  made  practically  con- 
stant for  all  frequencies  in  the  middle 
and  upper  audio  range.  The  result  is  an 
improvement  in  the  frequency  charac- 
teristic of  the  output  stage. 

The  resistance  to  be  used  in  the  fil- 
ter for  a  push-pull  stage  is  1.3  times  the 
recommended  plate-to-plate  load  resist- 
ance; or,  for  a  single-tube  stage,  is  1.3 
times  the  recommended  plate  load  re- 
sistance. The  capacitance  in  the  filter 
should  have  a  value  such  that  the  volt- 
age gain  of  the  output  stage  at  a  fre- 
quency of  1000  cycles  or  higher  is  equal 
to  the  voltage  gain  at  400  cycles. 

A  method  of  determining  the  proper 
value  of  capacitance  for  the  filter  is  to 
make  two  measurements  of  the  output 
voltage  across  the  primary  of  the  output 
transformer:  first,  when  a  400-cycle  sig- 
nal is  applied  to  the  input,  and  second, 
when  a  1000-cycle  signal  of  the  same 
voltage  as  the  400-cycle  signal  is  applied 
to  the  input.  The  correct  value  of  capaci- 
tance is  the  one  which  gives  equal  output 
voltages  for  the  two  signal  inputs.  In 
practice,  this  value  is  usually  found  to 
be  in  the  order  of  0.05  microfarad. 

Volume  Compressors  and  Expanders 

Volume  compression  and  expansion 
are  used  in  FM  transmitters  and  re- 
ceivers and  in  recording  devices  and  am- 
plifiers to  make  more  natural  the  repro- 
duction of  music  which  has  a  very  large 
volume  range.  For  example,  in  the  music 
of  a  symphony  orchestra  the  sound  in- 
tensity of  the  soft  passages  is  very  much 
lower  than  that  of  the  loud  passages. 
When  this  low  volume  level  is  raised 
above  the  background  noise  for  trans- 
mitting or  recording,  the  peak  level  of 
the  program  material  may  be  raised  to 
an  excessively  high  volume  level.  It  is 


32 


Electron  Tube  Applications 


often  necessary,  therefore,  to  compress 
the  volume  range  of  the  program  con- 
tent within  the  maximum  capabilities  of 
the  FM  transmitter  or  the  recording  de- 
vice. Exceeding  a  maximum  peak  volume 
level  for  FM  modulation  corresponds  to 
exceeding  the  allowed  bandwidth  for 
transmission.  In  some  recording  de- 
vices, excessive  peak  volume  levels  may 
cause  overloading  and  distortion. 

Volume  compression  may  be  ac- 
complished by  either  manual  or  auto- 
matic control.  The  types  of  compression 
used  include  peak  limiters,  volume  Km- 
iters,  and  volume  compressors.  A  peak 
limiter  limits  the  peak  power  to  some  pre- 
determined level.  A  volume  limiter  pro- 
vides gain  reduction  based  on  an  aver- 
age signal  level  above  a  predetermined 
level.  A  volume  compressor  provides 
gain  reduction  for  only  the  sustained 
loud  portions  of  the  sound  level.  Only 
volume  compressors  can  be  correctly 
compensated  for  with  volume  expanders. 

For  faithful  reproduction  of  the 
original  sound,  the  volume  expander 
used  in  the  FM  receiver  or  audio  ampli- 
fier should  have  the  reverse  characteris- 
tic of  the  volume  compressor  used  in  the 
FM  transmitter  or  recording  device.  In 
general,  the  basic  requirements  for  either 
a  volume  compressor  or  expander  are 
shown  in  the  block  diagram  of  Fig.  33. 


INPUT 


V| 

VARIABLE-GAIN 
AMPLIFIER 


OUTPUT 


V2 

V3 

AMPLIFIER 

RECTIFIER 

signal  to  be  amplified  is  applied  to  Vi, 
and  a  portion  of  the  signal  is  also  applied 
to  Vs.  The  amplified  output  from  V2  is 
then  rectified  by  Vs,  and  applied  as  a 
negative  (for  compressors)  or  positive 
(for  expanders)  bias  voltage  to  Vi,  As 
this  bias  voltage  varies  with  variations 
in  signal  amplitude,  the  gain  of  Vi  also 
varies  to  produce  the  desired  compres- 
sion or  expansion  of  the  signal. 

Tubes  having  a  large  dynamic  range 
provide  the  best  results  in  volume  com- 
pressor or  expander  applications.  Ex- 
amples of  such  types  are  the  6BJ6  and 
6BE6.  Push-pull  operation  is  generally 
desired  for  the  variable-gain  amplifier 
to  prevent  high  distortion  and  other  un- 
desirable effects  which  may  occur  in 
volume  compressors  and  expanders. 

Phase  Inverters 

A  phase  inverter  is  a  circuit  used  to 
provide  resistance  coupling  between  the 
output  of  a  signal-tube  stage  and  the  in- 
put of  a  push-pull  stage.  The  necessity 
for  a  phase  inverter  arises  because  the 
signal-voltage  inputs  to  the  grids  of  a 
push-pull  stage  must  be  180  degrees  out 
of  phase  and  approximately  equal  in 
amplitude  with  respect  to  each  other. 
Thus,  when  the  signal  voltage  input  to 
a  push-pull  stage  swings  the  grid  of  one 
tube  in  a  positive  direction,  it  should 
swing  the  grid  of  the  other  tube  in  a 
negative  direction  by  a  similar  amount. 
With  transformer  coupling  between 
stages,  the  out-of-phase  input  voltage  to 
the  push-pull  stage  is  supplied  by  means 
of  the  center-tapped  secondary.  With 
resistance  coupling,  the  out-of-phase  in- 
put voltage  is  obtained  by  means  of  the 
inverter  action  of  a  tube. 


Fig.  33 

In  a  volume  compressor,  the  variable- 
gain  amplifier  Vi  has  greater  gain  for  a 
low-amplitude  signal  than  for  a  high- 
amplitude  signal ;  therefore,  soft  passages 
are  amplified  more  than  loud  ones.  In 
an  expander,  the  gain  is  greater  for  high- 
amplitude  signals  than  for  low-ampli- 
tude signals;  therefore,  loud  passages  are 
amplified  more  than  soft  ones  and  the 
original  amplitude  ratio  is  restored. 
In  the  diagram  shown  in  Fig.  33,  the 


Fig.  34 

Fig.  34  shows  a  push-pull  power 
amplifier,  resistance-coupled  by  means 

33 


RCA  Receiving  Tube  Manual 


of  a  phase-inverter  circuit  to  a  single- 
stage  triode  Ti.  Phase  inversion  in  this 
circuit  is  provided  by  triode  T2.  The  out- 
put voltage  of  Ti  is  applied  to  the  grid 
of  triode  T3.  A  portion  of  the  output 
voltage  of  Ti  is  also  applied  through  the 
resistors  Rs  and  Rs  to  the  grid  of  T2.  The 
output  voltage  of  T,  is  applied  to  the 
grid  of  triode  T4. 

When  the  output  voltage  of  Ti 
swings  in  the  positive  direction,  the 
plate  current  of  T2  increases.  This  action 
increases  the  voltage  drop  across  the 
plate  resistor  R2  and  swings  the  plate  of 
T2in  the  negative  direction.  Thus,  when 
the  output  voltage  of  Ti  swings  positive, 
the  output  voltage  of  T2  swings  negative 
and  is,  therefore,  180**  out  6f  phase  with 
the  output  voltage  of  Ti. 

In  order  to  obtain  equal  voltages  at 
Ea  and  Eb,  (R3+R«)/Ri  should  equal 
the  voltage  gain  of  T,.  Under  the  condi- 
tions where  a  twin-type  tube  or  two 
tubes  having  the  same  characteristics  are 
used  at  Ti  and  T2,  R4  should  be  equal  to 
the  sum  of  Ra  and  Re.  The  ratio  of 
Ra-f  Rg  to  Rs  should  be  the  same  as  the 
voltage  gain  ratio  of  T2  in  order  to  apply 
the  correct  value  of  signal  voltage  to  T2. 
The  value  of  R5  is,  therefore,  equal  to  R4 
divided  by  the  voltage  gain  of  T2;  R3  is 
equal  to  R4  minus  Rs.  Values  of  Ri,  R2, 
R3  plus  R5,  and  R4  may  be  taken  from 
the  chart  in  the  RESISTANCE-COU- 
PLED AMPLIFIER  SECTION.  In  the 
practical  application  of  this  circuit, 
it  is  convenient  to  use  a  twin-triode  tube 
combining  Ti  and  T2. 

Tone  Controls 

A  tone  control  is  a  variable  filter  (or 
one  in  which  at  least  one  element  is  ad- 
justable) by  means  of  which  the  user 
may  vary  the  frequency  response  of  an 
amplifier  to  suit  his  own  taste.  In  radio 
receivers  and  home  amplifiers,  the  tone 
control  usually  consists  of  a  resistance- 
capacitance  network  in  which  the  resist- 
ance is  the  variable  element. 

The  simplest  form  of  tone  control 
is  a  fixed  tone-compensating  or  "equali- 
zing" network  such  as  that  shown  in 
Fig.  35.  This  type  of  network  is  often 
used  to  equalize  the  low-  and  high-fre- 
quency response  of  a  crystal  phono- 
graph pickup.  At  low  frequencies  the  at- 
tenuation of  this  network  is  20.8  db.  As 

34 


the  frequency  is  increased,  the  100-mi- 
cromicrofarad  capacitor  serves  as  a  by- 
pass for  the  5»megohm  resistor,  and  the 
combined  impedance  of  the  resistor-ca- 
pacitor network  is  lowered.  Thus,  more 


I 

CZZl 

I 


-^AA^r■ 


5  MEGOHMS 
0.5 

CRYSTAL  MEGOHM 


Fig.  35 

of  the  crystal  output  appears  across  the 
0.5-megohm  resistor  at  high  frequencies 
than  at  low  frequencies,  and  the  fre- 
quency response  at  the  grid  is  reason- 
ably flat  over  a  wide  frequency  range. 
Fig.  36  shows  a  comparison  between  the 
output  of  the  crystal  (curve  A)  and  the 
output  of  the  equalizing  network  (curve 
B)  .The  response  curve  can  be  "flattened" 
still  more  if  the  attenuation  at  low  fre- 
quencies is  increased  by  changing  the 
0.5-megohm  resistor  to  0.125  megohm. 


1000   

FREQUENCY-CPS 
Fig.  36 

The  tone-control  network  shown  in 
Fig.  37  has  two  stages  with  completely 
separate  bass  and  treble  controls.  Fig.  38 
shows  simplified  representations  of  the 
bass  control  of  this  circuit  when  the 
potentiometer  is  turned  to  its  extreme 
variations  (usually  labeled  "Boost"  and 
"Cut") .  In  this  network,  as  in  the  crystal- 
equalizing  network  shown  in  Fig.  35, 
the  parallel  RC  combination  is  the  con- 
trolling factor.  For  bass  "boost",  the 
capacitor  C2  bypasses  resistor  Rs  so  that 
less  impedance  is  placed  across  the  out- 
put to  grid  B  at  high  frequencies  than 
at  low  frequencies.  For  bass  "cut,"  the 
parallel  combination  is  shifted  so  that 
Ci  bypasses  Rs,  causing  more  high-fre- 
quency than  low-frequency  output.  Es- 
sentially, the  network  is  a  variable-fre- 
quency voltage  divider.  With  proper 


Electron  Tube  Applications 


BASS 


TREBLE 


Fig.  37 


values  for  the  components,  it  may  be 
made  to  respond  to  changes  in  the  Rs 
potentiometer  setting  for  only  low  fre- 
quencies (below  1000  cycles). 


BASS  BOOST 


BASS  CUT 

A  R|  I  B 
CWVAA-WW^  O 


R3 


O  o~ 

Fig.  38 


Fig.  39  shows  extreme  positions  of 
the  treble  control.  The  attenuation  of 
the  two  circuits  is  approximately  the 
same  at  1000  cycles.  The  treble  **boost" 
circuit  is  similar  to  the  crystal-equaliz- 
ing network  shown  in  Fig.  35.  In  the 
treble  **cut"  circuit,  the  parallel  RC  ele- 
ments serve  to  attenuate  the  signal  vol- 
tage further  because  the  capacitor  by- 
passes the  resistance  across  the  output. 


TREBLE  BOOST 
R4 


TREBLE  CUT 
R4 


ml  sAA/^^  


C4  ^6 
C5: 


o  o  

Fig.  39 

The  effect  of  the  capacitor  is  negligible 
at  low  frequencies;  beyond  1000  cycles, 
the  signal  voltage  is  attenuated  at  a 
maximum  rate  of  6  db  per  octave. 

The  location  of  a  tone-control  net- 
work is  of  considerable  importance.  In  a 
typical  radio  receiver,  it  may  be  inserted 


in  the  plate  circuit  of  the  power  tube, 
the  coupling  circuit  between  the  first  af 
amplifier  tube  and  the  power  tube,  or 
the  grid  circuit  of  the  first  tube.  In  an 
amplifier  using  a  beam  power  tube  or 
pentode  power  amplifier  without  nega- 
tive feedback,  it  is  desirable  to  connect 
a  resistance-capacitance  filter  across  the 
primary  of  the  output  transformer.  This 
filter  may  be  fixed,  with  a  supplemen- 
tary tone  control  elsewhere,  or  it  may 
form  the  tone  control  itself.  If  the  am- 
plifier incorporates  negative  feedback, 
the  tone  control  may  be  inserted  in  the 
feedback  network  or  else  should  be  con- 
nected to  a  part  of  the  amplifier  which 
is  external  to  the  feedback  loop.  The 
over-all  gain  of  a  well  designed  tone-con- 
trol network  should  be  approximately 
unity. 

Phonograph  and  Tape  Preamplifiers 

The  frequency  range  and  dynamic 
range  which  can  be  recorded  on  a  phono- 
graph record  or  on  magnetic  tape  de- 
pend on  several  factors,  including  the 
composition,  mechanical  characteristics, 
and  speed  of  the  record  or  tape,  and  the 
electrical  and  mechanical  characteristics 
of  the  recording  equipment.  To  achieve 
wide  frequency  and  dynamic  ranges, 
manufacturers  of  commercial  recordings 
use  equipment  which  introduces  a  non- 
uniform relationship  between  amplitude 
and  frequency.  This  relationship  is 
known  as  a  ^'recording  characteristic." 
To  assure  proper  reproduction  of  a  high- 
fidelity  recording,  therefore,  some  part 
of  the  reproducing  system  must  have  a 
frequency-response  characteristic  which 
is  the  inverse  of  the  recording  character- 
istic. Most  manufacturers  of  high-fidelity 
recordings  use  the  RCA  **New  Ortho- 
phonic"  (RIAA)  characteristic  for  discs 


35 


RCA  Receiving  Tube  Manual 


and  the  NARTB  characteristic  for  mag- 
netic tape. 

Some  typical  preamplifier  stages 
are  shown  in  the  CIRCUITS  SECTION. 
The  location  of  the  frequency-compen- 
sating network  or  "equalizer"  in  the  re- 
producing system  will  depend  on  the 
types  of  recordings  which  are  to  be  re- 
produced and  on  the  pickup  devices  used. 

A  ceramic  high-fidelity  phonograph 
pickup  is  usually  designed  to  provide 
proper  compensation  for  the  RIAA  re- 
cording characteristic  when  the  pickup 
is  operated  into  the  load  resistance  spec- 
ified by  its  manufacturer.  Because  this 
type  of  pickup  also  has  relatively  high 
output  (0.5  to  1.5  volts),  it  does  not  re- 
quire the  use  of  either  an  equalizer  net- 
work or  a  preamplifier,  and  can  be  con- 
nected directly  to  the  input  of  a  tone- 
control  amplifier  and/or  power  amplifier. 

A  magnetic  high-fidelity  phono- 
graph pickup,  on  the  other  hand,  usually 
has  an  essentially  flat  frequency-re- 
sponse characteristic  and  very  low  out- 
put (1  to  10  millivolts).  Because  a  pickup 
of  this  type  merely  reproduces  the  re- 
cording characteristic,  it  must  be  fol- 
lowed by  an  equalizer  network,  as  well 
as  by  a  preamplifier  having  sufiicient 
voltage  gain  to  provide  the  input  voltage 
required  by  the  tone-control  amplifier 
and/or  power  amplifier.  Many  designs 
include  both  the  equalizing  and  ampli- 
fying circuits  in  a  single  unit. 

A  high-fidelity  magnetic-tape  pick- 
up head,  like  a  magnetic  phonograph 
pickup,  reproduces  the  recording  char- 
acteristic and  has  an  output  of  only  a 
few  millivolts.  This  type  of  pickup  de- 
vice, therefore,  must  also  be  followed  by 
an  equalizing  network  and  preamplifier, 
or  by  a  preamplifier  which  provides 
"built-in"  equalization  for  the  NARTB 
characteristic. 

limifers 

An  amplifier  may  also  be  used  as  a 
limiter.  One  use  of  a  limiter  is  in  receiv- 
ers designed  for  the  reception  of  fre- 
quency-modulated signals.  The  limiter 
in  FM  receivers  has  the  function  of 
eliminating  amplitude  variations  from 
the  input  to  the  detector.  Because  in  an 
FM  system  amplitude  variations  are 
primarily  the  result  of  noise  disturbances, 
the  use  of  a  limiter  prevents  such  dis- 
turbances from  being  reproduced  in  the 


audio  output.  The  limiter  usually  fol- 
lows the  last  if  stage  so  that  it  can  mini- 
mize the  effects  of  disturbances  coming 
in  on  the  rf  carrier  and  those  produced 
locally. 

The  limiter  is  essentially  an  if  volt- 
age amplifier  designed  for  saturated 
operation.  Saturated  operation  means 
that  an  increase  in  signal  voltage  above 
a  certain  value  produces  very  little  in- 
crease in  plate  current.  A  signal  voltage 
which  is  never  less  than  sufficient  to 
cause  saturation  of  the  limiter,  even  on 
weak  signals,  is  supplied  to  the  limiter 
input  by  the  preceding  stages.  Any 
change  in  amplitude,  therefore,  such  as 
might  be  produced  by  noise  voltage 
fluctuation,  is  not  reproduced  in  the 
limiter  output.  The  limiting  action,  of 
course,  does  not  interfere  with  the  repro- 
duction of  frequency  variations. 

Plate-current  saturation  of  the  lim- 
iter may  be  obtained  by  the  use  of  grid- 
No.l-resistor-and-capacitor  bias  with 
plate  and  grid-No.2  voltages  which  are 
low  compared  with  customary  if-ampli- 
fier  operating  conditions. 

As  a  result  of  these  design  features, 
the  limiter  is  able  to  maintain  its  output 
voltage  at  a  constant  amplitude  over  a 
wide  range  of  input-signal  voltage  varia- 
tions. The  output  of  the  limiter  is  fre- 
quency-modulated if  voltage,  the  mean 
frequency  of  which  is  that  of  the  if  am- 
plifier. This  voltage  is  impressed  on  the 
input  of  the  detector. 

The  reception  of  FM  signals  with- 
out serious  distortion  requires  that  the 
response  of  the  receiver  be  such  that 
satisfactory  amplification  of  the  signal 
is  provided  over  the  entire  range  of  fre- 
quency deviation  from  the  mean  fre- 
quency. Since  the  frequency  at  any  in- 
stant depends  on  the  modulation  at  that 
instant,  it  follows  that  excessive  attenu- 
ation toward  the  edges  of  the  band,  in 
the  rf  or  if  stages,  will  cause  distortion. 
In  a  high-fidelity  receiver,  therefore,  the 
amplifiers  must  be  capable  of  amplifying, 
for  the  maximum  permissible  frequency 
deviation  of  75  kilocycles,  a  band  150 
kilocycles  wide.  Suitable  tubes  for  this 
purpose  are  the  6BA6  and  6B J6. 

Television  RF  Amplifiers 

In  a  radio  or  television  receiver, 
noise  generated  in  the  first  amplifier 


36 


Electron  Tube  Applications 


stage  is  often  the  controlling  factor  in 
determining  the  over-all  sensitivity  of 
the  receiver.  The  "front  end"  of  a  re- 
ceiver, therefore,  is  designed  with  special 
attention  to  both  gain  and  noise  charac- 
teristics. 

The  input  circuit  of  an  amplifier  in- 
herently contains  some  thermal  noise 
contributed  by  the  resistive  elements  in 
the  input  device.  When  an  input  signal 
is  amplified,  therefore,  the  thermal  noise 
generated  in  the  input  circuit  is  also 
amplified.  If  the  ratio  of  signal  power  to 
noise  power  (signal-to-noise  ratio,  S/N) 
is  the  same  in  the  output  circuit  as  in 
the  input  circuit,  the  amplifier  is  con- 
sidered to  be  "noiseless"  and  is  said  to 
have  a  noise  figure  of  unity,  or  zero  db. 

In  practical  circuits,  however,  all 
amplifier  stages  generate  a  certain 
amount  of  noise  as  a  result  of  thermal 
agitation  of  electrons  in  resistors  and 
other  components,  minute  variations  in 
the  cathode  emission  of  tubes  (shot  ef- 
fect), and  minute  grid  currents  in  the 
amplifier  tubes.  As  a  result,  the  ratio  of 
signal  power  to  noise  power  is  inevitably 
impaired  during  amplification.  A  meas- 
ure of  the  degree  of  impairment  is  called 
the  noise  figure  (NF)  of  the  amplifier, 
and  is  expressed  as  the  ratio  of  signal 
power  to  noise  power  at  the  input 
(Si/Ni)  divided  by  the  ratio  of  signal 
power  to  noise  power  at  the  output 
(So/No),  as  follows: 

(So/So) 

The  noise  figure  in  db  is  equal  to 
ten  times  the  logarithm  of  this  power 
ratio.  For  example,  an  amplifier  having 
a  one-db  noise  figure  decreases  the  signal- 
to-noise  ratio  by  a  factor  of  1.26,  a  3-db 
noise  figure  by  a  factor  of  2,  a  10-db 
noise  figure  by  a  factor  of  10,  and  a  20-db 
noise  figure  by  a  factor  of  100. 

Tuner  input  circuits  of  vhf  television 
receivers  use  either  a  triode  or  a  pentode 
in  the  rf  amplifier  stage.  Such  stages  are 
required  to  amplify  signals  ranging  from 
55  to  216  Mc  and  having  a  bandwidth 
of  4.5  Mc,  although  the  tuner  is  usually 
aligned  for  a  bandwidth  of  6  Mc  to  as- 
sure complete  coverage  of  the  band.  In 
the  early  rf  tuners,  pentodes  rather  than 
triodes  were  used  because  the  grid-plate 
capacitance  of  triodes  created  stability 
problems.  The  use  of  twin  triodes  in 


direct-coupled  cathode-drive  circuits 
makes  it  possible  to  obtain  stable  opera- 
tion along  with  the  low-noise  character- 
istics of  triodes. 

Pentodes  or  tetrodes  do  not  provide 
the  sensitivity  of  triodes  because  of  the 
"partition  noise"  introduced  by  the 
screen  grid.  The  direct-coupled  cathode- 
drive  circuit  provides  both  the  gain  and 
the  stability  capabilities  of  the  pentode 
and  a  low-noise  triode  input  stage.  Be- 
cause the  cathode-drive  stage  provides 
a  low-impedance  load  to  the  grounded- 
cathode  stage,  its  gain  is  very  low  and 
there  is  no  necessity  for  neutralizing  the 
grid-plate  capacitance.  An  interstage 
impedance,  usually  an  inductance  in 
series  with  the  plate  of  the  first  stage 
and  the  cathode  of  the  second  stage,  is 
often  used  at  higher  frequencies  to  pro- 
vide a  degree  of  impedance  matching 
between  the  units.  The  cathode-drive 
portion  of  the  circuit  is  matched  to  the 
input  network  and  provides  most  of  the 
stage  gain.  Because  the  feedback  path 
of  the  cathode-drive  circuit  is  the  plate- 
cathode  capacitance,  which  in  most  cases 
is  very  small,  excellent  isolation  is  pro- 
vided between  the  antenna  and  the  local 
oscillator. 

Development  of  single  triodes  hav- 
ing low  grid-plate  capacitance  has  made 
possible  the  design  of  a  neutralized  tri- 
ode rf  circuit.  The  6BN4  has  been  used 
commercially  in  neutralized  triode  cir- 
cuits.Tubes  such  as  the  6GK5  and6C  W4, 
now  in  common  usage,  were  specially 
designed  to  minimize  grid-plate  capaci- 
tance to  permit  easier  neutralization  of 
a  grounded-cathode  circuit  over  the  wide 
frequency  band.  The  bridge-neutralized 
rf  amplifier  circuit  has  become  widely 
used  in  television  tuners.  In  this  arrange- 
ment, a  portion  of  the  output  signal  is 
returned  to  the  grid  out  of  phase  with 
the  feedback  signal  from  the  grid-plate 
capacitance.  This  circuit  provides  excel- 
lent gain  and  noise  performance  with 
stable  operation  across  the  band. 

Video  Amplifiers 

The  video  amplifier  stage  in  a  tele- 
vision receiver  usually  employs  a  pen- 
tode-type tube  specially  designed  to  am- 
plify the  wide  band  of  frequencies  con- 
tained in  the  video  signal  and,  at  the 
same  time,  to  provide  high  gain  per 


37 


RCA  Receiving  Tube  Manual 


stage.  Pentodes  are  more  useful  than 
triodes  in  such  stages  because  they  have 
high  transconductance  (to  provide  high 
gain)  together  with  low  input  and  out- 
put interelectrode  capacitances  (to  per- 
mit the  broadband  requirements  to  be 
satisfied).  An  approximate  **figure  of 
merit"  for  a  particular  tube  for  this 
application  can  be  determined  from  the 
ratio  of  its  transconductance,  gm,  to  the 
sum  of  its  input  and  output  capacitances, 
Cin  and  Cout,  as  follows: 


Figure  of  Merit  «=  : 


Cin  +  Cout 

Typical  values  for  this  figure  are  in  the 
order  of  500  x  10«  or  greater. 

A  typical  video  amplifier  stage, 
such  as  that  shown  in  Fig.  40,  is  con- 
nected between  the  second  detector  of 
the  television  receiver  and  the  picture 


Fig.  40 

tube.  The  contrast  control,  Ri,  in  this 
circuit  controls  the  gain  of  the  video 
amplifier  tube.  The  inductance.  La,  in 
series  with  the  load  resistor,  Rl,  main- 
tains the  plate  load  impedance  at  a  rela- 
tively constant  value  with  increasing 
frequency.  The  inductance  Li  isolates 
the  output  capacitance  of  the  tube  so 
that  only  stray  capacitance  is  placed 
across  the  load.  As  a  result,  a  higher- 
value  load  resistor  is  used  to  provide 
higher  gain  without  affecting  frequency 
response  or  phase  relations.  The  de- 
coupling circuit,  C1R2,  is  used  to  improve 
the  low-frequency  response.  Tubes  used 
as  video  amplifiers  include  types  6CL6 
and  12BY7A,  or  the  pentode  sections 
of  types  6AW8A  and  6AN8. 

The  luminance  amplifier  in  a  color- 
television  receiver  is  a  conventional  video 
amplifier  having  a  bandwidth  of  approx- 
imately 3.5  Mc.  In  a  color  receiver,  the 
portion  of  the  output  of  the  second  de- 
tector which  lies  within  the  frequency 

38 


band  from  approximately  2.4  to  4.5  Mc 
is  fed  to  a  bandpass  amplifier,  as  shown 
in  the  block  diagram  in  Fig.  41.  The  color 


SECOND 
DETECTOR 


LUMINANCE 
AMPLIFIER 


BANDPASS 
AMPLIFIER 


TO  CATHODES  OF 
COLOR  PICTURE  TUBE 

TO  GRIDS  OF 
COLOR  PICTURE  TUBE 
 t  


DEMODULATORS 


BURST  KEYER 
AND  AMPLIFIER 


«~  COLOR  KILLER 


3.58  Mc 
OSCILLATOR 


Fig.  41 

sjmchronizing  signal,  or  "burst,"  con- 
tained in  this  signal  may  then  be  fed  to 
a  "burst-keyer"  tube.  At  the  same  time, 
a  delayed  horizontal  pulse  may  be  ap- 
plied to  the  keyer  tube.  The  output  of 
the  keyer  tube  is  applied  to  the  burst 
amplifier  tube  and  the  signal  is  then  fed 
to  the  3.58-Mc  oscillator  and  to  the 
"color-killer"  stage 

The  color  killer  applies  a  bias  volt- 
age to  the  bandpass  amplifier  in  the  ab- 
sence of  burst  so  that  the  color  section, 
or  chrominance  channel,  of  the  receiver 
remains  inoperative  during  black-and- 
white  broadcasts.  A  threshold  control 
varies  the  bias  and  controls  the  burst 
level  at  which  the  killer  stage  operates. 

The  output  of  the  3.58-Mc  oscil- 
lator and  the  output  of  the  bandpass 
amplifier  are  fed  into  phase  and  ampli- 
tude demodulator  circuits.  The  output 
of  each  demodulator  circuit  is  an  elec- 
trical representation  of  a  color-difference 
signal,  i.e.,  an  actual  color  signal  minus 
the  black-and-white,  or  luminance,  sig- 
nal. The  two  color-difference  signals  are 
combined  to  produce  the  third  color- 
difference  signal;  each  of  the  three  sig- 
nals then  represents  one  of  the  primary 
colors. 

The  three  color-difference  signals 
are  usually  applied  to  the  grids  of  the 
three  electron  guns  of  the  color  picture 
tube,  in  which  case  the  black-and-white 
signal  from  the  luminance  amplifier  may 
be  applied  simultaneously  to  the  cath- 
odes. The  chrominance  and  luminance 
signals  then  combine  to  produce  the 
color  picture.  In  the  absence  of  trans- 


Electron  Tube  Applications 


mitted  color  information,  the  chromi- 
nance channel  is  cut  off  by  the  color 
killer,  as  described  above,  and  only  the 
luminance  signal  is  applied  to  the  pic- 
ture tube,  producing  a  black-and-white 
picture. 

Television  Sync  Circuits 
In  addition  to  picture  information, 
the  composite  video  signal  supplied  to  a 
television  receiver  contains  information 
to  assure  that  the  picture  produced  on 
the  receiver  is  synchronized  with  the 
picture  being  viewed  by  the  camera  or 
pickup  tube.  The  "sync"  pulses,  which 
have  a  greater  amplitude  than  the  video 
signal,  trigger  the  scanning  generators 
of  the  receiver  when  the  electron  beam 
of  the  pickup  tube  ends  each  trace. 

The  sync  pulses  in  the  composite 
video  signal  may  be  separated  from  the 
video  information  in  the  output  of  the 
second  or  video  detector  by  means  of  the 
triode  circuit  shown  in  Fig.  42.  In  this 
circuit,  the  time  constant  of  the  network 


FROM 
SECOND  (t, 
DETECTOR  '^l 


Fig.  42 

RiCi  is  long  with  respect  to  the  interval 
between  pulses.  During  each  pulse,  the 
grid  is  driven  positive  and  draws  cur- 
rent, thereby  charging  capacitor  Ci. 
Consequently,  the  grid  develops  a  bias 
which  is  slightly  greater  than  the  cutoff 
voltage  of  the  tube.  Because  plate  cur- 
rent flows  only  during  the  sync-pulse 
period,  only  the  amplified  pulse  appears 
in  the  output.  This  sync-separator  stage 
discriminates  against  the  video  informa- 
tion. Because  the  bias  developed  on  the 
grid  is  proportional  to  the  strength  of 
the  incoming  signal,  the  circuit  also  has 
the  advantage  of  being  relatively  inde- 
pendent of  signal  fluctuations. 

Because  the  electron  beam  scans 
the  face  of  the  picture  tube  at  different 
rates  in  the  vertical  and  horizontal  di- 
rections, the  receiver  incorporates  two 
different  scanning  generators.  The  repe- 


tition rate  of  the  vertical  generator  is  60 
cycles  per  second,  and  the  rate  of  the 
horizontal  generator  is  approximately 
15,750  cycles  per  second.  The  composite 
video  signal  includes  information  which 
enables  each  generator  to  derive  its  cor- 
rect triggering.  One  horizontal  sync  pulse 
is  supplied  at  the  end  of  each  horizontal 
line  scan.  At  the  end  of  each  frame, 
several  pulses  of  longer  duration  than 
the  horizontal  sync  pulses  are  supplied 
to  actuate  the  vertical  generator.  The 
vertical  information  is  separated  from 
the  horizontal  information  by  differ- 
entiating and  integrating  circuits. 

In  fringe  areas,  two  conditions  com- 
plicate the  process  of  sync  separation. 
First,  the  incoming  signal  available  at 
the  antenna  is  weak  and  susceptible  to 
fading  and  other  variations;  second,  the 
receiver  is  operating  at  or  near  maximum 
gain  which  makes  it  extremely  sus- 
ceptible to  interference  from  pulse-type 
noise  generated  by  certain  types  of  elec- 
trical equipment,  ignition  systems, 
switches,  or  the  like.  Some  type  of  noise- 
immunity  provision  is  almost  essential 
for  acceptable  performance.  Noise  may 
be  reduced  or  eliminated  from  the  sync 
and  age  circuits  by  gating  or  by  a  com- 
bination of  gating,  inversion,  and  can- 
cellation. An  example,  of  the  latter 
method  is  shown  in  Fig.  43.  In  this  cir- 
cuit the  6GY6,  which  has  two  indepen- 
dent control  grids,  serves  the  dual  func- 
tion of  age  amplifier  and  noise  inverter. 


Fig.  43 


Because  the  sync  tips  of  the  video  signal 
at  grid  No.l  of  the  6GY6  drive  the  tube 
near  its  cutoff  region,  any  noise  signal 
extending  above  the  tip  level  will  ap- 
pear inverted  across  the  grid-No.2  load 
resistor  R.  This  inverted  noise  signal  is 
re-combined  with  the  video  signal  and 

39 


RCA  Receiving  Tube  Manual 


fed  to  the  sync  separator  at  point  "A" 
Fig.  43  where  noise  cancellation  takes 
place.  This  process  leaves  the  sync  pulses 
relatively  free  of  disturbing  noise  and 
results  in  a  stable  picture.  To  prevent 
reduction  of  receiver  gain  due  to  the  ef- 
fect of  noise  on  the  age  amplifier,  a  por- 
tion of  the  inverted  noise  signal  is  fed  to 
the  second  control  grid,  grid  No.  3,  of  the 
6GY6  to  cut  off  or  gate  the  AGC  am- 
plifier when  a  noise  pulse  occurs. 

Rectification 

The  rectifying  action  of  a  diode 
finds  important  applications  in  supply- 
ing a  receiver  with  dc  power  from  an  ac 
line  and  in  supplying  high  dc  voltage 
from  a  high-voltage  pulse.  A  typical 
arrangement  for  converting  ac  to  dc  in- 
cludes a  rectifier  tube,  a  filter,  and  a 
voltage  divider.  The  rectifying  action  of 
the  tube  is  explained  briefly  under 
Diodes,  in  the  ELECTRONS,  ELEC- 
TRODES, AND  ELECTRON  TUBE 
SECTION.  High-voltage  pulse  rectifi- 
cation is  described  later  under  Horizon^ 
tal  Output  Circuits. 

The  function  of  a  filter  is  to  smooth 
out  the  ripple  of  the  tube  output,  as  in- 
dicated in  Fig.  44  and  to  increase  recti- 
fier efliciency.  The  action  of  the  filter  is 


3WV 


TRANSFORMER 
SECONDARY 
VOLTAGE 


"M/N  /\  /\         RECTFED  VOI 


IhAAAAA 

^  

]  — 


FlEO  VOLTAGE 
PLATE  N«2 


COMBINED 
RECrriED 

PLATES  N91«.  2 


N.J»KIOOTICD  VOLT- 
AGE AFTER 
FIRST  SECTION 

-  f>C  VOLTAGE 
.  RADK)  RECEIVER 


FULL-WAVE  RECTIFICATION 
Fig.  44 

explained  in  ELECTRON  TUBE  IN- 
STALLATION SECTION  under  Fil- 
ters, The  voltage  divider  is  used  to  cut 
down  the  output  voltage  to  the  values 
required  by  the  plates  and  the  other 
electrodes  of  the  tubes  in  the  receiver. 

40 


A  half-wave  rectifier  and  a  full- 
wave  rectifier  circuit  are  shown  in  Fig. 
45.  In  the  half-wave  circuit,  current 
flows  through  the  rectifier  tube  to  the 
filter  on  every  other  half-cycle  of  the  ac 
input  voltage  when  the  plate  is  positive 
with  respect  to  the  cathode.  In  the  full- 
wave  circuit,  current  flows  to  the  filter 
on  every  half-cycle,  through  plate  No.  1 
on  one  half-cycle  when  plate  No.  1  is 

half-wave:  rectifier 


FULL- WAVE  RECTIFIER 


FILTER 
O 


Fig.  45 

positive  with  respect  to  the  cathode,  and 
through  plate  No.  2  on  the  next  half- 
cycle  when  plate  No.  2  is  positive  with 
respect  to  the  cathode. 

Because  the  current  flow  to  the  fil- 
ter is  more  uniform  in  the  full-wave  cir- 
cuit than  in  the  half-wave  circuit,  the 
output  of  the  full-wave  circuit  requires 
less  filtering.  Rectifier  operating  infor- 
mation and  circuits  are  given  under  each 
rectifier  tube  type  and  in  the  CIRCUIT 
SECTION,  respectively. 

Parallel  operation  of  rectifier  tubes 
furnishes  an  output  current  greater  than 
that  obtainable  with  the  use  of  one  tube. 
For  example,  when  two  full-wave  recti- 
fier tubes  are  connected  in  parallel,  the 
plates  of  each  tube  are  connected  to- 
gether and  each  tube  acts  as  a  half-wave 
rectifier.  The  allowable  voltage  and  load 
conditions  per  tube  are  the  same  as  for 
full-wave  service  but  the  total  load- 
handling  capability  of  the  complete  rec- 
tifier is  approximately  doubled. 


Electron  Tube  Applications 


When  mercury-vapor  rectifier  tubes 
are  connected  in  parallel,  a  stabilizing 
resistor  of  50  to  100  ohms  should  be  con- 
nected in  series  with  each  plate  lead  in 
order  that  each  tube  will  carry  an  equal 
share  of  the  load.  The  value  of  the  re- 
sistor to  be  used  will  depend  on  the 
amount  of  plate  current  that  passes 
through  the  rectifier.  Low  plate  current 
requires  a  high  value;  high  plate  cur- 
rent, a  low  value.  When  the  plates  of 
mercury-vapor  rectifier  tubes  are  con- 
nected in  parallel,  the  corresponding 
filament  leads  should  be  similarly  con- 
nected. Otherwise,  the  tube  drops  will 
be  considerably  unbalanced  and  larger 
stabilizing  resistors  will  be  required. 

Two  or  more  vacuum  rectifier  tubes 
can  also  be  connected  in  parallel  to  give 
correspondingly  higher  output  current 
and,  as  a  result  of  paralleling  their  in- 
ternal resistances,  give  somewhat  in- 
creased voltage  output.  With  vacuum 
types,  stabilizing  resistors  may  or  may 
not  be  necessary  depending  on  the  tube 
type  and  the  circuit. 

^       r   "       ~~  i  OUTPUT 

— ^ 

TjjT^s  SEPARATE  FILAMENT 

TRANSFORMER  WINDINGS 

Fig.  46 

A  voltage- doubler  circuit  of  simple 
form  is  shown  in  Fig.  46.  The  circuit  de- 
rives its  name  from  the  fact  that  its  dc 
voltage  output  can  be  as  high  as  twice 
the  peak  value  of  ac  input.  Basically,  a 
voltage  doubler  is  a  rectifier  circuit  ar- 
ranged so  that  the  output  voltages  of 
two  half-wave  rectifiers  are  in  series. 

The  action  of  a  voltage  doubler  can 
be  described  briefly  as  follows.  On  the 


VOLTAGE-DOUBLER  CIRCUIT 
FULL  -  WAVE 


11  =  HEATERS  OF  OTHER  TUBES  m  SLtTES 
WITH  VOLTAOE-DSOWIMG  «eStSTm 

Fig. 


positive  half-cycle  of  the  ac  input,  that 
is,  when  the  upper  side  of  the  ac  input 
line  is  positive  with  respect  to  the  lower 
side,  the  upper  diode  passes  current  and 
feeds  a  positive  charge  into  the  upper 
capacitor.  As  positive  charge  accumu- 
lates on  the  upper  plate  of  the  capacitor, 
a  positive  voltage  builds  up  across  the 
capacitor.  On  the  next  half-cycle  of  the 
ac  input,  when  the  upper  side  of  the  line 
is  negative  with  respect  to  the  lower 
side,  the  lower  diode  passes  current  so 
that  a  negative  voltage  builds  up  across 
the  lower  capacitor. 

So  long  as  no  current  is  drawn  at 
the  output  terminals  from  the  capacitor, 
each  capacitor  can  charge  up  to  a  volt- 
age of  magnitude  E,  the  peak  value  of 
the  ac  input.  It  can  be  seen  from  the 
diagram  that  with  a  voltage  of  +E  on 
one  capacitor  and  -E  on  the  other,  the 
total  voltage  across  the  capacitors  is  2E. 
Thus  the  voltage  doubler  supplies  a  no- 
load  dc  output  voltage  twice  as  large  as 
the  peak  ac  input  voltage.  When  current 
is  drawn  at  the  output  terminals  by  the 
load,  the  output  voltage  drops  below  2E 
by  an  amount  that  depends  on  the  mag- 
nitude of  the  load  current  and  the  capaci- 
tance of  the  capacitors.  The  arrange- 
ment shown  in  Fig.  46  is  called  a  full- 
wave  voltage  doubler  because  each 
rectifier  passes  current  to  the  load  on 
each  half  of  the  ac  input  cycle. 

Two  rectifier  types  especially  de- 
signed for  use  as  voltage  doublers  are 
the  25Z6GT  and  117Z6GT.  These  tubes 
combine  two  separate  diodes  in  one 
tube.  As  voltage  doublers,  the  tubes  are 
used  in  "transformerless"  receivers.  In 
these  receivers,  the  heaters  of  all  tubes 
in  the  set  are  connected  in  series  with  a 
voltage-dropping  resistor  acr«ss  the  line. 
The  connections  for  the  heater  supply 
and  the  voltage-doubliag  circuit  are 
shown  in  Fig.  47. 


VOLTACE -DOUBLER  ClRCUWI 
HALF -WAVE 


47 


41 


RCA  Receiving  Tube  Manual 


With  the  full-wave  voltage-doubler 
circuit  in  Fig.  47,  it  will  be  noted  that 
the  dc  load  circuit  can  not  be  connected 
to  ground  or  to  one  side  of  the  ac  supply 
line.  This  circuit  presents  certain  dis- 
advantages when  the  heaters  of  all  the 


AtA  Defecfion 
The  effect  of  amplitude  modula- 
tion  on  the  waveform  of  the  rf  wave  is 
shown  in  Fig.  48.  There  are  three  differ- 
ent basic  circuits  used  for  the  detection 
of  amplitude-modulated  waves:  the  di- 


UNMODULATEO 
RF  CARRIER 


AP  MODULATING 
WAVE 

Fig.  48 


4VIPUTUDE- MODULATED 
RF  WAVE 


tubes  in  the  set  are  connected  in  series 
with  a  resistance  across  the  ac  line.  Such 
a  circuit  arrangement  may  cause  hum 
because  of  the  high  ac  potential  between 
the  heaters  and  cathodes  of  the  tubes. 

The  half-wave  voltage-doubler  cir- 
cuit in  Fig.  47  overcomes  this  difficulty 
by  making  one  side  of  the  ac  line  com- 
mon with  the  negative  side  of  the  dc 
load  circuit.  In  this  circuit,  one  half  of 
the  tube  is  used  to  charge  a  capacitor 
which,  on  the  following  half  cycle,  dis- 
charges in  series  with  the  line  voltage 
through  the  other  half  of  the  tube.  This 
circuit  is  called  a  half-wave  voltage 
doubler  because  rectified  current  flows 
to  the  load  only  on  alternate  halves  of 
the  ac  input  cycle.  The  voltage  regula- 
tion of  this  arrangement  is  somewhat 
poorer  than  that  of  the  full-wave  voltage 
doubler. 

Detection 

When  speech,  music,  or  video  infor- 
mation is  transmitted  from  a  radio  or 
television  station,  the  station  radiates 
ii  radio-frequency  (rf)  wave  which  is  of 
either  of  two  general  types.  In  one  type, 
the  wave  is  said  to  be  amplitude  modu- 
lated when  its  frequency  remains  con- 
st2tnt  and  the  amplitude  is  varied.  In  the 
other  type,  the  wave  is  said  to  be  fre- 
quency modulated  when  its  amplitude 
remains  essentially  constant  but  its  fre- 
quency is  varied. 

The  function  of  the  receiver  is  to 
reproduce  the  original  modulating  wave 
from  the  modulated  rf  wave.The  receiver 
stage  in  which  this  function  is  performed 
is  called  the  demodulator  or  detector 
stage. 


ode  detector,  the  grid-bias  detector,  and 
the  grid-resistor  detector.  These  circuits 
are  alike  in  that  they  eliminate,  either 
partially  or  completely,  alternate  half- 
cycles  of  the  rf  wave.  With  alternate 
half-cycles  removed,  the  audio  variations 
of  the  other  half-cycles  can  be  amplified 
to  drive  headphones  or  a  loudspeaker. 

A  diode-detector  circuit  is  shown 
in  Fig.  49.  The  action  of  this  circuit 


Fig.  49 

when  a  modulated  rf  wave  is  applied  is 
illustrated  by  Fig.  50.  The  rf  voltage 
applied  to  the  circuit  is  shown  in  light 
line;  the  output  voltage  across  capacitor 
C  is  shown  in  heavy  line. 


Fig.  50 

Betweien  points  fa)  and  (b)  on  the 
first  positive  half-cycle  of  the  applied  rf 
voltage,  capacitor  C  charges  up  to  the 
peak  value  of  the  rf  voltage.  Then  as  the 
applied  rf  voltage  falls  away  from  its 
peak  value,  the  capacitor  holds  the  cath- 
ode at  a  potential  more  positive  than  the 
voltage  applied  to  the  anode.The  capaci- 


42 


Electron  Tube  Applications 


tor  thus  temporarily  cuts  off  current 
through  the  diode.  While  the  diode  cur- 
rent is  cut  off,  the  capacitor  discharges 
from  (b)  to  (c)  through  the  diode  load 
resistor  R. 

When  the  rf  voltage  on  the  anode 
rises  high  enough  to  exceed  the  potential 
at  which  the  capacitor  holds  the  cath- 
ode, current  flows  again  and  the  capaci- 
tor charges  up  to  the  peak  value  of  the 
second  positive  half-cycle  at  (d).  In  this 
way,  the  voltage  across  the  capacitor 
follows  the  peak  value  of  the  applied  rf 
voltage  and  reproduces  the  af  modu- 
lation. 

The  curve  for  voltage  across  the 
capacitor,  as  drawn  in  Fig.  50,  is  some- 
what jagged.  However,  this  jaggedness, 
which  represents  an  rf  component  in  the 
voltage  across  the  capacitor;  is  exagger- 
ated in  the  drawing.  In  an  actual  circuit 
the  rf  component  of  the  voltage  across 
the  capacitor  is  negligible.  Hence,  when 
the  voltage  across  the  capacitor  is  ampli- 
fied, the  output  of  the  amplifier  repro- 
duces the  speech  or  music  originating  at 
the  transmitting  station. 

Another  way  to  describe  the  action 
of  a  diode  detector  is  to  consider  the 
circuit  as  a  half -wave  rectifier.  When  the 
rf  signal  on  the  plate  swings  positive,  the 
tube  conducts  and  the  rectified  current 
flows  through  the  load  resistance  R.  Be- 
cause the  dc  output  voltage  of  a  rectifier 
depends  on  the  voltage  of  the  ac  input, 
the  dc  voltage  across  C  varies  in  accord- 
ance with  the  amplitude  of  the  rf  carrier 
and  thus  reproduces  the  af  signal.  Ca- 
pacitor C  should  be  large  enough  to 
smooth  out  rf  or  if  variations  but  should 
not  be  so  large  as  to  affect  the  audio 
variations.  Two  diodes  can  be  connected 
in  a  circuit  similar  to  a  full-wave  rectifier 
to  give  full-wave  detection.  However,  in 
practice,  the  advantages  of  this  connec- 
tion generally  do  not  justify  the  extra 
circuit  complication. 

The  diode  method  of  detection  pro- 
duces less  distortion  than  other  methods 
because  the  dynamic  characteristics  of  a 
diode  can  be  made  more  linear  than 
those  of  other  detectors.  The  disad- 
vantages of  a  diode  are  that  it  does  not 
amplify  the  signal,  and  that  it  draws 
current  from  the  input  circuit  and  there- 
fore reduces  the  selectivity  of  the  input 
circuit.  However,  because  the  diode 


method  of  detection  produces  less  dis- 
tortion and  because  it  permits  the  use 
of  simple  avc  circuits  without  the  neces- 
sity for  an  additional  voltage  supply, 
the  diode  method  of  detection  is  most 
widely  used  in  broadcast  receivers. 

Atypical  diode-detector  circuitusing 
a  twin-diode  triode  tube  is  shown  in  Fig. 
51.  Both  diodes  are  connected  together. 
Ri  is  the  diode  load  resistor.  A  portion 
of  the  af  voltage  developed  across  this 
resistor  is  applied  to  the  triode  grid 
through  the  volume  control  R3.  In  a 
typical  circuit,  resistor  Ri  may  be  tapped 


Fig.  51 

so  that  five-sixths  of  the  total  af  voltage 
across  Ri  is  applied  to  the  volume  con- 
trol. This  tapped  connection  reduces  the 
af  voltage  output  of  the  detector  circuit 
slightly  but  it  reduces  audio  distortion 
and  improves  the  rf  filtering. 

DC  bias  for  the  triode  section  is 
provided  by  the  cathode-bias  resistor  R2 
and  the  audio  bypass  capacitor  C3.  The 
function  of  capacitor  C2  is  to  block  the 
dc  bias  of  the  cathode  from  the  grid.  The 
function  of  capacitor  C4  is  to  bypass 
and  rf  voltage  on  the  grid  to  cathode.  A 
twin-diode  pentode  may  also  be  used  in 
this  circuit.  With  a  pentode,  the  af  out- 
put should  be  resistance-coupled  rather 
than  transformer-coupled. 

Another  diode-detector  circuit, 
called  a  diode-biased  circuit,  is  shown  in 
Fig.  52.  In  this  circuit,  the  triode  grid  is 


Fig.  52 

connected  directly  to  a  tap  on  the  diode 
load  resistor.  When  an  rf  signal  voltage 
is  applied  to  the  diode,  the  dc  voltage  at 


43 


RCA  Receiving  Tube  Manual 


'the  tap  supplies  bias  to  the  triode  grid. 
When  the  rf  signal  is  modulated,  the  af 
voltage  at  the  tap  is  applied  to  the  grid 
and  is  amplified  by  the  triode. 

The  advantage  of  the  circuit  shown 
in  Fig.  52  over  the  self-biased  arrange- 
ment shown  in  Fig.  51  is  that  the  diode- 
biased  circuit  does  not  employ  a  capaci- 
tor between  the  grid  and  the  diode  load 
resistor,  and  consequently  does  not  pro- 
duce as  much  distortion  of  a  signal  hav- 
ing a  high  percentage  of  modulation. 

However,  there  are  restrictions  on 
the  use  of  the  diode-biased  circuit.  Be- 
cause the  bias  voltage  on  the  triode  de- 
pends on  the  average  amplitude  of  the 
rf  voltage  applied  to  the  diode,  the  aver- 
age amplitude  of  the  voltage  applied  to 
the  diode  should  be  constant  for  all 
values  of  signal  strength  at  the  antenna. 
'Otherwise  there  will  be  different  values 
of  bias  on  the  triode  grid  for  different 
signal  strengths  and  the  triode  will  pro- 
duce distortion.  Because  there  is  no  bias 
applied  to  the  diode-biased  triode  when 
no  rf  voltage  is  applied  to  the  diode, 
sufficient  resistance  should  be  included 
in  the  plate  circuit  of  the  triode  to  limit 
its  zero-bias  plate  current  to  a  safe  value. 

These  restrictions  mean,  in  practice, 
that  the  receiver  should  have  a  separate- 
channel  automatic-volume-control  (avc) 
system.  With  such  an  avc  system,  the 
average  amplitude  of  the  signal  voltage 
applied  to  the  diode  can  be  held  within 
very  close  limits  for  all  values  of  signal 
strength  at  the  antenna. 

The  tube  used  in  a  diode-biased  cir- 
cuit should  be  one  which  operates  at  a 
fairly  large  value  of  bias  voltage.  The 
variations  in  bias  voltage  are  then  a 
tsmall  percentage  of  the  total  bias  and 
hence  produce  small  distortion.  Tubes 
taking  a  fairly  large  bias  voltage  are 
types  such  as  the  6BF6  or  6SR7  having 
a  medium-mu  triode.  Tube  types  having 
a  high-mu  triode  or  a  pentode  should  not 
be  used  in  a  diode-biased  circuit. 

A  grid-bias  detector  circuit  is 
shown  in  Fig.  53.  In  this  circuit,  the  grid 
is  biased  almost  to  cutoff,  t.e.,  operated 
so  that  the  plate  current  with  zero  signal 
is  practically  zero.  The  bias  voltage  can 
be  obtained  from  a  cathode-bias  resistor, 
a  C-battery,  or  a  bleeder  tap.  Because  of 
the  high  negative  bias,  only  the  positive 
half-cycles  of  the  rf  signal  are  amplified 

44 


by  the  tube.  The  signal  is,  therefore,  de- 
tected in  the  plate  circuit.  The  advan- 
tages of  this  method  of  detection  are 
that  it  amplifies  the  signal,  besides  de- 
tecting it,  and  that  it  does  not  draw 


Fig.  53 

current  from  the  input  circuit  and  there- 
fore does  not  lower  the  selectivity  of  the 
input  circuit. 

The  grid  -  resistor  -  and  -  capacitor 
method,  illustrated  by  Fig.  54,  is  some- 
what more  sensitive  than  the  grid-bias 
method  and  gives  its  best  results  on 
weak  signals.  In  this  circuit,  there  is  no 
negative  dc  bias  voltage  applied  to  the 
grid.  Hence,  on  the  positive  half-cycles 
of  the  rf  signal,  current  flows  from  grid 
to  cathode.  The  grid  and  cathode  thus 
act  as  a  diode  detector,  with  the  grid 
resistor  as  the  diode  load  resistor  and  the 
grid  capacitor  as  the  rf  bypass  capacitor. 
The  voltage  across  the  capacitor  then 
reproduces  the  af  modulation  in  the 
same  manner  as  has  been  explained  for 
the  diode  detector.  This  voltage  appears 
between  the  grid  and  cathode  and  is 
therefore  amplified  in  the  plate  circuit. 


RF  CH0K8 


BYPASS^ 
CAPACITOR 


AF 
0UTPU1 


'  J|— 

A-A+  B* 
8- 

Fig.  54 

The  output  voltage  thus  reproduces  the 
original  af  signal. 

In  this  detector  circuit,  the  use  of  a 
high-resistance  grid  resistor  increases 
selectivity  and  sensitivity.  However,  im- 
proved af  response  and  stability  are  ob- 
tained with  lower  values  of  grid-circuit 
resistance.  This  detector  circuit  ampli- 
fies the  signal,  but  draws  current  from 


Electron  Tube  Applications 


the  input  circuit  and  therefore  lowers 
the  selectivity  of  the  input  circuit. 

FM  Defecf/on 
The  effect  of  frequency  modulation 
on  the  waveform  of  the  rf  wave  is  shown 
in  Fig.  55.  In  this  type  of  transmission, 


UNMODULATED  RF  CARRIER 


FREQUENCY- MODULATED  RF  WAVR, 


Fig.  55 

the  frequency  of  the  rf  wave  deviates 
from  a  mean  value,  at  an  rf  rate  depend- 
ing on  the  modulation,  by  an  amount 
that  is  determined  in  the  transmitter 
and  is  proportional  to  the  amplitude  of 
the  af  modulation  signal. 

For  this  type  of  modulation,  a  de- 
tector is  required  to  discriminate  be- 
tween deviations  above  and  below  the 
mean  frequency  and  to  translate  those 
deviations  into  a  voltage  whose  ampli- 
tude varies  at  audio  frequencies.  Since 
the  deviations  occur  at  an  audio  fre- 
quency, the  process  is  one  of  demodula- 
tion, and  the  degree  of  frequency  devia- 
tion determines  the  amplitude  of  the 
demodulated  (af)  voltage. 

A  simple  circuit  for  converting  fre- 
quency variations  to  amplitude  varia- 
tions is  a  circuit  which  is  tuned  so  that 
the  mean  radio  frequency  is  on  one  slope 
of  its  resonance  characteristic,  as  at  A 
of  Fig.  56.  With  modulation,  the  fre- 
quency swings  between  B  and  C,  and 
the  voltage  developed  across  the  circuit 
varies  at  the  modulating  rate.  In  order 
that  no  distortion  will  be  introduced  in 
this  circuit,  the  frequency  swing  must  be 
restricted  to  the  portion  of  the  slope 
which  is  effectively  straight.  Since  this 


portion  is  very  short,  the  voltage  de- 
veloped is  low.  Because  of  these  limita- 
tions, this  circuit  is  not  commonly  used 
but  it  serves  to  illustrate  the  principle. 


FREQUENCY 
Fig.  56 


The  faults  of  the  simple  circuit  are 
overcome  in  a  push-pull  arrangement, 
sometimes  called  a  discriminator  cir- 
cuit, such  as  that  shown  in  Fig.  57.  Be- 
cause of  the  phase  relationships  between 
the  primary  and  each  half  of  the  second- 
ary of  the  input  transformer  (each  half 
of  the  secondary  is  connected  in  series 
with  the  primary  through  capacitor  C2), 
the  rf  voltages  applied  to  the  diodes  be- 
come unequal  as  the  rf  signal  swings 


Fig.  57 


from  the  resonant  frequency  in  each 
direction. 

Since  the  swing  occurs  at  audio 
frequencies  (determined  by  the  af  modu- 
lation), the  voltage  developed  across  the 
diode  load  resistors,  Ri  and  R2  connected 
in  series,  varies  at  audio  frequencies.  The 
output  voltage  depends  on  the  difference 
in  amplitude  of  the  voltages  developed 
across  Ri  and  R2.  These  voltages  are 
equal  and  of  opposite  sign  when  the  rf 
carrier  is  not  modulated  and  the  output 
is,  therefore,  zero.  When  modulation  is 
applied,  the  output  voltage  varies  as 
indicated  in  Fig.  58. 

Because  this  type  of  FM  detector  is 
sensitive  to  ampUtude  variations  in  the 
rf  carrier,  a  limiter  stage  is  frequently 


45 


RCA  Receiving  Tube  Manual 


used  to  remove  most  of  the  amplitude 
modulation  from  the  carrier.  (See  Lim- 
iters  under  Amplification.) 


4. 

CARRIER 

FREQUENCY 

Fig.  58 

Another  form  of  detector  for  fre- 
quency-modulated waves  is  called  a  ratio 
detector.  This  FM  detector,  unlike  the 
previous  one  which  responds  to  a  differ- 
ence in  voltage,  responds  only  to  changes 
in  the  ratio  of  the  voltage  across  two 
diodes  and  is,  therefore,  insensitive  to 
changes  in  the  differences  in  the  voltages 
due  to  amplitude  modulation  of  the  rf 
carrier. 

The  basic  ratio  detector  is  given  in 
Fig.  59.  The  plate  load  for  the  final  if 
amplifier  stage  is  the  parallel  resonant 


even  at  the  lowest  audio  frequencies  to 
be  reproduced. 

The  rectified  voltage  across  C3  is 
proportional  to  the  voltage  across  diode 

1,  and  the  rectified  voltage  across  C4  is 
proportional  to  the  voltage  across  diode 

2.  Since  the  voltages  across  the  two 
diodes  differ  according  to  the  instan- 
taneous frequency  of  the  carrier,  the 
voltages  across  C3  and  C4  differ  propor- 
tionately, the  voltage  across  C3  being 
the  larger  of  the  two  voltages  at  carrier 
frequencies  below  the  intermediate  fre- 
quency and  the  smaller  at  frequencies 
above  the  intermediate  frequency. 

These  voltages  across  C3  and  C4  are 
additive  and  their  sum  is  fixed  by  the 
constant  voltage  across  Ce.  Therefore, 
while  the  ratio  of  these  voltages  varies 
at  an  audio  rate,  their  sum  is  always 
constant.  The  voltage  across  C4  varies 
at  an  audio  rate  when  a  frequency- 
modulated  rf  carrier  is  applied  to  the 
ratio  detector;  this  audio  voltage  is  ex- 
tracted and  fed  to  the  audio  amplifier. 
For  a  complete  circuit  utilizing  this  type 
of  detector,  refer  to  the  CIRCUIT 
SECTION. 


IF 
INPUT 
O  


Tax 


OIODE  2 
Fig.  59 


53 
C5 


-56 


AF 
OUTPUT 
I  o 


>R2 


circuit  consisting  of  Ci  and  the  primary 
transformer  T.  The  tuning  and  coupling 
of  the  transformer  is  practically  the 
same  as  in  the  previous  circuit  and 
therefore,  the  rf  voltages  applied  to  the 
diodes  depend  upon  how  much  the  rf 
signal  swings  from  the  resonant  fre- 
quency in  each  direction.  At  this  point 
the  similarity  ends. 

Diode  1,  R2,  and  diode  2  complete  a 
series  circuit  fed  by  the  secondary  of  the 
transformer  T.  The  two  diodes  are  con- 
nected in  series  so  that  they  conduct  on 
the  same  rf  half-cycle.  The  rectified  cur- 
tent  through  R2  causes  a  negative  volt- 
age to  appear  at  the  plate  of  diode  1. 
Because  Ce  is  large,  this  negative  voltage 
at  the  plate  of  diode  1  remains  constant 

46 


Automatic  Volume  or  Gain  Control 

The  chief  purposes  of  automatic 
volume  control  (ave)  or  automatic  gain 
control  (age)  in  a  radio  or  television 
receiver  are  to  prevent  fluctuations  in 
loudspeaker  volume  or  picture  bright- 
ness when  the  audio  or  video  signal  at 
the  antenna  is  fading  in  and  out. 

An  automatic  volume  control  cir- 
cuit regulates  the  receiver  rf  and  if  gain 
so  that  this  gain  is  less  for  a  strong  signal 
than  for  a  weak  signal.  In  this  way, 
when  the  signal  strength  at  the  antenna 
changes,  the  avc  circuit  reduces  the  re- 
sultant change  in  the  voltage  output  of 
the  last  if  stage  and  consequently  re- 
duces the  change  in  the  speaker  output 
volume. 


Electron  Tube  Applications 


The  avc  circuit  reduces  the  rf  and  if 
gain  for  a  strong  signal  usually  by  in- 
creasing the  negative  bias  of  the  rf,  if, 
and  frequency-mixer  stages  when  the 
signal  increases.  A  simple  avc  circuit  is 
shown  in  Fig.  60.  On  each  positive  half- 
cycle  of  the  signal  voltage,  when  the 
diode  plate  is  positive  with  respect  to 
the  cathode,  the  diode  passes  current. 


Because  of  the  flow  of  diode  current 
through  Ri,  there  is  a  voltage  drop  across 
Ri  which  makes  the  left  end  of  Ri  nega- 
tive with  respect  to  ground.  This  voltage 
drop  across  Ri  is  applied,  through  the 
filter  R2  and  C,  as  negative  bias  on  the 
grids  of  the  preceding  stages.  When  the 
signal  strength  at  the  antenna  increases, 
therefore,  the  signal  applied  to  the  avc 
diode  increases,  the  voltage  drop  across 
Ri  increases,  the  negative  bias  voltage 
appHed  to  the  rf  and  if  stages  increases, 
and  the  gain  of  the  rf  and  if  stages  is  de- 
creased. Thus  the  increase  in  signal 
strength  at  the  antenna  does  not  pro- 
duce as  much  increase  in  the  output  of 
the  last  if  stage  as  it  would  produce 
without  avc. 

When  the  signal  strength  at  the 
antenna  decreases  from  a  previous  steady 
value,  the  avc  circuit  acts,  of  course,  in 
the  reverse  direction,  applying  less  nega- 
tive bias,  permitting  the  rf  and  if  gain 
to  increase,  and  thus  reducing  the  de- 
crease in  the  signal  output  of  the  last 
if  stage.  In  this  way,  when  the  signal 
strength  at  the  antenna  changes,  the  avc 
circuit  acts  to  reduce  change  in  the  out- 
put of  the  last  if  stage,  and  thus  acts  to 
reduce  change  in  loudspeaker  volume. 

The  filter,  C  and  R2,  prevents  the 
avc  voltage  from  varying  at  audio  fre- 
quency. The  filter  is  necessary  because 
the  voltage  drop  across  Ri  varies  with 
the  modulation  of  the  carrier  being  re- 
ceived. If  avc  voltage  were  taken  directly 
from  Ri  without  filtering,  the  audio 
variations  in  avc  voltage  would  vary  the 
receiver  gain  so  as  to  smooth  out  the 
modulation  of  the  carrier.  To  avoid  this 


efifect,  the  avc  voltage  is  taken  from  the 
capacitor  C.  Because  of  the  resistance 
R2  in  series  with  C,  the  capacitor  C  can 
charge  and  discharge  at  only  a  compara- 
tively slow  rate.  The  avc  voltage  there- 
fore cannot  vary  at  frequencies  as  high 
as  the  audio  range  but  can  vary  at  fre- 
quencies high  enough  to  compensate  for 
most  fading.  Thus  the  filter  permits  the 
avc  circuit  to  smooth  out  variations  in 
signal  due  to  fading,  but  prevents  the 
circuit  from  smoothing  out  audio  modu- 
lation. 

It  will  be  seen  that  an  avc  circuit 
and  a  diode-detector  circuit  are  much 
alike.  It  is  therefore  convenient  in  a  re- 
ceiver to  combine  the  detector  and  the 
avc  diode  in  a  single  stage.  Examples  of 
how  these  functions  are  combined  in 
receivers  are  shown  in  CIRCUIT 
SECTION. 

In  the  circuit  shown  in  Fig,  60,  a 
certain  amount  of  avc  negative  bias  is 
applied  to  the  preceding  stages  on  a 
weak  signal.  Since  it  may  be  desirable 
to  maintain  the  receiver  rf  and  if  gain 
at  the  maximum  possible  value  for  a 
weak  signal,  avc  circuits  are  designed  in 
some  cases  to  apply  no  avc  bias  until  the 
signal  strength  exceeds  a  certain  value. 
These  avc  circuits  are  known  as  delayed 
avc  or  davc  circuits. 

A  davc  circuit  is  shown  in  Fig.  61. 
In  this  circuit,  the  diode  section  Di  of 
the  6H6  acts  as  detector  and  avc  diode. 


Fig. 61 


Ri  is  the  diode  load  resistor  and  R2  and 
C2  are  the  avc  filter.  Because  the  cathode 
of  diode  D2  is  returned  through  a  fixed 
supply  of  -3  volts  to  the  cathode  of  Di,  a 
dc  current  flows  through  Ri  and  R2  in 
series  with  D2.  The  voltage  drop  caused 
by  this  current  places  the  avc  lead  at 
approximately  -3  volts  (less  the  negligi- 
ble drop  through  D2).  When  the  average 

47 


RCA  Receiving  Tube  Manual 


amplitude  of  the  rectified  signal  devel- 
oped across  Ri  does  not  exceed  3  volts, 
the  avc  lead  remains  at  -3  volts.  Hence, 
for  signals  not  strong  enough  to  develop 
3  volts  across  Ri,  the  bias  applied  to  the 
controlled  tubes  stays  constant  at  a 
value  giving  high  sensitivity. 

However,  when  the  average  ampli- 
tude of  rectified  signal  voltage  across  Ri 
exceeds  3  volts,  the  plate  of  diode  D2  be- 
comes more  negative  than  the  cathode 
of  D2  and  current  flow  in  diode  D2  ceases. 
The  potential  of  the  avc  lead  is  then  con- 
trolled by  the  voltage  developed  across 
Ri.  Therefore,  with  further  increase  in 
signal  strength,  the  avc  circuit  applies 
an  increasing  avc  bias  voltage  to  the 
controlled  stages.  In  this  way,  the  cir- 
cuit regulates  the  receiver  gain  for 
strong  signals,  but  permits  the  gain  to 
stay  constant  at  a  maximum  value  for 
weak  signals. 

It  can  be  seen  in  Fig.  61  that  a  por- 
tion of  the  -3  volts  delay  voltage  is 
applied  to  the  plate  of  the  detector 
diode  Di,  this  portion  being  approxi- 
mately equal  to  Ri/(Ri  +  R2)  times  -3 
volts.  Hence,  with  the  circuit  constants 
as  shown,  the  detector  plate  is  made 
negative  with  respect  to  its  cathode  by 
approximately  one-half  volt.  However, 
this  voltage  does  not  interfere  with  de- 
tection because  it  is  not  large  enough  to 
prevent  current  flow  in  the  tube. 

Automatic  gain  control  (age)  com- 
pensates for  fluctuations  in  rf  picture 
carrier  amplitude.  The  peak  carrier  level 
rather  than  the  average  carrier  level  is 
controlled  by  the  age  voltage  because 
the  peaks  of  the  sync  pulses  are  fixed 
when  inserted  on  a  fixed  carrier  level. 
The  peak  carrier  level  may  be  determined 
by  measurement  of  the  peaks  of  the 
sync  pulses  at  the  output  of  the  video 
detector. 

A  conventional  age  circuit,  such  as 
that  shown  in  Fig.  62,  consists  of  a  diode 

AGC 
VOLTAGE  TO 
IFANDRF 


Fig.  62 

detector  circuit  and  an  RC  filter.  The 
time  constant  of  the  detector  circuit  is 
made  large  enough  to  prevent  the  pic- 

48 


ture  content  from  influencing  the  mag- 
nitude of  the  age  voltage.  The  output 
voltage  (age  voltage)  is  equal  to  the 
peak  value  of  the  incoming  signal. 

The  diode  detector  receives  the  in- 
coming signal  from  the  last  if  stage  of 
the  television  receiver  through  the  ca- 
pacitor Ci.  The  resistor  Ri  provides  the 
load  for  the  diode.  The  diode  conducts 
only  when  its  plate  is  driven  positive 
with  respect  to  its  cathode.  Electrons 
then  flow  from  the  cathode  to  the  plate 
and  thence  into  capacitor  Ci,  where  the 
negative  charge  is  stored.  Because  of  the 
low  impedance  offered  by  the  diode  dur- 
ing conduction,  Ci  charges  up  to  the 
value  of  the  peak  applied  voltage. 

During  the  negative  excursion  of 
the  signal,  the  diode  does  not  conduct, 
and  Ci  discharges  through  resistor  Ri. 
Because  of  the  large  time  constant  of 
RiCi,  however,  only  a  small  percentage 
of  the  voltage  across  Ci  is  lost  during  the 
interval  between  horizontal  sync  pulses. 
During  succeeding  positive  cycles,  the 
incoming  signal  must  overcome  the  neg- 
ative charge  stored  in  Ci  before  the  diode 
conducts,  and  plate  current  flows  only 
at  the  peak  of  each  positive  cycle.  The 
voltage  across  Ci,  therefore,  is  deter- 
mined by  the  level  of  the  peaks  of  the 
positive  cycles,  or  the  sync  pulses. 

The  negative  voltage  developed 
across  resistor  Ri  by  the  sync  pulses  is 
filtered  by  resistor  R2  and  capacitor  Ci 
to  remove  the  15,750-cycle  ripple  of  the 
horizontal  sync  pulse.  The  dc  output  is 
then  fed  to  the  if  and  rf  amplifiers  as  an 
age  voltage. 

This  age  system  may  be  expanded 
to  include  amplification  of  the  age  signal 
before  detection  of  the  peak  level,  or 
amplification  of  the  dc  output,  or  both. 
A  direct-coupled  amplifier  must  be  used 
for  amplification  of  the  dc  signal.  The 
addition  of  amplification  makes  the  sys- 
tem more  sensitive  to  changes  in  carrier 
level. 

A  "keyed"  age  system  such  as  that 
shown  in  Fig.  63  is  used  to  eliminate  flut- 
ter and  to  improve  noise  immunity  in 
weak  signal  areas.  This  system  provides 
more  rapid  action  than  the  conventional 
age  circuits  because  the  filter  circuit  can 
employ  lower  capacitance  and  resistance 
values. 

In  the  keyed  age  system,  the  nega- 


Electron  Tube  Applications 


tive  output  of  the  video  detector  is  fed 
directly  to  the  grid  No.l  of  the  first 
video  amplifier.  The  positive  output  of 
the  video  amplifier  is,  in  turn,  fed  di- 
rectly to  the  grid  No.l  of  the  keyed  age 
amplifier.  The  video  stage  increases  the 
gain  of  the  age  system  and,  in  addition, 

VIDEO 
OUTPUT 

KEYED  AGC 
AMPUFIER 

tRANSFORMER 
WINDING  FOR 
KEYING  PULSE 


(FROM  LAST  ^ 
IF  STAGE  Fig.  63 

provides  noise  clipping.  The  plate  volt- 
age for  the  age  amplifier  is  a  positive 
pulse  obtained  from  a  small  winding  on 
the  horizontal  output  transformer  which 
is  in  phase  with  the  horizontal  sync  pulse 
obtained  from  the  video  amplifier.  The 
polarity  of  this  pulse  is  such  that  the 
plate  of  the  age  amplifier  tube  is  positive 
during  the  retrace  time.  The  tube  is 
biased  so  that  current  flows  only  when 
the  grid  No.l  and  the  plate  are  driven 
positive  simultaneously.  The  amount  of 
current  flow  depends  on  the  grid-No.l 
potential  during  the  pulse.  These  pulses 
are  smoothed  out  in  the  RC  network  in 
the  plate  circuit  (RiCi).  Because  the  dc 
voltage  developed  across  Ri  is  negative, 
it  is  suitable  for  application  to  the  grids 
of  the  rf  and  if  tubes  as  an  age  voltage. 

Tuning  Indication  With 
Electron-Ray  Tubes 

Electron-ray  tubes  are  designed  to 
indicate  visually  by  means  of  a  fluores- 
cent target  the  effects  of  a  change  in 
controlling  voltage.  One  application  of 
them  is  as  tuning  indicators  in  radio 
receivers.  Types  such  as  the  6U5,  6E6, 
and  tke  6AB5/6N5  contain  two  main 
parts:  (1)  a  triode  which  operates  as  a  dc 
amplii«r  and  (2)  an  electron-ray  indi- 
cator which  is  located  in  the  bulb  as 
shown  in  Fig.  64.  The  target  is  operated 
at  a  positive  voltage  and,  therefore,  at- 
tracts electrons  from  the  cathode.  When 
the  electrons  strike  the  target  they  pro- 
duce a  glow  on  the  fluorescent  coating 
of  the  target.  Under  these  conditions, 


the  target  appears  as  a  ring  of  light. 

A  ray-control  electrode  is  mounted 
between  the  cathode  and  target.  When 
the  potential  of  this  electrode  is  less  posi- 
tive than  the  target,  electrons  flowing  to 
the  target  are  repelled  by  the  electro- 
static field  of  the  electrode,  and  do  not 

CATHODE   FLUORESCENT 

LIGHT y  ^  COATING 

SHIELD 


TARGET - 


TRIODE^ 
GRID 


RAY-CONTROU 
ELECTRODE 

TRIODE 
-'-'PLATE 


•^CATHODE 


Fig.  64 


reach  that  portion  of  the  target  behind 
the  electrode.  Because  the  target  does 
not  glow  where  it  is  shielded  from  elec- 
trons, the  control  electrode  casts  a 
shadow  on  the  glowing  target.  The  ex- 
tent of  this  shadow  varies  from  approx- 
imately 100°  of  the  target  when  the  con- 
trol electrode  is  much  more  negative 
than  the  target  to  0°  when  the  control 
electrode  is  at  approximately  the  same 
potential  as  the  target. 

In  the  application  of  the  electron- 
ray  tube,  the  potential  of  the  control 
electrode  is  determined  by  the  voltage 
on  the  grid  of  the  triode  section,  as  can 
be  seen  in  Fig.  65.  The  flow  of  the  triode 
plate  current  through  resistor  R  produces 


TO  CX)NTROLUNG 
-  VOLTAGE 


Fig.  65 


a  voltage  drop  which  determines  the  po- 
tential of  the  control  electrode.  When 
the  voltage  of  the  triode  grid  change*  in 
the  positive  direction,  plate  current  in- 
creases, the  potential  of  the  control  elec- 
trode goes  down  becauie  of  the  inareaied 
drop  across  R,  and  the  ihadow  anfle 
widens.  When  the  potential  of  the  triode 
grid  changes  in  the  negative  direction, 
the  shadow  angle  narrowi. 

Another  type  of  indicator  tube  is 
the  6AF6G.  This  tube  contains  only  an 
indicator  unit  but  employs  two  ray-con- 

49 


RCA  Receiving  Tube  Manual 


trol  electrodes  mounted  on  opposite  sides 
of  the  cathode  and  connected  to  indi- 
vidual base  pins.  It  employs  an  external 
dc  amphfier.  (See  Fig.  66.)  Thus,  two 
symmetrically  opposite  shadow  angles 


TYPE  6K7 
TRIODE 
CONNECTED 


R:  TYPICAL  VALUE  IS  0.5  MEGOHM 

Fig.  66 

may  be  obtained  by  connecting  the  two 
ray-control  electrodes  together;  or,  two 
unlike  patterns  may  be  obtained  by  in- 
dividual connection  of  each  ray-control 
electrode  to  its  respective  amplifier. 

In  radio  receivers,  avc  voltage  is 
applied  to  the  grid  of  the  dc  amplifier. 
Because  avc  voltage  is  at  maximum 
when  the  set  is  tuned  to  give  maximum 
response  to  a  station,  the  shadow  angle 
is  at  minimum  when  the  receiver  is 
tuned  to  resonance  with  the  desired 
station. 

The  choice  between  electron-ray 
tubes  depends  on  the  avc  characteristic 
of  the  receiver.  The  6E5  contains  a 
sharp-cutoff  triode  which  closes  the 
shadow  angle  on  a  comparatively  low 
value  of  avc  voltage.  The  6AB5/6N5 
and  6U5  each  have  a  remote-cutoff  tri- 
ode which  closes  the  shadow  on  a  larger 
value  of  avc  voltage  than  the  6E5.  The 
6AF6G  may  be  used  in  conjunction 
with  dc  amplifier  tubes  having  either 
remote-  or  sharp-cutoff  characteristics. 

Oscillation 

As  an  oscillator,  an  electron  tube 
can  be  employed  to  generate  a  continu- 
ously alternating  voltage.  In  present- 
day  radio  broadcast  receivers,  this  ap- 
plication is  limited  practically  to  super- 
heterodyne receivers  for  supplying  the 
heterodyning  frequency.  Several  circuits 
(represented  in  Figs.  67  and  68)  may  be 
utilized,  but  they  all  depend  on  feeding 
more  energy  from  the  plate  circuit  to  the 
grid  circuit  than  is  required  to  equal  the 
power  loss  in  the  grid  circuit.  Feedback 
may  be  produced  by  electrostatic  or 
electromagnetic  coupling  between  the 
grid  and  plate  circuits.  When  sufficient 
energy  is  fed  back  to  more  than  compen- 
sate for  the  loss  in  the  grid  circuit,  the 

50 


8-     A-  Bi¥ 


Fig.  67 

tube  will  oscillate.  The  action  consists 
of  regular  surges  of  power  between  the 
plate  and  the  grid  circuit  at  a  frequency 
depeiident  on  the  circuit  constants  of 
inductance  and  capacitance.  By  proper 
choice  of  these  values,  the  frequency 
may  be  adjusted  over  a  very  wide  range. 


Fig.  68 

hAulViyibraiors 

Relaxation  oscillators,  which  are 
widely  used  in  present-day  electronic 
equipment,  are  used  to  produce  non- 
sinusoidal  waveshapes  such  as  rectangu- 
lar and  sawtooth  pulses.  Probably  the 
most  common  relaxation  oscillator  is  the 
multivibrator,  which  may  be  considered 
as  a  two-stage  resistance-coupled  ampli- 
fier in  which  the  output  of  each  tube  is 
coupled  into  the  input  of  the  other  tube. 

Fig.  69  is  a  basic  multivibrator  cir- 
cuit of  the  free-running  type.  In  this  cir- 
cuit, oscillations  are  maintained  by  the 


Fig.  69 


alternate  shifting  of  conduction  from 
one  tube  to  the  other.  The  cycle  usually 
starts  with  one  tube,  Vi,  at  zero  bias, 
and  the  other,  V2,  at  cutoff  or  beyond. 
At  this  point,  the  capacitor  Ci  is  charged 


Electron  Tube  Applications 


sufficiently  to  cut  off  Va.  Ci  then  begins 
to  discharge  through  the  resistor  R4,  and 
the  voltage  on  the  grid  of  V2  rises  until 
V2  begins  to  conduct.  The  voltage  on  the 
plate  of  V2  then  decreases,  causing  Vi  to 
conduct  less  and  less.  At  the  same  time, 
the  plate  voltage  of  Vi  begins  to  rise, 
causing  V2  to  conduct  still  more  heavily. 
Because  of  the  amplification,  this  cumu- 
lative effect  builds  up  extremely  fast, 
and  conduction  switches  from  Vi  to  V2 
within  a  few  microseconds,  depending 
on  the  circuit  components. 

In  this  circuit,  therefore,  conduc- 
tion switches  from  Vi  to  V2  over  the 
interval  during  which  Ci  discharges 
from  the  voltage  across  R4  to  the  cutoff 
voltage  for  V2.  The  actual  transfer  ot 
conduction  does  not  occur  until  cutoff 
is  reached.  Conduction  switches  back  to 
Vl  through  a  similar  process  to  complete 
the  cycle.  The  plate  waveform  is  essen- 
tially rectangular  in  shape,  and  may  be 
adjusted  as  to  symmetry  frequency, 
and  amplitude  by  proper  choice  of  cir- 
cuit constants,  tubes,  and  voltages. 

Although  this  type  of  multivibrator 
is  free-running,  it  may  be  triggered  by 
pulses  of  a  given  amplitude  and  frequency 
to  provide  a  frequency-stabilized  out- 
put. Multivibrator  circuits  may  also  be 
designed  so  that  they  are  not  free-run- 
ning, but  must  be  triggered  externally 
to  shift  conduction  from  one  tube  to  the 
other.  Depending  on  the  type  of  circuit, 
conduction  may  shift  back  to  the  first 
tube  after  a  given  time  interval,  or  the 
second  tube  may  continue  conducting 
until  another  trigger  signal  is  applied. 

Synchro  guide  Circuits 
The  "synchroguide"  is  a  controlled 
type  of  oscillator  used  in  television  re- 
ceivers to  generate  and  control  the  syn- 
chronized sawtooth  voltage  necessary  for 
adequate  line-  or  horizontal-frequency 
scanning.  A  simplified  synchroguide  cir- 
cuit is  shown  in  Fig.  70.  This  circuit  pro- 
vides stable,  noise-free  control  of  a  block- 
ing oscillator  which  generates  a  horizon- 
tal-frequency signal.  It  permits  com- 
parison of  the  received  sync  pulses  and 
the  generated  sawtooth  voltages  so  that 
properly  locked-in  horizontal  scanning 
results. 

The  triode  V2in  Fig.  70  is  a  conven- 
tional blocking  oscillator  which  enables 


a  sawtooth  voltage  to  be  developed 
across  the  capacitor  C2.  A  portion  of  this 
sawtooth  is  fed  back  to  the  grid  of  the- 
control  tube,Vi.  The  positive  sync  pulsesi 


TO 

HORIZONTAL 
■  SCANNING 
AMPLIFIER 


Fig.  70  ~ 

are  also  applied  to  the  grid  of  Vi.  The 
waveforms  shown  in  Fig.  71  illustrate 
the  sawtooth  and  sync  pulses  (A  and  B) 
and  their  proper  "in-sync"  combination 
(C).  The  sync  pulse  occurs  partly  during 
the  portion  of  the  sawtooth  voltage  in 
which  the  triode  Vi  draws  current.  Any 
shift  in  sync  pulse  as  it  is  superimposed 

CUJOFF^ 
A  ~ 


=\-  SAWTOOTH 


SYNC- PULSES 
IN -SYNC" 


^  ^      r\c/-i\  I  \TtK\n. 


'TOFF—  ■■■■■■ 


Fi^.  71 


OSCILLATING 
FREQUENCY 
LOWER  THAN 
SYNC- PULSE 
FREQUENCY 


on  the  sawtooth,  therefore,  will  affect 
the  amount  of  conduction  of  the  control 
tube.  A  change  in  control-tube  conduc- 
tion ultimately  affects  the  bias  on  the 
oscillator-tube  grid  by  changing  the 
voltage  to  which  the  capacitor  Ci  in  the 
cathode  circuit  may  charge.  An  increase 
in  the  positive  bias  increases  the  fre- 
quency of  oscillation. 

For  example,  waveform  D  in  Fig. 
71  illustrates  a  condition  in  which  the 
sawtooth  voltage  is  advanced  in  phase 
with  respect  to  the  sync-pulses.  The 
widening  of  the  pulse  which  occurs  at 
the  corner  of  the  sawtooth  waveform 
allows  the  control  tube  to  conduct  more 
current  and,  consequently,  allows  the 
capacitor  Ci  to  charge  to  a  higher  volt- 
age. This  increased  reference  voltage  also* 
appears  in  the  grid  circuit  of  V2  and 
makes  the  grid  more  positive.  The  in- 
creased grid  voltage  then  speeds  up  the 
frequency  of  oscillations  until  proper 
synchronization  results. 

51 


RCA  Receiving  Tube  Manual 


The  blocking  oscillator  can  be  made 
more  immune  to  changes  in  frequency 
and  noise  if  V2  is  brought  out  of  cutoff 
very  sharply.  This  effect  is  obtained  by 
sine-wave  stabilization.  The  tuned  cir- 
cuit L3-C3  in  the  plate  circuit  of  Fig.  70 
superimposes  a  shock-excited  sine  wave 
on  the  plate  and  grid  waveforms,  as 
shown  in  Fig.  72. 


GRID  CUTOFF 


GRADUAL  approach; 
TUBE  CAN  BE  DRIVEN 
OUT  OF  CUTOFF  BY 
SLIGHT  CIRCUIT 
VARIATIONS. 

SHARPER  APPROACH 
MAKES  OSCILLATOR  LESS 
SUSCEPTIBLE  TO 
FREQUENCY  CHANGES, 

Fig.  72 

Deflection  Circuits 

Vertical  Output  Circuits 

A  modified  multivibrator  in  which 
the  vertical  output  tube  is  part  of  the 
oscillator  circuit  is  used  in  the  vertical 
deflection  stage  of  many  television  re- 
ceivers. This  stage  supplies  the  deflec- 
tion energy  required  for  vertical  deflec- 
tion of  the  picture-tube  beam.  A  simpli- 
fied combined  vertical-oscillator-output 
stage  is  shown  in  Fig.  73.  Waveshapes  at 
critical  points  of  the  circuit  are  included 


the  inductive  components  in  the  yoke 
and  transformer.  The  effect  of  these  in- 
ductive components  must  be  taken  in- 
to consideration,  however,  particularly 
during  retrace.  The  fast  rate  of  current 
change  during  retrace  time  (which  is 
approximately  1/15  as  long  as  trace 
time)  causes  a  high-voltage  pulse  at 
the  plate  which  could  give  a  trapezoi- 
dal waveshape  to  the  plate  voltage  and 
cause  increased  plate  current,  excess 
damping,  and  lengthened  retrace  time. 
However,  the  grid  voltage  is  made  suffi- 
ciently negative  during  retrace  to  keep 
the  tube  close  to  cutoff  ,  asdescribedbelow. 

The  frequency,  and  the  relative  de- 
viation of  the  positive  and  negative  por- 
tions of  each  cycle,  are  dependent  on  the 
values  of  resistors  Ri  and  R3  and  the  RC 
combination  R3C2,  as  explained  previ- 
ously in  the  section  on  multivibrators. 
The  desired  trapezoidal  waveshape  at 
the  grid  of  V2  is  created  by  capacitor  Ci 
and  resistor  R2.  If  R2  were  equal  to  zero, 
Ci  would  cause  the  grid-voltage  wave- 
shape to  take  the  form  shown  in  Fig. 
74(a).  When  R2  is  sufficiently  large,  Ci 
does  not  discharge  completely  when  Vi 
conducts.  When  Vi  is  cut  off,  therefore, 
the  voltage  on  the  grid  of  V2  immedi- 
ately rises  to  the  voltage  across  Ci.  The 
resulting  waveshape  is  shown  in  Fig. 


m 


VERTICAL 

-WV  1  OUTPUT 

TRANSFORMER 


VERTICAL 
WINDINGS  OF 
'EFLECTING  YOKE 


to  illustrate  the  development  of  the  de- 
sired current  through  the  vertical  out- 
put transformer  and  deflecting  yoke. 

The  current  waveform  through  the 
deflecting  yoke  and  output  transformer 
should  be  a  sawtooth  to  provide  the  de- 
sired deflection.  The  grid  and  plate  volt- 
age waveforms  of  the  output  tube  could 
also  be  sawtooth  except  for  the  effect  of 

52 


74(b),  The  negative-going  pulse  of  the 
grid-voltage  waveshape  prevents  the  high 
plate  pulse  from  causing  excess  conduc- 
tion, and  thereby  prevents  overdamping. 


Fig.  74 


Electron  Tube  Applications 


This  vertical  deflection  stage  uti- 
lizes twin-triode  tubes  such  as  the  6DR7 
and  6EM7.  The  6EM7  is  particularly 
suitable  for  this  application  because  it 
incorporates  dissimilar  units  to  provide 
for  the  different  operating  requirements 
of  the  oscillator  and  output  sections. 

Horizontal  Output  Circuits 
Fig.  75  shows  a  typical  horizontal- 
output-and-deflection  circuit  used  in  tele- 
vision receivers.  In  addition  to  supplying 
the  deflection  energy  required  for  hori- 
zontal deflection  of  the  picture-tube 
beam,  this  circuit  provides  the  high  dc 


HIGH-VOLTAGE 
RECTIFIER 


TO  ULTOR  OF 
PICTURE  TUBE 


"^Jil^i^Ii^.  LINEARITY 
CONTROL  CONTROL 


voltage  required  for  the  ultor  of  the  pic- 
ture tube  and  the  "boosted"  B  voltage 
for  other  portions  of  the  receiver.  The 
horizontal-output  tube  is  usually  a  beam 
power  tube  such  as  the  6DQ6B,  6CD6- 
GA,  or  6GW6. 

In  this  circuit,  a  sawtooth  voltage 
from  the  horizontal-oscillator  tube  is  ap- 
plied to  the  grid  No.l  of  the  horizontal- 
output  tube.  When  this  voltage  rises 
above  the  cutoff  point  of  the  output  tube, 
the  tube  conducts  a  sawtooth  of  plate 
current  which  is  fed  through  the  auto- 
transformer  to  the  horizontal-deflecting 
yoke.  At  the  end  of  the  horizontal-scan- 
ning cycle,  which  lasts  for  63.4  micro- 
seconds, the  sawtooth  voltage  on  the 
grid  suddenly  cuts  off  the  output  tube. 
This  sudden  change  sets  up  an  oscillation 
of  about  50  to  70  Kc  in  the  output  cir- 
cuit, which  may  be  considered  as  an  in- 
ductor shunted  by  the  stray  capacitance 
of  the  circuit.  During  the  first  half  of 
this  oscillation,  a  positive  voltage  ap- 
pears across  the  transformer.  In  the  sec- 


ond half  of  the  cycle,  the  voltage  swings 
below  the  plate  supply  voltage,  and  the 
damper  diode  conducts,  damping  out  the 
oscillation.  At  the  same  time,  the  current 
through  the  deflecting  yoke  reverses  and 
reaches  its  negative  peak.  As  the  damper- 
diode  current  decays  exponentially  to 
zero,  the  output  tube  begins  to  conduct 
again.  The  yoke  current,  therefore,  is 
composed  of  current  resulting  from 
damper-diode  conduction  followed  by 
output-tube  conduction. 

When  the  output  tube  is  suddenly 
cut  off,  the  high-voltage  pulse  produced 
by  shock  excitation  of  the  load  circuit  is 
increased  by  means  of  an  extra  winding 
on  the  transformer.  This  high-voltage 
pulse  charges  a  high-voltage  capacitor 
through  the  high-voltage  rectifier.  The 
output  of  this  circuit  is  the  dc  high- 
voltage  supply  for  the  picture  tube.  The 
high-voltage  rectifier  also  obtains  its 
filament  power  through  a  separate  wind- 
ing on  the  horizontal-output  transformer. 

Current  flowing  through  the  damper 
diode  charges  the  "boost"  capacitor 
through  the  damper  portion  of  the  trans- 
former winding.  The  polarity  of  the 
charge  on  the  capacitor  is  such  that  the 
voltage  at  the  low  end  of  the  winding  is 
increased  above  the  plate  supply  volt- 
age, or  B+.  This  higher  voltage  or 
"boost"  is  used  for  the  output-tube 
plate  supply,  and  may  also  supply  the 
deflection  oscillators  and  the  vertical- 
output  circuit  provided  the  current  drain 
is  not  excessive. 

High-Voltage  Regulator  Circuit 

In  color-television  receivers,  it  is 
very  important  to  regulate  the  high- vol- 
tage supply  to  the  picture  tube.  A  suitable 
circuit  using  the  6BK4  for  regulation  of 


(UNREguLateo 

IWPUT) 


6 
eo 

(REGULATe^ 
OUTPUT) 

o 


Fig.  76 

the  output  of  a  high-voltage,  high-impe- 
dance supply  is  shown  in  Fig.  76.  In  this 

53 


RCA  Receiving  Tube  Manual 


circuit,  the  cathode  is  held  at  a  fixed 
positive  potential  with  respect  to  ground. 
Because  the  grid  potential  is  kept  slightly 
less  positive  by  the  voltage  drop  across 
resistor  R2,  the  tube  operates  in  the  nega- 
tive grid  region  and  no  grid  current  is 
drawn. 

When  the  output  voltage,  e©,  rises 
as  a  result  of  a  decrease  in  load  current, 
a  small  fraction  of  the  additional  vol- 
tage is  appUed  to  the  grid  of  the  tube  by 
the  voltage-divider  circuit  consisting  of 
Ri  and  R2.  This  increased  grid  voltage 
causes  the  tube  to  draw  an  increased 
current  from  the  unregulated  supply. 
The  increased  current,  in  turn,  causes 
a  voltage  drop  across  the  high  internal 
impedance  of  the  unregulated  supply, 
Rs,  which  tends  to  counteract  the  origi- 
nal rise  of  the  voltage.  If  desired,  the 
grid  may  be  connected  to  a  variable 
point  on  the  voltage  divider  to  allow 
some  adjustment  of  the  output-voltage 
level. 

The  grid  voltage  for  the  6BK4  can 
also  be  obtained  from  a  tap  on  the  B- 
boost  voltage  supply.  The  use  of  this 
lower  voltage  (about  375  volts)  elimi- 
nates the  need  for  costly  and  trouble- 
some high-voltage  resistors.  In  this  ar- 
rangement, variations  in  high  voltage 
also  vary  the  tapped-down  B-boost  volt- 
age at  the  regulator  grid,  and  the  result- 
ing variations  in  conduction  of  the  regu- 
lator increase  or  decrease  the  loading  of 
the  high- voltage  supply  so  that  the  total 
load  remains  nearly  constant. 

Frequency  Conversion 

Frequency  conversion  is  used  in 
superheterodyne  receivers  to  change  the 
frequency  of  the  rf  signal  to  an  inter- 
mediate frequency.  To  perform  this 
change  in  frequency,  a  frequency-con- 
verting device  consisting  of  an  oscillator 
and  a  frequency  mixer  is  employed.  In 
such  a  device,  shown  diagrammatically 
in  Fig.  77,  two  voltages  of  different  fre- 
quency, the  rf  signal  voltage  and  the 
voltage  generated  by  the  oscillator,  are 


FREQUENCY 

FREQUENCY 

INTERMEDIATE 
FREQUENCY  ^ 

IWPUT 

MIXER 

OUTPUT 

<   OSCILLATOR 

FREOUENCY  CONVERTER 
Fig.  77 


applied  to  the  input  of  the  frequency 
mixer.  These  voltages  beat,  or  hetero- 
dyne, within  the  mixer  tube  to  produce 
a  plate  current  having,  in  addition  to  the 
frequencies  of  the  input  voltages,  numer- 
ous sum  and  difference  frequencies. 

The  output  circuit  of  the  mixer 
stage  is  provided  with  a  tuned  circuit 
which  is  adjusted  to  select  only  one  beat 
frequency,  i.e.,  the  frequency  equal  to 
the  difference  between  the  signal  fre- 
quency and  the  oscillator  f requency.The 
selected  output  frequency  is  known  as 
the  intermediate  frequency,  or  if.  The 
output  frequency  of  the  mixer  tube  is 
kept  constant  for  all  values  of  signal  fre- 
quency by  tuning  the  oscillator  to  the 
proper  frequency. 

Important  advantages  gained  in  a 
receiver  by  the  conversion  of  signal  fre- 
quency to  a  fixed  intermediate  frequency 
are  high  selectivity  with  few  tuning 
stages  and  a  high,  as  well  as  stable,  over- 
all gain  for  the  receiver. 

Several  methods  of  frequency  con- 
version for  superheterodyne  receivers 
are  of  interest.  These  methods  are  alike 
in  that  they  employ  a  frequency-mixer 
tube  in  which  plate  current  is  varied  at 
a  combination  frequency  of  the  signal 
frequency  and  the  oscillator  frequency. 
These  variations  in  plate  current  pro- 
duce across  the  tuned  plate  load  a  volt- 
age of  the  desired  intermediate  fre- 
quency. The  methods  differ  in  the  types 
of  tubes  employed  and  in  the  means  of 
supply  input  voltages  to  the  mixer  tube. 

A  method  widely  used  before  the 
availability  of  tubes  especially  designed 
for  frequency-conversion  service  and 
currently  used  in  many  FM,  television, 
and  standard  broadcast  receivers,  em- 
ploys as  mixer  tube  either  a  triode,  a 
tetrode,  or  a  pentode,  in  which  oscillator 
voltage  and  signal  voltage  are  appHed  to 
the  same  grid.  In  this  method,  coupling 
between  the  oscillator  and  mixer  circuits 
is  obtained  by  means  of  inductance  or 
capacitance. 

A  second  method  employs  a  tube 
having  an  oscillator  and  frequency  mixer 
combined  in  the  same  envelope.  In  one 
form  of  such  a  tube,  coupling  between 
the  two  units  is  obtained  by  means  of 
the  electron  stream  within  the  tube. 
Because  five  grids  are  used,  the  tube  is 
called  a  pentagrid  converter. 


54 


Electron  Tube  Applications 


Grids  No.  1  and  No.  2  and  the  cath- 
ode are  connected  to  an  external  circuit 
to  act  as  a  triode  oscillator.  Grid  No.  1 
is  the  grid  of  the  oscillator  and  grid  No. 
2  is  the  anode.  These  and  the  cathode 
can  be  considered  as  a  composite  cath- 
ode which  supplies  to  the  rest  of  the 
tube  an  electron  stream  that  varies  at 
the  oscillator  frequency. 

This  varying  electron  stream  is  fur- 
ther controlled  by  the  rf  signal  voltage 
on  grid  No.  4.  Thus,  the  variations  in 
plate  current  are  due  to  the  combination 
of  the  oscillator  and  the  signal  frequen- 
cies. The  purpose  of  grids  No.  3  and  No. 
5,  which  are  connected  together  within 
the  tube,  is  to  accelerate  the  electron 
stream  and  to  shield  grid  No.  4  electro- 
statically from  the  other  electrodes. 

Pentagrid-converter  tubes  of  this 
design  are  good  frequency-converting 
devices  at  medium  frequencies.  How- 
ever, their  performance  is  better  at  the 
lower  frequencies  because  the  output  of 
the  oscillator  drops  off  as  the  frequency 
is  raised  and  because  certain  undesirable 
effects  produced  by  interaction  between 
oscillator  and  signal  sections  of  the  tube 
increase  with  frequency. 

To  minimize  these  effects,  several 
of  the  pentagrid-converter  tubes  are  de- 
signed so  that  no  electrode  functions 
alone  as  the  oscillator  anode.  In  these 
tubes,  grid  No.  1  functions  as  the  oscil- 
lator grid,  and  grid  No.  2  is  connected 
within  the  tube  to  the  screen  grid  (grid 
No.  4).  The  combined  two  grids,  Nos.  2 
and  4,  shield  the  signal  grid  (grid  No.  3) 
and  act  as  the  composite  anode  of  the 
oscillator  triode.  Grid  No.  5  acts  as  the 
suppressor  grid. 

Converter  tubes  of  this  type  are  de- 
signed so  that  the  space  charge  around 
the  cathode  is  unaffected  by  electrons 
from  the  signal  grid.  Furthermore,  the 
electrostatic  field  of  the  signal  grid  also 
has  little  effect  on  the  space  charge.  The 
result  is  that  rf  voltage  on  the  signal 
grid  produces  little  effect  on  the  cathode 
current.  There  is,  therefore,  little  detun- 
ing of  the  oscillator  by  avc  bias  because 
changes  in  avc  bias  produce  little  change 
in  oscillator  transconductance  or  in  the 
input  capacitance  of  grid  No.  1. 

Examples  of  the  pentagrid  conver- 
ters discussed  in  the  preceding  para- 
graph are  the  single-ended  types  1R5  and 


6BE6.  A  schematic  diagram  illustrating 
the  use  of  the  6BE6  with  self-excitation 
is  given  in  Fig.  78;  the  6BE6  may  also 


RF  ^ 
INPUT 


GRID  N2  3 
(RF  SIGNAL) 


  ,     -GRID  N2  5 

<rr>(  (SUPPRESSOR) 


OSCILLATOR 
CIRCUIT 


Fig.  78 

be  used  with  separate  excitation.  A  com- 
plete circuit  is  shown  in  the  CIRCUIT 
SECTION. 

Another  method  of  frequency  con- 
version utilizes  a  separate  oscillator  hav- 
ing its  grid  connected  to  the  No.  1  grid 
of  a  mixer  hexode.  The  cathode,  triode 
grid,  and  triode  plate  form  the  oscillator 
unit  of  the  tube.  The  cathode,  hexode 
mixer  grid  (gridNo.  l)hexodescreen  grids 
(grids  Nos.  2  and  4),  hexode  signal  grid 
(grid  No.  3),  and  hexode  plate  constitute 
the  mixer  unit.  The  internal  shields  are 
connected  to  the  shell  of  the  tube  and 
act  as  a  suppressor  grid  for  the  hexode 
unit. 

The  action  of  this  tube  in  convert- 
ing a  radio-frequency  signal  to  an  inter- 
mediate frequency  depends  on  (1)  the 
generation  of  a  local  frequency  by  the 
triode  unit,  (2)  the  transferring  of  this 
frequency  to  the  hexode  grid  No.  1,  and 
(3)  the  mixing  in  the  hexode  unit  of  this 
frequency  with  that  of  the  rf  signal  ap- 
plied to  the  hexode  grid  No.  3.  The  tube 
is  not  critical  to  changes  in  oscillator- 
plate  voltage  or  signal-grid  bias  and, 
therefore,  finds  important  use  in  all- 
wave  receivers  to  minimize  frequency- 
shift  effects  at  the  higher  frequencies. 

A  further  method  of  frequency  con- 
version employs  a  tube  called  a  penta- 
grid mixer.  This  type  has  two  independ- 
ent control  grids  and  is  used  with  a 
separate  oscillator  tube.  RF  signal  volt- 
age is  applied  to  one  of  the  control  grids 
and  oscillator  voltage  is  applied  to  the 
other.  It  follows,  therefore,  that  the 
variations  in  plate  current  are  due  to 
the  combination  of  the  oscillator  and 
signal  frequencies. 

55 


RCA  Receiving  Tube  Manual 


The  tube  contains  a  heater-cathode, 
five  grids,  and  a  plate.  Grids  Nos.  1  and 
3  are  control  grids.  The  rf  signal  voltage 
is  applied  to  grid  No.  1.  This  grid  has  a 
remote-cutoff  characteristic  and  is  suited 
for  control  by  avc  bias  voltage.  The 
oscillator  voltage  is  applied  to  grid  No. 
3.  This  grid  has  a  sharp-cutoff  character- 
istic and  produces  a  comparatively  large 
effect  on  plate  current  for  a  small  amount 
of  oscillator  voltage.  Grids  Nos.  2  and  4 
are  connected  together  within  the  tube. 
They  accelerate  the  electron  stream  and 
shield  grid  No.  3  electrostatically  from 
the  other  electrodes.  Grid  No.  5,  con- 
nected within  the  tube  to  the  cathode, 
functions  similarly  to  the  suppressor 
grid  in  a  pentode. 

In  the  converter  or  mixer  stage  of  a 
television  receiver,  stable  oscillator  oper- 
ation is  most  readily  obtained  when 
separate  tubes  or  tube  sections  are  used 
for  the  oscillator  and  mixer  functions.  A 
typical  television  mixer-oscillator  circuit 
is  shown  in  Fig.  79.  In  such  circuits,  the 
oscillator  voltage  is  applied  to  the  mixer 
grid  by  inductive  coupling,  capacitive 
coupling,  or  a  combination  of  the  two. 


RF  INPUT 


Fig.  79 

Tubes  containing  electrically  independ- 
ent oscillator  and  mixer  units  in  the 
same  envelope,  such  as  the  6U8A  and 
6X8,  are  designed  especially  for  this 
application. 

Automatic  Frequency  Control 

An  automatic  frequency  control 
(afc)  circuit  provides  a  means  of  correct- 
ing automatically  the  intermediate  fre- 
qmency  of  a  superheterodyne  receiver 
when,  for  any  reason,  it  drifts  from  the 
frequency  to  which  the  if  stages  are 
turned.  This  correction  is  made  by  ad- 
juiting  the  frequency  of  the  oscillator. 
Such  a  circuit  will  automatically  com- 
pensate for  slight  changes  in  rf  carrier  or 
oicillator  frequency  as  well  as  for  inac- 
curate manual  or  push-button  tuning. 

An  afc  system  requires  two  sections: 
a  frequency  detector  and  a  variable  re- 


actance. The  detector  section  may  be 
essentially  the  same  as  the  FM  detector 
illustrated  in  Fig.  57  and  discussed  un- 
der Detection,  In  the  afc  system,  how- 
ever, the  output  is  a  dc  control  voltage, 
the  magnitude  of  which  is  proportional 
to  the  amount  of  frequency  shift.  This 
dc  control  voltage  is  used  to  control  the 
grid  bias  of  an  electron  tube  which  com- 
prises the  variable  reactance  section 
(Fig.  80). 


Fig.  80 


The  plate  current  of  the  reactance 
tube  is  shunted  across  the  oscillator  tank 
circuit.  Because  the  plate  current  and 
plate  voltage  of  the  reactance  tube  are 
almost  90°  out  of  phase,  the  control  tube 
affects  the  tank  circuit  in  the  same  man- 
ner as  a  reactance.  The  grid  bias  of  the 
tube  determines  the  magnitude  of  the 
effective  reactance  and,  consequently, 
a  control  of  this  grid  bias  can  be  used  to 
control  the  oscillator  frequency. 

Automatic  frequency  control  is  also 
used  in  television  receivers  to  keep  the 
horizontal  oscillator  in  step  with  the 
horizontal-scanning  frequency  (15,750 
cps)  at  the  transmitter.  A  widely  used 
horizontal  afc  circuit  is  shown  in  Fig.  81. 
This  circuit,  which  is  often  referred  to 
as  a  balanced-phase-detector  or  phase- 
discriminator  circuit,  is  usually  em- 
ployed to  control  the  frequency  of  a 
multivibrator-type  horizontal-oscillator 
circuit.  The  6AL5  detector  supplies  a  dc 
control  voltage  to  the  grid  of  the  hori- 
zontal-oscillator tube  which  counteracts 
changes  in  its  operating  frequency.  The 
magnitude  and  polarity  of  the  control 
voltages  are  determined  by  phase  rela- 
tionships in  the  afc  circuit  at  a  given 
moment. 

The  horizontal  sync  pulses  obtained 
from  the  sync-Beparator  circuit  are  fed 
through  a  single-triode  phase-inverter  or 


56 


Electron  Tube  Applications 


phase-splitter  circuit  to  the  two  diode 
units  of  the  6AL5.  Because  of  the  action 
of  the  phase-inverter  circuit,  the  signals 


ROM  PHASE    n  rv-J(  . 

INVERTER    tJ  L^^^ 

  .  L 


DC  CORRECTION 
VOLTAGE  TO  GRID 
OF  HORIZONTAL 
OSCILLATOR 

Fig.  81 

applied  to  the  two  diode  units  are  equal 
in  amplitude  but  180  degrees  out  of 
phase.  A  reference  sawtooth  voltage  ob- 
tained from  the  horizontal  output  cir- 
cuit is  also  applied  simultaneously  to 


both  units.  Any  change  in  the  oscillator 
frequency  alters  the  phase  relationship 
between  the  reference  sawtooth  and  the 
incoming  horizontal  sync  pulses,  causing 
one  diode  unit  of  the  6AL5  to  conduct 
more  heavily  than  the  other,  and  thus 
producing  a  correction  signal.  The  sys- 
tem remains  balanced  at  all  times,  there- 
fore, because  momentary  changes  in 
oscillator  frequency  are  instantaneously 
corrected  by  the  action  of  the  control 
voltage. 

The  diode  units  of  the  6AL5  are 
biased  so  that  conduction  takes  place 
only  during  the  tips  of  the  sync  pulses. 
The  relative  position  of  the  sync  pulses 
on  the  retrace  portion  of  the  sawtooth 
waveform  at  any  given  instant  deter- 
mines which  diode  unit  conducts  more 
heavily,  and  thereby  establishes  the 
magnitude  and  polarity  of  the  control 
voltage.  The  network  between  the  diode 
units  and  the  grid  of  the  horizontal-oscil- 
lator tube  is  essentially  a  low-pass  filter 
which  prevents  the  horizontal  sync  pulses 
from  affecting  the  horizontal-oscillator 
performance. 


57 


Electron  Tube 
Installation 


The  installation  of  electron  tubes 
requires  care  if  high-quality  performance 
is  to  be  obtained  from  the  associated 
circuits.  Installation  suggestions  and 
precautions  which  are  generally  com- 
mon to  all  types  of  tubes  are  covered  in 
this  section.  Careful  observance  of  these 
suggestions  will  do  much  to  help  the  ex- 
perimenter and  electronic  technician  ob- 
tain the  full  performance  capabilities  of 
radio  tubes  and  circuits.  Additional  per- 
tinent information  is  given  under  each 
tube  type  and  in  the  CIRCUIT  SEC- 
TION. 

Filament  and  Heater  Power  Supply 

The  design  of  electron  tubes  allows 
for  some  variation  in  the  voltage  and 
current  supplied  to  the  filament  or  heater, 
but  most  satisfactory  results  are  obtained 
from  operation  at  the  rated  values. When 
the  voltage  is  low,  the  temperature  of 
the  cathode  is  below  normal,  with  the 
result  that  electron  emission  is  limited. 
The  limited  emission  may  cause  unsatis- 
factory operation  and  reduced  tube  life. 
On  the  other  hand,  high  cathode  voltage 
may  cause  rapid  evaporation  of  cathode 
material  and  shorten  tube  life. 

To  insure  proper  tube  operation,  it 
is  important  that  the  filament  or  heater 
voltage  be  checked  at  the  socket  termi- 
nals by  means  of  a  high-resistance  volt- 
meter while  the  equipment  is  in  opera- 
tion. In  the  case  of  series  operation  of 
heaters  or  filaments,  correct  adjustment 
can  be  checked  by  means  of  an  ammeter 
in  the  heater  or  filament  circuit. 

The  filament  or  heater  voltage  sup- 
ply may  be  a  direct-current  source  (a 
battery  or  a  dc  power  line)  or  an  alter- 
nating-current power  line,  depending  on 
the  type  of  service  and  type  of  tube. 
Frequently,  a  resistor  (either  variable 
or  fixed)  is  used  with  a  dc  supply  to  per- 
mit compensation  for  battery  voltage 
variations  or  to  adjust  the  tube  voltage 
at  the  socket  terminals  to  the  correct 
value.  Ordinarily,  a  step-down  trans- 
former is  used  with  an  ac  supply  to  pro- 


vide the  proper  filament  or  heater  volt- 
age. Receivers  intended  for  operation  on 
both  dc  and  ac  power  lines  have  the 
heaters  connected  in  series  with  a  suit- 
able resistor  and  supplied  directly  from 
the  power  line. 

DC  filament  or  heater  operation 
should  be  considered  on  the  basis  of  the 
source  of  power.  In  the  case  of  the  bat- 
tery supply  for  the  1.4-volt  filament 
tubes,  it  is  unnecessary  to  use  a  voltage- 
dropping  resistor  in  series  with  the  fila- 
ment and  a  single  dry-cell;  the  filaments 
of  these  tubes  are  designed  to  operate 
satisfactorily  over  the  range  of  voltage 
variations  that  normally  occur  during 
the  life  of  a  dry-cell.  Likewise,  no  series 
resistor  is  required  when  the  1.2  5- volt 
filament  subminiatures  are  operated  from 
a  single  1.6-volt  flashlight-type  dry-cell, 
when  the  2-volt  filament  type  tubes  are 
operated  from  a  single  storage  cell,  or 
when  the  6.3-volt  series  are  operated 
from  a  6-volt  storage  battery. 

In  the  case  of  dry-battery  supply 
for  2-volt  filament  tubes,  a  variable  re- 
sistor in  series  with  the  filament  and  the 
battery  is  required  to  compensate  for 
battery  variations.  Turning  the  set  on 
and  off  by  means  of  the  rheostat  is  ad- 
vised to  prevent  over-voltage  conditions 
after  an  off-period  because  the  voltage  of 
dry-cells  rises  during  off-periods. 

In  the  case  of  storage-battery  sup- 
ply, air-cell-battery  supply,  or  dc  power 
supply,  a  non-adjustable  resistor  of  suit- 
able value  may  be  used.  It  is  well  to 
check  initial  operating  conditions,  and 
thus  the  resistor  value,  by  means  of  a 
voltmeter  or  ammeter. 

AC  filament  or  heater  operation 
should  be  considered  on  the  basis  of 
either  a  parallel  or  a  series  arrangement 
of  filaments  and/or  heaters.  In  the  case 
of  the  parallel  arrangement,  a  step-down 
transformer  is  employed.  Precautions 
should  be  taken  to  see  that  the  line  volt- 
age is  the  same  as  that  for  which  the 
primary  of  the  transformer  is  designed. 
The  line  voltage  may  be  determined  by 


58 


Electron  Tube  Installation 


measurement  with  an  ac  voltmeter 
(0-150  volts). 

If  the  line  voltage  measures  in  ex- 
cess of  that  for  which  the  transformer  is 
designed,  a  resistor  should  be  placed  in 
series  with  the  primary  to  reduce  the 
line  voltage  to  the  rated  value  of  the 
transformer  primary  .Unless  this  is  done, 
the  excess  input  voltage  will  cause  pro- 
portionally excessive  voltage  to  be  ap- 
plied to  the  tubes.  Any  electron  tube 
may  be  damaged  or  made  inoperative  by 
excessive  operating  voltages. 

If  the  line  voltage  is  consistently 
below  that  for  which  the  primary  of  the 
transformer  is  designed,  it  may  be  nec- 
essary to  install  a  booster  transformer 
between  the  ac  outlet  and  the  tr ansf  ormer 
primary.  Before  such  a  transformer  is  in- 
stalled, the  ac  line  fluctuations  should  be 
very  carefully  noted.  Some  radio  sets  are 
equipped  with  a  line-voltage  switch 
which  permits  adjustment  of  the  power 
transformer  primary  to  the  line  voltage. 
When  this  switch  is  properly  adjusted, 
the  series-resistor  or  booster-transformer 
method  of  controlling  line  voltage  is 
seldom  required. 

In  the  case  of  the  series  arrange- 
ments of  filaments  and/or  heaters,  a 
voltage-dropping  resistance  in  series  with 
the  heaters  and  the  supply  line  is  usually 
required.  This  resistance  should  be  of 
such  value  that,  for  normal  line  voltage, 
tubes  will  operate  at  their  rated  heater 
or  filament  current.  The  method  for  cal- 
culating the  resistor  value  is  given  below. 

When  the  filaments  of  battery-type 
tubes  are  connected  in  series,  the  total 
filament  current  is  the  sum  of  the  cur- 
rent due  to  the  filament  supply  and  the 
plate  and  grid-No.2  currents  (cathode 
current)  returning  to  B(-)  through  the 
tube  filaments.  Consequently,  in  a  series 
filament  string  it  is  necessary  to  add 
shunt  resistors  across  each  filament  sec- 
tion to  bypass  this  cathode  current  in 
order  to  maintain  the  filament  voltage 
at  its  rated  value. 

The  filament  or  heater  resistor 
required  when  filaments  and/or  heaters 
are  operated  in  parallel  can  be  deter- 
mined easily  by  a  simple  formula  de- 
rived from  Ohm's  law. 

Required  resistance  (ohms) 

supply  volts  -  rated  volts  of  tube  type 
total  rated  filament  current  (amperes) 


Thus,  if  a  receiver  using  two  IT4's,  one 
IRS,  one  IU5,  and  one  3V4  is  to  be 
operated  from  a  storage  battery,  the 
series  resistor  is  equal  to  2  volts  (the 
voltage  from  a  single  storage  cell)  minus 
1.4  volts  (voltage  rating  for  these  tubes) 
divided  by  0.3  ampere  (the  sum  of 
4  X  0.05  ampere  +  1  X  0.1  ampere),  i.e., 
approximately  2  ohms.  Since  this  resis- 
tor should  be  variable  to  allow  adjust- 
ment for  battery  depreciation,  it  is  ad- 
visable to  obtain  the  next  larger  com- 
mercial size,  although  any  value  between 
2  and  3  ohms  will  be  quite  satisfactory. 

Where  much  power  is  dissipated  in 
the  resistor,  the  wattage  rating  should 
be  sufficiently  large  to  prevent  over- 
heating. The  power  dissipation  in  watts 
is  equal  to  the  voltage  drop  in  the  resis- 
tor multiplied  by  the  total  filament  cur- 
rent in  amperes.  Thus,  for  the  example 
above,  0.6  X  0.3  =  0.18  watt.  In  this 
case,  the  value  is  so  small  that  any  com- 
mercial rheostat  with  suitable  resistance 
will  be  adequate. 

For  the  case  where  the  heaters  and/ 
or  filaments  of  several  tubes  are  oper- 
ated in  series,  the  resistor  value  is  calcu- 
lated by  the  following  formula,  also  de- 
rived from  Ohm's  law. 


Required  resistance  (ohms)  — 

supply  volts  -  total  rated  volts  of  tubes 
rated  amperes  of  tubes 

Thus,  if  a  receiver  having  one  6BE6,  one 
6BA6,  one  6AT6,  one  25L6GT,  and  one 
25Z6GT  is  to  be  operated  from  a  117- 
volt  power  line,  the  series  resistor  is 
equal  to  117  volts  (the  supply  voltage) 
minus  68.9  volts  (the  sum  of  3  X  6.3 
volts  +2X25  volts)  divided  by  0.3  am- 
pere (current  rating  of  these  tubes),  i.e., 
approximately  160  ohms.  The  wattage 
dissipation  in  the  resistor  will  be  117 
volts  minus  68.9  volts  times  0.3  ampere, 
or  approximately  14.4  watts.  A  resistor 
having  a  wattage  rating  in  excess  of  this 
value  should  be  chosen. 

When  the  series-heater  connection 
is  used  in  ae/dc  receivers,  it  is  usually 
advisable  to  arrange  the  heaters  in  the 
circuit  so  that  the  tubes  most  sensitive 
to  hum  disturbances  are  at  or  near  the 
ground  potential  of  the  circuit.  This  ar- 
rangement reduces  the  amount  of  ac 


59 


RCA  Receiving  Tube  Manual 


voltage  between  the  heaters  and  cath- 
odes of  these  tubes  and  minimizes  the 
hum  output  of  the  receiver.  The  order 
of  heater  connection,  by  tube  function, 
from  chassis  to  the  rectifier-cathode  side 
of  the  ac  line  is  shown  in  Fig.  82. 


The  balanced  arrangement  described 
above  also  minimizes  heater-grid  hum. 
High  grid-circuit  impedances  should  be 
avoided,  if  possible.  High  heater  volt- 
ages should  also  be  avoided  because 
heater-cathode  hum  rises  sharply  when 


AUDIO 
DETECTOR 


FIRST 
AF 

AMPLIFIER 


CON- 
VERTER 


RF 
AND  IF 
STAGES 


POWER 
AMPLIFIER 


RECTI- 
FIER 


VOLTAGE 
DROPPING 
RESISTOR 


1)  117  V.  <f 

AC  OR  DC 

Fig.  82 


Heater-fo-Cathode  Connection 

When  heater-type  tubes  are  oper- 
ated from  ac,  their  cathodes  may  be  re- 
turned (through  resistors,  capacitors,  or 
other  components)  to  the  mid-tap  on 
the  heater  supply  winding,  to  the  mid- 
tap  of  a  small  resistor  (about  50  ohms) 
connected  across  the  winding,  or  to  one 
end  of  the  heater  supply  winding,  de- 
pending on  circuit  requirements.  In  all 
circuits,  it  is  important  to  keep  the 
heater-cathode  voltage  within  the  maxi- 
mum ratings  specified  for  the  tube. 

Heater-type  tubes  may  produce  hum 
as  a  result  of  conduction  between  heater 
and  cathode  or  between  heater  and  con- 
trol grid,  or  by  modulation  of  the  elec- 
tron stream  by  the  alternating  magnetic 
field  surrounding  the  heater.  When  a 
large  resistor  is  used  between  heater  and 
cathode  (as  in  series-connected  heater 
strings),  or  when  one  side  of  the  heater 
is  grounded,  even  a  minute  pulsating 
leakage  current  between  heater  and  cath- 
ode can  develop  a  small  voltage  across 
the  cathode-circuit  impedance  and  cause 
objectionable  hum.  The  use  of  a  large 
cathode  bypass  capacitor  is  recom- 
mended to  minimize  this  source  of  hum. 

Much  lower  hum  levels  can  be 
achieved  when  heaters  are  connected  in 
parallel  systems  in  which  the  center-tap 
of  the  heater  supply  is  grounded  or, 
preferably,  connected  to  a  positive  bias 
source  of  15  to  80  volts  dc  to  reduce  the 
flow  of  alternating  current.  The  heater 
leads  of  the  tubes  should  be  twisted  and 
kept  away  from  high-impedance  circuits. 
The  balanced  ac  supply  provides  almost 
complete  cancellation  of  the  alternat- 
ing-current components. 


the  heater  voltage  is  increased  above 
the  published  value. 

Certain  tube  types  are  designed  es- 
pecially to  minimize  hum  in  high-quality, 
high-fidelity  audio  equipment.  Examples 
are  the  5879,  7025,  and  7199. 

Plate  Voltage  Supply 

The  plate  voltage  for  electron  tubes 
is  obtained  from  batteries,  rectifiers, 
direct-current  power  lines,  and  small 
local  generators.  The  maximum  plate- 
voltage  value  for  any  tube  type  should 
not  be  exceeded  if  most  satisfactory  per- 
formance is  to  be  obtained.  Plate  volt- 
age should  not  be  applied  to  a  tube  un- 
less the  corresponding  recommended 
voltage  is  also  supplied  to  the  grid. 

It  is  recommended  that  the  primary 
circuit  of  the  power  transformer  be  fused 
to  protect  the  rectifier  tube(s),  the  power 
transformer,  filter  capacitor,  and  chokes 
in  case  a  rectifier  tube  fails. 

Grid  Voltage  Supply 

The  recommended  grid  voltages  for 
different  operating  conditions  have  been 
carefully  determined  to  give  the  most 
satisfactory  performance.  Grid  voltage 
may  be  obtained  from  a  fixed  source 
such  as  a  separate  C-battery  or  a  tap  on 
the  voltage  divider  of  the  high-voltage 
dc  supply,  from  the  voltage  drop  across 
a  resistor  in  the  cathode  circuit,  or  from 
the  voltage  drop  across  a  resistor  in  the 
grid  circuit.  The  first  method  is  called 
"fixed  bias";  the  second  is  called  "cath- 
ode bias"  or  "self  bias";  the  third  is 
called  "grid-resistor  bias"  and  is  some- 
times incorrectly  referred  to  in  receiving- 
tube  practice  as  "zero-bias  operation." 

In  any  case,  the  object  is  to  make 


60 


Electron  Tube  Installation 


the  grid  negative  with  respect  to  the 
cathode  by  the  specified  voltage.  When 
a  C-battery  is  used,  the  negative  termi- 
nal is  connected  to  the  grid  return  and 
the  positive  terminal  is  connected  to  the 
negative  filament  socket  terminal,  or  to 
the  cathode  terminal  if  the  tube  is  of  the 
heater-cathode  type.  If  the  filament  is 
supplied  with  alternating  current,  this 
connection  is  usually  made  to  the  cen- 
ter-tap of  a  low  resistance  (20-50  ohms) 
shunted  across  the  filament  terminals. 
This  method  reduces  hum  disturbances 
caused  by  the  ac  supply.  If  bias  voltages 
are  obtained  from  the  voltage  divider  of 
a  high-voltage  dc  supply,  the  grid  return 
is  connected  to  a  more  negative  tap 
than  the  cathode. 

The  cathode-biasing  method  uti- 
lizes the  voltage  drop  produced  by  the 
cathode  current  flowing  through  a  re- 
sistor connected  between  the  cathode 
and  the  negative  terminal  of  the  B-sup- 
ply.  (See  Fig.  83.)  The  cathode  current 
is,  of  course,  equal  to  the  plate  current 
in  the  case  of  a  triode,  or  to  the  sum  of 
the  plate  and  grid-No.2  currents  in  the 
case  of  a  tetrode,  pentode,  or  beam 
power  tube.  Because  the  voltage  drop 
along  the  resistance  is  increasingly  nega- 
tive with  respect  to  the  cathode,  the  re- 
quired negative  grid-bias  voltage  can  be 


1000/3  =  3000  ohms.  If  the  cathode  cur- 
rent of  more  than  one  tube  passes  through 
the  resistor,  or  if  the  tube  or  tubes  em- 
ploy more  than  three  electrodes,  the 
total  current  determines  the  size  of  the 
resistor. 

Bypassing  of  the  cathode-bias  re- 
sistor depends  on  circuit-design  require- 
ments. In  rf  circuits  the  cathode  resistor 
usually  is  bypassed.  In  af  circuits  the  use 
of  an  unbypassed  resistor  will  reduce 
distortion  by  introducing  degeneration 
into  the  circuit.  However,  the  use  of  an 
unbypassed  resistor  decreases  gain  and 
power  sensitivity.  When  bypassing  is 
used,  it  is  important  that  the  bypass 
capacitor  be  sufficiently  large  to  have 
negligible  reactance  at  the  lowest  fre- 
quency to  be  amplified. 

In  the  case  of  power-output  tubes 
having  high  transconductance  such  as 
the  beam  power  tubes,  it  may  be  neces- 
sary to  shunt  the  bias  resistor  with  a 
small  mica  capacitor  (approximately 
O.OOljuf)  in  order  to  prevent  oscillations. 
The  usual  af  bypass  may  or  may  not  be 
used,  depending  on  whether  or  not  de- 
generation is  desired.  In  tubes  having 
high  values  of  transconductance,  such 
as  the  6BA6,  6CB6,  and  6AC7,  input 
capacitance  and  input  conductance 
change  appreciably  with  plate  current. 


Rs  GRID-BIASING  RESISTOR  Ts FILAMENT  TRANSFORMER 

Fig.  83 


obtained  by  connecting  the  grid  return 
to  the  negative  end  of  the  resistance. 

The  value  of  the  resistance  for 
cathode-biasing  a  single  tube  can  be  de- 
termined from  the  following  formula: 

Resistance  (ohms)  - 

desired  grid-bias  voltage  X  1000 
rated  cathode  current  in  milliamperes 

Thus,  the  resistance  required  to  produce 
9  volts  bias  for  a  triode  which  operates 
at  3  milliamperes  plate  current  is  9  X 


When  such  a  tube  having  a  separate 
suppressor-grid  connection  is  used  as  an 
rf  amplifier,  these  changes  may  be  mini- 
mized by  leaving  a  certain  portion  of  the 
cathode-bias  resistor  unbypassed.  In 
order  to  minimize  feedback  when  this 
method  is  used,  the  external  grid-No.  1- 
to-plate  (wiring)  capacitances  should  be 
kept  to  a  minimum,  the  grid  No.2  should 
be  bypassed  to  ac  ground,  and  the  grid 
No.3  should  be  connected  to  ac  ground. 
The  use  of  a  cathode  resistor  to 


61 


RCA  Receiving  Tube  Manual 


obtain  bias  voltage  is  not  recommended 
for  amplifiers  in  which  there  is  appreci- 
able shift  of  electrode  currents  with  the 
application  of  a  signal.  In  such  ampli- 
fiers, a  separate  fixed  supply  is  recom- 
mended. 

The  grid-resistor  biasing  method 
is  also  a  self-bias  method  because  it 
utilizes  the  voltage  drop  across  the  grid 
resistor  produced  by  small  amounts  of 
grid  current  flowing  in  the  grid-cathode 
circuit.  This  current  is  due  to  (1)  an 
electromotive  potential  difference  be- 
tween the  materials  comprising  the  grid 
and  cathode  and  (2)  grid  rectification 
when  the  grid  is  driven  positive.  A  large 
value  of  resistance  is  required  in  order 
to  limit  this  current  to  a  very  small 
value  and  to  avoid  undesirable  loading 
effects  on  the  preceding  stage. 

Examples  of  this  method  of  bias  are 
given  in  circuits  22-1  and  22-4  in  the 
CIRCUIT  SECTION.  In  both  of  these 
circuits,  the  audio  amplifier  type  1U5  or 
12AV6  has  a  10-megohm  resistor  be- 
tween the  grid  and  the  negative  filament 
or  cathode  to  furnish  the  required  bias 
which  is  usually  less  than  1  volt.  This 
method  of  biasing  is  used  principally  in 
the  early  voltage  amplifier  stages  (usu- 
ally employing  high-mu  triodes)  of  audio 
amplifier  circuits,  where  the  tube  dissi- 
pation will  not  be  excessive  under  zero- 
signal  conditions. 

A  grid  resistor  is  also  used  in  many 
oscillator  circuits  for  obtaining  the  re- 
quired bias.  In  these  circuits,  the  grid 
voltage  is  relatively  constant  and  its 
magnitude  is  usually  in  the  order  of  5 
volts  or  more.  Consequently,  the  bias 
voltage  is  obtained  only  through  grid 
rectification.  A  relatively  low  value  of 
resistor,  0.1  megohm  or  less,  is  used. 
Oscillator  circuits  employing  this  method 
of  bias  are  given  in  circuits  22-1  and 
22-4  in  the  CIRCUIT  SECTION. 

Grid-bias  variation  for  the  rf  and 
if  amplifier  stages  is  a  convenient  and 
frequently  used  method  for  controlling 
receiver  volume.  The  variable  voltage 
supplied  to  the  grid  may  be  obtained: 
(1)  from  a  variable  cathode  resistor  as 
shown  in  Figs.  84  and  85;  (2)  from  a 
bleeder  circuit  by  means  of  a  potentiom- 
eter as  shown  in  Fig.  86;  or  (3)  from  a 
bleeder  circuit  in  which  the  bleeder  cur- 
rent is  varied  by  a  tube  used  for  auto- 

62 


Fig.  84 

matic  volume  control.  The  latter  circuit 
is  shown  in  Fig.  60. 

In  all  cases  it  is  important  that  the 
control  be  arranged  so  that  at  no  time 
will  the  bias  be  less  than  the  recom- 
mended minimum  grid-bias  voltage  for 
the  particular  tubes  used.  This  require- 
ment can  be  met  by  providing  a  fixed 
stop  on  the  potentiometer,  by  connecting 


Fig.  85 

a  fixed  resistance  in  series  with  the  vari- 
able resistance,  or  by  connecting  a  fixed 
cathode  resistance  in  series  with  the 
variable  resistance  used  for  regulation. 
Where  receiver  gain  is  controlled  by 
grid-bias  variation,  it  is  advisable  to 
have  the  control  voltages  extend  over  a 
wide  range  in  order  to  minimize  cross- 
modulation  and  modulation-distortion. 


—31 

-    -        <5  %  A 

A*  A-         B-      >  B* 

Fig.  86 

A  remote-cutoff  type  of  tube  should, 
therefore,  be  used  in  the  controlled 
stages. 

In  most  tubes  employing  a  unipo- 
tential  cathode,  a  positive  grid  current 
begins  to  flow  when  the  grid  is  slightly 
negative  and  increases  rapidly  as  the 


Electron  Tube  Installation 


grid  is  made  more  positive,  as  shown  in 
Fig.  87.  The  value  of  grid  voltage  at 
which  the  grid-current  curve  intercepts 
the  horizontal  axis  is  determined  by 
several  different  physical  processes,  in- 
cluding an  electrothermal  effect  due  to 
the  differences  in  temperature  and  in 
material  composition  of  the  grid  and  the 
cathode,  and  by  the  positive  grid  cur- 
rent. For  values  of  grid  potentials  which 


GRID  VOLTS 


Fig.  87 


are  larger  than  this  intercept,  the  direc- 
tion of  the  grid  current  is  positive  (i.e., 
from  the  grid  to  the  cathode).  At  smaller 
values  of  grid  potential,  the  direction  of 
the  grid  current  is  negative  (i.e.,  from 
the  cathode  to  the  grid). 

Positive  grid  current  consists  of 
electrons  emitted  from  the  cathode 
which  are  intercepted  by  the  control  grid. 
Negative  grid  current,  which  becomes 
appreciable  only  when  the  grid  potential 
is  more  negative  than  the  value  of  the 
intercept,  is  a  result  of  the  emission  of 
electrons  from  the  heated  control  grid  to 
the  cathode,  the  effect  of  gas  molecules 
in  the  tube,  and  the  influence  of  leakage 
currents  between  the  grid  and  cathode 
and  the  grid  and  the  plate. 

The  value  of  grid  potential  at  the 
intercept  of  the  grid-current  curve  on 
the  horizontal  axis  (often  mistakenly 
called  contact  potential)  may  be  as  high 
as  1 3^  volts.  If  the  operating  bias  of  the 
tube  is  less  than  this  intercept,  it  is  found 
that  two  effects  are  present.  Direct  cur- 
rent flows  in  the  grid  circuit,  and  the 
dynamic  input  resistance  of  the  tube 
may  be  relatively  low.  It  is  generally  de- 
sirable to  supply  the  tube  with  a  value 
of  bias  sufficiently  high  so  that  the  oper- 
ating point  of  the  tube  is  not  near  the 
value  of  this  intercept.  If  the  value  of 


the  operating  bias  is  near  the  value  of 
the  intercept,  care  should  be  taken  to 
avoid  undesirable  effects  in  the  grid  cir- 
cuit due  to  grid  current  or  low  input  re- 
sistance. 

Screen-Grid  Voltage  Supply 

The  positive  voltage  for  the  screen 
grid  (grid  No.2)  of  screen-grid  tubes 
may  be  obtained  from  a  tap  on  a  voltage 
divider,  from  a  potentiometer,  or  from 
a  series  resistor  connected  to  a  high-volt- 
age source,  depending  on  the  particular 
tube  type  and  its  application. The  screen- 
grid  voltage  for  tetrodes  should  be  ob- 
tained from  a  voltage  divider  or  a  poten- 
tiometer rather  than  through  a  series 
resistor  from  a  high-voltage  source  be- 
cause of  the  characteristic  screen-grid 
current  variations  of  tetrodes.  Fig.  88 
shows  a  tetrode  with  its  screen-grid  volt- 
age obtained  from  a  potentiometer. 

When  pentodes  or  beam  power  tubes 
are  operated  under  conditions  where  a 
large  shift  of  plate  and  screen-grid  cur- 
rents does  not  take  place  with  the  appli- 
cation of  the  signal,  the  screen-grid  volt- 
age may  be  obtained  through  a  series 
resistor  from  a  high-voltage  source.This 
method  of  supply  is  possible  because  of 


Fie:.  88 

the  high  uniformity  of  the  screen-grid 
current  characteristic  in  pentodes  and 
beam  power  tubes.  Because  the  screen- 
grid  voltage  rises  with  increase  in  bias 
and  resulting  decrease  in  screen-grid 
current,  the  cutoff  characteristic  of  a 
pentode  is  extended  by  this  method  of 
supply. 

This  method  is  sometimes  used  to 
increase  the  range  of  signals  which  can 
be  handled  by  a  pentode.  When  used  in 
resistance-coupled  amplifier  circuits  em- 
plo3ring  pentodes  in  combination  with 
the  cathode-biasing  method,  it  mini- 
mizes the  need  for  circuit  adjustments. 
Fig.  89  shows  a  pentode  with  its  screen- 


63 


RCA  Receiving  Tube  Manual 


grid  voltage  supplied  through  a  series 
resistor. 

When  power  pentodes  and  beam 
power  tubes  are  operated  under  condi- 
tions such  that  there  is  a  large  change 
in  plate  and  screen-grid  currents  with 
the  application  of  signal,  the  series- 
resistor  method  of  obtaining  screen-grid 
voltage  should  not  be  used.  A  change  in 
screen-grid  current  appears  as  a  change 


Fig.  89 


in  the  voltage  drop  across  the  series 
resistor  in  the  screen-grid  circuit;  the 
result  is  a  change  in  the  power  output 
and  an  increase  in  distortion.  The  screen- 
grid  voltage  should  be  obtained  from  a 
point  in  the  plate-voltage-supply  filter 
system  having  the  correct  voltage,  or 
from  a  separate  source. 

It  is  important  to  note  that  the 
plate  voltage  of  tetrodes,  pentodes,  and 
beam  power  tubes  should  be  applied  be- 
fore or  simultaneously  with  the  screen- 
grid  voltage.  Otherwise,  with  voltage  on 
the  screen  grid  only,  the  screen-grid  cur- 
rent may  rise  high  enough  to  cause 
excessive  screen-grid  dissipation. 

Screen-grid  voltage  variation  for 
the  rf  amplifier  stages  has  sometimes 
been  used  for  volume  control  in  older- 
type  receivers.  Reduced  screen-grid  volt- 
age lowers  the  transconductance  of  the 
tube  and  results  in  reduced  gain  per 
stage.  The  voltage  variation  is  obtained 
by  means  of  a  potentiometer  shunted 
across  the  screen-grid  voltage  supply. 
(See  Fig.  88.)  When  the  screen-grid  volt- 
age is  varied,  it  must  never  exceed  the 
rating  of  the  tube.  This  requirement  can 
be  met  by  providing  a  fixed  stop  on  the 
potentiometer. 

Shidding 

In  high-frequency  stages  having 
high  gain,  the  output  circuit  of  each 
stage  must  be  shielded  from  the  input 
circuit  of  that  stage.  Each  high-frequency 


stage  also  must  be  shielded  from  the 
other  high-frequency  stages.  Unless 
shielding  is  employed,  undesired  feed- 
back may  occur  and  may  produce  many 
harmful  effects  on  receiver  performance. 

To  prevent  this  feedback,  it  is  a 
desirable  practice  to  shield  separately 
each  unit  of  the  high-frequency  stages. 
For  instance,  in  a  superheterodyne  re- 
ceiver, each  if  and  rf  coil  may  be  mounted 
in  a  separate  shield  can.  Baffle  plates 
may  be  mounted  on  the  ganged  tuning 
capacitor  to  shield  each  section  of  the 
capacitor  from  the  other  section.  The 
oscillator  coil  may  be  especially  well 
shielded  by  being  mounted  under  the 
chassis. 

The  shielding  precautions  required 
in  a  receiver  depend  on  the  design  of  the 
receiver  and  the  layout  of  the  parts.  In 
all  receivers  having  high-gain  high-fre- 
quency stages,  it  is  necessary  to  shield 
separately  each  tube  in  high-frequency 
stages.  When  metal  tubes,  and  in  partic- 
ular the  single-ended  types,  are  used, 
complete  shielding  of  each  tube  is  pro- 
vided by  the  metal  shell  which  is 
grounded  through  its  grounding  pin  as 
the  socket  terminal.  The  grounding  con- 
nection should  be  short  and  sturdy. 
Many  modern  tubes  of  glass  construc- 
tion have  internal  shields,  usually  con- 
nected to  the  cathode;  where  present, 
these  shields  are  indicated  in  the  socket 
diagram. 

Dress  of  Circuit  Leads 

At  high  frequencies  such  as  are  en- 
countered in  FM  and  television  receiv- 
ers, lead  dress,  that  is,  the  location  and 
arrangement  of  the  leads  used  for  con- 
nections in  the  receiver,  is  very  impor- 
tant. Because  even  a  short  lead  provides 
a  large  impedance  at  high  frequencies, 
it  is  necessary  to  keep  all  high-frequency 
leads  as  short  as  possible.  This  precau- 
tion is  especially  important  for  ground 
connections  and  for  all  connections  to 
bypass  capacitors  and  high-frequency 
filter  capacitors.  The  ground  connections 
of  plate  and  screen-grid  bypass  capaci- 
tors of  each  tube  should  be  kept  short 
and  made  directly  to  cathode  ground. 

Particular  care  should  be  taken 
with  the  lead  dress  of  the  input  and  out- 
put circuits  of  high-frequency  stages  so 
that  the  possibility  of  stray  coupling  is 


Electron  Tube  Installation 


minimized.  Unshielded  leads  connected 
to  shielded  components  should  be  dressed 
close  to  the  chassis.  As  the  frequency  in- 
creases, the  need  for  careful  lead  dress 
becomes  increasingly  important. 

In  high-gain  audio  amplifiers,  these 
same  precautions  should  be  taken  to 
minimize  the  possibility  of  self-oscil- 
lation. 

Filters 

Feedback  effects  also  are  caused  in 
radio  or  television  receivers  by  coupling 
between  stages  through  common  volt- 
age-supply circuits.  Filters  find  an  im- 
portant use  in  minimizing  such  effects. 
They  should  be  placed  in  voltage-supply 
leads  to  each  tube  in  order  to  return  the 
signal  current  through  a  low-impedance 
path  direct  to  the  tube  cathode  rather 
than  by  way  of  the  voltage-supply  cir- 
cuit. Fig.  90  illustrates  several  forms  of 
filter  circuits.  Capacitor  C  forms  the 


DC 
VOLTAGE 
LEAD 


1  TO  < 


T 

T' 

f  TO 


L 


DC 
VOLTAGE 
LEAD 


DC 
VOLTAGE 

TO  CATHODE  f 

DC 
VOLTAGE 
LEAD 

000000  J^*' 

T*c 
TO  CATHODE  T 


R  =  RESISTOR      C  =  BYPASS  CAPACITOR 
L  =  A  F  OR  R  F  CHOKE, 

Fig.  90 

low-impedance  path,  while  the  choke  or 
resistor  assists  in  diverting  the  signal 
through  the  capacitor  by  offering  a  high 
impedance  to  the  power-supply  circuit. 

The  choice  between  a  resistor  and  a 
choke  depends  chiefly  upon  the  permis- 
sible dc  voltage  drop  through  the  filter. 
In  circuits  where  the  current  is  small  (a 


fewmilliamperes),  resistors  are  practical ; 
where  the  current  is  large  or  regulation 
important,  chokes  are  more  suitable. 

The  minimum  practical  size  of  the 
capacitors  may  be  estimated  in  most 
cases  by  the  following  rule:  The  imped- 
ance of  the  capacitor  at  the  lowest  fre- 
quency amplified  should  not  be  more 
than  one-fifth  of  the  impedance  of  the 
filter  choke  or  resistor  at  that  frequency. 
Better  results  will  be  obtained  in  special 
cases  if  the  ratio  is  not  more  than  one- 
tenth. 

Radio-frequency  circuits,  particu- 
larly at  high  frequencies,  require  high- 
quality  capacitors.  Mica  or  ceramic  ca- 
pacitors are  preferable.  Where  stage 
shields  are  employed,  filters  should  be 
placed  within  the  shield. 

Another  important  application  of 
filters  is  to  smooth  the  output  of  a  recti- 
fier tube.  See  Rectification,  A  smoothing 
filter  usually  consists  of  capacitors  and 
iron-core  chokes.  In  any  filter-design 
problem,  the  load  impedance  must  be 
considered  as  an  integral  part  of  the  fil- 
ter because  the  load  is  an  important 
factor  in  filter  performance.  Smoothing 
effect  is  obtained  from  the  chokes  be- 
cause they  are  in  series  with  the  load  and 
offer  a  high  impedance  to  the  ripple  volt- 
age. Smoothing  effect  is  obtained  from 
the  capacitors  because  they  are  in  paral- 
lel with  the  load  and  store  energy  on  the 
voltage  peaks;  this  energy  is  released  on 
the  voltage  dips  and  serves  to  maintain 
the  voltage  at  the  load  substantially 
constant.  Smoothing  filters  are  classified 
as  choke-input  or  capacitor-input  ac- 
cording to  whether  a  choke  or  capacitor 
is  placed  next  to  the  rectifier  tube.  See 
Fig.  91. 

The  CIRCUIT  SECTION  ^ves  a 
number  of  examples  of  rectifier  circuits 
with  recommended  filter  constants. 

If  an  input  capacitor  is  used,  con- 
sideration must  be  given  to  the  instan- 


CHOKE-INPUT  TYPE  FILTER 


CAPACltOR- INPUT  TYPE  FILTER, 


IN»»UT 
FROM 
HtCTIFIER 
TUBE 


INPUT 
FROM 
RECTinCP  -T-c 
TUBE 


CAPACltOR  riLTEA 


'WPUT 
FROM 
AECTiriER 
VUBE 


U« FILTER  CHOKE  C*  FILTER  CAPACITpR 

Fig.  91 


65 


RCA  Receiving  Tube  Manual 


taneous  peak  value  of  the  ac  input  volt- 
age. This  peak  value  is  about  1.4  times 
the  rms  value  as  measured  by  an  ac 
voltmeter.  Filter  capacitors,  therefore, 
especially  the  input  capacitor,  should 
have  a  rating  high  enough  to  withstand 
the  instantaneous  peak  value  if  break- 
down is  to  be  avoided.  When  the  input- 
choke  method  is  used,  the  available  dc 
output  voltage  will  be  somewhat  lower 
than  with  the  input-capacitor  method 
for  a  given  ac  plate  voltage.  However, 
improved  regulation  together  with  lower 
peak  current  will  be  obtained. 

Mercury-vapor  and  gas-filled  recti- 
fier tubes  occasionally  produce  a  form  of 
local  interference  in  radio  receivers 
through  direct  radiation  or  through  the 
power  line.  This  interference  is  generally 
identified  in  the  receiver  as  a  broadly 
tunable  120-cycle  buzz  (100  cycles  for 
50-cycle  supply  line,  etc.).  It  is  usually 
caused  by  the  formation  of  a  steep  wave 
front  when  plate  current  within  the  tube 
begins  to  flow  on  the  positive  half  of 
each  cycle  of  the  ac  supply  voltage. 

There  are  several  ways  of  elimi- 
nating this  type  of  interference.  One  is 
to  shield  the  tube.  Another  is  to  insert 
an  rf  choke  having  an  inductance  of  one 
millihenry  or  more  between  each  plate 
and  transformer  winding  and  to  connect 
high-voltage,  rf  bypass  capacitors  be- 
tween the  outside  ends  of  the  transformer 
winding  and  the  center  tap.  (See  Fig. 
92.)  The  rf  chokes  should  be  placed  with- 
in the  shielding  of  the  tube.The  rf  bypass 


TO  AC  ^ 
POWER  LINE  S 


the  plate  leads  of  the  rectifier  extremely 
short.  In  general,  the  particular  method 
of  interference  elimination  must  be  select- 
ed by  experiment  for  each  installation. 

Output-Coupling  Devices 

An  output-coupling  device  is  used 
in  the  plate  circuit  of  a  power  output 
tube  to  keep  the  comparatively  high  dc 
plate  current  from  the  winding  of  an 
electromagnetic  speaker  and,  also,  to 
transfer  power  efficiently  from  the  out- 
put stage  to  a  loudspeaker  of  either  the 
electromagnetic  or  dynamic  type. 

Output-coupling  devices  are  of  two 
types,  (1)  choke-capacitor  and  (2)  trans- 
former. The  choke-capacitor  type  in- 
cludes an  iron-core  choke  having  an 
inductance  of  not  less  than  10  henries 
which  is  placed  in  series  with  the  plate 
and  B-supply.  The  choke  offers  a  very 
low  resistance  to  the  dc  plate  current 
component  of  the  signal  voltage  but  op- 
poses the  flow  of  the  fluctuating  compo- 
nent. A  bypass  capacitor  of  2  to  6  micro- 
farads supplies  a  path  to  the  speaker 
winding  for  the  signal  voltage.  The 
choke-coil  output  coupling  device,  how- 
ever, is  now  only  of  historical  interest. 

The  transformer  type  is  constructed 
with  two  separate  windings,  a  primary 
and  a  secondary  wound  on  an  iron  core. 
This  construction  permits  designing  each 
winding  to  meet  the  requirements  of  its 
position  in  the  circuit.  Typical  arrange- 
ments of  each  type  of  coupling  device 
are  shown  in  Fig.  93.  Examples  of  trans- 
formers for  push-pull  stages  are  shown 

PLATE 

o- — — _ 


CLECTROSTATI' 
SHIELD 

C  =  R  F  B Y  PASS  CAPAC  IT0R,MICA      L  =  R  F  CHOKE 
Fig.  92 

capacitors  should  have  a  voltage  rating 
high  enough  to  withstand  the  peak  volt- 
age of  each  half  of  the  secondary,  which 
is  approximately  1.4  times  the  rms  value. 

Transformers  having  electrostatic 
shielding  between  primary  and  second- 
ary are  not  likely  to  transmit  rf  disturb- 
ances to  the  line.  Often  the  interference 
may  be  eliminated  simply  by  making 

66 


INPUT 


o— 


►  LOUDSPEAKER 

:  ? 


TRANSFORMER  METHOD 
,  .C»  2-6iL*f 


III  10-30  H 

[[choke 


LOUDSPEAKER 

 ? 


CHOKE-COIL  METHOD 
Fig.  93 

in  several  of  the  circuits  given  in  the 
CIRCUIT  SECTION. 

High-Fidelity  Systems 

The  results  achieved  from  any  high- 


Electron  Tube  Installation 


ddelity  amplifier  system  depend  to  a 
large  degree  upon  the  skill  and  care  with 
which  the  system  is  constructed.  Im- 
proper placement  of  transformers,  other 
components,  and  wiring,  and  attempts 
to  achieve  excessive  compactness,  can 
only  result  in  instability,  oscillation, 
hum,  and  other  operating  difficulties,  as 
well  as  in  damage  to  components  by 
overheating.  It  is  important,  therefore, 
that  construction  of  high-fidelity  am- 
plifier S3rstems  be  undertaken  only  by 
persons  who  have  had  some  experience 
in  the  layout,  mechanical  construction, 
and  wiring  of  audio  equipment. 

It  is  impractical  to  give  specific 
construction  data  for  various  amplifiers 
and  supplementary  units  because  the 
best  arrangement  for  each  unit  or  com- 
bination of  units  will  depend  on  the  re- 
quirements of  the  user.  It  is  possible, 
however,  to  list  some  general  considera- 
tions which  should  be  observed  in  the 
construction  of  any  high-fidelity  am- 
plifier system. 

Any  amplifier  having  two  or  more 
stages  should  be  constructed  with  a 
straight-line  layout  so  that  maximum 
separation  is  provided  between  the 
signal  input  and  output  circuits  and  ter- 
minals. Power-supply  connections,  par- 
ticularly those  carrjdng  ac,  should  be 
isolated  as  far  as  possible  from  signal 
connections,  especially  from  the  input 
connection.  Signal-carrying  conductors, 
even  when  shielded,  should  not  be  cabled 
together  with  power-supply  conductors. 
Internal  wiring  for  ac-operated  tube 
heaters,  switches,  pilot-light  sockets, 
and  other  devices,  should  be  twisted  and 
placed  flat  against  the  chassis.  All  con- 
nections to  the  ground  side  of  the  circuit 
in  each  unit  should  be  made  to  a  common 
bus  of  heavy  wire.  This  bus  should  be 
connected  to  the  chassis  only  at  the  point 
of  minimum  signal  voltage,  i.e.,  at  the 
signal-input  terminal  of  the  unit. 

All  internal  wiring  that  carries  sig- 
nal voltages  should  be  as  short  as  pos- 
sible, and  as  far  as  possible  above  the 
chassis,  to  minimize  losses  at  the  higher 
audio  frequencies  due  to  stray  shunt 
capacitance.  All  connections  between 
units  should  be  made  with  shielded  cable 
having  a  capacitance  of  not  more  than 
30  picofarads  per  foot,  such  as  Alpha 
Type  1249  or  1704,  Belden  Type  8401 


or  8410,  or  equivalent  cable. 

Because  power  amplifiers  and  pow- 
er-supply units  of  high-fidelity  systems 
normally  dissipate  large  amounts  of  heat, 
they  should  be  constructed  and  installed 
in  such  a  manner  as  to  assure  adequate 
ventilation  for  the  tubes  and  other  com- 
ponents. A  beam  power  tube  or  rectifier 
tube  should  be  separated  from  any  other 
tube  or  component  on  the  same  side  of 
the  chassis  by  at  least  IJ^  tube  diam- 
eters. 

Power  amplifiers  and  power-supply 
units  which  are  to  be  installed  horizon- 
tally (i.e.,  with  the  tubes  vertical)  in 
cabinets  or  on  shelves  should  be  pro- 
vided with  mounting  feet,  perforated 
bottom  covers,  and  a  number  of  small 
holes  around  each  tube  socket  to  permit 
relatively  cool  air  to  enter  from  below 
and  provide  ventilation  for  the  under 
side  of  the  chassis  and  tubes. 

If  a  power  amplifier,  tonercontrol 
amplifier,  and  one  or  more  preamplifiers 
are  to  be  constructed  on  the  same  chassis, 
the  mechanical  layout  should  be  planned 
so  that  the  circuits  operating  at  the  low- 
est signal  levels  are  farthest  from  the 
output  stage  and  power  supply.  Ampli- 
fier units  which  normally  operate  at  com- 
parable signal  levels  but  are  not  used 
simultaneously  (such  as  preamplifiers  for 
tape  pickup  heads  and  magnetic  phono- 
graph pickups)  may  be  installed  side  by 
side  on  the  same  chassis  without  danger 
of  interaction.  Units  which  operate  si- 
multaneously, however  (such  as  the  chan- 
nels of  a  stereophonic  system),  should 
not  be  installed  side  by  side  on  the  same 
chassis  without  careful  consideration  to 
placement  of  components  and  wiring, 
and  the  possible  use  of  shielding  to  pre- 
vent interaction. 

When  an  amplifier,  preamplifier, 
mixer,  or  other  unit  requiring  heater 
power  is  located  more  than  five  or  six 
feet  from  its  power-supply  unit,  the 
heater-current  conductors  in  the  power- 
supply  cable  must  be  large  enough  to 
assure  that  each  tube  receives  its  rated 
heater  voltage.  In  cases  where  very  large 
heater  currents  or  very  long  power-sup- 
ply cables  are  involved,  it  may  be  de- 
sirable to  install  a  heater-supply  trans- 
former on  or  near  the  amplifier  unit.  If 
such  a  transformer  is  installed  on  or  near 
a  preamplifier  for  a  magnetic-tape  pick- 


67 


RCA  Receiving  Tube  Manual 


up  heady  a  magnetic  phonograph  pickup, 
or  a  dynamic  microphone,  the  trans- 
former should  be  completely  shielded 
and  positioned  to  prevent  its  field  from 
inducing  hum  in  the  pickupl  device. 

High-Voltage  Considerations  for 
Television  Picture  Tubes 

Like  other  high-voltage  devices, 
television  picture  tubes  require  that 
certain  precautions  be  observed  to  mini- 
mize the  possibility  of  failure  caused  by 
humidity,  dust,  and  corona. 

Humidity  Considerations.  When 
humidity  is  high,  a  continuous  film  of 
moisture  may  form  on  the  glass  bulb  im- 
mediately surrounding  the  ultor  cavity 
cap  of  all-glass  picture  tubes  or  on  the 
glass  part  of  the  envelope  of  metal  pic- 
ture tubes.  This  film  may  permit  spark- 
ing to  take  place  over  the  glass  surface 
to  the  external  conductive  coating  or  to 
the  metal  shell.  Such  sparking  may  in- 
troduce noise  into  the  receiver.  To  pre- 
vent such  a  possibility,  the  uncoated 
bulb  surface  around  the  cap  and  the 
glass  part  of  the  envelope  of  metal  pic*- 
ture  tubes  should  be  kept  clean  and  dry. 

Dust  Considerations.  The  accumu- 
lation of  dust  on  the  uncoated  area  of 
the  bulb  around  the  ultor  cap  of  all-glass 
picture  tubes  or  on  the  glass  part  of  the 
envelope  or  insulating  supports  for  metal 
picture  tubes  will  decrease  the  insulating 
qualities  of  these  parts.  The  dust  usually 
consists  of  fibrous  materials  and  may 
contain  soluble  salts.  The  fibers  absorb 
and  retain  moisture;  the  soluble  salts 
provide  electrical  leakage  paths  that  in- 
crease in  conductivity  as  the  humidity 
increases.  The  resulting  high  leakage 
currents  may  overload  the  high-voltage 
power  supply. 

It  is  recommended,  therefore,  that 
the  uncoated  bulb  surface  of  all-glass 
picture  tubes  and  the  coated  glass  sur- 
face and  insulating  supports  for  metal 
picture  tubes  be  kept  clean  and  free 
from  dust  or  other  contamination  such 
as  finger-prints.  The  frosted  Filterglass 
faceplate  of  the  metal  picture  tubes  may 
be  cleaned  with  a  soapless  detergent, 
such  as  Dreft,  then  rinsed  with  clean 
water,  and  immediately  dried. 

Corona  Considerations.  A  high- 
voltage  system  may  be  sub  ject  to  corona, 
especially  when  the  humidity  is  high. 


unless  suitable  precautions  are  taken. 
Corona,  which  is  an  electrical  discharge 
appearing  on  the  surface  of  a  conductor 
when  the  voltage  gradient  exceeds  the 
breakdown  value  of  air,  causes  deterio- 
ration of  organic  insulating  materials 
through  formation  of  ozone,  and  induces 
arc-over  at  points  and  sharp  edges.  Sharp 
points  or  other  irregularities  on  any  part 
of  the  high-voltage  system  may  increase 
the  possibility  of  corona  and  should  be 
avoided. 

In  the  metal-shell  picture  tubes,  the 
metal  lip  at  the  maximum  diameter  has 
rounded  edges  to  prevent  corona.  Ade- 
quate spacing  between  the  lip  and  any 
grounded  element  in  the  receiver,  or  be- 
tween the  small  end  of  the  metal  shell 
and  any  pounded  element,  should  be 
provided  to  preclude  the  possibility  of 
corona.  Such  spacing  should  not  be  less 
than  1  inch  of  air.  Similarly,  an  air  space 
of  1  inch,  or  equivalent,  should  be  pro- 
vided around  the  body  of  the  metal 
shell.  As  a  further  precaution  to  prevent 
corona,  the  deflecting-yoke  surface  on 
the  end  adjacent  to  the  shell  should  pre- 
sent a  smooth  electrical  surface  with 
respect  to  the  small  end  of  the  metal 
shell  or  the  ultor  terminal  of  all-glass 
tubes. 

Picture-Tube  Safety  Considerations 

Tube  Handling.  Breakage  of  pic- 
ture tubes,  which  contain  a  high  vacu- 
um, may  result  in  injury  from  flying 
glass.  Do  not  strike  or  scratch  the  tube 
or  subject  it  to  more  than  moderate 
pressure  when  installing  it  in  or  remov- 
ing it  from  electronic  equipment. 

High- Voltage  Precautions.  In  pic- 
ture-tube circuits,  high  voltages  may  ap- 
pear at  normally  low-potential  points  in 
the  circuit  because  of  capacitor  break- 
down or  incorrect  circuit  connections. 
Therefore,  before  any  part  of  the  circuit 
is  touched  the  power-supply  switch 
should  be  turned  off,  the  power  plug  dis- 
connected, and  both  terminals  of  any 
capacitors  grounded. 

X-Ray  Radiation  Precautions.  All 
types  of  picture  tubes  may  be  operated 
at  voltages  (if  ratings  permit)  up  to  16 
kilovolts  without  producing  harmful 
x-ray  radiation  or  danger  of  personal 
injury  on  prolonged  exposure  at  close 
range.  Above  16  kilovolts,  special  x-ray 
shielding  precautions  may  be  necessary. 


68 


Interpretation 
of  Tube  Data 


The  tube  data  given  in  the  follow- 
ing TUBE  TYPES  SECTION  include 
ratings,  typical  operation  values,  char- 
acteristics, and  characteristic  curves. 

The  values  for  grid-bias  voltages, 
other  electrode  voltages,  and  electrode 
supply  voltages  are  given  with  reference 
to  a  specified  datum  point  as  follows: 
For  types  having  filaments  heated  with 
dc,  the  negative  filament  terminal  is 
talcen  as  the  datum  point  to  which  other 
electrode  voltages  are  referred.  For  types 
having  filaments  heated  with  ac,  the 
mid-point  (t.c,  the  center  tap  on  the  fila^ 
ment-transf  ormer  secondary,  or  the  mid- 
point on  a  resistor  shunting  the  filament) 
is  taken  as  the  datum  point.  For  types 
having  unipotential  cathodes  indirectly 
heated,  the  cathode  is  taken  as  the 
datum  point. 

Ratings  are  established  on  electron 
tube  types  to  help  equipment  designers 
utilize  the  performance  and  service  capa- 
bilities of  each  tube  type  to  best  advan- 
tage. Ratings  are  given  for  those  charac- 
teristics which  careful  study  and  experi- 
ence indicate  must  be  kept  within  cer- 
tain limits  to  insure  satisfactory  per- 
formance. 

Three  rating  systems  are  in  use  by 
the  electron-tube  industry.  The  oldest 
is  known  as  the  Absolute  Maximum 
system,  the  next  as  the  Design  Center 
system,  and  the  latest  and  newest  as  the 
Design  Maximum  system.  Definitions  of 
these  systems  have  been  formulated  by 
the  Joint  Electron  Tube  Engineering 
Council  (JETEC)*  and  standardized  by 
the  National  Electrical  Manufacturers 
Association  (NEMA)  and  the  Electronic 
Industries  Association  (EI A)  as  follows: 

Absolute  Maximum  ratings  are  lim- 
iting values  which  should  not  be  ex- 
ceeded with  any  tube  of  the  specified 
type  under  any  condition  of  operation. 
These  ratings  are  used  only  in  rare  in- 
stances for  receiving  types,  but  are  gen- 

*Now  identified  as  the  Joint  Electron  Device  En- 
gineering Council  (JEDEC). 


erally  used  for  transmitting  and  indus- 
trial types. 

Design  Center  ratings  are  limiting 
values  which  should  not  be  exceeded 
with  a  tube  of  the  specified  type  having 
characteristics  equal  to  the  published 
values  under  normal  operating  condi- 
tions. These  ratings,  which  include  al- 
lowances for  normal  variations  in  both 
tube  characteristics  and  operating  con- 
ditions, were  used  tor  tttoit  receiving 
tubes  prior  to  1^57.  Unless  specified 
otherwise,  ratings  given  in  the  TUBE 
TYPES  SECTION  are  based  on  the 
Design  Center  System. 

Design  Maximum  ratings  are  limit- 
ing values  which  should  not  be  exceeded 
with  a  tube  of  the  specified  type  having 
characteristics  equal  to  the  published 
values  under  any  conditions  of  opera- 
tion. These  ratings  include  allowances 
for  normal  variations  in  tube  character- 
istics, but  do  not  provide  for  variations 
in  operating  conditions.  Design  Maxi- 
mum ratings  were  adopted  for  receiving 
tubes  in  1957. 

Electrode  voltage  and  current  rat- 
ings are  in  general  self-explanatory,  but 
a  brief  explanation  of  other  ratings  will 
aid  in  the  understanding  and  interpre- 
tation of  tube  data. 

Heater  warm-up  time  is  defined  as 
the  time  required  for  the  voltage  across 
the  heater  to  reach  80  per  cent  of  the 
rated  value  in  the  circuit  shown  in  Fig. 
94.  The  heater  is  placed  in  series  with  a 


Fig.  94 


69 


RCA  Receiving  Tube  Manual 


resistance  having  a  value  3  times  the 
nominal  heater  operating  resistance 
(R  =  3  Ef/If),  and  a  voltage  having  a 
value  4  times  the  rated  heater  voltage 
( V  =  4  Ef)  is  then  applied.  The  warm-up 
time  is  determined  when  E  =  0.8  Ei. 

Plate  dissipation  is  the  power  dissi- 
pated in  the  form  of  heat  by  the  plate  as 
a  result  of  electron  bombardment.  It  is 
the  difference  between  the  power  sup- 
plied to  the  plate  of  the  tube  and  the 
power  delivered  by  the  tube  to  the  load. 

Grid-No.2  (Screen-grid)  Input  is  the 
power  applied  to  the  grid-No.  2  electrode 
and  consists  essentially  of  the  power  dis- 
sipated in  the  form  of  heat  by  grid  No.2 
as  a  result  of  electron  bombardment. 
With  tetrodes  and  pentodes,  the  power 
dissipated  in  the  screen-grid  circuit  is 
added  to  the  power  in  the  plate  circuit  to 
obtain  the  total  B-supply  input  power. 

When  the  screen-grid  voltage  is  sup- 
plied through  a  series  voltage-dropping 
resistor,  the  maximum  screen-grid  volt- 
age rating  may  be  exceeded,  provided 
the  maximum  screen-grid  dissipation 
rating  is  not  exceeded  at  any  signal  con- 
dition, and  the  maximum  screen-grid 
voltage  rating  is  not  exceeded  at  the 


maximum-signal  condition.  Provided 
these  conditions  are  fulfilled,  the  screen- 
grid  supply  voltage  may  be  as  high  as, 
but  not  above,  the  maximum  plate  volt- 
age rating. 

For  certain  voltage  amplifier  types, 
as  listed  in  the  data  section,  the  maxi- 
mum permissible  screen-grid  (grid-No.2) 
input  varies  with  the  screen-grid  voltage, 
as  shown  in  Fig.  95.  (This  curve  cannot 
be  assumed  to  apply  to  types  other  than 
those  for  which  it  is  specified  in  the  data 
section.)  Full  rated  screen-grid  input  is 
permissible  at  screen-grid  voltages  up  to 
50  per  cent  of  the  maximum  rated  screen- 
grid  supply  voltage.  From  the  50-per- 
cent point  to  the  full  rated  value  of  sup- 
ply voltage,  the  screen-grid  input  must 
be  decreased.  The  decrease  in  allowable 
screen-grid  input  follows  a  curve  of  the 
parabolic  form.  This  rating  chart  is  use- 
ful for  applications  utilizing  either  a 
fixedscreen-gridvoltageoraseriesscreen- 
grid  voltage-dropping  resistor.  When  a 
fixed  voltage  is  used,  it  is  necessary  only 
to  determine  that  the  screen-grid  input 
is  within  the  boimdary  of  the  operating 
area  on  the  chart  at  the  selected  value 
of  screen-grid  voltage  to  be  used.  When 
a  voltage-dropping  resistor  is  used,  the 


70 


Interpretation  of  Tube  Data 


minimum  value  of  resistor  that  will  as- 
sure tube  operation  within  the  boundary 
of  the  curve  can  be  determined  from  the 
following  relation: 

P      >   Em  (Ecca— Eo) 
=  Pea 

where  Rg2  is  the  minimum  value  for  the 
voltage-dropping  resistor  in  ohms,  Eca  is 
the  selected  screen-grid  voltage  in  volts, 
Ecc2  is  the  screen-grid  supply  voltage  in 
volts,  and  Pc2  is  the  screen-grid  input  in 
watts  corresponding  to  Ec2. 

Peak  heater-cathode  yoltage  is  the 
highest  instantaneous  value  of  voltage 
that  a  tube  can  safely  stand  between  its 
heater  and  cathode.  This  rating  is  ap- 
plied to  tubes  having  a  separate  cathode 
terminal  and  used  in  applications  where 
excessive  voltage  may  be  introduced 
between  heater  and  cathode. 

Maximum  do  output  current  is  the 
highest  average  plate  current  which  can 
be  handled  continuously  by  a  rectifier 
tube.  Its  value  for  any  rectifier  tube  type 
is  based  on  the  permissible  plate  dissipa- 
tion of  that  type.  Under  operating  con- 
ditions involving  a  rapidly  repeating 
duty  cycle  (steady  load),  the  average 
plate  current  may  be  measured  with  a 
dc  meter. 

The  nomograph  shown  in  Fig.  96 
can  be  used  to  determine  tube  voltage 
drop  or  plate  current  for  any  diode  unit 
when  values  for  a  single  plate-voltage, 
plate-current  condition  are  available 
from  the  data.  It  can  also  be  used  to 
compare  the  relative  perveance  (G=Ib/ 
Eb  3/2)  of  several  diodes.  Perveance  can 
be  considered  a  figure  of  merit  for  di- 
odes; high-perveance  units  have  lower 
voltage  drop  at  a  fixed  current  level. 

Tube  voltage  drop  or  plate  current 
for  a  specific  diode  unit  can  be  deter- 
mined as  follows :  First,  convenient  values 
are  selected  for  the  plate-voltage  and 
plate-current  scales  of  the  nomograph. 
The  published  plate-current  and  plate- 
voltage  values  are  then  located  on  the 
scales  and  connected  with  a  straight 
edge.  The  intersection  of  the  connect- 
ing line  with  the  perveance  scale  is  then 
used  as  a  pivot  point  to  determine  the 
value  of  tube  voltage  drop  correspond- 
ing to  a  desired  current  value,  or  the 
value  of  plate  current  corresponding  to 
a  desired  tube  voltage  drop.  Because  the 
pivot  point  for  a  specific  diode  unit  rep- 


resents its  perveance,  the  pivot  points 
for  several  units  (plotted  to  the  same 
scales)  can  be  used  to  compare  their 
relative  perveance. 

For  example,  type  5U4GB  has  a 
tube  voltage  drop  (per  plate)  of  44  volts 
at  a  plate  current  of  225  milliamperes. 


9- 

e:: 


\". 


6  "J 


Fig.  96 


•^1 

02CM-II244 

Convenient  scales  for  this  type  are  from 
1  to  100  volts  for  plate  voltage  and  from 
10  to  1000  milliamperes  for  plate  cur- 
rent. The  points  44  volts  and  225  milli- 
amperes are  then  connected  with  a 
straight  line  to  determine  the  pivot  point. 
Using  this  pivot  point,  it  is  easy  to  de- 
termine such  values  as  a  plate  current 
of  150  milliamperes  at  a  tube  voltage 
drop  of  33  volts,  or  a  voltage  drop  of  25 
for  a  current  of  100  milliamperes. 

For  readings  in  the  order  of  one 
volt  and/or  one  milliampere,  the  nomo- 
graph is  not  accurate  because  of  the 
effects  of  contact  potential  and  initial 
electron  velocity. 

Maximum  peak  plate  current  is 
the  highest  instantaneous  plate  current 
that  a  tube  can  safely  carry  recurrently 
in  the  direction  of  normal  current  flow. 

71 


RCA  Receiving  Tube  Manual 


The  safe  value  of  this  peak  current  in 
hot-cathode  types  of  rectifier  tubes  is  a 
function  of  the  electron  emission  avail- 
able and  the  duration  of  the  pulsating 
current  flow  from  the  rectifier  tube  in 
each  half-cycle. 

The  value  of  peak  plate  current  in 
a  given  rectifier  circuit  is  largely  deter- 
mined by  filter  constants.  If  a  large 
choke  is  used  at  the  filter  input,  the  peak 
plate  current  is  not  much  greater  than 
the  load  current;  but  if  a  large  capacitor 
is  used  as  the  filter  input,  the  peak  cur- 
rent may  be  many  times  the  load  cur- 
rent. In  order  to  determine  accurately 
the  peak  plate  current  in  any  rectifier 
circuit,  measure  it  with  a  peak-indicating 
meter  or  use  an  oscillograph. 

Maximum  peak  inyerse  plate  volt- 
age is  the  highest  instantaneous  plate 
voltage  which  the  tube  can  withstand 
recurrently  in  the  direction  opposite  to 
that  in  which  it  is  designed  to  pass  cur- 
rent. For  mercury-vapor  tubes  and  gas- 
filled  tubes,  it  is  the  safe  top  value  to 
prevent  arc-back  in  the  tube  operating 
within  the  specified  temperature  range. 

Referring  to  Fig.  97,  when  plate  A 
of  a  full-wave  rectifier  tube  is  positive, 
current  flows  from  A  to  C,  but  not  from 
B  to  C,  because  B  is  negative.  At  the  in- 
stant plate  A  is  positive,  the  filament  is 
positive  (at  high  voltage)  with  respect  to 
plate  B.  The  voltage  between  the  posi- 
tive filament  and  the  negative  plate  B  is 


'  O 

Fig.  97 

in  inverse  relation  to  that  causing  cur- 
rent flow.  The  peak  value  of  this  voltage 
is  limited  by  the  resistance  and  nature 
of  the  path  between  plate  B  and  fila- 
ment. The  maximum  value  of  this  volt- 
age at  which  there  is  no  danger  of  break- 
down of  the  tube  is  known  as  maximum 
peak  inverse  voltage. 

The  relations  between  peak  inverse 
voltage,  rms  value  of  ac  input  voltage, 
and  dc  output  voltage  depend  largely  on 
the  individual  characteristics  of  the  rec- 

72 


tifier  circuit  and  the  power  supply.  The 
presence  of  line  surges  or  any  other 
transient,  or  wave-form  distortion,  may 
raise  the  actual  peak  voltage  to  a  value 
higher  than  that  calculated  for  sine-wave 
voltages.  Therefore,  the  actual  inverse 
voltage,  and  not  the  calculated  value, 
should  be  such  as  not  to  exceed  the  rated 
maximum  peak  inverse  voltage  for  the 
rectifier  tube.  A  calibrated  cathode-ray 
oscillograph  or  a  peak-indicating  elec- 
tronic voltmeter  is  useful  in  determining 
the  actual  peak  inverse  voltage. 

In  single-phase,  full-wave  circuits 
with  sine-wave  input  and  with  no  ca- 
pacitor across  the  output,  the  peak  in- 
verse voltage  on  a  rectifier  tube  is  ap- 
proximately 1.4  times  the  rms  value  of 
the  plate  voltage  appKed  to  the  tube.  In 
single-phase,  half-wave  circuits  with 
sine-wave  input  and  with  capacitor  in- 
put to  the  filter,  the  peak  inverse  voltage 
may  be  as  high  as  2.8  times  the  rms 
value  of  the  applied  plate  voltage.  In 
polyphase  circuits,  mathematical  deter- 
mination of  peak  inverse  voltage  requires 
the  use  of  vectors. 

The  Rating  Chart  for  full-wave 
rectifiers  presents  graphically  the  rela- 
tionships between  maximum  ac  voltage 
input  and  maximum  dc  output  current 
derived  from  the  fundamental  ratings 
for  conditions  of  capacitor-input  and 
choke-input  filters.  This  graphical  pres- 
entation provides  for  considerable  lati- 
tude in  choice  of  operating  conditions. 

The  Operation  Characteristics 
for  a  full-wave  rectifier  with  capacitor- 
input  filter  show  by  means  of  boundary 
line  the  limiting  current  and  voltage 
relationships  presented  in  the  Rating 
Chart. 

The  Operation  Characteristics 
for  a  full-wave  rectifier  with  choke-input 
filter  not  only  show  by  means  of  bound- 
ary line  the  limiting  current  and  volt- 
age relationships  presented  in  the  Rating 
Chart,  but  also  give  some  information 
as  to  the  effect  on  regulation  of  various 
sizes  of  chokes.  The  solid-line  curves 
show  the  dc  voltage  outputs  which  would 
be  obtained  if  the  filter  chokes  had  in- 
finite inductance.  The  long-dash  lines 
radiating  from  the  zero  position  are 
boundary  lines  for  various  sizes  of  chokes 
as  indicated.  The  intersection  of  one  of 
these  lines  with  a  solid-line  curve  indi- 


Interpretation  of  Tube  Data 


cates  the  point  on  the  curve  at  which  the 
choke  no  longer  behaves  as  though  it 
had  infinite  inductance.  To  the  left  of 
the  choke  boundary  line,  the  regulation 
curves  depart  from  the  solid-line  curves 
as  shown  by  the  representative  short- 
dash  regulation  curves. 

Typical  Operation  Values.  Values 
for  typical  operation  are  given  for  many 
types  in  the  TUBE  TYPES  SECTION. 
These  typical  operating  values  are  given 
to  show  concisely  some  guiding  informa- 
tion for  the  use  of  each  type.  These  val- 
ues should  not  be  confused  with  ratings, 
because  a  tube  can  be  used  under  any 
suitable  conditions  within  its  maximum 
ratings,  according  to  the  application. 

The  power  output  value  for  any 
operating  condition  is  an  approximate 
tube  output— that  is,  plate  input  minus 
plate  loss.  Circuit  losses  must  be  sub- 
tracted from  tube  output  in  order  to 
determine  the  useful  output. 

Characteristics  are  covered  in  the 
ELECTRON  TUBE  CHARACTER- 
ISTICS SECTION  and  such  data  should 
be  interpreted  in  accordance  with  the 
definitions  given  in  that  section.  Char- 
acteristic curves  represent  the  charac- 
teristics of  an  average  tube.  Individual 
tubes,  like  any  manufactured  product, 
may  have  characteristics  that  range 
above  or  below  the  values  given  in  the 
characteristic  curves. 

Although  some  curves  are  extended 
well  beyond  the  maximum  ratings  of  the 
tube,  this  extension  has  been  made  only 
for  convenience  in  calculations.  Do  NOT 
operate  a  tube  outside  of  its  maximum 
ratings. 

Interelectrode  capacitances  are  di- 
rect capacitances  measured  between 
specified  elements  or  groups  of  elements 
in  electron  tubes.  Unless  otherwise  indi- 
cated in  the  data,  all  capacitances  are 
measured  with  filament  or  heater  cold, 
with  no  direct  voltages  present,  and  with 
no  external  shields.  All  electrodes  other 
than  those  between  which  capacitance 
is  being  measured  are  grounded.  In  twin 
or  multi-unit  types,  inactive  units  are 
also  grounded. 

The  capacitance  between  the  input 
electrode  and  all  other  electrodes,  except 
the  output  electrode,  connected  together 
is  commonly  known  as  the  input  capaci- 
tance. The  capacitance  between  the  out- 


put electrode  and  all  other  electrodes, 
except  the  input  electrode,  connected 
together  is  known  as  the  output  capaci- 
tance. 

Hum  and  noise  characteristics  of 
high-fidelity  audio  amplifier  tube  types 
such  as  the  7025  and  the  7199  are  tested 
in  an  amplifier  circuit  such  as  that  shown 
in  Fig.  98.  The  output  of  the  test  circuit 
is  fed  into  a  low-noise  amplifier.  The 


rAAAr-OB+ 


Fig.  98 

bandwidth  of  this  amplifier  depends  on 
the  characteristic  being  measured.  If 
hum  alone  is  being  tested,  a  relatively 
narrow  bandwidth  is  used  to  include  both 
the  line  frequency  and  the  major  har- 
monics generated  by  the  tube  under  test. 
In  noise  or  combination  hum-and-noise 
measurements,  the  bandwidth  is  defined 
in  the  registration  of  the  tube  type. 

The  amplifier  gain  is  calibrated  so 
that  the  vacuum-tube  voltmeter  meas- 
ures hum  and  noise  in  microvolts  refer- 
enced to  the  grid  of  the  tube  under  test.  A 
pentode  can  also  be  evaluated  in  this 
manner  by  the  addition  of  a  screen-grid 
supply  adequately  bypassed  at  the  tube 
screen-grid  pin  connection.  Power-sup- 
ply ripple  at  the  plate  of  the  tube  under 
test  must  be  negligible  compared  to  its 
hum  and  noise  output.  Extraordinary 
shielding  of  both  the  test  socket  and  the 
associated  operating  circuit  is  required 
to  minimize  capacitances  between  heater 
leads  and  high-impedance  connections. 

The  test-circuit  components  are  de- 
termined by  the  tube  type  being  tested 
and  the  type  of  hum  to  be  controlled. 
Heater-cathode  hum  can  be  eliminated 
from  the  measurement  by  closing  Si. 
The  circuit  can  also  be  made  more  or 
less  sensitive  to  heater-grid  hum  by  in- 
creasing or  decreasing  the  grid  resistance 
Rg.  No  circuit  changes  affect  the  com- 
ponent of  magnetic  hum  generated  by 
the  tube. 

73 


GRID 
RADIATOR 


Parfs  of  a  Novar  Tube. 


74 


Application  Guide 
for  RCA  Receiving  Tubes 


In  the  Application  Guide  on  the  fol- 
lowing pages,  RCA  receiving  tubes  are 
classified  in  two  ways:  (a)  by  function, 
and  (b)  by  structure  (diode,  triode,  etc.). 
The  functional  classification  covers  38 
principal  types  of  application,  as  listed 
below. 

Tube  types  are  grouped  by  struc- 
ture under  each  classification;  they  are 
also  keyed  to  indicate  miniature,  octal, 
nuvistor,  and  novar  types. 

Triodes  are  designated  as  low-,  me- 
dium-, or  high-mu  types  on  the  following 
basis:  low,  less  than  10;  medium,  10  or 
more,  but  less  than  50;  high,  50  or  more. 


Where  applicable,  tubes  are  designated 
as  sharp-,  semiremote,  or  remote-cutoff  on 
the  basis  of  the  ratio,  in  per  cent,  of  the 
negative  control-grid  voltage  to  the 
screen-grid  voltage  (or,  for  triodes,  the 
plate  voltage)  as  given  in  the  character- 
istics or  typical  operation  values.  These 
terms  are  defined  as  follows:  sharp,  less 
than  10  per  cent;  semiremote,  10  or  more, 
but  less  than  20  per  cent;  remote,  20  per 
cent  or  more. 

For  more  complete  data  on  these 
types,  refer  to  the  TECHNICAL  DATA 
FOR  RCA  RECEIVING  TUBES  start- 
ing on  page  83. 


1.  Audio-Frequency 
Amplifiers 

2.  Automatic  Gain  Control 
(AGC  and  AVC)  Circuits 

3.  Burst  Amplifiers 

4.  Cathode-Drive  RF  Ampli- 
fiers (Grounded-Grid) 

5.  Color  Killers 

6.  Color  Matrixing  Circuits 

7.  Complex- Wave 
Generators 

8.  Converters 
9«  Dampers 

10.  Demodulators  (Color  TV) 

11.  Detectors 

12.  DC  Restorers 


APPLICATIONS: 

13.  Discriminators 

14.  Frequency  Dividers 

15.  FM  Detectors 

16.  Gated  Noise,  AGC,  and 
Sync  Amplifiers 

17.  Harmonic  Generators 

18.  Horizontal-Deflection 
Circuits 

19.  Intermediate-Frequency 
Amplifiers 

20.  Limiters 

21.  Mixers— RF 

22.  Mixer-Oscillators— RF 

23.  Multivibrators 

24.  Noise  Inverters 

25.  Oscillators 


26.  Phase  Inverters 

27.  Phase  Splitters 

28.  Radio-Frequency 
Amplifiers 

29.  Reactance  Circuits 

30.  Rectifiers 

31.  Regulators 

32.  Relay  Control  Circuits 

33.  Sync  Amplifiers 

34.  Sync  Clippers 

35.  Sync  Separators 

36.  Tuning  Indicators 

37.  Vertical-Deflection 
Circuits 

38.  Video  Amplifiers 


1.  AUDIO-FREQUENCY 

High-Mu  Triode 

AMPLIFIERS 

o 12SF5 

High-Mu  Triode  with  Twin  Diode 

Voltage  Amplifiers 

•  3AV6 

•  6CNT 

0  12SQ7 

•  4AV6 

06SQT 

0  12SQ7GT 

Medium-Mu  Triode  with  Twin  Diode 

•  6AT6 

0  6SQTGT 

•  14GT8 

•  6BF6               • 12BF6                o 12SR7 

•  6AV6 

•  12AT6 

•  18FY6 

o6SR7 

•  6BN8 

• 12Ay6 

•  18FY6A 

Medium-Mu  Triode— Sharp-CutoflF  Pentode 

High-Mu  Triode  with  Triple  Diode 

•  7199t 

•  5X8 

•  6T8A 

•  19T8 

High-Mu  Twin  Triode 

Medium-Mu  Twin  Triode 

•  6EUT  t 

•  12AZ7 

0  12SL7GT 

•  5J6                  •  TAUT                  0  12SNTGTA 

o  6SLTGT 

• 12AZTA 

• 20EZ7 

•  6J6A               •  9AUT                 •  19J6 

•  12AXT  t 

• 12BZ7 

•  7025t 

o  6SNTGTB        • 12AUTA 

• 12AXTAt 

•  Miniature         o  Octal                  >  INuvistor 

►  Novar 

t  For  high-fidelity  equipment. 

75 


RCA  Receiving  Tube  Manual 


Sharp-Cutoff  Pentode 
• 3DT6A*  • 6DT6A* 

• 4DT6A*  • 6GX6* 

•  5GX6*  •  6HZ6* 


•  5879t 

•  7543 1 


Kemo^.e-Cutoff  Pentode  with  Diode 
• 12CR6 

Power  Amplifiers 

Power  Triode 
2A3 

Seam  Power  Tube 


•  5AQ5 

0  OljOlFt^  y 

•  5CZ5 

o6V6 

• 34GD5 

0  5V6GT 

0  6V6GTA 

• 34GD5A 

• 6AQ5A 

0  6W6GT 

•  35B5 

•  6AS5 

06Y6G 

•  35C5 

•  6CM6 

•  12AB5 

0  35L6GT 

•  6CU5 

•  12AQ5 

•  SOBS 

•  6CZ5 

• 12CA5 

•  S0C5 

0  6DG6GT 

•  12CU5/12C5 

0  50FE5 

•  6DS5 

0 12L6GT 

a50L6GT 

*6GC5 

0  12V6GT 

•  6973 1 

o6F£5 

0  12W6GT 

o7027At 

o6L6 

•  25C5 

o7408t 

0  6L6GB  t 

Power  Pentode 

•  6BQ5 

•  8BQ5 

•  SOFKS 

•  6EH5 

•  12EHS 

•  60FX5 

o6F6 

• 25EH5 

•  7189t 

•  6GK6 

•  35EH5 

p  7868 1 

0  6K6GT 

•  50EH5 

2.  AUTOMATIC  GAIN  CONTROL 
CIRCUITS  (AGC  &  AVC) 

Diode— Sharp-Cutoff  Pentode 

•  6KL8  •  12KL8 

Diode — Remote-Cutoff  Pentode 
• 6EQ7  • 12EQ7  • 20EQ7 

Twin  Diode— Medium-Mu  Triode 
• 6BF6  • 12BF6  o 12SR7 

o6SR7 

Twin  Diode— High-Mu  Triode 

•  3AV6  o  6SQ7  o  12SQ7 

•  4AV6  o  6SQ7GT  o  12SQ7GT 

•  6AT6  • 12AT6  • 18FY6 

•  6AV6  • 12AV6  • 18FY6A 

Medium-Mu  Triode— Sharp-Cutoff  Pentode 

•  SANS  •  6BA8A  •  6CU8 

•  5GH8  •  6BH8  •  6GH8 

•  6AN8A  •  6CH8  •  6GH8A 

•  6AZ8 

High-Mu  Triode— Sharp-Cutoff  Pentode 

•  6AW8A  aSAWSA  •  8  JV8 

•I&JV8 


Sharp4^utoff  Twin  Pentode 
•3BU8  •4BU8  • 6BU8 

•  3GS8  •4GS8  •  6HS8 


3.  BURST  AMPLIFIERS 

Medium-Mu  Triode— Sharp-Cutoff  Pentode 

•  SEA8  •  6EA8  •  6GH8A 

•  SGH8  •  6GH8 

High-Mu  Triode  with  Twin  Diodes 

•  6BN8 


4.  CATHODE-PRIVE  RF  AMPLI- 
FIERS  (GROUNDED-GRID) 

Medium-Hu  Triode 

•  6BC4 

Medium-Mu  Twin  Triode 

• 4BC8  • SBK7A  • 6BQ7A 

•  4BQ7A  •  S6Q7A  •  6BS8 

•  4BS8  •  6BC8  •  6BZ7 

•  4BZ7  •6BK7A  •6FW8 

High-Mu  Triode 

>2CW4  •6AB4  >6DS4> 

>  2DS4  >  6CW4 

High-Mu  Twin  Triode 

•  6DT8  • 12AZ7  • 12DT8 

•  12AT7  •  12AZ7A 


5.  COLOR  KILLERS 

Quadruple  Diode 
•  6JU8 


6.  COLOR  MATRIXING  CIRCUITS 

Medium-Mu  Twin  Triode 

•  6CG7  •6GU7  tSFQy 

•  6FQ7  • 8CG7  • 12BH7A 


7.  COMPLEX-WAVE  GENERA- 
TORS 

High-Mu  Twin  Douhle-PIate  Triode 

•  12FQ8 

Sharp-Cutoff  Twin-Plate  Tetrode— Diode 

•  6FA7 

Sharp-Cutoff  Three-Plate  Tetrode— Diode 

•  6KM8 

Three-Plate  Tetrode— Medium-Mu  Triode 

•  6FH8 


•  Miniature     o  Octal     >  Nuvistor     ►  Novar    *  Dual-control  grids    f  For  high-fidelity  equipment 


76 


Application  Guide 


8.  CONVERTERS 

Mediiim-Mu  Triode — Sharp-Cutoff  Pentode 

•  5EA8  •  5X8  •  6KE8 

•  5GH8  •  6EA8  •  6U8A 

•  5KE8  • 6GH8  •  6X8 

•  5U8  •  6GH8A  •  19X8 

High-Mu  Twin  Triode 

•  6DT8  •  12AZ7  •  12DT8 

•  12AT7  •  12AZ7A 

Sharp-Cutoff  Pentode 

•  6AU6  •  12AU6 

Pentagrid 

•  6BA7  • 12BA7 
• 6BE6  • 12BE6 
o  6SA7  o  12SA7 
o  6SA7GT 


•  18GD6A 


o  12SA7GT 

•  18FX6 

•  18FX6A 


9.  DAMPERS 

Half-Wave  (Diode) 


o  6AU4GTA 
o  6AX4GT 
o  6AX4GTB 

>  6AY3 

>  6BA3 

>  6BH3 

>  6BS3 
o6CQ4 
o6DA4 
o6DE4 
o6DM4 

>  6DW4 


o  6W4GT 
o 12AX4GTA 
o 12AX4GTB 
► 12AY3 

►  12BS3 
ol2D4 

o  12DM4 
o  17AX4GT 
o 17AX4GTA 
► 17AY3 

>  17BH3 


►  17BS3 
o  17D4 
o  17DE4 
o  17DM4 
o  19AU4 
o  19AU4- 

GTA 

>  22BH3 
o  22DE4 
o  25AX4. 

GT 


10.  DEMODULATORS  (COLOR  TV) 

Medium-Mu  Twin  Triode 

•  12BH7A 

High-Mu  Twin  Triode 

•  12AZ7  •  12AZ7A 

Sharp-Cutoff  Pentode 

•  6GY6 

Pentagrid  Amplifier 

•  6BY6 

11.  DETECTORS 

Diode — Sharp-Cutoff  Pentode 

•  5AM8  •  6AM8A  •  6KL8 

•  5AS8  •  6AS8  •  12KL8 


Diode — Remote-Cutoff  Pentode 
•  6EQ7  •  12EQ7 

• 12CR6 


Twin  Diode 

•  SALS 

•  6AL5 


o6H6 
• 12AL5 


•  20EQ7 


ol2H6 


Twin  Diode— Medium-Mu  Triode 
•  6BF6  • 12BF6  o 12SR7 

o6SR7 


Twin  Diode— High-Mu  Triode 
• 3AV6  • 6CN7 

•  4AV6  o  6SQ7 

•  6AT6  o  6SQ7GT 

•  6Ay6  • 12AT6 

•  6BN8  • 12AV6 

Triple  Diode 

•  6BJ7 

Triple  Diode— High-Mu  Triode 
• 5T8  • 6T8A 

Quadruple  Diode 

•  6JU8 

Sharp-Cutoff  Pentode 
• 3DT6A*  • 5GX6* 

• 4DT6A*  • 6DT6A* 

12.  DC  RESTORERS 

Diode — Sharp-Cutoff  Pentode 

•  5AM8  •  6AM8A 

•  5AS8 

Triple  Diode 

•  6BJ7 

13.  DISCRIMINATORS 

FM 

Twin  Diode 

•  SALS  • 6AL5 

Twin  Diode— High-Mu  Triode 

•  6BN8  • 14GT8 

Triple  Diode— High-Mu  Triode 
• ST8  • 6T8A 

Beam  Tube 

•  SBN6  •  4BN6 

FM  Quadrature-Grid 
Sharp-Cutoff  Pentode 


•  3DT6A* 
• 4DT6A* 

•  SGX6* 

Beam  Tube 

•  3BN6 


•  5GY6* 

• 6DT6A* 

•  6GX6* 


0  12SQ7 
o  12SQ7GT 
• 14GT8 

•  18FY6 

•  18FY6A 


•  19T8 


•  6GX6* 

•  6HZ6* 


•  6AS8 


•  12AL5 


•  19T8 


•  6BI\6 


•  6GY6* 

•  6HZ6* 


•  4BN6  •  6BN6 

Horizontal  AFC 

Twin  Diode— High-Mu  Triode 

•  6BN8  •  6CN7 

14.  FREQUENCY  DIVIDERS 

High-Mu  Twin  Double-Plate  Triode 

•  12FQ8 


•  Miniature 


o  Octal 


>  NuTistor 


>  Novar 


*  Dual-control  grids 


77 


RCA  Receiving  Tube  Manual 


15.  FM  DETECTORS 

(See  13.  DISCRIMINATORS) 

16.  GATED  NOISE,  AGC,  AND 
SYNC  AMPLIFIERS 

High-Mu  Triode— -Sharp-Cu'woflf  Pentode 

•  6KA8  •8KA8 

Sharp-Cutoff  Pentode 
• 6GY6* 

Pentagrid  Amplifier 

•  3BY6  •6BY6  •  6CS6 

•  3CS6 

17.  HARMONIC  GENERATORS 
(See  7.  COMPLEX-WAVE  GENERATORS) 

18.  HORIZONTAL-DEFLECTION 
CIRCUITS 

Oscillators 

Medium-Mu  Triode— Sharp-Cutoff  Pentode 

•  5GH8  • 6GH8  • 6GH8A 

Medium-Mu  Twin  Triode 

•  6CG7  •8CG7  •  12AU7 

• 6FQ7  • 8FQ7  • 12BH7A 

o  6SN7GTB         •  9AU7  o  12SN7. 

• 7AU7  GTA 

Amplifiers 

Beam  Power 
o  6AU5GT 
o  6AV5GA 
06BG6A 
o  6BQ6GTB/ 

6CU6 
0  6CB5 A 
o  6CD6GA 
06DN6 
06DQ5 
06DQ6B 
06EX6 
»^6GJ5 
»6GT5 


Tube 

06GW6 

>  6JB6 
»^6JE6 

o  12Ay5GA 
o  12BQ6GTB/ 

12CU6 
o  12DQ6A 
o  12DQ6B 

>  12GJ5 

>  12GT5 
o  12GW6 
»  12JB6 


o  17BQ6. 

GTB 
o  17DQ6B 

►  17GJ5 

►  17GT5 
o  17GW6 

►  17JB6 

►  22JG6 

o  25AV5GA 
o  25BQ6. 
GTB/25CU6 
o  25CD6GB 
o  25DN6 


19.  INTERMEDUTE-FREQUENCY 
AMPLIFIERS 

Medium-Mu  Triode— Sharp-Cutoff  Tetrode 

•  5CQ8  •  6CQ8 

Medium-Mu  Triode— Sharp-Cutoff  Pentode 

•  5AN8  •6AZ8  •  6CU8 

•  6AN8A  •  6BH8  •  6CX8 

•  6AU8A  •  6CH8  •  8CX8 


High-Mu  Triode— Sharp-Cutoff  Pentode 

•  6AW8A  •  6KV8  •  8JV8 

•  6GN8  •  8AW8A  •  10HF8 

•  6HF8  •  8GN8  •  11KV8 

•  6JV8 

Sharp-Cutoff  Pentode 


•  3AU6 

•  5EW6 

•  6DC6 

•  3CB5 

o6AB7 

•  6DE6 

•  3CB6 

o6AC7 

•  6DK6 

•  3CF6 

•  6AG5 

•  6EJ7 

•  3DK6 

•  6AH6 

•  6EW6 

•  3JC6 

•  6AK5 

•  6HS6 

•  3JD6" 

•  6AU6 

•  6JC6 

•  4AU6 

• 6AU6A 

•  6JD6" 

•  4CB6 

•  6BC5 

•  12AU6 

•  4EW6 

•  6CB6 

•  12AW6 

•  4JC6 

• 6CB6A 

•  18GD6A 

•  4JD6" 

•  6CF6 

•  19HS6 

Sharp-Cutoff  Pentode  with  Diode 

•  5AM8 

•  6AM8A 

•  6KL8 

•  5AS8 

•  6AS8 

•  12KL8 

Semiremote-Cutoff  Pentode 

•  3BZ6 

•  6EH7 

•  6JH6 

•  4BZ6 

•  6GM6 

•  12BZ6 

•  5GM6 

•  6HR6 

•  19HR6 

•  6BZ6 

Remote-Cutoff  Pentode 

•  6BA6 

• 12BA6 

•  18FW6 

o6SK7 

0  12SK7 

•  18FW6A 

0  6SK7GT 

0  12SK7GT 

Remote-Cutoff  Pentode  with  Diode 

•  6EQ7 

•  12EQ7 

• 20EQ7 

20.  LIMITERS 

Beam  Tube 

•  3BN6 

•  4BN6 

•  6BN6 

Sliarp-Cutoff  Pentode 

•  3AU6 

•  6GX6 

•  12AU6 

•  4Ar  • 

•  6HS6 

0  12SH7 

•  5GX6 

•  6HZ6 

•  19HS6 

• 6AU6A 

o6SH7 

Sharp-Cutoff  Pentode  with  Diode 

•  6KL8  •  12KL8 

21.  MIXERS-RF 

Medium-Mu  Twin  Triode 

•  5J6  •  12AV7  •  19J6 

•  6J6A 

High  Mu  Triode 

>2CW4  •6AB4  >6CW4 

22.  MIXER-OSCILLATORS-RF 

Medium-Mu  Triode— Sharp-Cutoff  Tetrode 

•  5CL8A  • 6CL8A  •  6CQ8 

•  5CQ8 


•  Miniature      o  Octal 

*  Daal-Gontrol  grids 

78 


>  Nuvistor    ►  Novar 


*  Approaches  semiremote-cntoff  characteristic; 
used  in  first-if  amplifier  applications 


Application  Guide 


Medium-Mu  Triode — Sharp-CutoflF  Pentode 


•  5AT8 

•  5B8 

•  5BR8 

•  5CG8 

•  SEAS 

•  5KE8 


•  5U8 

•  5X8 

• 6AT8A 
• 6BR8A 
• 6CG8A 

•  6EA8 


•  6FG7 

•  6KE8 

•  6U8A 

•  6X8 

• 19EA8 

•  19X8 

•  12DT8 


High-Mu  Twin  Triode 
•  6Dr8  •  12AT7 

Triode-Hexode 
o  6K8  o 12K8 

23.  MULTIVIBRATORS 


Medium-Mu  Triode — Sharp-CutoflF  Pentode 
• 5GH8  • 6GH8  • 6GH8A 

Medium-Mu  Twin  Triode 

•  6CG7  •  7AU7  o  12SN7- 

•  6GU7  •  9AU7  GTA 
o  6SN7GTB         • 12AU7A 

High-Mu  Twin  Triode 
• 12AX7  • 12AX7A 

24.  NOISE  INVERTERS 

High-Mu  Triode — Sharp-Cutoflf  Pentode 
• 6KA8  • 8KA8 

Sharp-CutoflF  Pentode 

•  6GY6* 

25.  OSCILLATORS 

Radio  Frequency — UHF 
Medium-Mu  Triode 


• 2AF4B 
>2DV4 
•  2DZ4 


• 3AF4A 

•  3DZ4 

•  6AF4 


• 6AF4A 
>6DV4 
•  6DZ4 


H9J6 


Radio  Frequency — VHF 

Medium-Mu  Twin  Triode 

•  5J6  • 12AV7 

•  6J6A 

High-Mu  Triode 

•  6AB4 


Power  Triode 

•  6C4  (Class  C) 

Low  Frequency y  Sweep  Type 

Medium-Mu  Triode — Sharp-CutoflF  Pentode 
• 5AN8  • 6BA8A  • 6CU8 

•  6AN8A  •  6BH8  •  6CX8 

•  6AU8A  • 6CH8  •  8CX8 

•  6AZ8 

High  Mu  Triode  with  Twin  Diode 

•  6BN8  •  6CI\7 

High-Mu  Triode — Sharp-CutoflF  Pentode 

•  6AW8A  •  8AW8A 


High-Mu  Twin  Triode 
• 12AX7  • 12AX7A 


26.  PHASE  INVERTERS 

Medium-Mu  Triode— -High-Mu  Triode 

•  12DW7 

Medium-Mu  Twin  Triode 

•  6CG7  •  7AU7  o  12S1V7- 

•  6GU7  •  9AU7  GTA 
o  6S1\7GTB         •  12AU7A 

High-Mu  Triode— Sharp-CutoflF  Pentode 

•  6AW8A  •  6HF8  •  8GN8 

•  6EB8  •  8AW8A  •  10HF8 

•  6G1V8  •  8EB8 

High-Mu  Twin  Triode 
o  6SC7  • 12AX7A  o  12SL7GT 

0  6SL7GT  0  12SC7  •7U25 

• 12AX7 


27.  PHASE  SPLITTERS 

Medium-Mu  Triode— Sharp-CutoflF  Tetrode 
•5CQ8  •6CQ8 

Medium-Mu  Triode — Sharp-CutoflF  Pentode 

•  5AN8  •  6BA8A  •  6CU8 

•  6AN8  •6CH8  ^7199 

•  6AZ8 

High-Mu  Triode— Sharp-CutoflF  Pentode 

•  6AW8A  •  8AW8A 


28.  RADIO-FREQUENCY 
AMPLIFIERS 

Medium-Mu  Triode 
• 2BN4A  • 6BC4  • 6BN4A 

• 3BN4A 

Medium-Mu  Triode— Sharp-CutoflF  Tetrode 
•  5CQ8  •  6CQ8 


Medium-Mu  Twin  Triode 

•  4BC8  •  5J6 

•  4BQ7A  •  6BC8 

•  4BS8  • 6BK7B 
• 4BZ7  • 6BQ7A 

•  5BK7A  •  6BS8 
• 5B07A 

High-Mu  Triode 

>  2CW4  •  6AB4 

>  2DS4  >  6CW4 

•  2FH5  >  6DS4 

•  3GK5  •  6ER5 

High-Mu  Twin  Triode 

•  6DT8  •  12AZ7A 

•  12AZ7 


•  6BZ7 

•  6FW8 

•  6J6A 

• 12AV7 

•  19J6 


•  6FH5 

• 6FQ5A 

•  6GK5 
>  13CW4 

• 12DT8 


•  Miniature 


*  Dual-control  grids 


79 


RCA  Receiving  Tube  Manual 


Power  Triode 

•  6C4  (Class  C) 

Sharp-Cutofif  Tetrode 

•  2CY5  •  6CY5  •  6FV6 

•  3CY5 

Sharp-Cutoff  Pentode 


•  3AU6 

•  6AK5 

•  6DE6 

•  3BC5 

• 6AU6A 

o6SH7 

•  3CB6 

•  6BC5 

o6SJ7 

•  3CF6 

•  6BH6 

• 12AU6 

•  4AU6 

•  6CB6 

•  12AW6 

•  4CB6 

• 6CB6A 

0  12SH7 

o6AB7 

•  6CF6 

0 12SJ7 

o6AC7 

•  6DC6 

•  18GD6A 

•  6AG5 

Sharp-Cutoff  Pentode  with  Diode 

•  6KL8  •  12KL8 

Semiremote-Cutoff  Pentode 
o  6SG7  o  12SG7 

Remote-Cutoff  Pentode 

•  3BA6  o  6SK7GT  o  12SK7GT 

•  6BA6  •  12BA6  •  18FW6 

•  6BJ6  o  12SK7  •  18FW6A 
o6SK7 

Remote-Cutoff  Pentode  with  Diode 

• 6EQ7  • 12EQ7  • 20EQ7 


29.  REACTANCE  CIRCUITS 

Medium-Mu  Triode — Sharp-Cutoff  Pentode 

•  5AN8  •  6AZ8  •  6CH8 

•  6AN8A  • 6BA8A  •  6CU8 

High-Mu  Triode  with  Twin  Diodes 

•  6CN7 

High-Mu  Triode— Sharp-Cutoff  Pentode 

•  6AW8A  •  8AW8A 


30.  RECTIFIERS 


Power-Supply  Types — Vacuum 


Half-Wave 

(Diode) 

•  35W4 

•  36AM3A 

• 50DC4 

o  35Z5GT 

•  36AM3B 

Full-Wave 

(Twin  Diode) 

o3DG4 

o5V3A 

o5Z4 

o  5AS4A 

o5VG4 

o  6AX5GT 

►  5BC3 

0  5V4GA 

•  6CA4 

o5DJ4 

o5XG4 

•  6X4 

o5U4G 

0  5Y3GT 

o  6X5GT 

0  5U4GB 

0  5Y4GT 

•  12X4 

•  Miniature  o  Octal 


High-Voltage  Types  {For  rf -rectifier  or 
pulsed  low-current  applications) — Vacuum 

Half-Wave  (Diode) 
o  1B3GT  o  1K3  •  3A2 

o  1G3GT/  •  1V2  o  3A3 

1B3GT  •  1X2B  0  3B2 

o  1J3 


31.  REGULATORS 

High-Voltage,  Low  Current 

Sharp-Cutoff  Beam  Triode 
o6BK4 


32.  RELAY  CONTROL  CIRCUITS 

Medium-Mu  Twin  Triode 
• 12FV7 

High-Mu  Twin  Triode 
•  6EV7 


33.  SYNC  AMPLIFIERS 

Medium-Mu  Triode — Sharp-Cutoff  Pentode 

•  6AU8A  • 6CX8  •  8CX8 

•  6AZ8 

Medium-Mu  Twin  Triode 

•  6CG7  •7AU7  •  12AU7A 

High-Mu  Triode  with  Twin  Diode 

•  6CN7 

High-Mu  Triode— Sharp-Cutoff  Pentode 

•  6AW8A  •  8AW8A  •  8JV8 

•  6JV8 

High-Mu  Twin  Triode 

•  12BZ7 


34.  SYNC  CLIPPERS 

Medium-Mu  Triode— Sharp-Cutoff  Tetrode 

•  5CQ8  •  6CQ8 

Medium-Mu  Triode— Sharp-Cutoff  Pentode 
• 5AN8  • 6AZ8  • 6CX8 

•  6AN8A  •6CH8  •  8CX8 

•  6AU8A  •  6CU8 

High-Mu  Triode — Sharp-Cutoff  Pentode 

•  6AW8A  •  6JV8  •  8GN8 

•  6EB8  •  8AW8A  •  8JV8 

•  6GW8  •  8EB8  •  10HF8 

•  6HF8 

High-Mu  Twin  Triode 
• 12BZ7 


>  Nuvistor  ►  Novar 


80 


Application  Guide 


•  6BU8 

•  6HS8 


•  6CS6 


Sharp-Cntoff  Twin  Pentode 
• 3BU8  • 4BU8 

•  3GS8  •  4GS8 

Pentagrid  Amplifier 

•  3BY6  •  6BY6 

•  3CS6 

35.  SYNG  SEPARATORS 

Medium-Mu  Triode— Sharp-Cutoff  Tetrode 

•  5CQ8  •  6CQ8 

Medium-Mu  Triode — Sharp-Cutoff  Pentode 

•  SANS  •  6AZ8  •  6GH8 

•  5GH8  • 6CH8  • 6GH8A 
• 6AN8A             • 6CU8  • 8CX8 

•  6AU8A  •  6CX8 

Medium-Mu  Twin  Triode 

•  6CG7  • 7AU7  • 12AU7A 

High-Mu  Triode  with  Twin  Diode 

•  6CN7 

High-Mu  Triode— Sharp-Cutoff  Pentode 


►  6AW8A 
>6EB8 
»6GN8 
»6HF8 

►  6JV8 


•  6KA8 

•  6KV8 

•  8AW8A 

•  8EB8 

•  8GN8 


•  8JV8 

•  8KA8 

•  10HF8 

•  IIKYS 


•  6BU8 

•  6HS8 


•  6CS6 


High-Mu  Twin  Triode 

•  12BZ7 

Sharp-Cutoff  Twin  Pentode 

•  3BU8  •  4BU8 

•  3GS8  •  4GS8 

Pentagrid  Amplifier 

•  3BY6  •  6BY6 

•  3CS6 

36.  TUNING  INDICATORS 

Indicator  with  Triode  Unit 
6E5  6U5 

Twin  Indicator  Units 
o  6AF6G 


37.  VERTICAL-DEFLECTION 
CIRCUITS 

Oscillators  and  Amplifiers  (Combined) 

Medium-Mu  Triode— Low-Mu  Triode 

•  6DE7  • 10DE7  • 13DE7 

•  6EW7 


Medium-Mu  Dual  Triode 
•  6CM7  •  6CS7 


•  8CM7 


High-Mu  Triode— Low-Mu  Triode 

•  6CY7  ► 6GF7  ► lOGFT 

•  6DR7  0  6GL7  o  ISEMT 

•  6EA7  • 10DR7  ►  13FD7 
o  6EM7               0  10EM7  ►  13GFT 

►  6FD7 

High-Mu  Triode— Beam  Power  Tube 

►  15KY8 

Amplifiers 

Low-Mu  Triode 
• 12B4A 

Medium-Mu  Triode 

•  6S4A 

Beam  Power  Tube 

•  5AQ5  •  6AQ5A  •  6EM5 

•  5CZ5  •  6CM6  •  8EM5 
o  5V6GT              •  6CZ5 

Power  Pentode 
o  6K6GT 


38.  VIDEO  AMPLIFIERS 

Medium-Mu  Triode— Sharp-Cutoff  Pentode 

•  5AN8  •  6BA8A  •  6CU8 

•  6AN8A  •  6BH8  •  6CX8 

•  6AU8A  •  6CH8  •  8CX8 

•  6AZ8 

High-Mu  Triode— Sharp-Cutoff  Pentode 

•  6AW8A  •  6JV8  •  8GN8 

•  6EB8  •  6KV8  •  8JV8 

•  6GN8  •  8AW8A  •  10HF8 

•  6HF8  •  8EB8  •  IIKYS 

Sharp-Cutoff  Pentode 

•  12BY7A 

Sharp-Cutoff  Pentode  with  Diode 

•  5AM8  •  6AM8A  •  6AS8 

•  5AS8 

Beam  Power  Tube 

•  25BK5 


Power  Pentode 
o  6AG7  •  6CL6 


•  6GK6 


•  Miniature 


o  Octal 


For  information  on  picture  tubes,  refer  to  the  RCA  PICTURE  TUBE  CHAR- 
ACTERISTICS CHART  at  the  end  of  the  TECHNICAL  DATA  section. 


81 


1 —  Gfass  Envelope 

2 —  Internal  Shield 

3—  ~Plate 

4—  Grid  No.  3  (Suppressor) 

5—  Grid  No.  2  (Screen) 

6—  Grid  No.  1  (Control  Grid) 

7—  Cathode 
S—Heater 
9-— Exhaust  Tip 

10—Getter 

1 1  —Spacer  Shield  Header 

12 —  insulating  Spacer 

13—  Spacer  Shield 

14—  Inter-Pin  Shield 

15—  Glass  Button-Stem  Seal 

16—  Lead  Wire 

17—  Base  Pin 

18—  Glass-to-Metal  Sea! 


Structure  of  a  Miniature  Tube 


Technical  Data 
for  RCA  Tube  Types 


This  section  contains  technical  descriptions  of  RCA  tubes  used  in  standard 
broadcast,  FM,  and  television  receivers,  in  audio  amplifiers,  and  in  many  other 
diverse  applications.  It  includes  data  on  current  types,  as  well  as  information  on 
those  RCA  discontinued  types  in  which  there  may  still  be  some  interest.  Unless 
otherwise  specified,  the  ratings  given  are  based  on  the  Design  Center  system.  Infor- 
mation on  picture  tubes  is  shown  at  the  end  of  this  section. 

In  choosing  tube  types  for  the  design  of  new  electronic  equipment,  the  designer 
should  refer  to  the  APPLICATION  GUIDE  FOR  RCA  RECEIVING  TUBES 
on  pages  76  to  81. 

Tube  types  are  listed  in  this  section  according  to  the  numerical-alphabetical- 
numerical  sequence  of  their  type  designations.  For  Key:  Basing  Diagrams,  see 
inside  back  cover. 


DIODE 


Miniature  type  used  as  detector  tube  in 
portable  FM  receivers  and  in  portable  high- 
frequency  measuring  equipment.  Outline  7B, 
OUTLINES  SECTION.  Tube  requires  minia- 
ture seven-contact  socket.  Heater  volts  (ac/ 
dc),  1.4;  amperes,  0.15.  Maximum  ratings  for 
half-wave  rectifier  service:  peak  inverse  plate 
volts,  330  max;  peak  plate  ma,  5  max;  dc  out- 
put ma.,  0.5  max;  peak  heater-cathode  volts, 
140  max.  This  type  is  used  principally  for  re- 
newal purposes. 


1A3 


REMOTE-CUTOFF  PENTODE 

Glass  type  used  in  battery-operated  re- 
ceivers as  rf  or  if  amplifier.  This  type  is  similar 
electrically  to  type  1D5-GP.  Outline  24B,  OUT- 
LINES SECTION.  Tube  requires  four-contact 
socket.  Filament  volts  (dc),  2.0;  amperes,  0.06. 
Type  1A4-P  is  a  DISCONTINUED  type  listed 
for  reference  only. 


1A4P 


POWER  PENTODE 

Glass  octal  type  used  in  output  stage  of  bat- 
tery-operated receivers.  Outline  14C,  OUT- 
LINES SECTION.  This  type  may  be  supplied  t  ik  C 
with  pin  No.l  omitted.  Tube  requires  octal  socket  |  Mjk  5  ^5  T 
and  may  be  mounted  in  any  position .  For  filament 
considerations,  refer  to  type  1U4.  Filament  volts 
(dc),  1.4;  amperes,  0.05.  Typical  operation  as 
class  Ai  amplifier:  plate  and  grid-No.2  volts,  90 
(110  max);  grid-No.l  volts,  -4.5;  peak  af  grid- 
No.l  volts,  4.5;  plate  ma.,  4.0;  grid-No.2  ma.,  1.1;  plate  resistance  (approx.),  0.3  megohm;  transcon- 
ductance,  850  ^nihos;  load  resistance,  25000  ohms;  power  output,  116  milliwatts.  Type  1A5-'gT  is  used 
principally  for  renewal  purposes. 


83 


RCA  Receiving  Tube  Manual 


PENTAGRID  CONVERTER 

Glass  type  used  in  battery-operated  re- 
ceivers. This  type  is  identical  electrically  with 
I  type  1D7-G,  except  for  interelectrode  capaci- 

tances.  Outline  24B,  OUTLINES  SECTION. 
Tube  requires  six-contact  socket.  Filament  volts 
(dc),  2.0;  amperes,  0.06.  Type  1A6  is  a  DISCON- 
TINUED type  listed  for  reference  only. 


1A7GT 


PENTAGRID  CONVERTER 

Glass  octal  type  used  in  superheterodyne 
circuits  having  battery  power  supplies.  Outline 
15A,  OUTLINES  SECTION.  Tube  requires  oc- 
tal socket  and  may  be  mounted  in  any  position. 
Filament  volts  (dc),  1.4;  amperes,  0.05.  Typical 
operation  as  converter:  plate  and  grid-No.2  volts, 
90  (110  max);  grids-No.3-and-No.5  supply  volts, 
110  max;  grids-No.3-and-No.5  volts,  45  (60  max) ; 
grid-No.4  volts,  0;  grid-No.l  resistor,  0.2  meg- 
«ohm;  plate  resistance  (approx.),  0.6  megohm;  plate  ma.,  0.6;  grids-No.3-and-No.5  ma.,  0.7;  grid-No.2 
ma.,  1.2;  grid-No.l  ma.,  0.035;  total  cathode  ma.,  2.5  (4  max);  conversion  transconductance,  250 
4<mhos.  This  type  is  used  principally  for  renewal  purposes. 


POWER  PENTODE 

Subminiature  type  used  in  output  stage  of 
small,  compact,  battery-operated  receivers  for 
the  standard  AM  broadcast  band.  Maximum 
1  A  dimensions:  over-all  length,  1.75  inches;  seated 

height,  1.6  inches;  diameter,  0.4  inch.  Tube  re- 
quires subminiature  eight-contact  socket.  Fila- 
ment volts  (dc),  1.25;  amperes,  0.04.  Filament 
voltage  should  never  exceed  1.6  volts.  Typical 
operation  as  Class  Ai  amplifier:  plate  and  grid- 
No.2  volts,  67.5  max;  grid-No.l  volts,  -4.5;  peak  af  grid-No.l  volts,  4.5;  zero-signal  plate  ma.,  2;  zero- 
signal  grid-No.2  ma.,  0.4;  cathode  ma.,  4  max;  plate  resistance,  0.15  megohm;  transconductance,750 
Mmhos;  load  resistance,  25000  ohms;  total  harmonic  distortion,  10  per  cent;  maximum-signal  power  out- 
put, 50  milliwatts.  This  is  a  DISCONTINUED  type  listed  for  reference  only. 


1AD2 


HALF-WAVE  VACUUM  RECTIFIER 

Duodecar  type  used  to  supply 
power  to  the  anode  of  the  picture  tube 
in  television  receivers.  Outline  16A, 
OUTLINES   SECTION.   Tube  re- 
quires duodecar  twelve-contact  socket 
and  may  be  mounted  in  any  position.  Socket  terminals  4  and  10  may  be  used  as 
tie  points  for  components  at  or  near  filament  potential.  Filament  volts  (ac/dc), 
1.25;  amperes,  0.2. 

PULSED  RECTIFIER 

For  operation  in  a  525-line,  SO-frame  system 
Maxfmum  Ratings,  {Design-Maximum  Values): 

Peak  Inverse  Plate  Voltage#  , 

Peak  Plate  Current  

Average  Plate  Current  


26000 "waaj 
50  max 
0.5  max 


volts 
ma 
ma 


Characteristics,  Instantaneous  Value: 

Tube  Voltage  Drop  for  plate  current  of  7  ma.   225  volts 

#  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  horizontal  scanning  cycle.  In  a 
525-line,  30-frame  system,  15  per  cent  of  one  horizontal  scanning  cycle  is  10  microseconds. 
■  The  dc  component  must  not  exceed  22000  volts. 

84 


Technical  Data 


1AD5 


SHARP-CUTOFF  PENTODE 

Subminiature  type  used  as  rf  or  if  amplifier 
In  stages  not  controlled  by  avc  in  small,  com- 
pact, battery-operated  receivers  for  the  stand- 
ard AM  broadcast  band.  Maximum  dimensions: 
over-all  length,  1.76  inches;  seated  height,  1.6 
inches;  diameter,  0.4  inch.  Tube  requires  sub- 
miniature  eight-contact  socket.  Filament  volts 
(dc),  1.26;  amperes,  0.04.  Filament  voltage 
should  never  exceed  1.6  volts.  Characteristics 
as  class  Ai  amplifier:  plate  and  grid-No.2  volts,  67.6  max;  grid-No.l  volts,  0;  plate  resistance,  0.7  meg- 
ohm; transconductance,  736  /tmhos;  total  cathode  ma.,  4  max;  plate  ma.,  1.86;  grid-No.2  ma.,  0.76.  This 
is  a  DISCONTINUED  type  listed  for  reference  only. 

HALF-WAVE  VACUUM  RECTIFIER 

Miniature  type  used  as  rectifier  of  high- 
voltage  pulses  produced  in  the  scanning  systems 
of  television  receivers.  Outline  9A,  OUTLINES 
SECTION.  Tube  requires  miniature  nine-con- 
tact socket.  Socket  terminals  8  and  7  may  be 
connected  to  the  filament,  or  used  as  tie  points 
for  the  filament-dropping  resistor ;  otherwise  they 
should  not  be  used.  Filament  volts  (ac),  1.4; 
amperes,  0.66.  Maximum  ratings  as  pulsed  rec- 
tifier in  626-line,  30-frame  system:  peak  inverse  plate  volts  {absolute  maximum) ^  26000  max  (dc  20000 
max) ;  peak  plate  ma.,  11  max;  average  plate  ma.,  1  mux.  For  filament  and  high-voltage  considerations, 
refer  to  type  1B3-GT.  Type  1AX2  is  used  principally  for  renewal  purposes. 


1AX2 


LC.   p  LC 


1B3GT 


HALF-WAVE  VACUUM  RECTIFIER 

Glass  octal  type  used  in  high-voltage, 
low-current  applications  such  as  the 
rectifier  in  a  high-voltage,  rf-operated 
power  supply  or  as  a  rectifier  of  high- 
voltage  pulses  produced  in  television 
scanning  systems. 

Filament  Voltage  (AC/DC)   1.25*  volts 

Filament  Current   0.2  ampere 

Direct  Interelectrode  Capacitance  (Approx.): 

Plate  to  Filament  and  Internal  Shield   1.3  pf 

*  Under  no  circumstances  should  the  filament  voltage  be  less  than  1.05  volts  or  greater  than  1.45  volts. 

PULSED  RECTIFIER 

For  operation  in  a  525-linet  SO-frame  system 
Maximum  Ratings,  (Design-Maximum  Values): 

Peak  Inverse  Plate  Voltage*   26000 •waa?  volts 

Peak  Plate  Current   50  max  ma 

Average  Plate  Current   0.5  max  ma 

Characteristics,  Instantaneous  Value: 

Tube  Voltage  Drop  for  plate  current  of  7  ma  

RADIO-FREQUENCY  RECTIFIER 
Maximum  Ratings,  {Design-Maximum  Values): 

Peak  Inverse  Plate  Voltage  

Peak  Plate  Current  

Average  Plate  Current  

Frequency  Range  of  Supply  Voltage  

*  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  horizontal  scanning  cycle.  In  a 
525-line,  30-frame  system,  15  per  cent  of  one  horizontal  scanning  cycle  is  10  microseconds. 

*  The  dc  component  must  not  exceed  22000  volts. 


100 


83000  max 
35  max 
1 . 1  max 
1.5  to  100 


volts 


volts 
ma 
ma 
Kc 


INSTALLATION  AND  APPLICATION 

Type  1B3-GT  requires  an  octal  socket  and  may  be  mounted  in  any  position. 
Plate  connection  is  cap  at  top  of  bulb.  Socket  terminals  1,  3,  4,  5,  6,  and  8  may  be 
connected  to  socket  terminal  7  or  to  a  corona  shield  which  is  connected  to  socket 
terminal  7.  Socket  terminals  4  and  6  may  be  used  as  tie  points  for  components  at 
or  near  filament  potential.  This  type  may  be  supplied  with  pins  1,  4,  and/or  6 
omitted.  Outline  15D,  OUTLINES  SECTION. 


85 


RCA  Receiving  Tube  Manual 


The  high  voltages  at  which  the  1B3-GT  is  operated  are  very  dangerous.  Great 
care  should  be  taken  to  prevent  coming  in  contact  with  these  high  voltages.  In 
those  circuits  where  the  filament  circuit  is  not  grounded,  the  filament  circuit  oper- 
ates at  dc  potentials  which  can  cause  fatal  shock.  Extreme  precautions  must  be 
taken  when  the  filament  voltage  is  measured.  These  precautions  must  include  safe- 
guards which  definitely  eliminate  all  hazards  to  personnel.  The  filament  transformer, 
whether  it  is  of  the  iron-core  or  the  air-core  type,  must  be  sufficiently  insulated. 

The  voltages  employed  in  some  television  receivers  and  other  high-voltage 
equipment  may  be  sufficiently  high  to  cause  high- voltage  rectifier  tubes  such  as  the 
1B3-GT  to  produce  soft  X-rays  which  can  constitute  a  health  hazard  unless  the 
tubes  are  adequately  shielded.  Relatively  simple  shielding  should  prove  adequate, 
but  the  need  for  this  precaution  should  be  considered. 


1B4P 


SHARP-CUTOFF  PENTODE 

Glass  type  used  as  rf  amplifier  or  detector 
in  battery-operated  receivers.  Outline  24B,  OUT- 
LINES SECTION.  Tube  requires  four-contact 
socket.  For  typical  operating  conditions  and 
maximum  ratings  as  a  class  Ai  amplifier,  refer 
to  type  1E5-GP.  Filament  volts  (dc),  2.0;  am- 
peres, 0.06.  Type  1B4-P  is  a  DISCONTINUED 
type  listed  for  reference  only. 


1B5/25S 


TWIN  DIODE— MEDIUM-MU  TRIODE 

Glass  type  used  as  combined  detector,  am- 
plifier, and  avc  tube  in  battery-operated  re- 
ceivers. Maximum  dimensions:  over-all  length, 
4-3/16  inches;  seated  height,  3-9/16  inches;  di- 
ameter, 1-9/16  inches.  Tube  requires  six-contact 
socket.  Filament  volts  (dc),  2.0;  amperes,  0.06. 
Typical  operation  as  class  Ai  amplifier:  plate 
volts,  135  max;  grid  volts,  -8;  plate  ma.,  0.8; 
plate  resistance,  35000  ohms;  amplification  fac- 
tor, 20;  transconductance,  575  /tmhos.  This  is  a  DISCONTINUED  type  listed  for  reference  only. 


1B7GT 


1C5GT 


(approx.),  116000  ohms; 


PENTAGRID  CONVERTER 

Glass  octal  type  used  in  superheterodyne  cir- 
cuits having  battery  power  supply.  Outline  15A, 
OUTLINES  SECTION.  Filament  volts  (dc), 
1.4;  amperes,  0.1.  This  is  a  DISCONTINUED 
type  listed  for  reference  only.  The  1B7-GT  may 
be  replaced  by  the  1A7-GT  if  circuit  adjust- 
ment is  made  for  lower  filament  current  of 
type  1A7-GT. 

POWER  PENTODE 

Glass  octal  type  used  in  output  stage  of 
battery-operated  receivers.  Outline  14C,  OUT- 
LINES SECTION.  This  type  may  be  supplied 
with  pin  No.l  omitted.  Tube  requires  octal 
socket.  Filament  volts  (dc),  1.4;  amperes,  0.1. 
Typical  operation  as  class  Ai  amplifier:  plate 
and  grid-No.2  volts,  90  (110  max)-,  grid-No.  1 
volts,  -7.5;  peak  af  grid-No.l  volts,  7.5;  plate 
ma.,  7.8;  grid-No.2  ma.,  3.5;  plate  resistance 
transconductance,  1550  Mmhos;  load  resistance,  8000  ohms;  power  output, 


840  milliwatts.  Type  1C6-GT  is  used  principally  for  renewal  purposes. 

PENTAGRID  CONVERTER 

Glass  type  used  in  battery-operated  re- 
ceivers. Similar  electrically  to  type  1C7-G  ex- 
1    A  ceP*  f  or  interelectrode  capacitances.  Outline  24B, 

I  KtO  OUTLINES  SECTION.  Tube  requires  six-con- 

tact socket.  Filament  volts  (dc),  2.0;  amperes, 
0.12.  Type  1C6  is  a  DISCONTINUED  type 
listed  for  reference  only. 


86 


Technical  Data 


PENTAGRID  CONVERTER 

Glass  octal  type  used  in  battery-operated 
receivers.  Outline  28,  OUTLINES  SECTION. 
Tube  requires  octal  socket.  Filament  volts  (dc),  ^'v^ 
2.0;  amperes,  0.12.  Typical  operation  as  conver-  |  O 

ter:  plate  volts,  180  max;  grids-No.S-and-No.S 
(screen-grid)  volts,  67.5  max;  grid-No.2  (anode- 
grid)  supply  volts,  180  (applied  through  20000- 
ohm  dropping  resistor  bypassed  by  0.01-/if 
capacitor);  grid-No.4  (control-grid)  volts,  -3; 
grid-No.l  (oscillator-grid)  resistor,  60000  ohms;  plate  ma.,  1.6;  grids-No.3-and-No.5  ma.,  2;  grid-No.2 
ma.,  4;  grid-No.I  ma.,  0.2.  This  is  a  DISCONTINUED  type  listed  for  reference  only. 


REMOTE-CUTOFF  PENTODE 

Glass  octal  type  used  in  battery-operated 
receivers  as  rf  or  if  amplifier.  Outline  23,  OUT- 
LINES SECTION.  Tube  requires  octal  socket. 
Filament  volts  (dc),  2.0;  amperes,  0.06.  Typical 
operation  as  class  Ai  amplifier:  plate  volts,  180 
max;  grid-No.2  (screen-grid)  volts,  67.5  max; 
grid-No.l  volts,  -3  min;  plate  ma.,  2.3;  grid-No.2 
ma.,  0.8;  plate  resistance  (approx.),  1.0  megohm; 
transconductance,  750  ^mhos;  transconductance 
at  bias  of  -15  volts,  15  Atmhos.  This  is  a  DIS- 
CONTINUED type  listed  for  reference  only. 


1D5GP 


REMOTE-CUTOFF  TETRODE 

Glass  octal  type  used  in  battery-operated 
receivers  as  rf  or  if  amplifier.  Outline  23,  OUT- 
LINES SECTION.  Filament  volts  (dc),  2.0; 
amperes,  0.06.  This  is  a  DISCONTINUED  type 
listed  for  reference  only.  It  is  similar  electrically 
to  type  1D5-GP. 


1D5GT 


PENTAGRID  CONVERTER 

Glass  octal  type  used  in  battery-operated 
receivers.  Outline  23,  OUTLINES  SECTION. 
Tube  requires  octal  socket.  Filament  volts  (dc), 
2.0;  amperes,  0.06.  Typical  operation  as  conver- 
ter: plate  volts,  grids-No.3-and-No.5  volts,  grid- 
No.2  supply  volts,  grid-No.4  volts,  and  grid-No.l 
resistor  are  same  as  for  type  1C7-G;  plate  ma., 
1.3;  grids-No.3-and-No.6  ma.,  2.4;  grid-No.2 
ma.,  2.3;  grid-No.l  ma.,  0.2.  This  is  a  DISCON- 
TINUED type  listed  for  reference  only. 


1D7G 


1D8GT 


DIODE— TRIODE— POWER  PENTODE 

Glass  octal  type  used  in  compact  battery- 
operated  receivers.  Diode  unit  is  used  as  detector 
or  avc  tube,  triode  as  first  audio  amplifier,  and 
pentode  as  power  output  tube.  Outline  15 A, 
OUTLINES  SECTION.  Tube  requires  octal 
socket.  Filament  volts  (dc),  1.4;  amperes,  0.1. 
Typical  operation  of  pentode  unit  as  class  Ai  am- 
plifier: plate  and  grid-No.2  volts,  90  (110  wax); 
grid-No.l  volts,  -9 ;  plate  ma.,  5 ;  grid^No.2  ma., 
1;  transconductance,  925  /imhos;  load  resistance,  12000  ohms;  total  harmonic  distortion,  10  per  cent; 
power  output,  200  milliwatts.  Characteristics  of  triode  unit  as  class  Ai  amplifier:  plate  volts,  90  (lio' 
mox);  grid  volts,  0;  amplification  factor,  25;  plate  resistance  (approx.),  43500  ohms;  transconductance, 
676  Mmhos;  plate  ma.,  1.1.  This  is  a  DISCONTINUED  type  listed  for  reference  only. 


87 


RCA  Receiving  Tube  Manual 


1DN5 


1E5GP 


1E7GT 


DIODE— 
SEMIREMOTE-CUTOFF  PENTODE 

Miniature  type  used  in  battery-operated 
portable  radio  receivers  as  combined  AM  de- 
tector and  af  voltage  amplifier.  Outline  7B, 
OUTLINES  SECTION.  Tube  requires  minia- 
ture seven-contact  socket  and  may  be  mounted 
in  any  position.  Filament  volts  (dc),  1.4;  am- 
peres, 0.05.  Characteristics  of  pentode  unit  as 
class  Ai  amplifier:  plate  and  grid-No.2  (screen- 
grid)  volts,  67.5  (90  max);  grid-No.l  volts,  0; 
plate  resistance  (approx.),  0.6  megohm;  transconductance,  630  jumhos;  plate  ma.,  2.1;  grid-No.2  ma.; 
0.55.  Maximum  diode  rating:  plate  ma.,  0.25  max.  This  type  is  used  principally  for  renewal  purposeB. 

SHARP-CUTOFF  PENTODE 

Glass  octal  type  used  as  rf  amplifier  or  de- 
tector in  battery-operated  receivers.  Outline  23, 
OUTLINES  SECTION.  Tube  requires  octal 
socket.  Filament  volts  (dc),  2.0;  amperes,  0.06. 
Characteristics  as  class  Ai  amplifier:  plate  volts, 
180  max;  grid-No.2  volts,  67.5  max;  grid-No.l 
volts, -3;  plate  ma.,  1.7;  grid-No.2  ma.,  0.6; 
plate  resistance,  1 . 5  megohms ;  transconductance, 
660  ^mhos.  This  is  a  DISCONTINUED  type 
listed  for  reference  only. 

TWIN  POWER  PENTODE 

Glass  octal  type  used  in  push-pull  output 
stage  of  battery-operated  receivers.  Outline  14C, 
OUTLINES  SECTION.  Tube  requires  octal 
socket.  Filament  volts  (dc),  2.0;  amperes,  0.24. 
Typical  operation  as  push-pull  class  Ai  ampli- 
fier: plate  and  grid-No.2  volts,  135  max;  grid- 
No.l  volts,  -7.5;  plate  ma.,  10.5;  grid-No.2  ma., 
3.5;  output  watts,  0.575.  This  is  a  DISCON- 
TINUED type  listed  for  reference  only. 

PENTAGRID  CONVERTER 

Subminiature  type  used  in  small,  compact, 
battery-operated  receivers  for  the  standard  AM 
broadcast  band.  Maximum  dimensions:  over-all 
length,  1.75  inches;  seated  height,  1.6  inches; 
diameter,  0.4  inch.  Tube  requires  subminiature 
eight-contact  socket.  Filament  volts  (dc),  1.25; 
amperes,  0.04.  Typical  operation  as  converter: 
plate  volts  and  grids-No.2-and-No.4  supply 
volts,  67.5  max;  grids-No.2-and-No.4  resistor, 
20000  ohms;  grid-No.3  volts,  0;  grid-No.l  resistor,  0.1  megohm;  plate  resistance  (approx.),  0.4  megohm; 
conversion  transconductance,  150  iumhos;  total  cathode  ma.,  2.5  (4  max);  plate  ma.,  1;  grids-No.2-and* 
No.4  ma.,  1.5;  grid-No.l  /ta.,  70.  This  is  a  DISCONTINUED  type  listed  for  reference  only. 

POWER  PENTODE 

Glass  type  used  in  output  stage  of  battery- 
operated  receivers.  Outline  27,  OUTLINES 
SECTION.  Tube  requires  five-contact  socket. 
Filament  volts  (dc),  2.0;  amperes,  0.12.  Type 
1F4  is  similar  electrically  to  type  1F5-G.  Type 
1F4  is  a  DISCONTINUED  type  listed  for  ref- 
erence only. 

POWER  PENTODE 

Glass  octal  type  used  in  output  stage  of 
battery-operated  receivers.  Outline  26,  OUT- 
LINES SECTION.  Tube  requires  octal  socket. 
Filament  volts  (dc),  2.0;  amperes,  0.12.  Typi- 
cal operation  as  class  Ai  amplifier:  plate  and 
grid-No.2  (screen-grid)  volts,  135  (180  moa;) ;  grid- 
No.l  volts,  -4.5;  plate  ma.,  8;  grid-No.2  ma., 
2.4;  cathode  resistor,  432  ohms;  output  watts, 
0.31.  This  is  a  DISCONTINUED  type  listed 
for  reference  only. 


1E8 


1F4 


1F5G 


88 


Technical  Data 


TWIN  DIODE— 
SHARP-CUTOFF  PENTODE 

Glass  type  used  as  combined  detector,  am- 
plifier, and  avc  tube  in  battery-operated  re- 
ceivers. Outline  23,  OUTLINES  SECTION. 
Tube  requires  six-contact  socket.  Filament  volts 
(dc),  2.0;  amperes,  0.06.  Typical  operation  of 
pentode  unit  as  class  Ai  amplifier:  plate  volts, 
180  max;  grid-No.2  (screen-grid)  volts,  67.5  max; 
grid-No.l  volts,  -1.5;  plate  ma.,  2.2;  grid-No.2 
ma.,  0.7.  This  is  a  DISCONTINUED  type 
listed  for  reference  only. 


1F6 


TWIN  DIODE— 
SHARP-CUTOFF  PENTODE 

Glass  octal  type  used  as  combined  detector, 
amplifier,  and  avc  tube  in  battery-operated  re- 
ceivers. Outline  23,  OUTLINES  SECTION. 
Tube  requires  octal  socket.  Filament  volts  (dc), 
2.0;  amperes,  0.06.  Similar  electrically  to  type 
1F6  except  for  interelectrode  capacitances.  Type 
1F7G  is  a  DISCONTINUED  type  listed  for 
reference  only. 


1F7G 


HALF-WAVE  VACUUM  RECTIFIER 

Glass  octal  type  used  in  high- 


1G3GT/ 
1B3GT 


voltage,  low-current  applications  such 
as  the  rectifier  in  a  high-voltage,  rf-op- 
erated  power  supply  or  as  a  rectifier  of 
high-voltage  pulses  produced  in  tele- 
vision scanning  systems.  Outline  15B,  OUTLINES  SECTION.  This  type  may  be 
supplied  with  pins  1,  4,  and/or  6  omitted.  Tube  requires  octal  socket  and  may  be 
mounted  in  any  position.  Except  for  physical  dimensions,  this  type  is  identical  with 
glass  octal  type  1B3-GT. 


MEDIUM-MU  TRIODE 

Glass  octal  type  used  in  battery-operated 
receivers  as  detector  or  voltage  amplifier.  Out- 
line 14C,  OUTLINES  SECTION.Tube  requires 
octal  socket.  Filament  volts  (dc),  1.4;  amperes, 
0.06.  Typical  operation  and  characteristics  as 
class  Ai  amplifier:  plate  volts,  90  (100  max)\ 
grid  volts, -6;  plate  ma.,  2.3;  plate  resistance, 
10700  ohms;  amplification  factor,  8.8;  trans- 
conductance,  825  Mmhos.  This  is  a  DISCON- 
TINUED type  listed  for  reference  only. 


1G4GT 


POWER  PENTODE 

Glass  octal  type  used  in  output  stage  of 
battery-operated  receivers.  Outline  26,  OUT- 
LINES SECTION.  Tube  requires  octal  socket. 
Filament  volts  (dc),  2.0;  amperes,  0.12.  Typical 
operation  as  class  Ai  amplifier:  plate  and  grid- 
No.2  (screen-grid)  volts,  135  max;  grid-No.l 
volts,  -13.5;  plate  ma.,  9.7;  output  watts,  0.55. 
This  is  a  DISCONTINUED  type  listed  for 
reference  only. 


1G5G 


89 


RCA  Receiving  Tube  Manual 


HIGH-MU  TWIN  POWER  TRIODE 

Glass  octal  type  used  in  output  stasre  of 
battery-operated  receivers.  Outline  14C,  OUT- 
LINES SECTION.  Tube  requires  octal  socket. 
1G6GT  Filament  volts  (dc),  1.4;  amperes,  0.1.  Typical 

^     I  operation  as  class  B  amplifier:  plate  volts,  90 

(110  max) ;  dc  grid  volts,  0;  peak  af  grid-to-grid 
volts,  48;  effective  grid-circuit  impedance  per 
unit,  2530  ohms;  plate  ma.  (zero  signal),  2, 
(maximum  signal),  11;  peak  grid  ma.  per  unit,  6; 
output  watts  (approx.),  0.35.  This  is  a  DISCON- 
TINUED type  listed  for  reference  only. 

MEDIUM-MU  TRIODE 

Glass  octal  type  used  as  detector  or  voltage 
amplifier  in  battery-operated  receivers.  Outline 
22,  OUTLINES  SECTION.  Tube  requires  octal 
1  H4G  socket.  Filament  volts  (dc),  2.0;  amperes,  0.06. 

Typical  operation  as  class  Ai  amplifier:  plate 
volts,  180  max;  grid  volts, -13.5;  amplification 
factor,  9.3;  plate  resistance,  10300  ohms;  trans- 
conductance,  900  /xmhos;  plate  ma.,  3.1.  This  is  a 
DISCONTINUED  type  listed  for  reference  only. 


1H5GT 


1H6G 


DIODE— HIGH-MU  TRIODE 

Glass  octal  type  used  as  combined  detector 
and  amplifier  in  battery-operated  receivers.  Out- 
line 15A,  OUTLINES  SECTION.  Tube  requires 
octal  socket.  Filament  volts  (dc),  1.4;  amperes, 
0.05.  Characteristics  of  triode  unit  as  class  Ai 
amplifier:  plate  volts,  90  (110  max);  grid  volts, 
0;  plate  ma.,  0.15;  plate  resistance  (approx.), 
240000  ohms;  amplification  factor,  65;  trans- 
conductance,  275  /umbos.  Diode  is  located  at 
negative  end  of  filament.  This  type  is  used  prin- 
cipally for  renewal  purposes. 


TWIN  DIODE— MEDIUM-MU  TRIODE 

Glass  octal  type  used  as  combined  detector, 
amplifier,  and  avc  tube  in  battery-operated  re- 
ceivers. Outline  22,  OUTLINES  SECTION. 
Tube  requires  octal  socket.  Filament  volts  (dc) 
2.0;  amperes,  0.06.  Type  1H6-G  is  similar  elec- 
trically to  type  1B5/25S.  Type  1H6G  is  a 
DISCONTINUED  type  listed  for  reference  only. 


PD2 


HALF-WAVE  VACUUM  RECTIFIER 

Glass  octal  type  used  as  a  recti- 
I J  3  fier  of  high- voltage  pulses  produced  in 

the  scanning  systems  of  black-and- 
white  television  receivers.  Outline  15D, 
OUTLINES  SECTION.  Except  for 
physical  dimensions,  this  type  is  identical  with  glass  octal  type  1K3. 


POWER  PENTODE 

Glass  octal  type  used  in  output  stage  of 
battery-operated  receivers.  Outline  26,  OUT- 
LINES SECTION.  Tube  requires  octal  socket. 
Filament  volts  (dc)^  2.0;  amperes,  0.12.  Typical 
operation  as  class  Ai  amplifier:  plate  and  grid- 
No.2(screen-grid)  volts,  135maa;;grid-No.l  volts, 
-16.5;  plate  ma.,  7.0;  grid-No.2  ma.,  2.0;  plate 
resistance,  105000  ohms;  load  resistance,  13500 
ohms;  output  watts,  0.45.  This  is  a  DISCON- 
TINUED type  listed  for  reference  only. 


Technical  Data 


HIGH-MU  TWIN  POWER  TRIODE 

Glass  octal  types  used  in  output  stage  of 
battery-operated  receivers.  Type  1J6-G,  Out-  m  mm  ^ 

line  22 ;  type  1J6GT,  Outline  14E,  OUTLINES  1  JoG 

SECTION.  Tubes  require  octal  socket.  Fila-  -  .^^-i 

ment  volts  (dc),  2.0;  amperes,  0.24.  Typical  iJoGT 
operation  as  class  B  power  amplifier:  plate  volts, 
135  max;  peak  plate  ma.  per  plate,  60  max; 
grid  volts,  0;  zero-signal  plate  ma.  per  plate, 
5;  effective  plate-to-plate  load  resistance,  10000 
ohms;  average  input  watts,  0.17;  output  watts,  2.1.  These  are  DISCONTINUED  types  listed  for 
reference  only. 

LC 

Lc^X    I    \         HALF-WAVE  VACUUM  RECTIFIER 

Glass  octal  type  used  as  a  recti-  11/ o 

(2x-^.yv^--7j;F  IS  high-voltage  pulses  produced  in  1  |v3 

the  scanning  systems  of  black-and- 
white  television  receivers.  Type  1K3 
requires  an  octal  socket  and  may  be 
mounted  in  any  position.  Plate  connection  is  cap  at  top  of  bulb.  Socket  terminals 
1,  3,  4,  5,  6,  and  8  may  be  connected  to  socket  terminal  7  or  to  a  corona  shield 
which  is  connected  to  socket  terminal  7.  Socket  terminals  4  and  6  may  be  used  as 
tie  points  for  components  at  or  near  filament  potential.  Outline  15B,  OUTLINES 
SECTION.  For  high-voltage  considerations,  see  type  1B3-GT. 

Filament  Voltage  (ac/dc)   1.25*  volts 

Filament  Current   0.2  ampere 

Direct  Intbrelectrodb  Capacitance  (Approx.): 

Plate  to  Filament  and  Internal  Shield   1.6  pf 

*  Under  no  circumstances  should  the  filament  voltage  be  less  than  1.05  volts  or  greater  than  1.45  volts. 

PULSED  RECTIFIER 

For  operation  in  a  525-line,  80-frame  system 
Maximum  Ratings,  (Design-Maximum  Values): 

Peak  Inverse  Plate  Voltage*    26000  •waau  volts 

Peak  Plate  Current   50  max  ma 

Average  Plate  Current   O.B  max  ma 

Characteristics,  Instantaneous  Value: 

Tube  Voltage  Drop  for  plate  current  of  7  ma   225  volts 

♦The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  horizontal  scanning  cycle.  In  a 
525-line,  30-frame  system,  15  per  cent  of  one  horizontal  scanning  cycle  is  10  microseconds. 

•  The  dc  component  must  not  exceed  22000  volts. 


1L6 


PENTAGRID  CONVERTER 

Miniature  type  used  in  low-drain  battery- 
operated  receivers.  Outline  7B,  OUTLINES 
SECTION.  Tube  requires  miniature  seven-con- 
tact socket  and  may  be  mounted  in  any  posi- 
tion. Filament  volts  (dc),  1.4;  amperes,  0.05. 
Typical  operation  as  converter:  plate  and  grid- 
No.2  volts,  90  (110  max);  grids-No.3-and-No.5 
supply  volts,  110  max;  grids-No.3-and-No.5 
volts,  45  (65  max);  grid-No.4  volts,  0;  grid-No.l 
resistor,  0.2  megohm;  plate  resistance  (approx.),  0.65  megohm;  plate  ma.,  0.5;  grids-No.3-and-No.5  ma., 
0.6;  grid-No.2  ma.,  1.2;  grid-No.l  ma.,  0.035;  total  cathode  ma.,  2.35  (4  max);  conversion  transcon- 
ductance,  800  Mmhos.  This  type  is  used  principally  for  renewal  purposes. 

POWER  PENTODE 

Glass  lock-in  type  used  in  output  stage  of 
battery-operated  receivers.  Outline  13A,  OUT- 
LINES SECTION.  Tube  requires  lock-in  socket. 
Filament  volts  (dc),  1.4;  amperes,  0.05.  For 
electrical  characteristics  and  typical  operation, 
refer  to  glass-octal  type  1 A5-GT.  Type  1LA4  is  a 
DISCONTINUED  type  listed  for  reference  only. 

91 


1LA4 


RCA  Receiving  Tube  Manual 


1LA6 


1LB4 


1LC5 


1LC6 


PENTAGRID  CONVERTER 

Glass  lock-in  type  used  in  battery-operated 
receivers.  Outline  13A,  OUTLINES  SECTION. 
Tube  requires  lock-in  socket.  Filament  volts 
(dc),  1.4;  amperes,  0.05.  Typical  operation  as 
converter  is  the  same  as  for  type  1A7-GT  ex- 
cept thatgrid-No.2  voltsis  65  mox, total  cathode 
ma.  is  4.0  maa;,  plate  resistance  is  0.75  megohm, 
and  conversiontransconductance  for  a  grid-No.4 
bias  of  -3  volts  is  10  Mmhos.  This  type  is  used 
principally  for  renewal  purposes. 

POWER  PENTODE 

Glass  lock-in  type  used  in  output  stage  of 
battery-operated  receivers.  Outline  13A,  OUT- 
LINES SECTION .  Tube  requires  lock-in  socket. 
Filament  volts  (dc),  1.4;  amperes,  0.05.  For  elec- 
trical characteristics,  refer  to  pentode  unit  of 
glass-octal  type  1D8-GT.  Type  1LB4  is  used 
principally  for  renewal  purposes. 

SHARP-CUTOFF  PENTODE 

Glass  lock-in  type  used  as  rf  or  if  amplifier 
In  battery-operated  receivers.  Outline  13A,  OUT- 
LINES SECTION.  Tube  requires  lock-in  socket. 
Filament  volts  (dc),  1.4;  amperes,  0.05.  Typical 
operation  as  class  Ai  amplifier:  plate  volts,  90 
(110  max) ;  grid-No.2  (screen-grid)  volts,  45  max; 
grid-No.l  volts,  0;  plate  resistance  (approx.), 
greater  than  1  megohm;  transconductance,  775 
/nmhos;  plate  ma.,  1.15;  grid-No.2  ma.,  0.3.  This 
is  a  DISCONTINUED  type  listed  for  reference 
only. 

PENTAGRID  CONVERTER 

Glass  lock-in  type  used  in  battery-operated 
receivers.  Outline  13A,  OUTLINES  SECTION. 
Tube  requires  lock-in  socket.  Filament  volts 
(dc),  1.4*,  amperes,  0.05.  Typical  operation  as 
converter:  plate  volts.  90  (110  max) ;  grids-No.3- 
and-No.5  volts,  35  (45  max) ;  grid-No.2  volts,  45; 
grid-No.l  volts,  0;  plate  resistance,  0.65  meg- 
ohm; plate  ma.,  0.75;  grids-No.3-and-No.5  ma., 
0.70;  grid-No.2  ma.,  1.4;  total  cathode  ma.,  2.9; 
conversion  transconductance  (zero  bias), 275  iumhos.  This  type  is  used  principally  for  renewal  purposes* 


1LD5 


1LE3 


DIODE--SHARP-CUTOFF  PENTODE 

Glass  lock-in  type  used  as  combined  detec- 
tor and  af  voltage  amplifier  in  battery-operated 
receivers.  Outline  13A,  OUTLINES  SECTION. 
Tube  requires  lock-in  socket.  Filament  volts 
(dc),  1.4;  amperes,  0.05.  Characteristics  of  pen- 
tode unit:  plate  volts,  90  (110  max) ;  grid-No.2 
volts,  45;  grid-No.l  volts,  0;  plate  ma.,  0.6; 
grid-No.2  ma.,  0.1;  plate  resistance,  0.75  meg- 
ohm; transconductance,  575  /umbos.  This  is  a 
DISCONTINUED  type  listed  for  reference 
only. 

MEDIUM-MU  TRIODE 

Glass  lock-in  type  used  as  detector  or  volt- 
age amplifier  in  battery-operated  receivers.  Out- 
line 13A,  OUTLINES  SECTION.  Tube  requires 
lock-in  socket.  Filament  volts  (dc),  1.4;  amperes, 
0.05.  Typical  operation  as  class  Ai  amplifier: 
plate  volts,  90  (110  wax);  grid  volts,  -3;  plate 
ma.,  1.4;  plate  resistance,  19000  ohms;  trans- 
conductance, 760  /<mhos;  amplification  factor, 
14.5.  This  type  is  used  principally  for  renewal 
purposes. 


Technical  Data 


REMOTE-CUTOFF  PENTODE 

Lock-in  type  used  as  rf  or  if  amplifier  in 
battery-operated  receivers.  Outline  13A,  OUT- 
LINES SECTION.  Tube  requires  lock-in  socket. 
Filament  volts  (dc),  1.4;  amperes,  0.05.  Typical 
operation  as  class  Ai  amplifier:  plate  volts,  90 
(110  max)\  grid-No.2  volts,  45  (110  jreox);  grid- 
No.l  volts,  0;  plate  resistance  (approx.),  greater 
than  1  megohm;  transconductance,  800  /umbos; 
plate  ma.,  1.7;  grid-No*2  ma.,  jQ.4.  This  type  is 
used  principally  for  renewal  purposes. 


1LG5 


DIODE— HIGH-MU  TRIODE 

'Glass  lock-in  type  used  as  combined  detec- 
tor  and  amplifier  in  battery-operated  receivers. 
Outline  13A.  OUTLINES  SECTION.  Tube  re- 
quires lock-in  socket.  Filament  volts  (dc),  1.4; 
amperes,  0.05.  For  electricalasieharacteristics,  re- 
fer to  glass-octal  type  1H5GT.  Type  1LH4  ia 
used  principally  for  renewal  purposes. 


1LH4 


SHARP-CUTOFF  PENTODE 

Glass  lock-in  type  used  as  rf  or  if  amplifier 
in  battery-operated  receivers.  Outline  13A,  OUT- 
LINES SECTION.  Tube  requires  lock-in  socket. 
Filament  volts  (dc),  1.4;  amperes,  0.05.  Typical 
operation  as  class  Ai  amplifier:  plate  and  grid- 
No.2 (screen-grid)  volts,  90  (110  waa;);  grid-No.l 
volts,  0;  plate  ma.,  1.6;  grid-No.2  ma.,  0.35; 
plate  resistance  (approx.),  1.1  megohms;  trans- 
conductance,  800  /tnahos.  This  type  is  used 
principally  for  renewal  purposes. 


1LN5 


HALF-WAVE  VACUUM  RECTIFIER 

/Nc         Glass  octal  type  used  as  high-  IKIO  A 

voltage  rectifier  in  television  receivers.  1  |M  2  A 

,3  Maximum  over-all  length,3-9 /16  inches ; 
maximum  seated  length,  3  inches ;  max- 
imum  diameter,  1-9/16  inches.  Tube 
requires  octal  socket  and  may  be  operated  in  any  position.  For  installation  and 
application  considerations,  refer  to  type  1B3GT. 


Filament  Voltage  (ac)   1 . 25*  volts 

Filament  Current   0.2  ampere 

Direct  Interelectrode  Capacitance: 

Plate  to  Filament  and  Internal  Shield   1.4  pf 

PULSED  RECTIFIER 

For  operation  in  a  525-line,  SO-frame  system 
Maximum  Ratings,  (Design-Maximum  Values): 

Peak  Inverse  Plate  Volt AGE°"   28000  wax  volts 

Peak  Plate  Current   50  max  ma 

Average  Plate  Current   0.5  max  ma 

Characteristics,  Instantaneous  Value: 

Tube  Voltage  Drop  for  plate  current  of  7  ma   100  volts 

*  Under  no  circumstances  should  the  filament  voltage  be  less  than  1 . 05  volts  or  greater  than  1 . 45  volts. 
"  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  horizontal  scanning  cycle.  In  a 
625-line,  30-frame  system,  15  per  cent  of  one  horizontal  scanning  cycle  is  10  microseconds. 

*  The  dc  component  must  not  exceed  24000  volts. 


93 


RCA  Receiving  Tube  Manual 


1N5GT 


SHARP-CUTOFF  PENTODE 

Glass  octal  type  used  as  rf  or  if  amplifier  in 
battery-operated  receivers.  Outline  15A,  OUT- 
LINES SECTION.  Tube  requires  octal  socket. 
Filament  volts  (dc),  1.4;  amperes,  0.05.  Charac- 
teristics as  class  Ai  amplifier:  plate  and  grid- 
No.2  volts,  90  (110  max);  grid-No.l  volts,  0; 
plate  resistance  (approx.),  1.5  megohms;  trans- 
conductance,  750  /zmhos;  plate  ma.,  1.2;  grid- 
No.2  ma.,  0.3.  This  type  is  used  principally  for 
renewal  purposes. 


DIODE— POWER  PENTODE 

Glass  octal  type  used  as  combined  detec- 
tor and  power  output  tube  in  battery-operated 

receivers.  Maximum  over-all  length,  4  inches; 
1  N  6G  maximum  diameter,  1-3/16  inches.  Filament 

volts  (dc),  1.4;  amperes,  0.05.  Typical  operation 

of  pentode  unit  as  class  Ai  amplifier:  plate  and 

grid-No.2  (screen-grid)  volts,  90  (110  max)', 

grid-No.l  volts,  -4.5;  plate  ma.,  3.1;  grid-No.2 

ma.  (zero-signal),  0.6;  plate  resistance  (approx.), 
0.8  megohm;  transconductance,  800  jumhos;  load  resistance,  25000  ohms;  output  watts,  0.1.  This 
in  a  DISCONTINUED  type  listed  for  reference  only. 


REMOTE-CUTOFF  PENTODE 

Glass  octal  type  used  as  rf  or  if  amplifier  in 
battery-operated  receivers.  Outline  15A,  OUT- 
LINES SECTION.  Tube  requires  octal  socket. 
Filament  volts  (dc),  1.4;  amperes,  0.05.  Typical 
1  P'^riiT  operation  as  class  Ai  amplifier:  plate  volts,  90 

"     ^  ■  (110  max) ;  grid-No.2  (screen-grid)  volts,  90  (110 

max);  grid-No.l  volts,  0;  plate  resistance 
(approx.),  0.8  megohm;  transconductance,  750 
/umbos;  plate  ma.,  2.3;  grid-No.2  ma.,  0.7.  This 
is  a  DISCONTINUED  type  listed  for  reference 
only. 


BEAM  POWER  TUBE 

Glass  octal  type  used  in  the  output  stage 
ofbattery-operatedreceivers.Outlinel4C,OUT- 
1 Q5 GT  LINES  SECTION.  Tube  requires  octal  socket. 

Filament  volts  (dc),  1.4;  amperes,  0.1.  For  elec- 
trical characteristics  and  ratings,  refer  to  type 
3Q5-GT  with  parallel  filament  arrangement. 
Type  1Q5-GT  is  a  DISCONTINUED  type  for 
reference  only. 


PENTAGRID  CONVERTER 

Miniature  type  used  in  lightweight,  por- 
table, compact,  battery-operated  receivers.  Out- 
.  ^  .  line  7B,  OUTLINES  SECTION.  Tube  requires 

I  r!  ^  miniature  seven-contact  socket.  Characteristics 

as  converter  with  separate  excitation :  plate  volts, 
67.5  (90  max);  grids-No.2  and  No.4  volts,  67.5 
max;  grid-No.3  volts,  0;  rms  grid-No.l  volts, 
25;  grid-No.l  resistor,  0.1  megohm;  plate  re- 
sistance (approx.),  0.4  megohm;  conversion 
transconductance,  280  yumhos;  plate  ma.,  1.4;  grids-No.2  and  No.4  ma.,  3.5; 
cathode  ma.,  5.2.  This  type  is  used  principally  for  renewal  purposes. 

94 


grid-No.l  Ma,  250;  total 


Technical  Data 


POWER  PENTODE 

Miniature  type  used  in  output  stage  of 
lightweight,  compact,  portable,  battery-oper- 
ated equipment.  Types  1S4  and  3S4  are  identi- 
cal except  for  filament  arrangement.  Outline  7B, 
OUTLINES  SECTION.  Type  1S4  requires 
miniature  seven-contact  socket  and  may  be 
mounted  in  any  position.  For  ratings  and  typi- 
cal operation,  refer  to  type  3S4  with  parallel 
filament  arrangement.  Filament  volts  (dc),  1.4; 
amperes,  0.1.  This  type  is  used  principally  for 
renewal  purposes. 


1S4 


DIODE— 
SHARP-CUTOFF  PENTODE 

Miniature  type  used  in  lightweight,  por- 
table, compact,  battery-operated  receivers  as 
combined  detector  and  af  voltage  amplifier.  Out- 
line 7B,  OUTLINES  SECTION.  Tube  requires 
miniature  seven-contact  socket.  Filament  volts 
(dc),  1.4;  amperes,  0.05.  For  electrical  charac- 
teristics, refer  to  type  1U5.  Type  1S5  is  used 
principally  for  renewal  purposes. 


1S5 


REMOTE-CUTOFF  PENTODE 

Miniature  type  used  in  lightweight,  por- 
table, compact,  battery-operated  receivers  as 
rf  or  if  amplifier.  Outline  7B,  OUTLINES  SEC- 
TION. Tube  requires  miniature  seven-contact 
socket.  Filament  volts  (dc),  1.4;  amperes,  0.05. 
Characteristics  as  class  Ai  amplifier:  plate  and 
grid-No.2  volts,  67.5  (90  max);  grid-No.l  volts, 
0;  plate  resistance  (approx.),  0.25  megohm; 
transconductance,  875  /umbos;  plate  ma.,  3.4; 
grid-No.2  ma.,  1.5.  This  type  is  used  princi- 
pally for  renewal  purposes. 


1T4 


BEAM  POWER  TUBE 

Glass  octal  type  used  in  output  stage  of 
battery-operated  receivers.  Outline  14C,  OUT- 
LINES SECTION.  Tube  requires  octal  socket. 
Filament  volts  (dc),  1.4;  amperes,  0.05.  Typical  1 T5GT 

operation  as  class  Ai  amplifier:  plate  and  grid- 
No.2  volts,  90  (110  max)',  grid-No.l  volts,  -6; 
peak  af  grid-No.l  volts,  6;  plate  ma.,  6.5;  grid- 
No.2  ma.  (zero-signal),  0.8;  grid-No.2  ma. 
(maximum  signal),  1.5;  plate  resistance,  0.25 
megohm;  transconductance,  1150  /xmhos;  load  resistance,  14000  ohms;  total  harmonic  distortion, 
per  cent;  output  watts,  0.17.  This  is  a  DISCONTINUED  type  listed  for  reference  only. 


1T6 


DIODE'SHARP-CUTOFF  PENTODE 

Subminiature  type  used  as  combined  de- 
tector and  audio  amplifier  in  small,  compact, 
battery-operated  receivers  for  the  standard  AM 
broadcast  band.  Maximum  dimensions:  over-all 
length,  1.75  inches;  seated  height,  1.5  inches; 
diameter,  0.4  inch.  Tube  requires  subminiature 
eight-contact  socket.  Filament  volts  (dc),  1.25; 
amperes,  0.04.  Filament  voltage  should  never 
exceed  1.6  volts.  Typical  operation  of  pentode 
unit  as  class  Ai  amplifier:  plate  and  grid-No.2  volts,  67.5  max;  grid-No.l  volts,  0;  plate  resistance  (ap- 
prox.), 0.4  megohm;  transconductance,  600  /imhos;  plate  ma.,  1.6;  grid-No.2  ma.,  0.4;  total  cathode  ma 
2.0  max.  Maximum  diode  plate  ma.,  0.25.  This  is  a  DISCONTINUED  type  listed  for  reference  only 


95 


RCA  Receiving  Tube  Manual 


SHARP-CUTOFF  PENTODE 

Miniature  type  used  as  rf  or  if  amplifier  in 
stages  not  controlled  by  avc  in  lightweight, 
■  I  ^  compact,  portable,  battery-operated  equipment. 

I  Ut"  Outline  7B,  OUTLINES  SECTION.  Tube  re- 

quires miniature  seven-contact  socket.  Fila- 
ment volts  (dc),  1.4;  amperes,  0.05.  Charac- 
teristics as  class  Ai  amplifier:  plate  and  grid-No. 
2  volts,  90  (120  max);  grid-No.l  volts,  0;  plate 
resistance  (approx.),  1  megohm;  transconduct- 
ance,  900  jumhos;  plate  ma.,  1.6;  grid-No.2  ma.,  0.5.  This  type  is  used  principally  for  renewal  purposes. 


DIODE-SHARP-CUTOFF 
PENTODE 

Miniature  type  used  in  lightweight,  com- 
^  I  ■  F"  pact,  portable,  battery-operated  receivers  as 

I  ^0  O  combined  detector  and  af  voltage  amplifier. 

Outline  7B,  OUTLINES  SECTION.  Tube  re- 
quires miniature  seven-contact  socket.  Filament 
volts  (dc),  1.4;  amperes,  0.05.  Characteristics  of 
pentode  unit  as  class  Ai  amplifier:  plate  and 
grid-No.2  volts,  67.5  (100  max);  grid-No.l  volts, 
0;  plate  resistance  (approx.),  0.6  megohm; 
transconductance,  625  /xmhos;  plate  ma.,  1.6;  grid-No.2  ma.,  0.4.  Maximum  diode  plate  ma.,  0.28  max. 
This  type  is  used  principally  for  renewal  purposes. 


Iv 


HALF-WAVE  VACUUM  RECTIFIER 

Glass  type  used  in  ac/dc  or  automobile 
receivers.  Maximum  dimensions:  over-all  length, 
4-3/16  inches;  seated  height,  3-9/16  inches;  di- 
ameter, 1-9/16  inches.  Tube  requires  four-con- 
tact socket.  Heater  volts  (ac/dc),  6.3;  am- 
peres, 0.3.  Maximum  ratings  as  half-wave  recti- 
fier: peak  inverse  plate  volts,  1000;  peak  plate 
ma.,  270;  peak  heater-cathode  volts,  500;  dc 
output  ma.,  45.  This  type  is  used  principally 
for  renewal  purposes. 


HALF-WAVE  VACUUM  RECTIFIER 

-  -  Miniature  type  used  in  high-volt- 

1 V2  age,  low-current  applications  such  as 

the  rectifier  in  high-voltage,  pulse-op- 
erated voltage-doubling  power  supplies 
for  kinescopes.  The  very  low  power 
required  by  the  filament  permits  the  use  of  a  rectifier  transformer  having  small 
size  and  light  weight. 

Filament  Voltage  ( ac)  r.   0 . 625 ■  volt 

Filament  Current   0.3  ampere 

Direct  Interelectrodb  Capacitance: 

Plate  to  Filament  (Approx.)   0.8  pf 

"Under  no  circumstances  should  the  filament  voltage  be  less  than  0.525  volt  or  greater  than  0.725  volt. 


PULSED  RECTIFIER 

For  operation  in  a  525-line,  SO-frame  tystem 
Maximum  Ratings,  {Design-Maximum  Values): 

Peak  Inverse  Plate  Voltage*   8250«waa;  volts 

Peak  Plate  Current   11  max  ma 

Average  Plate  Current   0.6  max  ma 

*  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  horizontal  scanning  cycle.  In 
a  525-line  30-frame  system,  15  per  cent  of  one  horizontal  scanning  cycle  is  10  microseconds. 

•  The  dc  component  must  not  exceed  7000  volts. 

96 


Technical  Data 


INSTALLATION  AND  APPLICATION 

Type  1 V2  requires  a  miniature  nine-contact  socket  and  may  be  mounted  in  any 
position.  The  socket  should  be  made  of  material  having  low  leakage  and  should 
have  adequate  insulation  between  its  filament  and  plate  terminals  to  withstand 
the  maximum  peak  inverse  plate  voltage.  To  provide  the  required  insulation  in 
miniature  nine-contact  sockets  designed  with  a  cylindrical  center  shield,  it  is  necessary 
to  remove  the  center  shield.  In  addition,  socket  terminals  2,  3,  7,  and  8  shall  not 
be  used.  Socket  terminal  6  may  be  used  as  a  tie  point  for  components  at  or  near 
filament  potential.  Outline  8D,  OUTLINES  SECTION. 

The  filament  is  of  the  coated  type  and  is  designed  for  operation  at  0.625  volt. 
The  filament  windings  on  the  pulse  transformer  should  be  adjusted  to  provide  the 
rated  voltage  under  average  line-voltage  conditions.  When  the  filament  voltage  is 
measured,  it  is  recommended  that  an  rms  voltmeter  of  the  thermal  type  be  used. 
The  meter  and  its  leads  must  be  insulated  to  withstand  15000  volts  and  the  stray 
capacitances  to  ground  should  be  minimized. 

The  high  voltages  at  which  the  1 V2  is  operated  are  very  dangerous.  Great  care 
should  be  taken  to  prevent  coming  in  contact  with  these  high  voltages.  Particular 
care  against  fatal  shock  should  be  taken  in  measuring  the  filament  voltage  in  those 
circuits  where  the  filament  is  not  grounded.  Precautions  must  include  safeguards 
which  definitely  eliminate  all  hazards  to  personnel. 


1X2A 

1X2B 


HALF-WAVE  VACUUM  RECTIFIER 

Miniature  types  used  in  high-volt- 
age, low-current  appHcations  such  as 
the  rectifier  in  a  high-voltage,  rf-op- 
erated  power  supply,  or  as  the  rectifier  of 
high-voltage  pulses  produced  in  tele- 
vision scanning  systems.  Outline  9A,  OUTLINES  SECTION.  Tubes  require  min- 
iature nine-contact  socket  and  may  be  mounted  in  any  position.  Socket  terminals 
3  and  7  may  be  used  as  tie  points  for  components  at  or  near  filament  potential.  For 
high-voltage  considerations,  refer  to  type  1B3-GT.  Type  1X2-A  is  used  principally 
for  renewal  purposes. 

Filament  Voltage  (AC)   1.26*  volts 

Filament  Current   0.2  ampere 

Direct  Interblectrode  Capacitance: 

Plate  to  Filament  and  Internal  Shield  ( Approx.)   1.0  pf 

*  Under  no  circumstances  should  the  filament  voltage  be  less  than  1.05  volts  or  greater  than  1.45  volts. 

PULSED  RECTIFIER 

For  operation  in  a  625'line,  SO-frame  system 

1X2'A  IXX-B 
Design-Center  Design-Maximum 
Maximum  Ratings:  Valuesf  Values 

Peak  Inverse  Plate  Voltage"   20000tmaaJ       22000  max  volts 

Peak  Plate  Current   45  max  45  max  ma 

Average  Plate  Current   O.bmax         0.5  max  ma 

Characteristics,  Instantaneous  Value: 

Tube  Voltage  Drop  for  plate  current  of  7  ma   100  volts 

t  Absolute  Maximum.  Under  no  circumstances  should  this  absolute  value  be  exceeded. 

#  Except  as  noted. 

■  The  dc  component  must  not  exceed  16000  volts  for  1X2-A,  18000  volts  for  1X2-B. 


POWER  TRIODE 

Glass  type  used  in  output  stage  of  radio  re- 
ceivers and  amplifiers.  Outline  28,  OUTLINES 
SECTION.  Tube  requires  four-contact  socket. 
Filament  volts  (ac/dc),  2.5;  amperes,  2.5.  Typi- 
cal operation  as  class  Ai  amplifier:  plate  volts, 
250  (300  max);  grid  volts,  -45;  plate  ma.,  60; 
amplification  factor,  4.2;  load  resistance,  800 
ohms;  transconductance,  5250  /imhos;  plate  dis- 
sipation, 15  max  watts;  load  resistance,  2500 


2A3 


97 


RCA  Receiving  Tube  Manual 


ohms;  power  output,  3.5  watts.  Typical  operation  as  push-pull  class  ABi  amplifier  (values  are  for  two 
tubes):  plate  supply  volts,  300;  cathode-bias  resistor,  780  ohms;  peak  af  grid-to-grid  volts,  156;  zero- 
signal  plate  ma.,  80;  maximum-signal  plate  ma.,  100;  effective  load  resistance  (plate-to-plate),  5000 
ohms;  power  output,  10  watts.  This  type  is  used  principally  for  renewal  purposes. 


2A5 


2A6 


POWER  PENTODE 

Glass  type  used  in  output  stage  of  ac-oper- 
ated  receivers.  Outline  27,  OUTLINES  SEC- 
TION. Tube  requires  six-contact  socket.  Except 
for  its  heater  rating  (2.5  volts  ac/dc;  1.75 
amperes),  the  2A5  has  electrical  characteristics 
identical  with  type  6F6.  Type  2A5  is  a  DIS- 
CONTINUED type  listed  for  reference  only. 

TWIN  DIODE— HIGH-MU  TRIODE 

Glass  type  used  in  ac-operated  receivers 
chiefly  as  a  combined  detector,  amplifier,  and 
avc  tube.  Outline  24B,  OUTLINES  SECTION. 
Tube  requires  six-contact  socket.  Except  for  its 
heater  rating  (2.5  volts  ac/dc;  0.8  ampere), 
and  within  its  250-volt  maximum  plate  rating, 
the  2A6  has  electrical  characteristics  identical 
with  type  6SQ7.  Type  2A6  is  a  DISCONTIN- 
UED type  listed  for  reference  only. 


2A7 


2AF4A 

2AF4B 


Related  types: 
3AF4A,  6AF4A 


PENTAGRID  CONVERTER 

Glass  type  used  in  ac-operated  receivers. 
Outline  24B,  OUTLINES  SECTION.  Tube  re- 
quires small  seven-contact  (0.75-inch,  pin-circle 
diameter)  socket.  Except  for  its  heater  rating 
(2.5  volts  ac/dc;  0.8  ampere)  and  its  interelec- 
trode  capacitances,  the  2A7  has  electrical  charac- 
teristics identical  with  type  6A8.  Complete 
shielding  of  this  tube  is  generally  necessary. 
Type  2A7  is  a  DISCONTINUED  type  listed 
for  reference  only. 


MEDIUM-MU  TRIODE 


Miniature  types  used  as  local  os- 
cillator in  uhf  television  receivers  em- 
ploying series-connected  heater  strings. 
Outline  7A,  OUTLINES  SECTION. 
Heater  volts  (ac/dc),  2.35;  amperes, 
0.6;  warm-up  time  (average),  11  seconds.  Type  2AF4-B  only,  maximum  rating 
(design  maximum),  peak  heater-cathode  volts,  180  max.  When  the  heater  is  posi- 
tive with  respect  to  the  cathode,  the  dc  component  of  the  heater-cathode  voltage 
must  not  exceed  100  volts.  Typical  operation  of  2AF4-B  as  oscillator  at  1000  Mc; 
plate  ma.,  17.5;  grid  jua  (approx.),  700.  Except  for  heater  ratings  noted,  these 
types  are  identical  with  miniature  type  6AF4-A.  Type  2AF4-A  is  a  DISCONTIN- 
UED type  listed  for  reference  only. 

HALF-WAVE  VACUUM  RECTiFIER 

A  l_JO  Duodecar  type  used  to  supply 

2  AH  2         high  voltage  to  the  anode  of  picture 
tubes  in  television  receivers.  Outline 
16A,  OUTLINES  SECTION.  Tube  re- 
quires 12-contact  socket  and  may  be 
mounted  in  any  position.  Socket  terminals  2,  3,  5,  6,  7,  8,  9,  and  11  should  not  be 
used  as  tie  points;  terminals  4  and  10  may  be  used  as  tie  points  for  components  at 
or  near  cathode  potential.  For  high-voltage  and  X-ray  safety  considerations,  refer 
to  type  1B3-GT.  Heater  volts  (ac/dc),  2.5;  amperes,  0.3. 

98 


igs,H 


Technical  Data 


PULSED  RECTIFIER 

For  operation  in  a  dZS^linet  SO-frame  eystem 

Maximum  Ratings,  {Design-Maximum  Values): 

Peak  Inveirse  Plate  Voltage"   80000*maa;  volts 

Peak  Plate  Current   80  max  ma 

Average  Plate  Current   1.6  ma»  ma 

Characteristics,  Instantaneous  Value: 

Tube  Voltage  Drop  for  plate  current  of  7  ma   100  volts 

"The  duration  of  the  voltage  pulse  must  not  exceed  16  per  cent  of  one  horizontal  scanning  cyde.  In  a 
625-iine,  30-frame  system,  15  per  cent  of  one  horizontal  scanning  cycle  is  10  microseconds. 

•  The  do  component  must  not  exceed  24000  volts. 

H,K,IS  p  LC 

''©^Y^""  H.K  HALF-WAVE  VACUUM  RECTIFIER 

/^i         yvt^  Duodecar  type  used  to  supply         OA  CO 

ic(3jl  /'^     / W^^^    ^^^^  voltage  to  the  anode  of  picture  jCwKHtJL 

(^Cy^No/^  tubes  in  television  receivers.  Outline 
*is  (17 — ^  16B,  OUTLINES  SECTION.  Tube 

H.K.IS       H  requires    duodecar  twelve-contact 

socket  and  may  be  mounted  in  any  position.  Socket  terminals  4,  7,  and  10  may  be 
used  as  tie  points  for  components  at  or  near  heater  potential.  For  high-voltage  and 
X-ray  safety  considerations,  refer  to  type  1B3-GT.  Heater  volts  (ac/dc),  2.5; 
amperes,  0.33. 

PULSED  RECTIFIER 

For  operation  in  a  625-line,  SO-frame  austem 
Maximum  Ratings,  (Design-Maximum  Values): 

Peak  Inverse  Plate  Volt AGB°   80000*maaj  volts 

Peak  Plate  Current   80  max  ma 

Average  Plate  Current  l.b  max  ma 

Characteristics,  Instantaneous  Value: 

Tube  Voltage  Drop  for  plate  current  of  7  ma   100  volts 

°  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  horizontal  scanning  cycle.  In  a 
525-line,  30-frame  system,  15  per  cent  of  one  horizontal  scanning  cycle  is  10  microseconds. 

•  The  dc  component  must  not  exceed  24000  volts. 


P02 


TWIN  DIODE— 
REMOTE-CUTOFF  PENTODE 

Glass  type  used  as  combined  detector,  avc 
tube,  and  amplifier.  Outline  24B,  OUTLINES 
SECTION.  Tube  requires  small  seven-contact 
(0.75-inch,  pin-circle  diameter)  socket.  Except 
for  its  heater  rating  (2.5  volts  ac  /dc;  0.8  ampere) 
and  its  interelectrode  capacitances,  the  2B7 
has  electrical  characteristics  identical  with  type 
6B8-G.  Type  2B7  is  a  DISCONTINUED  type 
listed  for  reference  only. 


2B7 


MEDiUM-MU  TRIODE 

Miniature  types  used  as  rf  amplifier  in  vhf 
television  tuners  employing  series-connected 
heater  strings.  Outline  7B,  OUTLINES  SEC- 
TION. Heater  volts  (ac  /dc) ,  2BNU:  2.3, 2BNA-A: 
2.35:  amperes,  0.6;  warm-up  time  (average),  11 
seconds.  Except  for  heater  rating,  these  types 
are  identical  with  miniature  types  6BN4  and 
6BN4A,  respectively.  Type  2BN4  is  a  DIS- 
CONTINUED type  listed  for  reference  only. 
Type  2BN4-A  is  used  principally  for  renewal 
purposes. 


2BN4 

2BN4A 

Related  types: 
3BN4A,  6BN4A 


99 


2CW4 

Relafftd  types: 
6CW4,  13CW4 


2CY5 

Related  types: 
3CY5,  4CY5,  6CY5 


2DS4 

Related  type: 
6DS4 


RCA  Receiving  Tube  Manual 

HIGH-MU  TRIODE 

Nuvistor  type  used  as  a  grounded- 
cathode,  neutralized  rf  amplifier  in  vhf 
tuners  of  television  and  FM  receivers 
employing  series-connected  heater 
strings.  Outline  1,  OUTLINES  SEC- 
TION. Heater  volts  (ac/dc),  2.1;  am- 
peres, 0.45;  warm-up  time  (average),  8 
seconds.  Except  for  heater  ratings,  this 
type  is  identical  with  nuvistor  type  6CW4. 

SHARP-CUTOFF  TETRODE 

Miniature  type  used  as  rf  amplifier 
in  vhf  tuners  of  television  receivers 
employing  series-connected  heater 
strings.  Outline  7B,  OUTLINES  SEC- 
TION. Heater  volts  (ac/d<^,  2.4;  am- 
peres, 0.6;  warm-up  time  (average),  11  seconds.  Except  for  heater  ratings,  this  type 
is  identical  with  miniature  type  6CY5. 

HIGH-MU  TRIODE 

Nuvistor  type  used  as  grounded- 
cathode,  neutralized  rf  amplifier  in  vhf 
tuners  of  television  and  FM  receivers 
employing  series-connected  heater 
strings.  Because  of  its  cutoff  charac- 
teristics, the  2D 84  is  used  in  circuits 
to  reduce  cross-modulation  distortion. 
Outline  1,  OUTLINES  SECTION. 
Heater  volts  (ac/dc),  2.1;  amperes, 
0.45;  warm-up  time  (average),  8  seconds.  Except  for  heater  ratings,  this  type  is 
identical  with  nuvistor  type  6DS4. 

MEDIUM-MU  TRIODE 

:  Nuvistor  type  used  at  frequencies 

up  to  1000  megacycles  in  uhf  oscillator 
stages  of  television  receivers  employ- 
ing series-connected  heater  strings. 
Outline  1,  OUTLINES  SECTION. 
Heater  volts  (ac/dc),  2.1;  amperes, 
0.45;  warm-up  time  (average),  8  sec- 
onds. Except  for  heater  ratings,  this 

type  is  identical  with  nuvistor  type  tsSHORFpiNric-oo  notuse 
6DV4. 

MEDIUM-MU  TRIODE 

Miniature  type  used  as  a  local- 
oscillator  tube  in  uhf  television  re- 
ceivers covering  the  frequency  range 
from  470  to  890  megacycles  and  em- 
ploying series-connected  heater  strings. 
Outline  7A^  OUTLINES  SECTION.  Heater  volts  (ac/dc),  2.35;  amperes,  0.6; 
warm-up  time  (average),  11  seconds.  Peak  heater-cathode  volts,  180  max  (the  dc 
component  must  not  exceed  100  volts  when  heater  is  positive  with  respect  to  cathode). 
Except  for  heater  and  heater-cathode  ratings,  this  type  is  identical  with  miniature 
type  6DZ4. 


1NDEX»LARGE  LUO 
••SHORT  PINi  IC-00  NOT  USt 


2DV4 

Kelafed  type: 
6DV4 


1NDEX»LARGE  LUS 


2DZ4 

l«Iafcd  lypts: 
3DZ4,6DZ4 


100 


Technical  Data 


2E5 

Reioled  typet 
6E5 


ELECTRON-RAY  TUBE 

Glass  type  with  triode  unit  used  to  indicate  visu- 
ally by  means  of  a  fluorescent  target  the  effects 
of  a  change  in  a  controlling  voltage.  It  is  used 
as  a  convenient  means  of  indicating  accurate  ra- 
dio receiver  tuning. Maximum  dimensions: over- 
all length,  4-3/16  inches;  seated  height,  3-9/16 
inches:diameter,l-9/16inches.TuberequireBaix- 
"  "  contact  socket.  Except  for  its  heater  rating  (2.5 

volts  ac/dc;  0.8  ampere),  the  2E5  has  electrical 
characteristics  identical  with  type  6E5.  Type2E5  is  a  DISCONTINUED  type  listed  for  reference  only. 

TWIN  DIODE 

Miniature  type  used  as  a  horizontal  phase 
detector  in  television  receivers.  Outline  7B, 
OUTLINES  SECTION.  Tube  requires  minia- 
ture seven-contact  socket  and  may  be  mounted 
in  any  position.  Heater  volts  (ac/dc),  2.1;  am- 
peres, 0.45;  warm-up  time  (average),  11  seconds. 
Maximum  ratings  {design  maximum)  as  half- 
NC  wave  rectifier:  dc  output  ma.  per  plate,  5  max; 

peak  heater-cathode  volts,  200  max.  When  the 
heater  is  positive  with  respect  to  cathode,  the  dc  component  of  the  heater-cathode  voltage  must  not 
exceed  100  volts.  Type  2EN5  is  used  principally  for  renewal  purposes. 

SHARP-CUTOFF  TRIODE 

Miniature  type  with  frame  grid 
used  in  vhf  tuners  of  television  re- 
ceivers. Outline  7B,  OUTLINES 
SECTION.  Heater  volts  (ac/dc),  2.3; 
amperes,  0.6.  Except  for  heater  rat- 
ings, this  type  is  identical  with  mini- 
ature type  6ER5. 


2EN5 


2ER5 

Related  fypes: 
3ER5,  6ERS 


2FH5 

Related  types: 
3FH5,  6FH5 


SHARP-CUTOFF  TRIODE 

Miniature  type  used  as  an  rf  ampli- 
fier in  vhf  tuners  of  television  receivers 
employing  series-connected  heater 
strings.  Outline  7B,  OUTLINES  SEC- 
TION. Heater  volts  (ac/dc),2.35;  am- 
peres, 0.6;  warm-up  time  (average),  11  seconds.  Except  for  heater  ratings,  this 
type  is  identical  with  miniature  type  6FH5. 

BEAMHEXODE 

Miniature  type  used  as  rf-ampli- 
fier  tube  in  vhf  television  receivers 
employing  series-connected  heater 
strings.  Outline  7B,  OUTLINES  SEC- 
TION. Heater  volts  (ac/dc),  2.4;  am- 
peres, 0.6;  warm-up  time  (average),  11  seconds.  Except  for  heater  ratings,  this 
type  is  identical  with  miniature  type  6FS5. 

HIGH-MU  TRIODE 

Miniature  type  with  frame  grid 
used  as  grounded-cathode  rf-ampHfier 
tube  in  vhf  tuners  of  television  re- 
ceivers employing  series-connected 
heater  strings.  Outline  7B,  OUTLINES 
SECTION.  Heater  volts  (ac/dc),  2.3;  amperes,  0.6;  warm-up  time  (average),  11 
seconds.  Except  for  heater  ratings,  this  type  is  identical  with  miniature  type  6GK5. 

101 


2FS5 

Related  typo: 
6FS5 


2GK5 

Related  lyptts: 
3GK5,  6GK5 


RCA  Receiving  Tube  Manual 


HALF-WAVE  VACUUM  RECTIFIER 

Miniature  type  used  as  rectifier  of  high- volt- 
age pulses  produced  in  scanning  systems  of  color- 
television  receivers.  Outline  9A,  OUTLINES 
SECTION.  Tube  requires  miniature  9-contact 
socket  and  may  be  mounted  in  any  position. 
Socket  terminals  3  and  7  may  be  connected  to 
the  heater.  Heater  volts  (ac),  3.16;  amperes, 
0.22.  Maximum  ratings  as  pulsed  rectifier  in  625- 
line,  30-frame  system:  peak  inverse  plate  volts, 
180(K)  max;  peak  plate  ma.,  80  max;  average  plate  ma.,  1.5  max.  For  high-voltage  considerations, 
type  1B3-GT.  Type  3A2  is  used  principally  for  renewal  purposes. 


3A2 


(4 

H 

H,K 

b) 

IS 

IS 

HALF-WAVE  VACUUM  RECTIFIER 

Glass  octal  type  used  as  rectifier 
3/1^3  high-voltage  pulses  produced  in  the 

scanning  systems  of  color  television 
receivers.  Outline  15D,  OUTLINES 
SECTION.  Tube  requires  octal  socket 
and  may  be  mounted  in  any  position.  Socket  terminals  1,  3  4,  5,  6,  and  8  may  be 
connected  to  socket  terminal  7.  Socket  terminals  4  and  6  may  be  used  as  tie  points 
for  components  at  or  near  heater  potential.  For  high-voltage  considerations,  see 
type  1B3-GT. 

Heater  Voltage  (AC)  8. 15*  volts 

Heater  Current   0.22  ampere 

Direct  Interblbctrodb  Capacitance  (Approx.): 

Plate  to  Heater,  Cathode,  and  Internal  Shield   1.5  pf 

Under  no  circumstances  should  the  heater  voltage  be  less  than  2.65  volts  or  greater  than  3.65  volts. 

PULSED  RECTIFIER 

For  operation  in  a  626'line,  SO-Jrame  system 
Maximum  Ratings,  (Design-Maximum  Values): 

Peak  Inverse  Plate  Voltage"   80000  max  volts 

Peak  Plate  Current   88  max  ma 

Average  Plate  Current   1.7  max  ma 

■  The  duration  of  the  voltage  pulse  must  not  exceed  16  per  cent  of  one  horizontal  scanning  cycle.  In  a 
625-line,  30-frame  system,  16  per  cent  of  one  horizontal  scanning  cycle  is  10  microseconds. 


DIODE— TRIODE—PENTODE 

Glass  octal  type  used  as  combined  detector, 

af  amplifier,  and  rf  amplifier  In  battery-operated 

receivers.  Maximum  over-all  length,  3-7/16 
3  A8GT  inches;  maximum  diameter,  1-5/16  inches.  Fila- 

ment volts,  1.4  (parallel),  2.8  (series);  amperes, 

0.1  (parallel),  0.05  (series).  Typical  operation  as 

class  A 1  amplifier :  triode  unit— plate  volts,90  (110 

max);  grid  volts,  0;  amplification  factor,  65; 

plate  resistance ,  0.2  megohm ;  transconductance, 
825  Atmhos;  plate  ma.,  0.2;  pentode  unit— plate  and  grid-No.2  volts,  90  (110  max);  grid-No.l  volts,  0; 
plate  resistance,  0.8  megohm;  transconductance,  750  ^mhos;  plate  ma.,  1.5;  grid-No.2  ma.,  0.5.  This  is  a 
DISCONTINUED  type  listed  for  reference  only. 


MEDIUM-MU  TRIODE 

Miniature  type  used  as  local  os- 
cillator in  uhf  television  receivers  cov- 
ering the  frequency  range  of  470  to  890 
megacycles  per  second  and  employing 
series-connected  heater  strings.  Out- 
line 7A,  OUTLINES  SECTION.  Heater  volts  (ac/dc),  3.15;  amperes,  0.45;  warm- 
up  time  (average),  11  seconds.  Except  for  heater  ratings,  this  type  is  identical  with 
miniature  type  6AF4-A. 


3AF4A 

Related  types: 
2AF4B,  6AF4A 


102 


Technical  Data 


K02 


TWIN  DIODE 


Miniature  type  having  high-per- 
veance  used  as  detector  in  television 
receivers  employing  series-connected 
heaterstrings.  Outline  7A,  OUTLINES 
SECTION.  Heater  volts  (ac/dc),  3.15; 
amperes,  0.6;  warm-up  time  (average),  11  seconds.  Except  for  heater  ratings,  this 
type  is  identical  with  miniature  type  6AL5. 


3AL5 

Related  types: 
6AL5,  12AL5 


HALF-WAVE 
VACUUM  RECTIFIER 

Duodecar  type  used  to  supply  3  AT  2 
high  voltage  to  the  anode  of  picture 
tubes  in  television  receivers.  Outline 
16B,  OUTLINES  SECTION.  Tube 
requires  duodecar  twelve-contact 
socket  and  may  be  mounted  in  any  position.  For  high-voltage  and  X-ray  safety 
considerations,  refer  to  type  1B3-GT.  Heater  volts  (ac/dc),  3,15;  amperes,  0.22. 


H,K.IS 


PULSED  RECTIFIER 

For  operation  in  a  625'Une,  SO-frame  system 
Maximum  Ratings,  (Design-Maximum  Values): 

Peak  Inverse  Plate  Voltage"  ^      80000  max  volts 

Peak  Plate  Current   88  max  ma 

Average  Plate  Current   1,7  max  ma 

■  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  horizontal  scanning  cycle.  In  a 
625-line,  30-frame  system,  15  per  cent  of  one  horizontal  scanning  cycle  is  10  microseconds. 


SHARP-CUTOFF  PENTODE 

Miniature  type  used  as  rf  ampli- 
fier in  television  receivers  emplojdng 
series-connected  heater  strings.  Out- 
line 7B,  OUTLINES  SECTION. 
Heater  volts  (ac/dc),  3.15;  amperes, 
0.6;  warm-up  time  (average),  11  seconds.  Peak  heater-cathode  volts,  200  max.  When 
the  heater  is  positive  with  respect  to  the  cathode,  the  dc  component  of  the  heater- 
cathode  voltage  must  not  exceed  100  volts.  Except  for  heater  and  heater-cathode 
ratings,  this  type  is  identical  with  miniature  type  6AU6. 


3AU6 

Related  lyptts: 
4AU6,  6AU6A,  12AU6 


3AV6 

R«lat*d  typ*s 
4AV6,  6AV6,  12AV6 


TWIN  DIODE— HIGH-MU  TRIODE 

Miniature  type  used  as  combined 
detector,  amplifier,  and  avc  tube  in 
television  receivers  employing  series- 
connected  heater  strings.  Outline  7B, 
OUTLINES  SECTION.  Heater  volts 
(ac/dc),  3.15;  amperes,  0.6;  warm-up  time  (average),  11  seconds.  Peak  heater- 
cathode  volts,  200  max.  When  the  heater  is  positive  with  respect  to  the  cathode,  the 
dc  component  of  the  heater-cathode  voltage  must  not  exceed  100  volts.  Except  for 
heater  and  heater-cathode  ratings,  this  type  is  identical  with  miniature  type  6AV6. 

103 


RCA  Receiving  Tube  Manual 


3AW3 


HALF-WAVE  VACUUM  RECTIFIER 

Glass  octal  type  used  as  rectifier 
of  high- voltage  pulses  produced  in  the 
scanning  system  of  television  receivers. 
Outline  15B,  OUTLINES  SECTION. 
Tube  requires  octal  socket  and  may  be 
mounted  in  any  position.  Heater  volts 
(ac/dc),  3.15;  amperes,  0.22. 


PULSED  RECTIFIER 

For  operation  in  a  525-line,  SO-frame  system 
Maximum  Ratings,  (Design-Maximum  Values): 

Pejak  Inverse  Plate  Voltage*   30000  max  volts 

Peak  Plate  Current   88  max  ma 

Average  Plate  Current   1.7  max  ma 

*  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  horizontal  scanning  cycle.  In  a 
625-line,  30-frame  system,  16  per  cent  of  one  horizontal  scanning  cycle  is  10  microseconds. 


HALF-W AVE  VACUUM  RECTIFIER 

Glass  octal  type  used  as  rectifier  of  high- 
voltage  pulses  produced  in  the  scanning  systems 
O  D  O  television  receivers.  Outline  25B,  OUTLINES 

J%  U  SECTION.  Tube  requires  octal  socket  and  may 

be  mounted  in  any  position.  Low-potential  cir- 
cuits should  not  be  connected  to  any  of  the  socket 
terminals.  Any  or  all  of  the  following  socket- 
terminal  connections  are  permissible  and  may 
aid  in  corona  reduction:  socket  terminals  1,  3, 
5,  and  7  may  be  connected  together;  socket  terminals  2,  6,  and  8  may  be  connected  together;  socket 
terminal  4  may  be  connected  to  socket  terminals  2  or  7,  or  may  be  used  as  a  tie  point  for  a  heater- 
voltage  dropping  resistor.  Heater  volts  (ac/dc),  3.15;  amperes,  0.22.  Maximum  ratings  as  pulsed  rec- 
tifier in  525-line,  30-frame  system:  peak  inverse  plate  volts  (absolute  maximum),  35000  max  (dc  25000 
max);  peak  plate  ma.,  80  max;  average  plate  ma.,  1.1  max.  For  high-voltage  considerations,  see  type 
1B3-GT,  Type  3B2  is  used  principally  for  renewal  purposes. 


REMOTE-CUTOFF  PENTODE 

ak  M  Miniature  type  used  as  rf  ampli- 

OB  A6  fi^r  in  standard  broadcast  and  FM  re- 

Reiaied  fypes:  ceivers,  as  Well  as  in  wide-band,  high- 

6BA6, 1 2BA6  frequency  applications ;  for  use  in  equip- 

ment  employing  series-connected 
heater  strings.  Outline  7B,  OUTLINES  SECTION.  Heater  volts  (ac/dc),  3.15; 
amperes,  0.6;  warm-up  time  (average),  11  seconds.  Except  for  heater  ratings,  this 
type  is  identical  with  miniature  type  6BA6. 


SHARP-CUTOFF  PENTODE 

^  _  _  Miniature  type  used  as  rf  or  if  am- 

3  B  C  5  plifier  in  television  receivers  employing 

Related  types-  series-counected  heater  strings.  Out- 

4BC5,6BC5*  line  7B,  OUTLINES  SECTION. 

Heater  volts  (ac/dc),  3.15;  amperes, 
0.6;  warm-up  time  (average),  11  seconds.  Peak  heater-cathode  volts,  200  max.  When 
the  heater  is  positive  with  respect  to  the  cathode,  the  dc  component  of  the  heater- 
cathode  voltage  must  not  exceed  100  volts.  Except  for  heater  and  heater-cathode 
ratings,  this  type  is  identical  with  miniature  type  6BC5. 

104 


Technical  Data 


PENTAGRID  CONVERTER 

Miniature  type  used  as  converter 
in  superheterodyne  circuits  in  both  the 
standard  broadcast  and  FM  bands  in 
equipment  employing  series-connected 
heater  strings. Outline  7B,  OUTLINES 
SECTION.  Heater  volts  (ac/dc),  3.15;  amperes,  0.6;  warm-up  time  (average),  11 
seconds.  Except  for  heater  ratings,  this  type  is  identical  with  miniature  type  6BE6. 


3BE6 

Related  types: 
6BE6,  12BE6 


3BN4 

3BN4A 

Related  types: 
2BN4A,  6BN4A 


MEDIUM-MU  TRIODE 

Miniature  types  used  as  rf  ampli- 
fier in  grid-drive  circuits  of  vhf  tele- 
vision tuners.  The  double  base-pin 
connections  for  both  cathode  and  grid 
reduce  effective  lead  inductance  and 
lead  resistance  with  consequent  reduction  in  input  conductance.  In  addition,  the 
basing  arrangement  facilitates  isolation  of  input  and  output  circuits  and  permits 
short,  direct  connections  to  base-pin  terminals.  Outline  7B,0UTLINES  SECTION. 
Heater  volts  (ac/dc),  3;  amperes,  0.45;  warm-up  time  (average),  11  seconds.  Ex- 
cept for  heater  ratings,  the  3BN4  and  3BN4-A  are  identical  with  miniature  types 
6BN4  and  6BN4-A,  respectively.  Type  3BN4  is  a  DISCONTINUED  type  listed 
for  reference  only. 


BEAM  TUBE 

Miniature  type  used  as  combined  o  n  ^  ■  ^ 

limiter,  discriminator,  and  af  voltage  oBN6 

amplifier  in  intercarrier  television  and  Related  types: 

FM  receivers  employing  series-con-  4BN6,  6BN6 
nected  heater  strings.  Outline  7C, 
OUTLINES  SECTION.  Heater  volts  (ac/dc),  3.15;  amperes,  0.6;  warm-up  time 

(average),  11  seconds.  Except  for  heater  ratings,  this  type  is  identical  with  min- 
iature type  6BN6. 


SHARP-CUTOFF  TWIN  PENTODE 

Miniature  type  used  as  combined 
sync  separator,  sync  clipper,  and  age 
amplifier  tube  in  television  receivers 
employing  series-connected  heater 
strings.  Outline  8D,  OUTLINES  SEC- 
TION. Heater  volts  (ac/dc),  3.15;  amperes,  0.6;  warm-up  time  (average),  11  sec- 
onds. Except  for  heater  ratings,  this  type  is  identical  with  miniature  type  6BU8. 


3BU8 

Related  types: 
4BU8,  6BU8 


PENTAGRID  AMPLIFIER 

Miniature  type  used  as  gated  am-  ^  O 

plifier  in  television  receivers  employing  3  B  i  O 

series-connected  heater  strings.  Out-  Related  type: 

line  7B,  OUTLINES  SECTION.  6by6 
Heater  volts  (ac/dc),  3.15;  amperes, 
0.6;  warm-up  time  (average),  11  seconds.  Except  for  heater  ratings,  this  type  is 
identical  with  miniatur®  type  6BY6. 

105 


RCA  Receiving  Tube  Manual 


SEMIREMOTE-CUTOFF  PENTODE 

Miniature  type  used  in  gain-con- 
trolled video  if  stages  of  television  re- 
ceivers employing  series-connected 
heater  strings.  Outline  7B,  OUTLINES 
SECTION.  Heater  volts  (ac/dc),  3.15; 
amperes,  0.6;  warm-up  time  (average),  11  seconds.  Peak  heater-cathode  volts  when 
heater  is  negative  with  respect  to  cathode,  300  max  (the  dc  component  must  not 
exceed  200  volts).  Except  for  heater  and  heater-cathode  ratings,  this  type  is 
identical  with  miniature  type  6BZ6. 


3BZ6 

Related  types: 
4BZ6,  6BZ6,  12BZ6 


SHARP-CUTOFF  PENTODE 

Miniature  type  used  as  rf  or  if  am- 
plifier in  television  receivers  employing 
series-connected  heater  strings.  Out- 
line 7B,  OUTLINES  SECTION. 
Heater  volts  (ac/dc),  3.15;  amperes, 
0.6;  warm-up  time  (average),  11  seconds.  Peak  heater-cathode  volts:  heater  negative 
with  respect  to  cathode,  300  max;  heater  positive  with  respect  to  cathode,  200  max 
(the  dc  component  must  not  exceed  100  volts).  Except  for  heater  and  heater- 
cathode  ratings,  this  type  is  identical  with  miniature  types  6CB6  and  6CB6-A. 


3CB6 

Related  types: 
4CB6,  6CB6,  6CB6A 


SHARP-CUTOFF  PENTODE 

Miniature  type  used  as  rf  and  if 
amplifier  in  vhf  television  receivers  em- 
ploying series-connected  heater  strings. 
Outline  7B,  OUTLINES  SECTION. 
Heater  volts,  3.15;  amperes,  0.6;  heater 
warm-up  time  (average),  11  seconds.  Except  for  heater  ratings,  this  type  is  iden- 
tical with  miniature  type  6CE5. 


3CE5 

Related  typo: 
6CE5 


SHARP-CUTOFF  PENTODE 

^  ^  p  -  Miniature  type  used  as  rf  or  if  am- 

3  C PO  plifier  in  television  receivers  employing 

Related  type:  series-connected  heater  strings.  Out- 

6CF6  line  7B,  OUTLINES  SECTION. 

Heater  volts  ac/dc),  3.15;  amperes, 
0.6;  warm-up  time  (average),  11  seconds.  Peak  heater-cathode  volts:  heater  negative 
with  respect  to  cathode,  300  max;  heater  positive  with  respect  to  cathode,  200  max 
(the  dc  component  must  not  exceed  100  volts).  Except  for  heater  and  heater- 
cathode  ratings,  this  type  is  identical  with  miniature  type  6CF6. 


PENTAGRID  AMPLIFIER 

0%^^^  Miniature  type  used  as  gated  am- 

O  plifier  in  television  receivers  employing 

Related  types:  series-connected  heater  strings.  Out- 

4CS6,6CS6  line  7B,  OUTLINES  SECTION. 

Heater  volts  (ac/dc),  3.15;  amperes, 
0.6;  warm-up  time  (average),  11  seconds.  Except  for  heater  ratings,  this  type  is 
identical  with  miniature  type  6CS6. 

106 


Technical  Data 


SHARP-CUTOFF  TETRODE 

Miniature  type  used  as  rf  ampli-  ^  ^  V  C 
fier  in  vhf  tuners  of  television  receiv-  O^T  d 
ers  employing  series-connected  heater  Related  types: 
strings.  Outline  7B,  OUTLINES  SEC-  2CY5,  4CY5,  6CY5 
TION.  Heater  volts  (ac/dc),  2.9;  am- 
peres, 0.45;  warm-up  time  (average),  11  seconds.  Except  for  heater  ratings,  this 
type  is  identical  with  miniature  type  6CY5. 


FULL-WAVE  VACUUM  RECTIFIER 

Glass  octal  type  used  as  power  ^W\f>  A 

supply  in  television  receivers  and  other  w  D  w4 

equipment  having  high  dc  require- 
ments. Outline  19D,  OUTLINESSEC- 
TION.  Tube  requires  octal  socket  and 
may  be  operated  in  any  position.  It  is  especially  important  that  this  tube,  like 
other  power-handling  tubes,  be  adequately  ventilated.  For  discussion  of  Rating 
Chart,  refer  to  INTERPRETATION  OF  TUBE  DATA.  Filament  volts  (ac/dc), 
3.3;  amperes,  3.8. 

FULL- WAVE  RECTIFIER 
Maximum  Ratings,  {Design-Maximum  Values): 

Peak  Inverse  Plate  Voltage   1050  moa:  volts 

Peak  Plate  Current  (Per  Plate)   1.2  max  amperes 

Hot-Switching  Transient  Plate  Current  (Per  Plate)   6.5  max  amperes 

AC  Plate  Supply  Voltage  (Per  Plate,  rms)   See  Rating  Chart 

DC  Output  Current  (Per  Plate)   See  Hating  Chart 

Bulb  Temperature  (at  hottest  point  on  bulb  surface)  ^         200  max  °C 


RATING  CHART 


 1  1  1— 

TYPE  3DG4  I 
E^=3.3  VOLTS  AC  I 

MAX /MUM  OPERATING  VALUES  WITH: 
CHOKE-INPUT  FILTER 

CAPACITOR-INPUT  FILTER 


1^250 
J 

J  200 
t 

J  150 

;  100 


3  100  200  300  400 

AC  PLATE  SUPPLY  VOLTS  (RMS)  PER  PLATE  (WITHOUT  I 


Typical  Operation  with  Capacitor  Input  to  Filten 

AC  Plate-to-Plate  Supply  Voltage  (rms)    650  volts 

Filter-Input  Capacitor"   40 

Effective  Plate-Supply  Impedance  per  Plate .  . . .    82  ohms 

DC  Output  Voltage  at  Input  to  Filter  (Approx.) : 

At  full-load  current  of  350  ma   800  volts 

Characteristics: 

Tube  Voltage  Drop  for  plate  current  of  350  ma  (per  plate)  25  volts 

°  Higher  values  of  capacitance  than  indicated  may  be  used,  but  the  effective  plate-supply  Impedance 
may  have  to  be  increased  to  prevent  exceeding  the  maximum  rating  for  peak  plate  current. 


107 


RCA  Receiving  Tube  Manual 


SHARP-CUTOFF  PENTODE 

Miniature  types  used  as  interme- 
diate-frequency amplifier  in  television 
receivers.  Outline  7B,  OUTLINES 
SECTION.  Heater  volts  (ac/dc),  3.15, 
amperes.  0.6;  warm-up  time  (average), 
11  seconds,  Peak  heater-cathode  volts:  heater  negative  with  respect  to  cathode, 
300  max;  heater  positive  with  respect  to  cathode,  200  max  (the  dc  component  must 
not  exceed  100  volts).  Except  for  heater  and  heater-cathode  ratings,  this  type  is 
identical  with  miniature  type  6DK6. 


3DK6 

Related  types: 
6DK6,  12DK6 


3DT6 

3DT6A 

Related  types: 
4DT6A,  6DT6A 


SHARP-CUTOFF  PENTODE 

Miniature  types  used  as  FM  de- 
tector in  television  receivers  employing 
series-connected  heater  strings.  Outline 
7B,  OUTLINES  SECTION.  Heater 
volts  (ac/dc),  3.15;  amperes,  0.6; 
warm-up  time  (average),  11  seconds.  Except  for  heater  ratings,  these  types  are 
identical  with  miniature  types  6DT6  and  6DT6-A,  respectively.  Type  3DT6  is  a 
DISCONTINUED  type  listed  for  reference  only. 

MEDIUM-MU  TRIODE 

Miniature  type  used  as  a  local- 
oscillator  tube  in  uhf  television  re- 
ceivers covering  the  frequency  range 
from  470  to  890  megacycles  and  em- 
ploying series-connected  heater  strings. 
Outline  7A,  OUTLINES  SECTION.  Heater  volts  (ac/dc),  3.2;  amperes,  0.45; 
warm-up  time  (average),  11  seconds.  Peak  heater-cathode  volts,  180  max  (the  dc  com- 
ponent must  not  exceed  100  volts  when  heater  is  positive  with  respect  to  cathode). 
Except  for  heater  and  heater-cathode  ratings,  this  type  is  identical  with  miniature 
type  6DZ4. 

SHARP-CUTOFF  PENTODE 

Miniature  type  used  as  rf  ampli- 
fier in  vhf  tuners  of  television  receivers 
having  series-connected  heater  strings. 
Outline  7B,  OUTLINES  SECTION. 
Heater  volts  (ac/dc)  2.9;  amperes, 
0.45;  warm-up  time  (average),  11  seconds.  Except  for  heater  ratings,  this  type  is 
identical  with  miniature  type  6EA5. 


3DZ4 

Related  types: 
2DZ4,  6DZ4 


3EA5 

Related  type: 
6EA5 


3EH7 

Related  types: 
Am?,  6EH7 


3EJ7 

Related  types: 
4£J7,  6EJ7 


108 


SEMIREMOTE-CUTOFF  PENTODE 

Miniature  type  used  as  if-ampli- 
fier  tube  in  television  receivers.  Out- 
line 8C,0UTLINESSECTI0N.Heater 
volts  (ac/dc), 3.4;  amperes, 0.6;  Except 
for  heater  ratings,  this  type  is  identical 
with  miniature  type  6EH7. 

SHARP-CUTOFF  PENTODE 

Miniature  type  used  as  if-ampli- 
fier  tube  in  television  receivera.Outline 
8C,  OUTLINES  SECTION.  Heater 
volts  (ac/dc),  3.4;  amperes,  0.6.  Ex- 
cept for  heater  ratings,  this  type  is 
identical  with  miniature  type  6E  J7, 


Technical  Data 


HIGH-MU  TRIODE 

Miniature  type  with  frame  grid 
used  in  vhf  tuners  of  television  re- 
ceivers. Outline  7B,  OUTLINES  SEC- 
TION. Heater  volts  (ac/dc),  2.8;  am- 
peresj  0.45.  Except  for  heater  ratings, 
this  type  is  identical  with  miniature 
type  6ER5. 

HIGH-MU  TRIODE 

Miniature  type  used  as  rf-ampli- 
fier  tube  in  vhf  tuners  of  television  re- 
ceivers employing  series-connected 
heaterstrings.  Outline  7B,  OUTLINES 
SECTION.  Heater  volts  (ac/dc),  3; 
amperes,  0.45;  warm-up  time  (average),  11  seconds.  Except  for  heater  ratings,  this 
type  is  identical  with  miniature  type  6FH5, 


3ER5 

Rtlaled  types: 
2ER5,  6ER5 


3FH5 

Related  types: 
2FH5,  6FH5 


HIGH-MU  TRIODE 

Miniature  type  with  frame  grid 
used  as  grounded-cathode  rf-amplifier 
tube  in  vhf  tuners  of  television  re- 
ceivers employing  series-connected 
heaterstrings.  Outline  7B,  OUTLINES 
SECTION.  Heater  volts  (ac/dc),  2.8;  amperes,  0.45;  warm-up  time  (average),  11 
seconds.  Except  for  heater  ratings,  this  type  is  identical  with  miniature  type  6GK5. 


3GK5 

Related  type; 
2GK5,  66K5 


SHARP-CUTOFF  TWIN  PENTODE 


3GS8/ 
3BU8 


Miniature  type  used  as  combined 
sync  separator,  sync  clipper,  and  age 
amplifier  tube  in  television  receivers  Related  type: 

employing  series-connected  heater  4GS8/4BU8 
strings.  Outline  8D,  OUTLINES  SEC- 
TION. Heater  volts  (ac/dc),  3.15;  amperes,  0.6.  Except  for  heater  ratings,  this 
type  is  identical  with  miniature  type  4GS8/4BU8. 


G3PI 


HIGH-MU  TRIODE 

Miniature  type  used  as  rf-ampli- 
fier tube  in  vhf  television  tuners.  Out- 
line 7A,  OUTLINES  SECTION. 
Heater  volts  (ac/dc),  2.7;  amperes, 
0.45.  Except  for  heater  ratings,  this 
type  is  identical  with  miniature  type 
6HA5. 


SHARP-CUTOFF  TWIN  PENTODE 


Miniature  type  used  in  age  am- 
plifier, sync,  and  noise-limiting  cir- 
cuits of  television  receivers  employing 
series-connected  heater  strings.  One 
pentode  unit  is  used  as  a  combined 


3HA5 

Related  type: 
6HA5 


3HS8 

Related  types: 
4HS8,  6H$8 


sync  separator  and  sync  clipper;  the  other  pentode  unit  is  used  as  the  age  amplifier. 

109 


RCA  Receiving  Tube  Manual 


Outline  8D,  OUTLINES  SECTION.  Heater  volts  (ac/dc),  3.15;  amperes,  0.6; 
warm-up  time  (average),  11  seconds.  Except  for  heater  ratings,  this  type  is  identical 
with  miniature  type  6HS8. 

SHARP-CUTOFF  PENTODE 

0^  Miniature  type  with  frame  grid 

w  JCw  us^d  ii^  if -amplifier  stages  of  television 

Kttiafed  types:  receivers  utilizing  intermediate  fre- 

4JC6, 6JC6  quencies  in  the  order  of  40  megacycles 

and  employing  series-connected  heater 
strings.  Outline  8B,  OUTLINES  SECTION.  Heater  volts  (ac/dc),  3.5;  amperes, 
0.6;  heater  warm-up  time  (average),  11  seconds.  Except  for  heater  ratings,  this 
type  is  identical  with  miniature  type  6JC6. 


SHARP-CUTOFF  PENTODE 

Miniature  type  used  as  if-ampli- 
fier  tube  in  television  receivers  utiliz- 
ing intermediate  frequencies  in  the  or- 
der of  40  megacycles  and  employing 
series-connected  heater  strings.  Out- 
line SB,  OUTLINES  SECTION.  Heater  volts  (ac/dc),  3.5;  amperes,  0.6;  warm-up 
time  (average),  11  seconds.  Except  for  heater  ratings,  this  type  is  identical  with 
miniature  type  6JD6. 


3JD6 

Related  types: 
41D6,  6JD6 


63.rs 


3LF4 


BEAM  POWER  TUBE 

Glass  lock-in  type  used  in  output  staj^e  of 
ac /dc /battery  portable  receivers.  Outline  13A, 
OUTLINES  SECTION.  Tube  requires  lock-in 
socket.  Filament  volts  (dc),  1.4  (parallel),  2.8 
(series);  amperes,  (.1  (parallel),  0.05  (series). 
For  electrical  characteristics,  refer  to  glass-octal 
type  3Q5-GT.  Type  3LF4  is  used  principally 
for  renewal  purposes. 


3Q4 


POWER  PENTODE 

Miniature  type  used  in  outpuc  stage  of 
lightweight,  compact,  portable  battery-operated 
equipment.  Outline  7B,  OUTLINES  SECTION. 
Except  for  terminal  connections,  types  3Q4  and 
3V4  are  identical.  Refer  to  type  3V4  for  ratings 
and  typical  operation.  Type  3Q4  is  used  prin- 
cipally for  renewal  purposes. 


BEAM  POWER  TUBE 

Glass  octal  type  used  in  output  stage  of 
ac  /dc  battery  portable  receivers.  Outline  14C, 
^        ^  ^  wmt         OUTLINE b  SECTION .  This  type  may  be  sup- 
-jCtJ  J  Cy  I  plied  with  pm  1  omitted.  Filament  volts  (dc), 

2.8  in  series  filament  arrangement  and  1.4  in 
parallel  arrangement;  amperes   0.05  (series), 
0.1  (parallel).  Typical  operation  as  Class  Ai 
amplifier:  plate  and  grid-No.2  volts,  110  max\ 
grid-No.l  volts,  -6.6;  peak  af  grid-No.l  volts, 
6.1  (eeriea),  5.4  (parallel) ;  plate  ma.,  8.5  (series),  10  (parallel) ;  grid-No.2  ma.,  1.1  (series),  1.4  (parallel) ; 
total  cathode  ma.,  6  max  for  each  1.4- volt  filament  section;  plate  resistance  (approx.),  0.11  megohm 
(series),  0.1  megohm  (parallel);  transconductance,  2000  /«mhos  (series),  2200  jumhos  (parallel);  load 
resistance,  8000  ohms;  total  harmonic  distortion,  8.5  per  cent  (series),  6  per  cent  (parallel) ;  max.-signal 
power  output,  830  mw  (series),  400  mw  (parallel).  This  type  is  used  principally  Tor  renewal  purposes. 


110 


POWER  PENTODE 

Miniature  type  used  in  output  stage  of 
lightweight,  compact,  portable,  battery-oper- 
ated equipment.  Outline  7B,  OUTLINES  SEC-  O  C  il 
TION.  Tube  requires  miniature  seven-contact 
socket.  Filament  volts  (dc),  2.8  (series),  1.4 
(parallel);  amperes,  0.05  (series);  0.1  (parallel). 
Typical  operation  as  class  Ai  amplifier:  plate 
and  grid-No.2  volts,  67.5  (90  max);  grid-No.l 
volts,  -7 ;  peak  af  grid-No.l  volts,  7 ;  zero-signal 
plate  ma.,  6  (series)  7.2  (parallel) ;  zero-signal  grid-No.2  ma.,  1.2  (series),  1.5  (parallel) ;  plate  resistance 
(approx.);  0.1  megohm;  transconductance,  1400  /imhos  (series),  1550  /imhos  (parallel);  load  resistance, 
5000  ohms;  maximum-signal  power  output,  160  milliwatts  (series),  180  milliwatts  (parallel).  This  type 
is  used  principally  for  renewal  purposes. 


POWER  PENTODE 


Miniature  type  used  in  output  stage  of 
lightweight,  compact,  portable,  battery-oper- 
ated equipment.  Outline  7B,  OUTLINES  SEC- 
TION. Tube  requires  miniature  seven-contact 
socket.  Filament  volts  (dc),  2.8  (series),  1.4 
(parallel);  amperes,  0.06  (series),  0.1  (parallel). 
Typical  operation  as  class  Ai  amplifier;  plate 
and  grid-No.2  volts,  90  (100  max);  grid-No.l 


volts,  -4.5;  peak  af  grid-No.l  volts,  4.5;  zero- 
signal  plate  ma.,  7.7  (series),  9.5  (parallel);  grid-No.2  ma.,  zero-signal,  1.7  (series),  2.1  (parallel) ;  plate 
resistance  (approx.),  0.12  megohm  (series),  .1  megohm  (parallel);  transconductance,  2000  /xmhos 
(series),  2150  /xmhos  (parallel);  load  resistance,  10000  ohms;  maximum-signal  power  output,  240  milli- 
watts (series),  270  milliwatts  (parallel).  This  type  is  used  principally  for  renewal  purposes. 


4AU6 

Relatod  typos: 
3AU6,  6AU6A,  12AU6 


SHARP-CUTOFF  PENTODE 

Miniature  type  used  as  rf  ampli- 
fier in  television  receivers  employing 
series-connected  heater  strings. Outline 
7B,  OUTLINES  SECTION.  Heater 
volts  (ac/dc),  4.2;   amperes,  0.45; 
warm-up  time  (average),  11  seconds.  Peak  heater-cathode  volts:  heater  negative 
with  respect  to  cathode,  200  max;  heater  positive  with  respect  to  cathode,  200  max 
(the  dc  component  must  not  exceed  100  volts).  Except  for  heater  and  heater-cath- 
ode ratings,  this  type  is  identical  with  miniature  type  6AU6. 


TWIN  DIODE— HIGH-MU  TRIODE 

Miniature  type  used  as  combined 
detector,  amplifier,  and  avc  tube  in 
automobile  and  ac-operated  radio  re- 
ceivers employing  series-connected 
heater  strings.  OutHne  7B,  OUTLINES 
SECTION.  Heater  volts  (ac/dc),  4.2;  amperes,  0.45;  warm-up  time  (average),  11 
seconds.  Except  for  heater  ratings,  this  type  is  identical  with  miniature  type  6AV6. 


4AV6 

Rolatad  fyp*s: 
3AV6,  6AV6,  12AV6 


SHARP-CUTOFF  PENTODE 

Miniature  type  used  in  compact 
radio  equipment  as  an  rf  or  if  amplifier 
at  frequencies  up  to  400  megacycles 
per  second.  Outline  7B,  OUTLINES 
SECTION.  Heater  volts  (ac/dc),  4.2; 


4BC5 

Rttlatsd  typ«s: 
3BC5,  6BC5 


RCA  Receiving  Tube  Manual 


amperes,  0.45;  warm-up  time  (average),  11  seconds.  Peak  heater-cathode  volts: 
heater  negative  with  respect  to  cathode,  200  max;  heater  positive  with  respect  to 
cathode,  200  max  (the  dc  component  must  not  exceed  100  volts).  Except  for  heater 
and  heater-cathode  ratings,  this  type  is  identical  with  miniature  type  6BC5. 


MEDIUM-MU  TWIN  TRIODE 

Miniature  type  used  in  direct- 
coupled  cathode-drive  rf  amplifier  cir- 
cuits of  vhf  television  tuners  employ- 
ing series-connected  heater  strings. 
Outline  8B,  OUTLINES  SECTION.  ^^2- 
Heater  volts  (ac/dc),  4.2;  amperes,  0.6;  warm-up  time  (average),  11  seconds. 
Except  for  heater  rating,  this  type  is  identical  with  miniature  type  6BC8. 


4BC8 

Related  type: 
6BC8 


GT2^ 


4BL8 

Related  type: 
6BL8 


MEDIUM-MU  TRIODE— 
SHARP-CUTOFF  PENTODE 

Miniature  type  used  in  frequency- 
changer  service  in  television  receivers. 
Outline  8B,  OUTLINES  SECTION, 
Heater  volts  (ac/dc),  4.6;  amperes,  0.6 
Except  for  heater  ratings,  this  type  is 
identical  with  miniature  type  6BL8. 


BEAM  TUBE 

MV%^t£.  Miniature  type  used  as  combined 

4BNO  limiter,  discriminator,  and  audio-volt- 

Reiated  types:  age  amplifier  in  intercarrier  television 

3BN6, 6BN6  and  FM  receivers  employing  series- 

connected  heater  strings.  Outline  7C, 
OUTLINES  SECTION.  Heater  volts  (ac/dc),  4.2;  amperes,  0.45;  warm-up  time 
(average),  11  seconds.  Peak  heater-cathode  volts,  200  max.  When  the  heater  is 
positive  with  respect  to  the  cathode,  the  dc  component  of  the  heater-cathode  voltage 
must  not  exceed  100  volts.  Except  for  heater  and  heater-cathode  ratings,  this  type 
is  identical  with  miniature  type  6BN6. 


MEDIUM-MU  TWIN  TRIODE 


4BQ7A 

Related  types: 
5BQ7A,  6BQ7A 


KT2, 


Miniature  type  used  in  direct- 
coupled  cathode-drive  rf  amplifier  cir- 
cuits of  vhf  television  tuners  employ- 
ing series-connected  heater  strings. 
Outline  8B,  OUTLINES  SECTION. 
Heater  volts  (ac/dc),  4.2;  amperes,  0.6;  warm-up  time  (average),  11  seconds. 
Except  for  heater  ratings,  this  type  is  identical  with  miniature  type  6BQ7-A. 


MEDIUM-MU  TWIN  TRIODE 

Miniature  type  used  in  direct- 
coupled  cathode-drive  rf  amplifier  cir- 
cuits of  vhf  television  tuners  employ- 
ing series-connected  heater  strings. 
Outline  8B,  OUTLINES  SECTION. 
Heater  volts  (ac/dc),  4.5;  amperes,  0.6;  warm-up  time  (average),  11  seconds. 
Except  for  heater  ratings,  this  type  is  identical  with  miniature  type  6BS8. 

112 


4BS8 

Related  type: 
6BS8 


SHARP-CUTOFF  TWrN  PENTODE 

Miniature  type  used  as  combined 
sync  separator,  sync  clipper,  and  age 
amplifier  tube  in  television  receivers 
employing  series-connected  heater 
strings.  Outline  8D,  OUTLINES  SEC- 
TION. Heater  volts  (ac/dc),  4.2;  amperes,  0.45;  warm-up  time  (average),  11  seconds. 
Except  for  heater  ratings,  this  type  is  identical  with  miniature  type  6BU8. 


4BU8 

Related  types: 
3BU8,  6BU8 


SEMIREMOTE-CUTOFF  PENTODE 

Miniature  type  used  in  gain-con- 
trolled video  if  stages  of  television  re- 
ceivers employing  series-connected 
heater  strings.  Outline  7B,  OUT- 
LINES SECTION.  Heater  volts 
(ac/dc),  4.2;  amperes,  0.45;  warm-up  time  (average),  11  seconds.  Except  for  heater 
ratings,  this  type  is  identical  with  miniature  type  6BZ6. 


4BZ6 

Related  types: 
3BZ6,  6BZ6,  12BZ6 


KT2, 


4BZ7 

Related  type: 
6BZ7 


4CB6 

Related  types: 
3CB6,  6CB6,  6CB6A 


MEDIUM-MU  TWIN  TRIODE 

Miniature  type  used  in  direct- 
coupled  cathode-drive  rf  amplifier  cir- 
cuits of  vhf  television  tuners  employ- 
ing series-connected  heater  strings. 
Outline  8B,  OUTLINES  SECTION, 
(ac/dc),  4.2  amperes,  0.6;  warm-up  time  (average),  11  seconds. 
Except  for  heater  ratings,  this  type  is  identical  with  miniature  type  6BZ7. 

SHARP-CUTOFF  PENTODE 

Miniature  type  used  as  if  and  as 
rf  amplifier  in  television  receivers  em- 
ploying series-connected  heater  strings. 
Outline  7B,  OUTLINES  SECTION. 
Heater  volts  (ac/dc),  4.2;  amperes, 
0.45;  warm-up  time  (average),  11  seconds.  Peak  heater-cathode  volts:  heater  nega- 
tive with  respect  to  cathode,  300  max  (the  dc  component  must  not  exceed  200 
volts) ;  heater  positive  with  respect  to  cathode,  200  max  (  the  dc  component  must 
not  exceed  100  volts).  Except  for  heater  and  heater-cathode  ratings,  this  type  is 
identical  with  miniature  types  6CB6  and  6CB6-A. 

PENTAGRID  AMPLIFIER 

Miniature  type  used  as  a  gated 
amplifier  in  television  receivers.  In 
such  service,  it  may  be  used  as  a  com- 
bined sync  separator  and  sync  clipper. 
Outline  7B,  OUTLINES  SECTION. 
Heater  volts  (ac/dc),  4.2;  amperes,  0.45;  warm-up  time  (average),  11  seconds.  Ex- 
cept for  heater  ratings,  this  type  is  identical  with  miniature  type  6CS6. 


4CS6 

Related  types: 
3CS6,  6CS6 


SHARP-CUTOFF  TETRODE 

Miniature  type  used  as  rf  ampli- 
fier in  vhf  tuners  of  television  receivers 
employing  series-connected  heater 
strings.  Outline  7B,  OUTLINES  SEC- 
TION. Heater  volts  (ac/dc),  4.5;  am- 
peres, 0.3;  warm-up  time  (average),  11  seconds.  Except  for  heater  ratings,  this  type 
is  identical  with  miniature  type  6CY6. 

113 


4CY5 

Roiofed  types: 
2CY5,  3CY5,  6CY5 


RCA  Receiving  Tube  Manual 


SHARP-CUTOFF  PENTODE 

Miniature  type  used  in  the  gain-  at\^  JL 

controlled  picture  if  stages  of  television  E6 
receivers  utilizing  an  intermediate  fre-  Related  type: 

quency  in  the  order  of  40  megacycles  6de6 
per  second.  Also  used  as  an  rf  amplifier 
in  vhf  television  tuners.  Outline  7B,  OUTLINES  SECTION.  Heater  volts  (ac/dc), 
4.2;  amperes,  0.45;  warm-up  time  (average),  11  seconds.  Except  for  heater  ratings, 
this  tube  is  identical  with  miniature  type  6DE6. 


SHARP-CUTOFF  PENTODE 

Miniature  types  used  as  FM  de- 


4DT6 

4DT6A 


Related  types: 
3DT6A,  6DT6A 


tector  in  television  receivers  employing 
series-connected  heater  strings.  Outline 
7B,  OUTLINES  SECTION.  Heater 
volts  (ac/dc),  4.2;  amperes,  0.45; 
warm-up  time  (average),  11  seconds.  Except  for  heater  ratings,  these  types  are 
identical  with  miniature  types  6DT6  and  6DT6-A,  respectively.  Type  4DT6  is  a 
DISCONTINUED  type  listed  for  reference  only. 


SEMI  REMOTE-CUTOFF  PENTODE 

Miniature  type  used  as  if-ampli- 
fier  tube  in  television  receivers.  Out- 
line 8C,  OUTLINES  SECTION.  Heat- 
er volts  (ac/dc),  4.4;  amperes,  0.45; 
Except  for  heater  ratings,  this  type  is 
identical  with  miniature  type  6EH7. 

SHARP-CUTOFF  PENTODE 

Miniature  type  used  as  if-ampli- 
fier  tube  in  television  receivers.  Outline 
8C,  OUTLINES  SECTION.  Heater 
volts  (ac/dc),  4.4;  amperes,  0.45.  Ex- 
cept for  heater  ratings,  this  type  is 
identical  with  miniature  type  6EJ7. 

VARIABLE-MU  TWIN  TRIODE 

Miniature  type  used  in  direct- 
coupled  cathode-drive  rf  amplifier  cir- 
cuits of  television  receivers  employing 
series-connected  heater  strings.  Out- 
line 8B,  OUTLINES  SECTION. 
Heater  volts  (ac/dc),  4;  amperes,  0.6;  warm-up  time  (average),  11  seconds.  Except 
for  heater  ratings,  this  type  is  identical  with  miniature  type  6ES8. 


4EH7 

Related  types: 
3EH7,  6EH7 


4EJ7 

Related  types: 
3EJ7,  6EJ7 


4ES8 

Related  type: 
6ES8 


SHARP-CUTOFF  PENTODE 

Miniature  type  used  in  the  gain-  -      a  #  iT 

controlled  picture-if  stages  of  vhf  tele-  4E  wV  O 

vision  receivers  operating  at  an  inter-  Related  types: 

mediate  frequency  in  the  order  of  40  5EW6,  6EW6 

megacycles  per  second.  Outline  7B, 
OUTLINES  SECTION.  Heater  volts  (ac/dc),  4.2;  amperes,  0.6;  warm-up  time 
(average),  11  seconr>.  Except  for  heater  ratings,  this  type  is  identical  with  minia^ 
ture  type  W6. 

114 


Technical  Data ' 


SHARP-CUTOFF  TWIN  PENTODE 


4GS8 
/4BU8 


Miniature  type  used  as  combined 
sync  separator,  sync  clipper,  and  age 
amplifier  tube  in  television  receivers  Related  type: 

employing  series-connected  heater  3GS8/3bu8 
strings.  Outline  8D,  OUTLINES  SEC- 
TION. Tube  requires  miniature  nine-contact  socket  and  may  be  mounted  in  any 
position. 


Heater  Voltage  (ac/dc)  

Heater  Current  

Heater  Warm-Up  Time  (Average)  

Direct  Interelectrode  Capacitances: 

Grid  No.3  to  Plate  (Each  Unit)  

Grid  No.l  to  All  Other  Electrodes  

Grid  No.3  to  All  Other  Electrodes  (Each  Unit)  

Plate  to  All  Other  Electrodes  (Each  Unit)  

Grid  No.3  of  Unit  No.l  to  Grid  No.3  of  Unit  No.2. 


4.2 
0.45 
11 


3.8 

3.2 
0.015  max 


volts 
ampere 
Beconds 

pf 


CLASS  Ai  AMPLIFIER 
Maximum  Ratings,  (Design'Maximum  Values): 

Plate  Voltage  (Each  Unit)  

Grid-No.3  (suppressor-grid)  Voltage  (Each  Unit) : 

Peak  positive  value  

DC  negative  value  

DC  positive  value  

Grid-No.2  (screen-grid)  Voltage  

Grid-No.I  (control-grid)  Voltage,  Negative  bias  value  

Cathode  Current  

Grid-No.2  Input  

Plate  Dissipation  (Each  Unit)  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  

Characteristics: 


With  Both  Units  Operating 


Plate  Voltage  (Each  Unit)  

Grid-No.3  Voltage  (Each  Unit) . 

Grid-No.2  Voltage  

Grid-No.l  Voltage  

Plate  Current  (Each  Unit)  

Grid-No.2  Current  

Cathode  Current  


With  One  Unit  Operadng 

Plate  Voltage  

Grid-No.3  Voltage  

Grid-No.2  Voltage  

Grid-No.l  Voltage  

Grid-No.3  Transconductance  

Grid-No.l  Transconductance  

Plate  Current  

Grid-No.3  Voltage  (Approx.)  for  plate  current  of  100  na.  

Grid-No.l  Voltage  (Approx.)  for  plate  current  of  100  fia  


100 
-10 
67.5 


6 

6.1 


Maximum  Circuit  Values: 

Grid-No.3-Circuit  Resistance  (Each  Unit) . 
Grid-No.l-Circuit  Resistance  


cOO  max 

50  max 
-50  max 
c  max 
150  max 
-50  max 
12  max 
0 . 75  max 
1 . 1  max 

200  max 
200°max 


100 
0 

67.5 
■ 

2 

3.6 
7.7 


volts 

volts 
volts 
volts 
volts 
volts 
ma 
watt 
watts 

volts 
volts 


volts 
volts 
volts 
volts 
ma 
ma 
ma 


100 

100 

volts 

0 

0 

volts 

67.5 

67.5 

volts 

0 

■ 

volts 

270 

^mhos 

1200 

/umhos 

2 

ma 

-3.7 

volts 

-2 

volts 

0 . 5  max 
0 . 5  max 


megohm 
megohm 


"The  dc  component  must  not  exceed  100  volts. 
■  Adjusted  to  give  a  dc  grid-No.l  current  of  100  microampere?. 
•  With  plate  and  grid  No.3  of  the  other  unit  connected  to  ground. 

POWER  PENTODE 

Miniature  type  used  in  audio  out- 
put stages  of  radio  and  television  re- 
ceivers employing  series-connected 
heater  strings.  Outline  7B,  OUTLINES 
SECTION.  Tube  requires  miniature 
seven-contact  socket  and  may  be  mounted  in  any  position.  Heater  volts  (ac/dc),  4; 
amperes,  0.6;  warm-up  time  (average),  11  seconds. 


4GZ5 


RCA  Receiving  Tube  Manual 


CLASS  Ai  AMPLIFIER 
Maximum  Ratings,  {Design-Maximum  Values): 

Plate  Voltage  

Grid-No.2  (screen-grid)  Voltage  ..!.*.*.'.* 

Grid-No.1  (control-grid)  Voltage,  Positive-bias  value .... 

Average  Cathode  Current  

Plate  Dissipation.  

Grid-No.2  Input  .*..*......!. 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  

Bulb  Temperature  (At  hottest  point)  

Typical  Operation: 

Plate  Supply  Voltage  

Grid-No.2  Supply  Voltage  

Cathode-Bias  Resistor  

Peak  AF  Grld-No.l  Voltage  

Zero-Signal  Plate  Current  

Maximum-Signal  Plate  Current  

Zero-Signal  Grid-No.2  Current  

Maximum-Signal  Grid-No.2  Current  

Plate  Resistance  (Approx.)  

Transconductance  

Load  Resistance  

Total  Harmonic  Distortion  

Maximum-Signal  Power  Output.  


Maximum  Circuit  Valves: 

Grid-No.l-Circuit  Resistance: 

For  fixed-bias  operation  

For  cathode-bias  operation  

■  The  dc  component  must  not  exceed  100  volts. 
•  Bypassed. 


300 

max 

300 

max 

volts 

0 

max 

volts 

30 

max 

ma 

4.8 

max 

watts 

1.1 

max 

watts 

200 

max 

volts 

200"wax 

volts 

200 

max 

°C 

250 

250 

volts 

250 

250 

volts 

270 

270* 

ohms 

9.8 

2 

volts 

16 

16 

ma 

16 

16 

ma 

2.7 

2.7 

ma 

5 

5 

ma 

0.15 

megohm 

8400 

/xmhos 

15000 

15000 

ohms 

10 

10 

per  cent 

1.8 

1.1 

watts 

0.5  max 

1  max 


megohm 
megohm 


SHARP-CUTOFF  PENTODE 

A  LJ      JL  Miniature  type  with  frame  grid 

4rlAAO         used  in  the  if-amplifier  stages  of  tele- 
vision receivers  employing  series-con- 
nectedheaterstrings.OutlineSB, OUT- 
LINES SECTION.  Tube  requires  min- 
iature nine-contact  socket  and  may  be  mounted  in  any  position, 
(ac/dc),  4.2;  amperes,  0.45;  warm-up  time  (average),  11  seconds. 


Heater  volts 


CLASS  Ai  AMPLIFIER 
Maximum  Ratings,  {Design-Maximum  Values). 

Plate  Voltage  ,.  250  max  volts 

Grid-No.2  (screen-grid)  Supply  Voltage   250  maa;  volts 

Grid-No.2  Voltage   See  curve  page  70 

Grid-No.I  (control-grid)  Voltage,  Negative-bias  value   -50  max  volts 

Cathode  Current   25  max  ma 

Plate  Dissipation   2.5  max  watts 

Grid-No.2  Input: 

For  grid-No.2  voltages  up  to  125  volts  ,  0.6  max  watt 

For  grid-No.2  voltages  between  125  and  150  volts   See  curve  page  70 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  max  volts 

Heater  positive  with  respect  to  cathode  ,  . ...  200"maa;  volts 

Characteristics: 

Plate  Supply  Voltage   125  volts 

Grid  N9.3  (Suppressor  Grid)  Connected  to  cathode  at  socket 

Grid-No.2  Supply  Voltage   125  volts 

Cathode-Bias  Resistor   56  ohms 

Plate  Resistance  (Approx.)  ,   0. 156  megohm 

Transconductance   15000  /umhoa 

Plate  Current   13  ma 

Grid-No.2  Current   3.2  ma 

Grid-No.l  Voltage  (Approx.)  for  transconductance  of  100  mi^os.  . . . ... ... -3  volts 


116 


Technical  Data 


Maximum  Circuit  Values: 

Grid-No.l-Circuit  Resistance: 

For  fixed-bias  operation  , 

For  cathode-bias  operation  

■  The  dc  component  must  not  exceed  100  volts. 
H 


0.25  max 
1  max 


megohm 
megohm 


G3P| 


4HS8 

Related  types: 
3HS8,  6HS8 


SHARP-CUTOFF  TWIN  PENTODE 

Miniature  type  used  in  age  am- 
plifier, sync,  and  noise-limiting  circuits 
of  television  receivers  emplojang  series- 
connected  heater  strings.  One  pentode 
unit  is  used  as  a  combined  sync  sepa- 
rator and  sync  clipper;  the  other  pentode  unit  is  used  as  the  age  amplifier.  Outline 
8D,  OUTLINES  SECTION.  Heater  volts  (ac/dc),  4.2;  amperes,  0.45;  warm-up 
time  (average),  11  seconds.  Except  for  heater  ratings,  this  type  is  identical  with 
miniature  type  6HS8. 

H 

SEMIREMOTE-CUTOFF  PENTODE 

Miniature  type  with  frame  grid 
used  in  the  if-amplifier  stages  of  tele- 
vision receivers  employing  series-con- 
_  nected  heater  strings.Outline  8B,0UT- 

K  "^3.i»      LINES  SECTION.  Tube  requires  min- 

iature nine-contact  socket  and  may  be  mounted  in  any  position.  Heater  volts 
(ac/dc),  4.2;  amperes,  0.45;  warm-up  time  (average),  11  seconds. 

CLASS  Ai  AMPLIFIER 
Maximum  Ratings,  {Design-Maximum  Valuei): 

Plate  Voltage  

Grid-No.2  (screen-grid)  Supply  Voltage  

Grid-No.2  Voltage  

Grid-No.1  (control-grid)  Voltage,  Negative-bias  value. 

Cathode  Current  

Plate  Dissipation  

Grid-No.2  Input: 

For  grid-No.2  voltases  up  to  125  volt«  

For  srid-No.2  voltages  between  125  and  250  volts. ... 
Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  


4HT6 


250  max  volts 
250  max  volts 
See  curve  page  70 


-50  max 
25  max 
2.5  max 

0.6  max 


volts 
ma 
watts 

watt 


See  curve  page  70 


200  max 
200"maa; 


volts 
volts 


Characteristics: 

Plate  Supply  Voltage   125  volts 

Grid-No.3  (Suppressor  Grid)  Connected  to  cathode  at  locket 


Grid-No.2  Supply  Voltage. 

Cathode-Bias  Resistor  

Plate  Resistance  (Approz.)  

Transconductance  

Plate  Current  

Grid-No.2  Current  

Grid-No.l  Voltage  (Approx.)  for  transconductance  of  100  /umhos. 

Maximum  Circuit  Values: 
Grid-No.l-Circuit  Resistance: 

For  fixed-bias  operation  

For  cathode-bias  operation  

■  The  dc  component  must  not  exceed  100  volts. 
H 


125 
56 
0.143 
UOOO 
IS 
4 

-4.6 


volts 
ohms 
megohm 
Mmhos 
ma 
ma 
volts 


0.25  max  megohm 
1  max  megohm 


SHARP-CUTOFF  PENTODE 

Miniature  type  with  frame  grid  A  l^£. 

used  in  if-amplifier  stages  of  television         4  J  C6 
receivers  utilizing  intermediate  fre-  types: 
quenciesin  the  order  of  40  megacycles  3JC6,6jc6 
and  employing  series-connected  heater 
strings.  Outline  8B,  OUTLINES  SECTION.  Heater  volts  (ac/dc),  4.5;  amperes, 
0.45;  warm-up  time  (average),  11  seconds.  Except  for  heater  ratings,  this  type  is 
identical  with  miniature  type  6JC6. 

117 


^3.13 


RCA  Receiving  Tube  Manual 


4JD6 

Related  types: 
3JD6,  6JD6 


SHARP-CUTOFF  PENTODE 

Miniature  type  used  as  if-ampli- 
fier  tube  in  television  receivers  utiliz- 
ing intermediate  frequencies  in  the  or- 
der of  40  megacycles  and  employing 
series-connected  heater  strings.  Out- 
line 8B,  OUTLINES  SECTION.  Heater  volts  (ac/dc),  4.5;  amperes,  0.45;  warm-up 
time  (average),  11  seconds.  Except  for  heater  ratings,  this  type  is  identical  with 
miniature  type  6JD6. 

DIODE-SHARP-CUTOFF 
PENTODE 

Miniature  type  used  in  diversified 
applications  in  television  receivers  em- 
ploying series-connected  heater  strings. 
The  pentode  unit  is  used  as  an  ampli- 
fier and  the  high-perveance  diode  as  a 
detector  or  dc  restorer.  Outline  8B,  OUTLINES  SECTION.  Heater  volts  (ac/dc), 
4.7;  amperes,  0.6;  warm-up  time  (average),  11  seconds.  Except  for  heater  ratings, 
this  type  is  identical  with  miniature  type  6AM8-A. 


5AM8 

Related  type: 
6AM8A 


MEDIUM-MU  TRIODE— 
SHARP-CUTOFF  PENTODE 

Miniature  type  used  in  a  wide 
variety  of  applications  in  television  re- 
ceivers employing  series-connected 
heater  strings.  The  pentode  unit  is  used 
as  an  amplifier  and  the  triode  unit  is 
used  in  oscillator  or  sync  circuits.  Outline  SB,  OUTLINES  SECTION.  Heater  volts 
(ac/dc),  4.7;  amperes,  0.6;  warm-up  time  (average),  11  seconds.  Except  for  heater 
ratings,  this  type  is  identical  with  miniature  type  6AN8. 


5AN8 

Related  type: 
6AN8A 


BEAM  POWER  TUBE 

Miniature  type  used  as  audio  am- 
plifier in  television  receivers  employing 
series-connected  heater  strings.  Out- 
line 7C,  OUTLINES  SECTION. 
Heater  volts  (ac/dc),  4.7;  amperes,  0.6; 
warm-up  time  (average),  11  seconds.  Except  for  heater  ratings,  this  type  is 
identical  with  miniature  type  6AQ5-A. 


5AQ5 

Related  types: 
6AQ5A,  12AQ5 


5AS4 

5AS4A 


FULL-WAVE  VACUUM  RECTIFIER 

Glass  octal  types  used  in  power 
supply  of  television  receivers  having 
high  dc  requirements.  Type  5AS4-A, 
Outline  19C,  OUTLINES  SECTION. 
Type  5AS4  maximum  dimensions: 
over-all  length,  5-1/8  inches;  seated  height,  4-9/16  inches;  diameter,  2-1/16  inches. 
Type  5AS4-A  may  be  supplied  with  pins  3,  5,  and  7  omitted.  Tubes  require  octal 
socket.  Vertical  mounting  is  preferred,  but  horizontal  mounting  is  permissible  if 
pins  1  and  4  are  in  vertical  plane.  It  is  especially  important  that  these  tubes,  like 
other  power-handling  tubes,  be  adequately  ventilated.  Heater  volts  (ac),  5.0;  am- 
peres, 3.0.  For  maximum  ratings,  typical  operation,  and  curves,  refer  to  type 
5U4-GB.  Type  6AS4  is  a  DISCONTINUED  type  listed  for  reference  only. 

118 


5AS8 

Related  type: 
6AS8 


DIODE— SHARP-CUTOFF 
PENTODE 

Miniature  type  used  in  diversified 
applications  in  television  receivers  em- 
ploying series-connected  heater  strings. 
The  pentode  unit  is  used  as  an  ampli- 
fier  and  the  high-perveance  diode  as  a 
detector  or  dc  restorer.  Outline  8B,  OUTLINES  SECTION.  Heater  volts  (ac/dc), 
4.7;  amperes,  0.6;  warm-up  time  (average),  11  seconds.  Except  for  heater  ratings, 
this  type  is  identical  with  miniature  type  6AS8. 

MEDIUM-MU  TRIODE— 
SHARP-CUTOFF  PENTODE 

Miniature  type  used  as  combined 
oscillator  and  mixer  tube  in  television 
receivers  employing  series-connected 
heater  strings.  Outline  8B,  OUTLINES 
SECTION.  Heater  volts  (ac/dc),  4.7; 
amperes,  0.6;  warm-up  time  (average),  11  seconds.  Except  for  heater  ratings,  this 
type  is  identical  with  miniature  type  6AT8-A. 


5AT8 

Related  type: 
6AT8A 


5AU4 


FULL-WAVE  VACUUM  RECTIFIER 

Glass  octal  type  used  as  power 
supply  in  television  receivers  and  other 
equipment  having  high  dc  require- 
ments. Maximum  dimensions:  over-all 
length,  4-3/4  inches;  seated  height, 
4-3/16  inches;  diameter,  1-11/16  inches.  Tube  requires  octal  socket  and  must  be 
used  in  vertical  position;  horizontal  operation  is  permissible  only  if  pins  2  and  4 
are  in  vertical  plane.  It  is  especially  important  that  this  tube,  like  other  power- 
handling  tubes,  be  adequately  ventilated.  Filament  volts  (ac/dc),  5;  amperes,  3.75. 
For  discussion  of  Rating  Chart,  refer  to  INTERPRETATION  OF  TUBE  DATA. 

FULL- WAVE  RECTIFIER 
Maximum  Ratings,  (Design-Center  Values): 

Peak  Inverse  Plate  Voltage  

Peak  Plate  Current  (Per  Plate)  

Hot-Switching  Transient  Plate  Current 

(Per  Plate),  maximum  duration  0,2  aecond  

AC  Plate  Supply  Voltage  (Per  Plate,  rma)  

DC  Output  Current  (Per  Plate)  

RATING  CHART 


1400  max 
1075  max 


volts 
ma 


6.25  max  amperes 
See  Rating  Chart 
See  Rating  Chart 


TYPE  5AU4  « 
E| • 9  VOLTS  AC 


•  MAXIMUM  OPERffrm  VALUES  WITH'  • 
r- CHOKE-INPUT  FILTER 

CAPAaT0R-8W»UT  FILTER 


0  100  200  300  400  500 

AC  PLATE  SUPPLY  VOLTS  (RMS)  PER  PLATE  (WITHOUJLOAO) 


119 


RCA  Receiving  Tube  Manual 


Typical  Operation: 

Filter  Input  Capacitor 

AC  Plate-to-Plate  Supply  Voltage  (rms)                                  600  800 

Filter-Input  Capacitor                                                              40  40 

Effective  Plate  Supply  Impedance  per  x'late                              30  50 

Filter-Input  Choke   - 

DC  Output  Current                                                             350  325 

DC  Output  Voltage  at  Input  to  Filter  (Approx.)                      275  396 

Characteristics,  Instantaneous  Value: 

Tube  Voltage  Drop  for  plate  current  of  350  ma  (per  plate)  

MEDIUM-MU  TRIODE— 

SHARP-CUTOFF  PENTODE 

Miniature  type  used  in  a  wide 
C  A  \/Q  variety  of  applications  in  television  re-  ^'''i 
ceivers  employing  series-connected 
heater  strings.  Outline  8B,  OUTLINES  gj^ 
SECTION.  Tube  requires  miniature 
nine-contact  socket  and  may  be 
mounted  in  any  position. 


Choke 
1000 


10 
325 
395 


volts 

ohms 
henries 
ma 
volts 


volts 


Heater  Voltage  (AC/DC)   4.7  volts 

Heater  Current   0.6  ampere 

Heater  Warm-Up  Time  (Average)   11  seconds 

Direct  Interelectrode  Capacitances: 
Triode  Unit: 

Grid  to  Plate   1.5  pf 

Grid  to  Cathode  and  Heater   2  pf 

Plate  to  Cathode  and  Heater   0.34  pf 

Pentode  Unit: 

Grid  No.l  to  Plate   0.04  moof  pf 

GridNo.ltoCathode,Heater,GridNo.2,GridNo.3,and  Internal  Shield. .  7  pf 

Plate  to  Cathode,  Heater,  Grid  No.2,  Grid  No.3,  and  Internal  Shield. .  3  pf 

Triode  Grid  to  Pentode  Plate   0.005  pf 

Pentode  Grid  No.l  to  Triode  Plate   0.006  pf 

Pentode  Plate  to  Triode  Plate    0.045  pf 

CLASS  Ai  AMPLIFIER 

Maximum  Ratings,  (Design-Center  Values):  Triode  Unit  Pentode  Unit 

Plate  Voltage                                                                     300  max  300  max  volts 

Grid  No.2  Supply  Voltage                                                        -  300  wao;  volts 

Grid  -No.  2  (screen-grid)  Voltage                                              -  See  curve  page  70 

Grid-No.I  (control-grid)  Voltage,  Positive-bias  value  ....            0  max  0  max  volts 

Plate  Dissipation                                                                 2.5maaj  2  max  watts 

Grid-No.2  Input: 

For  grid-No.2  voltages  up  to  150  volts                                        ~  0.5  max  watt 

For  grid-No.2  voltages  between  150  and  300  volts                          -  See  curve  page  70 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode                                      200  max  200  max  volts 

Heater  positive  with  respect  to  cathode                                     200°waa5  200°wa»  volts 

Characteristics: 

Plate  Supply  Voltage                                                                     200  200  volts 

Grid-No.2  Supply  Voltage                                                                -  150  volts 

Grid-No.l  Voltage  .                                                                       -6  -  volts 

Cathode-Bias  Resistor                                                                     -  180  ohms 

Amplification  Factor                                                                         19  -  ohms 

Plate  Resistance  (Approx.)                                                           5750          800000  ohms 

Transconductance                                                                       3300  6200  #tmhos 

Grid-No.l  Voltage  (Approx.)  for  plate  current  of  10  /xa                     -19  -8  volts 

Plate  Current                                                                             13  9.6  ma 

Grid-No.2  Current                                                                        -  2,8  ma 

Grid-No.l-Circuit  Resistance:* 

For  fixed-bias  operation                                                          0.5  max  0 . 25  max  megohm 

For  cathode-bias  operation                                                     1.0  max  1 . 0  max  megohm 

®  The  dc  component  must  not  exceed  100  volts. 

*  If  either  unit  is  operating  at  maximum  rated  conditions,  grid-No.l-circuit  resistance  for  both  units 
should  not  exceed  the  stated  values. 


120 


Technical  Data 


PD2 


FULL-WAVE  VACUUM  RECTIFIER 


5AW4 


Glass  octal  type  used  in  power  sup- 
plies of  radio  and  television  receivers 
having  high  dc  requirements.  Maxi- 
mum dimensions :  over-all  len  gth  ,5-3/16 
inches;  seated  length,  4-5/8  inches; 
diameter,  1-9/16  inches.  Tube  requires  octal  socket  and  may  be  operated  in  any 
position.  It  is  especially  important  that  this  tube,  like  other  power-handling  tubes, 
be  adequately  ventilated.  Filament  volts  (ac/dc),  5;  amperes,  3.7.  For  discussion  of 
Rating  Chart,  refer  to  INTERPRETATION  OF  TUBE  DATA. 


FULL-WAVE  RECTIFIER 
Maximum  Ratings,  (Design-Center  Values): 

Peak  Inverse  Plate  Voltage  

Peak  Plate  Current  (Per  Plate)  

Hot-Switching  Transient  Plate  Current 

(Per  Plate)  maximum  duration  0.2  second  

AC  Plate  Supply  Voltage  (Per  Plate,  rms)  

DC  Output  Current  


1550  max 

750  max 


volt» 
ma 


4  max  amperes 
See  Rating  Chart 
See  Rating  Chart 


Typical  Operation: 

Filter  Input 

AC  Plate-to-Plate  Supply  Voltage  (rms)  

Filter-Input  Capacitor  

Effective  Plate  Supply  Impedance  per  Plate  

Filter-Input  Choke  

DC  Output  Current  

DC  Putput  Voltage  at  Input  to  Filter  (Approx.) . 


Capacitor 
900 
10 
153 

250 
422 


Characteristics,  Instantaneous  Value: 

Tube  Voltage  Drop  for  plate  current  of  250  ma  (per  plate) . 


Choke 
1100 


10 
250 
440 


voltff 
Mf 
ohms 
henries 
ma 
volts. 


volts 


RATING  CHART 


 1 

TYPE 
E|  =  5  \ 

5AW4  ' 

/OLTS  AC 

MAXIMU 

W  OPEh 
E-INPU 
=ACITOF 

lATING 
T  FILTE 
-INPUT 

B 

VALUES 
R 

FILTEF 

WITH: 

F  A 

-OA 

1"^ 
-  J- 

125 1 

1  \ 

C 

1 
1 
1 

\ 

D 

40[ 

— 1 — 
1 

^4o! 

>40 

G 

O  100      200      300  ,    400      500      600  700 

AC  PLATE  SUPPLY  VOLTS  (RMS)  PER  PLATE  (WITHOUT  LOAD) 

92CS-I1203T 


FULL-WAVE  VACUUM  RECTIFIER 

Lock-in  type  used  in  power  supply  of  radio 
equipment  having  moderate  dc  requirements. 
Outline  13B,  OUTLINES  SECTION.  Tube  re- 
quires lock-in  socket.  Filament  volts  (ac),  5.0; 
amperes,  2.0.  Maximum  ratings  as  full-wave 
rectifier:  peak  inverse  plate  volts,  1400  max\ 
peak  plate  ma.  (per  plate),  375  max',  dc  output 
ma.,  125  max.  This  type  is  used  principally  for 
renewal  purposes. 


Typical  Operation: 

Filter  Input 

AC  Plat«-to-Plate  Supply  Voltage  (rms)  

Filter-Input  Capacitor  

Total  Effective  Plate-Supply  Impedance  Per  Platef 
Filter-Imput  Ckoke  


Capacitor 
700 
4 
60 


5AZ4 


Choke 
1000 


▼oltii 

ohms 
henries 

121 


RCA  Receiving  Tube  Manual 


Filter  Input  Capacitor  Choke 

DC  Output  Current  ^  125  125  ma 

DC  Output  Voltage  at  Input  to  Filter  (Approx.): 

At  half-load  current  (62.5  ma.)   392 . 5  405  volts 

At  full-load  current  (125  ma.)   340  382  volts 

Voltage  Regulation  (Approx.) : 

Half-load  to  full-load  current    52 . 5  23  volts 

t  When  a  filter-input  capacitor  larger  than  40  is  used,  it  may  be  necessary  to  use  more  plate-supply 
impedance  than  the  value  shown  in  order  to  limit  the  peak  plate  current  to  the  rated  value. 


H 

r — 

MEDIUM-MU  TRIODE— 
l-nft  SHARP-CUTOFF  PENTODE 

Miniature  type  used  as  combined 

vhf  oscillator  and  mixer  in  television 

receivers  employing  series-connected 

heater  strings.  Outline  8B,0UTLINES 

SECTION.  Tube  requires  miniature 
nine-contact  socket  and  may  be  mounted  in  any  position.  Heater  volts  (ac/dc), 
4.7;  amperes,  0.6;  warm-up  time  (average),  11  seconds. 

CLASS  Ai  AMPLIFIER 

Maximum  Ratings,  {Design-Center  Values): 

Plate  Voltage  

GRm.-Jo.'i  (screen-grid)  Supply  Voltage  

Grid-No.2  Voltage  

Grid-No.1  (control-grid)  Voltage,  Positive-bias  value  

Plate  Dissipation  

Grid  No.2  Input: 

For  grid-No.2  voltages  up  to  150  volts  

For  grid-No.2  voltages  between  150  and  300  volts  

Peak  Heater-cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode .  

Characteristics: 

Plate  Supply  Voltage  

Grid-No.2  Supply  Voltage  

Grid  Voltage  

Cathode-Bias  Resistor  

Amplification  Factor  

Plate  Resistance  (Approx.)  

Transconductance  ,  

Plate  Current  

Grid-No.2  Current   

Grid-No.l  Voltage  (Approx.)  for  plate  current  of  10  /ua  

Maximum  Circuit  Values: 
Grid-No.l-Circuit  Resistance*: 

For  fixed-bias  operation  

For  cathode-bias  operation  

■  The  do  component  must  not  exceed  100  volts. 
*  If  either  unit  is  operated  at  maximum  rated  conditions,  grid- 

Bhould  not  exceed  the  stated  values. 


Triode 

Pentode 

Unit 

Unit 

800  max 

300  max 

volts 

300  max 

volts 

See  curve  page  70 

0  max 

0  max 

volts 

2.5  max 

2  max 

watts 

0.5  max 

watt 

See  curve  page  70 

200  max 

200  max 

volts 

200"majs 

200"waa; 

volts 

200 

200 

volts 

150 

volts 

-6 

volts 

180 

ohms 

19 

6750 

800000 

ohms 

3300 

6200 

limhos 

13 

9.5 

ma 

2.8 

ma 

-19 

-8 

volts 

0.5  max 

0.25  max 

megohm 

1.0  max 

1.0  max 

megohm 

No.l-circuit  resistance  for  both  units 


FULL-WAVE  VACUUM  RECTIFIER 

r*  n  ^  o  Novar  type  used  in  power  supplies 

5mCO  of  radio  equipment  and  television  re- 

ceivers having  high  dc  requirements. 
Outline  17B,  OUTLINES  SECTION. 
Tube  requires  novar  nine-contact 
socket.  Vertical  operation  is  preferred,  but  tube  may  be  operated  in  horizontal 
position  if  pins  2  and  7  are  in  vertical  plane.  It  is  especially  important  that  this 
tube,  like  other  power-handling  tubes,  be  adequately  ventilated.  Filament  volts 
(ac),  5;  amperes,  3. 

122 


Technical  Data 


FULL- WAVE  RECTIFIER 
Maximum  Ratings,  (.Design-Maximum  Values): 

Peak  Inverse  Plate  Voltage   1700  moaj  volts 

Peak  Plate  Current  (Per  Plate)   1  max  ampere 

Hot-Switching  Transient  Plate  Current  (Per  Plate)**   6  max  amperea 

AC  Plate-Supply  Voltage  (Per  Plate,  rms)   See  Rating  Chart 

DC  Output  Current  (Per  Plate)   See  Rating  Chart 

Typical  Operation  with  Capacitor  Input  to  Filter: 

AC  Plate-to-Plate  Supply  Voltage  (rms)   600  900  1100  volts 

Filter-Input  Capacitor"   40  40  40 

Total  Effective  Plate-Supply  Impedance  per  Plate   21  67  97  ohms 

DC  Output  Voltage  at  Input  to  Filter  (Approx.) : 

At  load  current  of :       300  ma   290  -  -  volts 

275  ma   -  460  -  volts 

162  ma   -  -  630  volts 

150  ma   335  -  -  volts 

137.5  ma   -  620  -  volts 

81  ma   -  -  680  volts 

Typical  Operation  with  Choke  Input  to  Filter: 

AC  Plate-to-Plate  Supply  Voltage  (rms)   900  1100  volts 

Filter-Input  Choke   10  10  henries 

DC  Output  Voltage  at  Input  to  Filter  (Approx.) : 

At  load  current  of :       348  ma   840  -  volts 

275  ma   -  440  volts 

174  ma   855  -  volta 

137 . 5  ma   -  455  volts 

°  If  hot  switching  is  regularly  required  in  operation,  the  use  of  choke-input  circuits  is  recommended. 

Such  circuits  limit  the  hot-switching  current  to  a  value  no  higher  than  that  of  the  peak  plate  current. 

When  capacitor-input  circuits  are  used,  a  maximum  peak  current  value  per  plate  of  5  amperes  during 

the  initial  cycles  of  the  hot-switching  transient  should  not  be  exceeded. 

■  Higher  values  of  capacitance  than  indicated  may  be  used,  but  the  effective  plate-supply  impedance 
may  have  to  be  increased  to  prevent  exceeding  the  maximum  rating  for  peak  plate  current. 


RATING  CHART 


TYPE  5BC3 
Ef  »5  VOLTS  AC 


MAXIMUM  OPERATING  VALUES  WITH:  ■ 
CHOKE-INPUT  FILTER 

CAPACITOR-INPUT  FILTER 


0  100      200     300     400      500  feOO 

AC  PLATE  SUPPLY  VOLTS  (RMS)  PER  PLATE  (WITHOUT  LOAD) 

92CS-IIS00Tt 


MEDIUM-MU  TRIODE— 
SHARP-CUTOFF  PENTODE 


5BE8 


Miniature  type  used  as  combined  vhf  mixer 
and  oscillator  tube  in  television  receivers  em- 
ploying series-connected  heater  strings.  Outline 
8B,  OUTLINES  SECTION.  Tube  requires  min- 
iature nine-contact  socket.  Heater  volts  (ac  /dc), 
4.7;  amperes,  0.6;  warm-up  time  (average),  11 
seconds.  Characteristics  of  triode  unit  as  class  Ai  amplifier:  plate  supply  volts,  150  (300  max);  cathode- 
bias  resistor,  56  ohms;  amplification  factor,  40;  plate  resistance  (approx.),  5000  ohms;  transconductance, 
8500  Mmhos;  plate  ma.,  18;  plate  dissipation,  2.5  max  watts.  Pentode  unit:  plate  supply  volts,  250  (300* 
max);  grid-No.2  supply  volts,  110  (300  max);  cathode-bias  resistor,  68  ohms;  plate  resistance  (approx.), 
0.4  megohm;  transconductance,  5200  nmho%',  plate  ma.,  10;  grid-No.2  ma.,  3.5;  plate  dissipation,  2.8* 
max  watts;  grid-No.2  input,  0.5  maac  watt.  This  type  is  used  principally  for  renewal  purposes. 

123 


RCA  Receiving  Tube  Manual 


MEDIUM-MU  TWIN  TRIODE 

Miniature  type  used  in  direct- 
coupled  cathode-drive  rf  amplifier  cir- 
cuits of  vhf  television  tuners  utilizing 
series-connected  heater  strings.  Out- 
line 8B,  OUTLINES  SECTION. 
Heater  volts  (ac/dc),  4.7;  amperes,  0.6;  warm-up  time  (average),  11  seconds.  Except 
for  heater  ratings,  this  type  is  identical  with  miniature  type  6BK7-B. 


5BK7A 

Related  type: 
6BK7B 


MEDIUM-MU  TWIN  TRIODE 

Miniature  type  used  in  direct- 
coupled  cathode- drive  rf  amplifier  cir- 
cuits of  vhf  television  tuners  employ- 
ing series-connected  heater  strings. 
Outline  8B,  OUTLINES  SECTION. 
Heater  volts  (ac/dc),  5.6;  amperes,  0.45;  warm-up  time  (average),  11  seconds. 
Except  for  heater  ratings,  this  type  is  identical  with  miniature  type  6BQ7-A. 


5BQ7A 

Related  types: 
4BQ7A,  6BQ7A 


MEDIUM-MU  TRIODE— 
SHARP-CUTOFF  PENTODE 

5BR8  Miniature  type  used  in  a  wide 

variety  of  applications  in  color  and 
black-and-white  television  receivers 
employing  series-connected  heater 
strings.  Outline  8B,  OUTLINES  SEC- 
TION. Heater  volts  (ac/dc),  4.7;  amperes,  0.6;  warm-up  time  (average),  11  seconds. 
Except  for  heater  ratings,  this  type  is  identical  with  miniature  type  6BR8-A. 


Related  type: 
6BR8A 


5BT8 


TWIN  DIODE— 
SHARP-CUTOFF  PENTODE 

Miniature  type  used  in  a  variety  of  appli- 
cations in  television  receivers  employing  series-  kqjj^q^ 


connected  heater  strings.  The  pentode  unit  is 
used  as  an  if  amplifier,  video  amplifier,  age  am- 
plifier, or  reactance  tube.  The  diode  unit  is 
used  in  automatic-frequency-control  and  detec- 
tor circuits.  Outline  8B,  OUTLINES  SECTION. 
Heater  volts  (ac/dc),  4.7;  amperes,  0.6;  warm- 
up  time  (average),  11  seconds.  Tube  requires 
miniature  nine-contact  socket.  Characteristics  of  pentode  unit  as  class  Ai  amplifier:  plate  supply  volts, 
200  (300  max)',  grid-No.2  supply  volts,  150  (300  max)',  cathode-bias  resistor,  180  ohms;  plate  resistance 
(approx.),  0.3  megohm;  transconductance,  6200  jumhos;  plate  ma.,  9.5;  grid-No.2  ma.,  2.8;  plate  dis- 
sipation, 2  max  watts;  grid-No.2  input,  0.5  max  watt.  Maximum  diode  plate  ma.  (each  unit),  1  max. 
This  type  is  used  principally  for  renewal  purposes. 


5BW8 

Related  type: 
6BW8 


TWIN  DIODE— 

SHARP-CUTOFF  PENTODE 

Miniature  type  used  in  television 
receivers  employing  series-connected 
heater  strings.  The  pentode  unit  is  Kg^^ 
used  as  a  sound  if  amplifier,  sound      ^  ^ 
limiter,  and  age  keyer.  The  diodes  are 
used  as  horizontal  phase  detectors.  Outline  8B,  OUTLINES  SECTION.  Heater 
volts  (ac/dc),  4.7;  amperes,  0.6;  warm-up  time  (average),  11  seconds.  Except  for 
heater  ratings,  this  type  is  identical  with  miniature  type  6BW8. 

124 


Technical  Data 


MEDIUM-MU  TRBODE— 

SHARP-CUTOFF  PENTODE 

Miniature  type  used  as  combined 
oscillator  and  mixer  tube  in  television 
receivers  employing  series-connected 
heater  strings.  Outline  8B,  OUT- 
LINES SECTION.  Heater  volts  (ac/ 
dc),  4.7;  amperes,  0.6;  warm-up  time  (average),  11  seconds.  Except  for  heater 
ratings,  this  type  is  identical  with  miniature  type  6CG8-A. 


5CG8 

Related  type: 
6CG8 


ptr 


MEDIUM-MU  TRIODE— 
SHARP-CUTOFF  TETRODE 


5CL8 

5CL8A 


'  Miniature  types  used  as  combined 
vhf  oscillator  and  mixer  in  television 
^ktr  receivers  employing  series-connected 
heater  strings.  Outline  8B,  OUTLINES 
cf^  ^ciTR  SECTION.  Heater  volts  (ac/dc),  4.7; 
amperes,  0.6;  warm-up  time  (average),  11  seconds.  Except  for  heater  ratings,  types 
5CL8  and  5CL8-A  are  identical  with  miniature  types  6CL8  and  6CL8-A,  respec- 
tively. Type  5CL8  is  a  DISCONTINUED  type  listed  for  reference  only. 


Related  types: 
6CL8A,  19CL8A 


G2p 


H8GH-MU  TRIODE- 

SHARP-CUTOFF  PENTODE 

Miniature  type  used  in  television 
receivers  employing  series-connected 
heater  strings.  The  pentode  unit  is  used 
as  an  intermediate-frequency  amplifier, 
a  video  amplifier,  an  age  amplifier,  or  as 
a  reactance  tube.  The  triode  unit  is  used  in  sweep-oscillator,  sync-separator,  sync- 
clipper,  and  phase-splitter  circuits.  OutUne  8B,  OUTLINES  SECTION.  Heater 
volts  (ac/dc),  4.7;  amperes,  0.6.  Except  for  heater  ratings,  this  type  is  identical 
with  miniature  type  6CM8. 


5CM8 

Related  type: 
6CM8 


MEDIUM-MU  TRIODE— 

SHARP-CUTOFF  TETRODE 

Miniature  type  used  in  a  wide 
variety  of  applications  in  color  and 
black-and-white  television  receivers 
employing  series-connected  heater 
strings.  The  tetrode  unit  is  used  as  a 
mixer  or  amplifier  and  the  triode  unit  is  used  in  oscillator  and  rf  amplifier  circuits. 
OutHne  8B,  OUTLINES  SECTION.  Heater  volts  (ac/dc),  4.7;  amperes,  0.6; 
warm-up  time  (average),  11  seconds.  Except  for  heater  ratings,  this  type  is  identical 
with  miniature  type  6CQ8. 


5CQ8 

Related  type: 
6CQ8 


BEAM  POWER  TUBE 

Miniature  type  used  as  vertical 
deflection  amplifier  and  as  audio  out- 
put tube  in  television  and  radio  receiv- 
ers employing  series-connected  heater 
strings.  Outline  8E,  OUTLINES  SEC- 
TION. Heater  volts  (ac/dc),  4.7;  amperes,  0.6;  warm-up  time  (average),  11  seconds. 
Except  for  heater  ratings,  this  type  is  identical  with  miniature  type  6CZ5. 

125 


5CZ5 

Related  type: 
6CZ5 


RCA  Receiving  Tube  Manual 


HIGH-MU  TRIODE—  A 

SHARP-CUTOFF  PENTODE       ^  V^^^^ 
C  n  U  O                Miniature  type  used  in  television  "^^p*'^  ©^l^^ztz^ 

receivers  having  series-connected  J^ti;  ^^il-v 
heater  strings.  Pentode  used  as  video  ptSaJss^^ 

or  audio  if  amplifier;  triode  used  as  0^  

sync  amplifier,  sync  clipper,  sync  sep-  ^'^ 
arator,  or  vertical  oscillator.  Outline  8B,  OUTLINES  SECTION.  Tube  requires 
miniature  nine-contact  socket  and  may  be  operated  in  any  position.  Heater  volts 
(ac/dc),  5.2;  amperes,  0.6;  heater  warm-up  time  (average),  11  seconds. 

CLASS  Ai  AMPLIFIER 

Maximum  Ratings^  {Design-Maximum  Values):                           Triode  Unit  Pentode  Unit 

Plate  Voltage                                                                      300  max  300  max  volts 

Grid-No.2  (screen-grid)  Supply  Voltage                                 -  300  max  volts 

Grid-No.2  Voltage                                                                     -  See  curve  page  70 

Grid-No.1  (control-grid)  Voltage,  Positive-bias  value                   0  max  0  max  volts 

Plate  Dissipation                                                                 2.0  max  2.2  max  watts 

Grid-No.2  Input 

For  grid-No.2  voltages  up  to  150  volts                                       -  0.55  wax  watt 

For  grid-No.2  voltages  between  150  and  300  volts                        -  See  curve  page  70 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode                                  200  max  200  max  volte 

Heater  positive  with  respect  to  cathode                                   200  °max  200  "max  volts 

Characteristics:  Triode  Unit   Pentode  Unit 

Plate  Supply  Voltage                                                                 250  125  volts 

Grid-No.2  Supply  Voltage                                                             -  125  volts 

Cathode-Bias  Resistor                                                                390  56  ohms 

Plate  Current                                                                           7.3  13.5  ma 

Grid-No.2  Current                                                                       -  3.8  ma 

Amplification  Factor                                                                   53  - 

Plate  Resistance  (Approx.)                                                       0.012  0.15  megohm 

Transconductance                                                                      4400  8600  /bimhos 

For  plate  current  of  10  iua                                                     -10  -  volts 

For  plate  current  of  20  /xa                                                        -  -6  volts 

Maximum  Circuit  Values: 

Grid-No. 1-Circuit  Resistance: 

For  fixed-bias  operation                                                          0.5  max  0.25  max  megohm 

For  cathode-bias  operation                                                    0.1  max  1 . 0  max  megohm 

VERTICAL  DEFLECTION  OSCILLATOR 

For  operation  in  a  525-line,  30-frame  system 

Maximum  Ratings,  (Design-Maximum  Values):  Triode  Unit 

DC  Plate  Voltage   300  max  volts 

Peak  Negative-Pulse  Grid  Voltage   400  max  volts 

Peak  Cathode  Current   35  max  ma 

Average  Cathode  Current   12  max  ma 

Plate  Dissipation   1  max  watt 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  max  volts 

Heater  positive  with  respect  to  cathode  -  200°  max  volts 

Maximum  Circuit  Vatues: 

Grid  Circuit  Resistance: 

For  fixed-bias,  cathode-bias,  or 

grid-resistor-bias  operation                                -  —  2.2  max  megohms 

"  The  dc  component  must  not  exceed  100  volts. 


5DJ4 


FULL-WAVE  VACUUM  RECTIFIER 

Glass  octal  type  used  in  power  sup- 
ply of  radio  and  television  receivers 
having  high  dc  requirements.  Outline 
19D,  OUTLINES  SECTION,  Tube  re- 
quires octal  socket;  operation  in  ver- 
tical position  is  preferred,  but  horizontal  operation  is  permissible  if  pins  2  and  4 

126 


are  in  vertical  plane.  It  is  especially  important  that  this  tube,  like  other  power- 
handling  tubes,  be  adequately  ventilated.  Filament  volts  (ac/dc),  5;  amperes,  3. 


FULL-WAVE  RECTIFIER 
Maximum  Ratings,  (Design'Maximum  Values): 

Peak  Inverse  Plate  Voltage  

Peak  Plate  Current  (Per  Plate)  

Hot-Switching  Transient  Plate  Current  (Per  Plate)  

AC  Plate-Supply  Voltage  (Per  Plate,  rms,  without  load)  

DC  Output  Current  (Per  Plate)  


1700  max  volts 
1  max  ampere 
5  max  amperes 
See  Rating  Chart 
See  Rating  Chart 


Typical  Operation: 

Filter  Input  Capacitor  Choke 

AC  Plate-to-Plate  Supply  Voltage  (rms,  without  load)   600    900  1100 

Filter-Input  Capacitor®   40  40 

Filter-Input  Choke   _      _  lo 

Effective  Plate-Supply  Impedance  per  Plate   21  67 

DC  Output  Voltage  at  Input  to  Filter  (Approx.)   290    460  420 

DC  Output  Current   300    275  275 

°  When  capacitor  values  greater  than  40  /nf  are  used,  the  effective  plate-supply  impedance  should  be 
increased  so  that  the  maximum  rating  for  peak  plate  current  is  not  exceeded. 

RATING  CHART 


volts 

henries 
ohms 
volts 
ma 


TYPE 
E^  =  5 

5DJ4 
/OLTS  AC 

M 

AXIMUM 
-CHOKE 
rCAP 

OPBdA 

-INPUT 
ACITOR 

TIN6VA 
FILTER 
-INPUT 

FILTER 

F  A- 

N 

190  j 
150  1 

B| 

1 
1 

C  — 

1 

 J 

D 

— i- 
1 

68 
  1 

4J 

,  i 

5 

0 

0  100       200      300      400      500  600 

AC  PLATE  SUPPLY  VOLTS  (RMS)  PER  PLATE  (WITHOUT  LOAD) 


92CS-II204T 


MEDIUM-MU  TRIODE— 

SHARP-CUTOFF  PENTODE 

^P'P^p  Miniature  type  used  as  combined 
oscillator  and  mixer  in  television  re- 
ceivers employing  series-connected 
heater  strings  and  operating  at  inter- 
mediate frequencies  in  the  order  of  40 


5EA8 

Related  types: 
SEAS,  19EA8 


megacycles.  Outline  8B,  OUTLINES  SECTION.  Heater  volts  (ac/dc),  4.7;  am- 
peres, 0.6;  warm-up  time  (average),  11  seconds.  Except  for  heater  ratings,  this 
type  is  identical  with  miniature  type  6EA8. 


MEDIUM-MU  TRIODE-- 
SHARP-CUTOFF  PENTODE 

Miniature  type  used  as  combined 


oscillator  and  mixer  in  television  re- 
'«p.03p«i$  ceivers    employing  series-connected 
heater  strings.  Outline  8B,  OUTLINES 
SECTION.  Heater  volts  (ac/dc),  4.7; 


5EU8 

Related  type: 
6EU8 


amperes,  0.6;  warm-up  time  (average),  11  seconds.  Cathode  warm-up  time  (time 
required  for  the  transconductance  to  reach  6500  /xmhos  when  the  tube  is  operated 
from  a  cold  start  with  dc  plate  volts= 100,  grid  volts=0,  and  heater  amperes=  0.560), 
35  seconds.  Except  for  heater  ratings  and  cathode  warm-up  characteristic,  this 
type  is  identical  with  miniature  type  6EU8. 


127 


RCA  Receiving  Tube  Manual 


5EW6 

Related  types: 
4EW6,  6EW6 


SHARP-CUTOFF  PENTODE 

Miniature  type  used  in  the  gain- 
controlled  picture-if  stages  of  vhf  tele- 
vision receivers  operating  at  an  inter- 
mediate frequency  in  the  order  of  40 
megacycles  per  second.  Outline  7B, 
OUTLINES  SECTION.  Heater  volts  (ac/dc),  5.6;  amperes,  0.45;  warm-up  time 
(average),  11  seconds.  Except  for  heater  ratings,  this*  type  is  identical  with  minia- 
ture type  6EW6. 

MEDIUM-MU  TRIODE— 
SHARP-CUTOFF  PENTODE 

Miniature  type  used  as  combined 
oscillator  and  mixer  tube  in  vhf  tele- 
vision receivers  employing  series-con- 
nected heater  strings.  OutlineSB,  OUT- 
LINES SECTION.  Heater  volts  (ac/ 
dc),  4.7;  amperes,  0.6;  warm-up  time  (average),  11  seconds.  Except  for  heater 
ratings,  this  type  is  identical  with  miniature  type  6FG7. 


5FG7 

Related  type: 
6FG7 


MEDIUM-MU  TRIODE— 
SHARP-CUTOFF  PENTODE 

Miniature  type  used  as  combined 
vertical  deflection  oscillator  and  gen- 
eral-purpose or  if  amplifier  in  television 
receivers  employing  series-connected 
heaterstrings.  OutlineSB,  OUTLINES 
SECTION.  Heater  volts  (ac/dc),  4.7;  amperes,  0.6;  warm-up  time  (average),  11 
seconds.  Except  for  heater  ratings,  this  type  is  identical  with  miniature  type  6FV8. 


5FV8 

Related  type: 
6FV8 


5GH8 

Related  type: 
6GH8 


MEDIUM-MU  TRIODE-* 
SHARP-CUTOFF  PENTODE 

Miniature  type  used  in  multivi- 
brator-type horizontal-deflection  cir- 
cuits in  television  receivers  employing 
a  series  heater-string  arrangement.  Also 
used  for  age-amplifier  or  sync-separa- 


tor  applications  in  such  receivers.  Outline  8B,  OUTLINES  SECTION.  Heater 
volts  (ac/dc),  4.7;  amperes,  0.6;  warm-up  time  (average),  11  seconds.  Except  for 
heater  ratings,  this  type  is  identical  with  miniature  type  6GH8, 


SEMIREMOTE-CUTOFF  PENTODE 

^  ^  AA£.  Miniature  type  used  in  gain-con- 

SGlVIO         trolled  picture-if  stages  of  television 
Related  type:  receivers  employing  series-connected 

6GM6  heater  strings  and  operating  at  inter- 

mediate frequencies  in  the  order  of  40 
megacycles.  Outline  7B,  OUTLINES  SECTION.  Heater  volts  (ac/dc),  5.6;  am- 
peres, 0.5;  warm-up  time  (average),  11  secondi.  Except  for  heater  ratings,  this 
type  ii  identical  with  miniature  type  6GM6. 

128 


Technical  Data 


SHARP-CUTOFF  PENTODE 

Miniature  type  used  for  FM  sound- 
detector  service  in  locked-oscillator, 
quadrature-grid  FM  detector  circuits, 
as  combined  detector,  limiter,  and 
audio-voltage  driver.  Tube  has  two 
independent  control  grids,  and  has  controlled  heater  warm-up  time  for  use  in 
receivers  employing  series-connected  heater  strings.  Outline  7B,  OUTLINES  SEC- 
TION. Heater  volts  (ac/dc),  4.7;  amperes,  0.6;  warm-up  time  (average),  11  sec- 
onds. Except  for  heater  ratings,  this  type  is  identical  with  miniature  type  6GX6. 


5GX6 

Related  type: 
6GX6 


MEDIUM-MU  TWIN  TRIODE 

Miniature  type  used  as  combined 
rf  power  amplifier  and  oscillator  in  tele- 
vision receivers  employing  series-con- 
nected heaterstrings.  Outline  7B,  OUT- 
LINES SECTION.  Heater  volts 
(ac/dc),  4.7;  amperes,  0.6;  warm-up  time  (average),  11  seconds.  Except  for  heater 
ratings,  this  type  is  identical  with  miniature  type  6J6. 


5J6 

Related  types: 
6J6,  19J6 


MEDIUM-MU  TRIODE— 
SHARP-CUTOFF  PENTODE 

Miniature  type  with  frame-grid 
pentode  unit  used  as  combined  oscil- 
lator-mixer tube  in  television  receivers 
using  an  intermediate  frequency  in  the 
order  of  40  megacycles  and  employing 
series-connected  heater  strings.  Outline  8B,  OUTLINES  SECTION.  Heater  volts 
(ac/dc),  5.6;  amperes,  0.45;  warm-up  time  (average),  11  seconds.  Except  for  heater 
ratings,  this  type  is  identical  with  miniature  type  6KE8. 


5KE8 

Related  type: 
6KE8 


FULL-WAVE  VACUUM  RECTIFIER 

Metal  type  used  in  power  supply  of  radio 
p         equipment  having  large  dc  requirements.  Out- 
line  6,  OUTLINES  SECTION.  Tube  requires 
octal  socket.  Vertical  tube  mounting  is  pre-  F"  »  ^ 

f erred  but  horizontal  mounting  is  permissible  if  ^  I  4» 

p(2^....,^/v      /  pins  2  and  4  are  in  vertical  plane.  Filament 

^       \^  volts  (ac),  5.0;  amperes,  2.0.  Maximum  ratings 

_  as  full- wave  rectifier:  peak  inverse  plate  volts, 

5  ^  1550  max\  peak  plate  ma.  (per  plate),  675  max; 

dc  output  ma.,  225  max.  This  type  is  used  prin- 
cipally for  renewal  purposes. 

Typical  Operation: 

Filter  Input  Capacitor  Choke 

AC  Plate-to-Plate  Supply  Voltage  (rms)   900  1100  volts 

Filter-Input  Capacitor   4  -  /if 

Total  Effective  Plate-Supply  Impedance  Per  Platef   150  -  ohms 

Filter-Input  Choke   -  10  henries 

DC  Output  Current   225  225  ma 

DC  Output  Voltage  at  Input  to  Filter  (Approx.) : 

At  half-load  current  (112.5  ma.)   539  465  volts 

At  full-load  current  (225  ma.)   480  450  volts 

Voltage  Regulation  (Approx.) : 

Half-load  to  full-load  current   59  15  volts 

tWhen  a  filter-input  capacitor  larger  than  40  fit  is  used,  it  may  be  necessary  to  use  more  plate-supply 
impedance  than  the  value  shown  in  order  to  limit  the  peak  plate  current  to  the  rated  value. 

129 


RCA  Receiving  Tube  Manual 


TRIPLE  DIODE-HIGH-MU  TRIODE 


Kt,D|8.D; 


.  i.  ^  Miniature  type  used  as  combined  ^^^^ 

AM  detector,  FM  detector,  and  af 
Related  types:  voltage  amplifier  in  radio  and  tele- 

6T8A,  19T8  vision  receivers  employing  series-con-  ^^2^ 

nected  heater  strings.  Outline  8B,  ^pt 
OUTLINES  SECTION.  Heater  volts  (ac/dc),  4.7;  amperes,  0.6;  warm-up  time 
(average),  11  seconds.  Peak  heater-cathode  volts,  200  max.  When  the  heater  is 
positive  with  respect  to  the  cathode,  the  dc  component  of  the  heater-cathode  voltage 
must  not  exceed  100  volts.  Except  for  heater  and  heater-cathode  ratings,  this  type 
is  identical  with  miniature  type  6T8-A. 

P02 


5U4G 
5U4GB 


FULL-WAVE  VACUUM  RECTIFIER 


Glass  octal  types  used  in  power 
supplies  of  radio  and  television  receiv- 
ers having  high  dc  requirements.  Type 
5U4-GB,  Outline  19D,  OUTLINES 
SECTION.  Type  5U4-G  maximum 
dimensions:  over-all  length,  5-5/16  inches;  seated  height,  4-3/4  inches;  diameter, 
2-1/16  inches.  Tubes  require  octal  socket.  Either  type  may  be  supplied  with  pins 
3,  5,  and  7  omitted.  Vertical  mounting  is  preferred  but  horizontal  mounting  is  per- 
missible if  pins  1  and  4  are  in  vertical  plane.  The  coated  filament  is  designed  to 
operate  from  the  ac  line  through  a  step-down  transformer.  The  voltage  at  the  fila- 
ment terminals  should  be  5.0  volts  at  an  average  line  voltage  of  117  volts.  It  is 
especially  important  that  these  tubes,  like  other  power-handling  tubes,  be  ade- 
quately ventilated.  For  discussion  of  Rating  Chart  and  Operation  Characteristics, 
refer  to  INTERPRETATION  OF  TUBE  DATA.  Maximum  ratings  for  type 
5U4-G  as  full-wave  rectifier:  peak  inverse  plate  volts,  1550  max;  peak  plate  amperes 
per  plate,  0.8  max  (transient,  4.0  max).  Type  5U4-G  is  used  principally  for  renewal 
purposes.  Filament  volts  (ac),  5;  amperes,  3. 

FULL- WAVE  RECTIFIER 

Maximum  Ratings,  (^Design-Center  Values):  SU^-GB 

Peak  Inverse  Plate  Voltage   1550  max  volts 

Peak  Plate  Current  (Per  Plate)   1.0  max  ampere 

Hot-Switching  Transient  Plate  Current  (Per  Plate)   # 

AC  Plate  Supply  Voltage  (Per  Plate,  rms)   See  Rating  Chart 

DC  Output  Current  (Per  Plate)   See  Rating  Chart 

RATING  CHART 


—  1 ""  1 

TYPE  5U4-GB 
E|  =  5  VOLTS  AC 

MAX 

IMUM  OPERATING  VALUES  WITH.' 

HOKE -INPUT  FILTER 

r CAPACITOR -INPUT  FILTER 

F  A 

1 

175" — ■ 
_  jl37 

1 

1 

5.  

C 

1 

0 

— 1— 
1 
1 

|48 

l45C 

>  6 

55C 

0  100      200      300     400      500  600 

AC  PLATE  SUPPLY  VOLTS  (RMS)  PER  PLATE  (WITHOUT  LOAD) 

92CS-8450T1 


Typical  Operation  of  5U4-GB  with  Capacitor  Input  to  Filter: 

600  900  1100 

40  40  40 

21  67  97 


AC  Plate-to-Plate  Supply  Voltage  (rms) . 
Filter-Input  Capacitor*. 


Total  Eflfective  Plate-Supply  Impedance  per  Plate. . . 
130 


volts 
ohms 


DC  Output  Voltage  at  Input  to  Filter  (Approx.) : 

f      150  ma   335  -  -  volts 

At  half-load  current  of     j  137.5  ma   -  520  -  volts 

i       81  ma   -  -  680  volts 

(      300  ma   290  -  -  volts 

At  full-load  current  of      ]      275  ma   -  460  -  volts 

i      162  ma   -  -  630  volts 

Voltage  Regulation  (Approx.): 

Half-load  to  full-load  current   45  60  50  volts 

Typical  Operation  of  5U4-GB  with  Choke  Input  to  Filter; 

AC  Plate-to-Plate  Supply  Voltage  (rms)   900  1100  volts 

Filter-Input  Choke   10  10  henries 

DC  Output  Voltage  at  Input  to  Filter  (Approx.) : 

Athaif-ioadcurrentof  I  i3i^|™Sv.-;.;:::::::::::::.;::;  «5  TolS 

At  lulMoad  current  of  |      l^f  Sa"  ! ! ! !  i ! !  1 ! ! !  1 ! ! ! ! ! ! !  ] !  1    '1"  4l0  J^iS 

Voltage  Regulation  (Approx.) : 

Half-load  to  full-load  current   15  15  volts 

#If  hot  switching  is  regularly  required  in  operation,  the  use  of  choke-input  circuits  is  recommended. 
Such  circuits  limit  the  hot-switching  current  to  a  value  no  higher  than  that  of  the  peak  plate  current. 
When  ^capacitor-input  circuits  are  used,  a  maximum  peak  current  value  per  plate  of  4.6  amperes  during 
the  initial  cycles  of  the  hot-switching  transient  should  not  be  exceeded. 

♦Higher  values  of  capacitance  than  indicated  may  be  used,  but  the  effective  plate-supply  impedance 
may  have  to  be  increased  to  prevent  exceeding  the  maximum  rating  for  peak  plate  current. 


OPERATION  CHARACTERISTICS 

FULL-WAVE  CIRCUIT.  CAPAaTOR  INPUT  TO  FILTER 


TYPE  5U4-GB 

tr-  =  5.0  VOLTS  AC 

SUPPLY  FREQUENCY  =  60  CPS 

CAPACITOR  (C)  INPUT  TO  FILTER:  40  \Xf 

TOTAL  EFFECTIVE  PLATE- SUPPLY  IMPEDANCE 

PER  plate; 

CURVE)  12   3    4    S    6    7  8 
OHMS  III  II  20  36  52  67  82  97 
CURRENT- AND -VOLTAGE  BOUNDARY  LINE  'DEA'= 
SEE  RATING  CHART 


OPERATION  CHARACTERISTICS 

FULL-WAVE  CIRCUIT,  CHOKE  INPUT  TO  FILTER 


TYPE  5U4-GB 

E^  =5.0  VOLTS  AC       SUPPLY  FREQUENCY=60CPS 

SOLID-LINE  CURVES  =  CH0KES  OF  INFINITE 
INDUCTANCE 

LONG-DASH  LINES  =  BOUNDARY  LINES  FOR 

CHOKE  SIZES  AS  SHOWN 

SHORT-DASH  CURVES=REGULATION  CURVES 
FOR  REPRESENTATIVE 
CHOKE  SIZES 

CURRENT-AND-VOLTACE  BOUNDARY  LINE  CBA 
IS  THE  SAME  AS  SHOWN  ON  RATING  CHART 


200  300  400 

DC  LOAD  MILLIAMPERES 

92CM-8447TI 


MEDIUM-MU  TRIODE— 
SHARP-CUTOFF  PENTODE 

Miniature  type  used  as  combined 
oscillator  and  mixer  tube  in  AM  /FM 
receivers  and  television  receivers  em- 
ploying series-connected  heater  strings. 
Outline  8B,  OUTLINES  SECTION. 


5U8 

Related  types: 
6U8A,  9U8A 


Heater  volts  (ac/dc),  4.7 :  amperes,  0.6 ;  warm-up  time  (average),  11  seconds.  Except 
for  heater  ratings,  this  type  is  identical  with  miniature  type  6U8-A. 


131 


RCA  Receiving  Tube  Manual 


FULL-WAVE  VACUUM  RECTIFIER 

JJYS  Glass  octal  types  used  as  power 

supply  in  color  television  receivers  and 
5\A3A  other  equipment  having  high  dc  re- 

^  ^  quirements.  Outline  19D,  OUTLINES 

SECTION.  Tubes  require  octal  socket. 
Vertical  mounting  is  preferred,  but  horizontal  mounting  is  permissible  if  pins  2 
and  4  are  in  vertical  plane.  It  is  especially  important  that  these  tubes,  like  other 
power-handling  tubes,  be  adequately  ventilated.  For  discussion  of  Rating  Chart, 
refer  to  INTERPRETATION  OF  TUBE  DATA.  Type  5V3  is  a  DISCONTINUED 
type  listed  for  reference  only.  Filament  volts  (ac/dc),  5;  amperes,  3.8  (5V3),3(5V3-A). 


FULL- WAVE  RECTIFIER 

5V3  5VS-A 

Maximum  Ratings:                                                             Center^Values  Ma^mum  Values 

Peak  Inverse  Plate  Voltage                                                1400  maa;  1550  wox  volts 

Peak  Plate  Current  (Per  Plate)                                             1.2  max  1 . 4  max  amperes 

Hot-Switching  Transient  Plate  Current  (Per  Plate)                 5.5  max  6.6  max  amperes 

AC  Plate-Supply  Voltage  (Per  Plate,  rms,  without  load) . . .  See  Rating  550  max  volts 

DC  Output  Current  (Per  Plate)                                          Chart  A15°max  ma 

With  capacitor-input  filter  for  ac  plate-supply  voits  (rms,  per  plate,  without  load)  =  470. 

Typical  Operation:  5V3  5VS-A 

Filter  Input  Capacitor  Choke     Capacitor  Choke 

AC  Plate-to-Plate  Supply  Voltage  (rms)                                 850  1000  850    1000  volts 

Filter-Input  Capacitor"                                                          40       -  40       -  /if 

Effective  Plate-Supply  Impedance  per  Plate                             56       -  50       -  ohms 

Minimum  Filter-Input  Choke                                                  -     10              -       10  henries 

DC  Output  Current                                                            350    350  350     350  ma 

DC  Output  at  Input  to  Filter  (Approx.)                                 430    385  440     390  volts 

Characteristics:  6VS  5VS-A 

Tube  Voltage  Drop  for  plate  current  of  350  ma  (per  plate) ...        47  42  volts 

■  When  capacitor  values  greater  than  40  /*f  are  used,  the  effective  plate-supply  impedance  should  be 
increased  so  that  the  maximum  rating  for  peak  plate  current  is  not  exceeded. 


RATING  CHART 


TYPE 

5V3 
VOLTS 

MA) 
AC  1  

<imum  operating  values  w 
:hoke-input  filter 
r-capacitor- input  filter 

ITH: 

F  A 

I 

B 

2251 — ■ 

— h- 

1 

C 

1 

MOJ 

0 

— i- 
1 

-I  

1 

-J  

1 

55 
1 

1 

1^ 

G 

5V4G 
5V4GA 


100  200  300  400  500  600  700  800 
AC  PLATE  SUPPLY  VOLTS  (RMS)  PER  PLATE  (WITHOUT  LOAD) 

92CS-l023iT2 


FULL-WAVE  VACUUM  RECTIFIER 


Glass  octal  types  used  in  full-wave 
power  supplies  having  high  dc  require- 
ments. Outlines  26  and  19A,  respec- 
tively, OUTLINES  SECTION.  Tubes 
require  octal  socket  and  may  be 
mounted  in  any  position.  The  heater  is  designed  to  operate  from  the  ac  line  through 
a  step-down  transformer.  The  voltage  at  the  heater  terminals  should  be  5.0  volts 

132 


under  operating  conditions  at  an  average  line  voltage  of  117  volts.  It  is  especially 
important  that  these  tubes,  like  other  power-handling  tubes,  be  adequately  ven- 
tilated. Heater  volts  (ac/dc),  5;  amperes,  2. 

FUU-WAVE  RECTIFIER 
Maximum  Ratings,  (Design-Center  Values): 

Peak  Inverse  ^latb  Voltage  

AC  Plate-Supply  Voltage  (Per  Plate,  rms): 

With  capacitor-input  filter  

With  choke-input  filter  

Peak  Plate  Current  (Per  Plate)  

DC  Output  Current  


1400  max 

375  max 
500  max 
625  max 
175  max 


volts 

volts 
volts 
ma 
ma 


Typical  Operation: 

Filter  Input  Capacitor 

AC  Plate-to-Plate  Supply  Voltage  (rms)   750 

Filter-Input  Capacitor*   10 

Total  Effective  Plate-Supply  Impedance  per  Plate   100 

Filter-Input  Choke  

DC  Output  Voltage  at  Input  to  Filter  (Approx.)  for  dc  output 

current  of  175  ma   410 

♦Higher  values  of  capacitance  than  indicated  may  be  used,  but  the  effective  plate-supply  impedance 
may  have  to  be  increased  to  prevent  exceeding  the  maximum  rating  for  peak  plate  current. 

OPERATION  CHARACTERISTICS 
FULL-WAVE  RECTIFIER  CIRCUIT 


Choke 
1000 


410 


volts 

ohms 
henries 

volts 


TYPE  5V4-GA 

Ef  =  5.0  VOLTS  _|  I  L_ 

SUPPLY  FREQUENCY  =  60  CPS  I 
*  CHOKE(L>  INPUT  TO  TILTER: 
L=4  HENRIES  (MIN.) 
lAPACITOR  (C)  INPUT  TO  FILTER: 
TOT.  EFFECT.  PLATE-  SUPPLY 
IMPEDANCE  PER  PLATE = 

100  OHMS 


iO        100       150  200 
DC  LOAD  MILLIAMPERES 

92CM-«090Ta 


BEAM  POWER  TUBE 

Glass  octal  type  used  as  output 
amplifier  in  television  receivers  em- 
ploying series-connected  heater  strings. 
Outline  14C,  OUTLINES  SECTION. 
This  type  may  be  supplied  with  pin 
No.l  omitted.  Heater  volts  (ac/dc),  4.7;  amperes,  0.6;  warm-up  time  (average),  11 
seconds.  Except  for  heater  ratings,  this  type  is  identical  with  glass  octal  type  6V6-GT. 


5V6GT 

Relat«d  types: 
6V66T,  12V6GT 


S:SW4 
NC:5W4-CT 


FULUWAVE  VACUUM  RECTIFIER 

Metal  type  5W4  and  glass-octal  type  5W4- 
GT  are  used  in  power  supply  of  radio  equipment 
having  low  dc  requirements.  Outlines  5  and  14D, 
respectively,  OUTLINES  SECTION.  Both 
types  require  octal  socket.  Filament  volts  (ac) , 
5.0;  amperes,  1.5.  Maximum  ratings:  peak  in- 
verse plate  volts,  1400  max;  peak  plate  ma.,  300 
max;  dc  output  ma,,  100  max.  Tliese  are  DIS- 
CONTINUED types  listed  for  reference  only. 


5W4 
5W4GT 


133 


RCA  Receiving  Tube  Manual 


5X4G 


FULL-WAVE  VACUUM  RECTIFIER 

Glass  octal  type  used  in  power  supply  of 
radio  equipment  having  large  dc  requirements. 
Maximum  dimensions:  over-all  length,  5-5/16 
inches;  seated  height,  4-3/4  inches;  diameter, 
2-1/16  inches.  Filament  volts,  5.0;  amperes,  3.0. 
Tube  requires  octal  socket.  Maximum  ratings 
as  full-wave  rectifier:  peak  inverse  plate  volts, 
1550  max;  peak  plate  amperes  per  plate,  675 
max.  Type  5X4-G  is  used  principally  for  re- 
newal purposes. 


Related  types: 
6X8,  19X8 


MEDIUM-MU  TRIODE- 

SHARP-CUTOFF  PENTODE 

_  «  -  ^  Miniature  type  used  as  combined 

5yVO  oscillator  and  mixer  in  AM/FM  re- 

ceivers and  television  receivers  em- 
ploying series-connected  heater  strings. 
Outline  8B,  OUTLINES  SECTION. 
Heater  volts  (ac/dc),  4.7;  amperes,  0.6;  warm-up  time  (average),  11  seconds.  Ex- 
cept for  heater  rating,  this  type  is  identical  with  miniature  type  6X8. 

FULL-WAVE  VACUUM  RECTIFIER 

5Y3G  Glass  octal  types  used  in  power 

supply  of  radio  equipment  having  mod- 
5Y3GT        erate  dc  requirements.  Type  5Y3-G, 
I  <^  w  I         Outline  26,  type  5Y3-GT,  Outline  14D, 
OUTLINES  SECTION.Tubes  require 
octal  socket.  Vertical  tube  mounting  is  preferred,  but  horizontal  mounting  is  per- 
missible if  pins  2  and  8  are  in  horizontal  plane.  It  is  especially  important  that  these 
tubes,  like  other  power-handling  tubes,  be  adequately  ventilated.  For  discussion 
of  Rating  Chart  and  Operation  Characteristics,  refer  to  INTERPRETATION  OF 
TUBE  DATA.  Maximum  ratings  for  type  5Y3-G  as  full-wave  rectifier:  peak  in- 
verse plate  volts,  1400  max\  peak  plate  ma.  per  plate,  375  max.  Type  5Y3-G  is  a 
DISCONTINUED  type  listed  for  reference  only.  Filament  volts  (ac),  5;  amperes,  2. 


FULL-WAVE  RECTIFIER 
Maximum  Ratings,  {Design-Center  Values): 

Peak  Inverse  Plate  Voltage  

Peak  Plate  Current  (Per  Plate)  

Hot-Switching  Transient  Plate  Current  (Per  Plate)  

AC  Plate  Supply  Voltage  (Per  P^ate,  rms)  

DC  Output  Current  (Per  Plate)  


5YS-GT 
1400  max  volts 
440  max  ma 
2 . 5  max  amperes 
See  Rating  Chart 
See  Rating  Chart 


RATING  CHART 


o  20 


TYPE  5Y3-GT 
e|«5  VOLTS  AC 

OPERAT 
NPUT  F 
:iTOR- 

{NG  VAL 
ILTER 
NPUT  F 

ues  Wl 

ILTER 

F  A 

Mm 

HOKE- 
rCAPA 

62.5 

^E.. 

C 

1 

3a|. 

1 
1 

 1_ 

1^ 

1 

1 

-I-' 
1 
1 

— 1  

D 

1 
1 

|62 

1 

|35( 

G 

100      200     300     400  500 


134 


Typical  Operation  of  5Y3-GT  with  Capacitor  Input  to  Filtert 

AC  Plate-to-Plate  Supply  Voltage  (rms)  

Filter  Input  Capacitor*  

Effective  Plate-Supply  Impedance  per  Plate  

DC  Output  Voltage  at  Input  to  Filter  (Approx.) : 

At  half-load  current  of  J  ^2  J  ma  

At  full-load  current  of  )    125  ma  

)      84  ma  

Voltage  Regulation  (Approx.) : 

Half-load  to  full-load  current  

Typical  Operation  of  5Y3-GT  with  Choke  Input  to  Filter: 

AC  Plate-to-Plate  Supply  Voltage  (rms)  

Filter  Input  Choke  #  

DC  Output  Voltage  at  Input  to  Filter  (Approx.): 

At  half-load  current  of  |  gg^^  ™J *.*.  *.'.  *.*.  '.*.  '. *. '. 

At  full-load  current  of  \    }S2  ™* 

)     125  ma  

Voltage  Regulation  (Approx.):  Half-load  to  full-load  current. . . . 


700 

1000 

volts 

20 

10 

60 

140 

ohms 

390 

- 

volts 

610 

volts 

360 

660 

volts 

40 

50 

volts 

700 

1000 

volts 

10 

10 

henries 

270 

volts 

406 

volts 

245 

volts 

380 

volts 

25 

15 

volts 

*  Higher  values  of  capacitance  than  indicated  may  be  used  but  the  effective  plate  supply  impedance 
may  have  to  be  increased  to  prevent  exceeding  the  maximum  rating  for  hot-switching  transient  plate 
current. 

#  This  value  is  adequate  to  maintain  optimum  regulation  in  the  region  to  the  right  of  line  L=10H  on 
curve  OPERATION  CHARACTERISTICS  with  Choke  Input  to  Filter,  provided  the  load  currents 
are  not  less  than  35  ma.,  and  50  ma. ,  respectively,  for  Plate-to-Plate  supply  voltages  of  700  and  1000 
volts  (rms). 


OPERATION  CHARACTERISTICS 

FULL -WAVE    CIRCUIT,  CAPACITOR  INPUT  TO  FILTER 


OPERATION  CHARACTERISTICS 

FULL-WAVE  CIRCUIT.  CHOKE  INPUT  TO  FILTER 


TYPE  5Y3-CT 


Ef.=  5.0  VOLTS  AC 

-CHOKES  OF  INFINITE 

INDUCTANCE 
•CHOKES  OF  VALUES 

SHOWN 
-BOUNDARY  LINE  FOR  - 
CHOKE  VALUES  SHOWN 
CEK=SEE  RATING 
CHART  - 


le/A'T  - 


40  80  120  I6C 

OC  LOAD  MILLIAMPERES 

92CM-7394T 


FULL-WAVE  VACUUM  RECTIFIER 

Glass  octal  types  used  in  power 
supplies  of  radio  equipment  having 
moderate  DC  requirements.  Outlines 
26,  14D,  and  19D,  respectively,  OUT- 
LINES SECTION.  Tubes  require  oc- 
tal socket.  Type  6Y4GT  is  supplied 


5Y4G 

5Y4GA 
5Y4GT 


135 


RCA  Receiving  Tube  Manual 


with  pins  4  and  6  missing.  Vertical  tube  mounting  is  preferred,  but  horizontal  mount- 
ing is  permissible:  if  pins  2  and  7  are  in  horizontal  plane  (6Y4-G) ;  if  pins  1  and  4  are 
in  vertical  plane  (6Y4-GA);  if  pins  2  and  3  are  in  vertical  plane  (5Y4-GT).  It  is 
especially  important  that  these  tubes,  like  other  power  handling  tubes,  be  adequately 
ventilated.  For  discussion  of  Rating  Chart,  refer  to  INTERPRETATION  OF 
TUBE  DATA.  Maximum  ratings  for  type  5Y4-G  as  full-wave  rectifier:  peak  in- 
verse plate  volts,  1400  max;  peak  plate  ma.  per  plate,  375  max  (transient  amperes, 
2.2  max).  Type  5Y4-G  is  a  DISCONTINUED  type  listed  for  reference  only.  Fila- 
ment volts  (ac/dc),  5;  amperes,  2. 


FULL-WAVE  RECTIFIER 
Maximum  Ratings,  {Design-Center  Value): 

Peak  Inverse  Plate  Voltage   

Peak  Plate  Current  (Per  Plate)  

Hot-Switching  Transient  Plate  Current   

AC  Plate  Supply  Voltage  (Per  Plate,  rms)  

DC  Output  Current  (Per  Plate)  


5YU-GA 
5YU-GT 
1400  max  volts 
400  max  ma 
2 . 2  max  amperes 
See  Rating  Chart 
See  Rating  Chart 


Typical  Operation  of  5Y4-GA  &  5Y4-GT: 

Filter  Input 

AC  Plate-to-Plate  Supply  Voltage  (rms)  

Filter-Input  Capacitor"  

Total  Effective  Plate-Supply  Impedance  per  Plate  . 

Filter-Input  Choke  

DC  Output  Current  

DC  Output  Voltage  at  Input  to  Filter  ( Approx.) : 
At  full-load  current  (125  ma.)  .  


Capacitor 

Choke 

700 

1000 

volts 

10 

Mf 

50 

ohms 

10 

henries 

125 

125 

ma 

350 

390 

volts 

Characteristics,  Instantaneous  Value: 

Tube  Voltage  Drop  for  plate  current  of  125  ma  (per  plate)   60  volts 

*  Values  of  capacitance  greater  than  20  nl  may  be  used,  provided  the  plate-supply  impedance  is  in- 
creased to  prevent  exceeding  the  maximum  peak-plate-current  rating. 


5Z3 


5Z4 


100      200      300      400      500      600  700 
AC  PLATE  SUPPLY  VOLTS  (RMS)  PER  PLATE  (WITHOUT  LOAD) 

<)2CS-I047JT2 

FULL-WAVE  VAtUUM  RECTIFIER 

Glass  type  used  in  power  supply  of  radio 
equipment  having  large  dc  requirements.  Out- 
line 28,  OUTLINES  SECTION.  Tube  requires 
four-contact  socket.  Vertical  mounting  is  pre- 
ferred but  horizontal  mounting  is  permissible  if 
pins  1  and  4  are  in  horizontal  plane.  Filament  volts 
(ac),  5.0;  amperes,  3.0.  Maximum  ratings  as  full- 
wave  rectifier:  peak  inverse  plate  volts,  1550 
max;  peak  plate  ma.  per  plate,  675  max.  Type 
5Z3  is  used  principally  for  renewal  purposes. 

FULL-WAVE  VACUUM  RECTIFIER 

Metal  type  used  in  power  supply 
of  radio  equipment  having  moderate 
dc  requirements.  Outline  5,  OUT- 
LINES SECTION.  Tube  requires 
octal  socket  and  may  be  mounted  in 


136 


any  position.  Heater  volts  (ac),  5.0;  amperes,  2.0.  Maximum  ratings:  peak  inverse 
plate  volts,  1400  max;  peak  plate  ma.  per  plate,  375  max.  Typical  operation  as  full- 
wave  rectifier  with  capacitor-input  filter:  ac  plate-to-plate  supply  volts  (rms),  700; 
total  effective  plate-supply  impedance  per  plate,  50  ohms;  dc  output  ma.,  125. 
Typical  operation  with  choke-input  filter:  ac  plate-to-plate  supply  volts,  1000; 
minimum  filter-input  choke,  5  henries;  dc  output  ma.,  125. 


6A3 


6A6 


POWER  TRIODE 

Glass  type  used  in  output  stage  of  radio  re- 
ceivers. Outline  28,  OUTLINES  SECTION. 
Tube  requires  four-contact  socket.  Filament 
volts  (ac/dc),  6.3;  amperes,  1.0.  This  type  is 
identical  electrically  with  type  6B4-G.  Type  6  A3 
is  a  DISCONTINUED  type  listed  for  reference 
only. 

HIGH-MU  TWIN  POWER  TRIODE 

Glass  type  used  in  output  stage  of  ac-oper- 
ated  receivers  as  a  class  B  power  amplifier  or 
with  units  in  parallel  as  a  class  Ai  amplifier  to 
drive  a  6A6  as  class  B  amplifier.  Outline  27, 
OUTLINES  SECTION.  Tube  requires  medium 
seven-contact  (0.855-inch,  pin-circle  diameter) 
socket.  Filament  volts  (ac/dc),  6.3;  amperes, 
0.8.  This  type  is  electrically  identical  with  type 
6N7.  Type  6A6  is  a  DISCONTINUED  type 
listed  for  reference  only. 

PENTAGRID  CONVERTER 

Glass  types  used  in  superheterodyne  cir- 
cuits. Outline  24B,  OUTLINES  SECTION. 
These  types  require  the  small  seven-contact 
(0.75-inch,  pin-circle  diameter)  socket.  Except 
for  interelectrode  capacitances,  the  6A7  is  iden- 
tical electrically  with  type  6 A8.  Type  6A7S,  now 
DISCONTINUED,  has  the  external  shield  con- 
nected to  cathode.  In  general,  its  electrical  char- 
acteristics are  similar  to  those  of  the  6A7,  but 
the  two  types  are  usually  not  directly  interchangeable.  Type  6  A7  is  used  principally  for  renewal  purposes. 


6A7 

6A7S 


PENTAGRID  CONVERTER 


6A8 
6A8G 
6A8GT 


Related  type: 
12A8GT 


Metal  type  6  A8  and  glass  octal  types  6A8-G 
and  6A8-GT  used  in  superheterodyne  circuits. 
6A8  Outline  3,  6A8-G  Outline  23,  6A8-GT 
Outline  15A,  OUTLINES  SECTION.  Tubes  re- 
quire octal  socket.  Heater  volts  (ac/dc),  6.3; 
amperes,  0.3.  Characteristics  as  coverter:  plate 
and  grid-No.2-supply  volts,  250  (300  max); 
grids-No.3-and-No.5  (screen-grid)  volts,  100 
max;  grid-No.4  (control-grid)  volts,  -3  (0  max); 
grid-No.2  (anode-grid)  resistor,  20000  ohms  (bypassed  by  0.1-/Lif  capacitor);  grid-No.l  (oscillator-grid) 
resistor,  50000  ohms;  plate  resistance  (approx.),  0.36  megohm;  conversion  transconductance,  550 
/Limhos;  plate  ma.,  3.5;  grids-No.3-and-No.5  ma.,  2.7;  grid-No.2  ma.,  4;  grid-No.l  ma.,  0.4;  total  cathode 
ma.,  10.6  (14  max);  plate  dissipation,  1  max  watt;  grids-No.3-and-No.5  input,  0.3  max  watt;  grid-No.2 
input,  0.75  max  watt;  peak  heater-cathode  volts,  90  max.  These  types  are  used  principally  for  renewal 
purposes. 

HIGH-MU  TRIODE 

Miniature  type  used  as  cathode- 
drive  amplifier,  frequency  converter, 
or  oscillator  at  frequencies  up  to  about 
300  megacycles  per  second  particularly 
in  television  and  FM  receivers.  Outline 
7B,0UTLINES  SECTION.  Tube  requires  miniature  seven-contact  socket  and  may 
be  mounted  in  any  position.  Heater  volts  (ac/dc),  6.3;  amperes,  0.15.  For  maximum 
ratings,  characteristics,  and  curves,  refer  to  type  12AT7. 


6AB4 


137 


RCA  Receiving  Tube  Manual 


6AB5/ 


ELEaRON-RAY  TUBE 

Glass  type  with  triode  unit  used  to  indicate 
visually  by  means  of  a  fluorescent  target  the 
effects  of  a  change  in  a  controlling  voltage.  It  is 
jr  |k  I  JF  used  as  a  convenient  means  of  indicating  accu- 

Q  |l|  ^  rate  radio-receiver  tuning.  Maximum  dimen- 

sions: over-all  length,  4-3/16  inches;  seated 
height,  3-9/16  inches;  diameter,  1-3/16  inches.  "  " 

Tube  requires  six-contact  socket.  Heater  volts 
(ac/dc),  6.3;  amperes,  0.15.  Maximum  ratings 
in  indicator  service:  triode-plate  supply  volts,  180  max;  fluorescent-target  volts,  180  max,  125  min. 
This  type  is  used  principally  for  renewal  purposes. 


SHARP-CUTOFF  PENTODE 

Metal  type  used  in  rf  and  if  stages  of  pic- 
^  m  mi  ture  amplifier  of  television  receivers  particularly 

\^r\M^  r  those  employing  automatic-gain  control.  Out- 

line 2,  OUTLINES  SECTION.  Tube  requires 
octal  socket.  Heater  volts  (ac/dc),  6.3;  amperes, 
0.45.  Maximum  ratings  as  class  Ai  amplifier: 
plate  and  grid-No.2  supply  volts,  300  max; 
grid  No.3,  connect  to  cathode  at  socket;  grid- 
No.2  volts,  200  max;  plate  dissipation,  3.75  max  watts;  grid  No.2  input,  0.65  max  watt.  Typical  oper- 
ation: plate  and  grid-No.2  supply  volts,  300;  grid-No.3  volts,  0;  grid-No.2  series  resistor,  30000  ohms; 
grid-No.l  volts,  -3;  plate  resistance  (approx.),  0.7  megohm;  transconductance,  5000  /nmhos;  grid-No.l 
volts  for  transconductance  of  50  Mnihos,  -22.5;  plate  ma.,  12.5;  grid-No.2  ma.,  3.2.  This  type  is  used 
principally  for  renewal  purposes. 


6AC5GT 


HIGH-MU  POWER  TRIODE 

Glass  octal  type  used  in  single-ended  or 
push-pull  audio-frequency  power  amplifiers  of 
the  direct-coupled  type  in  which  a  driver  tube 
develops  positive  grid  bias  for  the  6AC5-GT 
output  stage.  Outline  14C,  OUTLINES  SEC- 
TION. This  type  may  be  supplied  with  pin  No. 
1  omitted.  Tube  requires  octal  socket.  Heater 
volts  (ac/dc),  6.3;  amperes,  0.4.  Maximum  ratings  as  push-pull  class  B  power  amplifier 
250  max;  peak  plate  ma.,  110  max;  average  plate  dissipation,  10  max  watts.  This  type  is 
pally  for  renewal  purposes. 


plate  volts, 
used  princi- 


6AC7 


SHARP-CUTOFF  PENTODE 

Metal  type  used  as  video  amplifier  tube  in 
television  receivers,  and  as  a  mixer  or  oscillator 
tube  in  low-frequency  applications.  Outline  2, 
OUTLINES  SECTION.  Tube  requires  octal 
socket.  Heater  volts  (ac  /dc),  6.3;  amperes,  0.45. 
Characteristics  as  class  Ai  amplifier:  plate  and 
grid-No.2  supply  volts,  300  max;  grid  No.3  con- 
nected to  cathode  at  socket;  grid-No.2  series 
resistor,  60000  ohms;  cathode-bias  resistor,  160 
ohms;  plate  resistance  (approx.),  1  megohm;  transconductance,  9000  ^nihos;  plate  ma.,  10;  grid-No.2 
ma.,  2.5;  plate  dissipation,  3  max  watts;  peak  heater-cathode  volts,  90  max.  This  type  is  used  princi- 
pally for  renewal  purposes. 


6AD6G 


ELECTRON-RAY  TUBE 

Glass  octal  type  used  to  indicate  visually, 
by  means  of  two  shadows  on  the  fluorescent  tar- 
get, the  effects  of  changes  in  the  controlling 
voltages.  It  is  a  twin-indicator  type  and  is  used 
as  a  convenient  means  of  indicating  accurate 
radio-receiver  tuning.  Maximum  over-all  length, 
2-7/8  inches;  maximum  diameter,  1-5/16  inches. 
Heater  volts  (ac/dc),  6.3;  amperes,  0.15.  Maxi- 
mum target  volts,  150.  This  is  a  DISCON- 
TINUED type  listed  for  reference  only. 


RCb^ 


138 


6AD7G 


LOW-MU  TRIODE  — POWER  PENTODE 

Glass  octal  type  used  in  a  push-pull  ampli- 
fier circuit  in  conjunction  with  type  6F6-G.  Tri- 
ode  unit  serves  as  phase  inverter.  Outline  26, 
OUTLINES  SECTION.  Tube  requires  octal 
socket.  Heater  volts  (ac/dc),  6.3;  amperes,  0.85. 
For  typical  operation  of  pentode  unit,  refer  to 
type  6F6-G.  Maximum  ratings  of  pentode  unit 
as  class  Ai  or  push-pull  class  ABi  amplifier:  plate 
volts,  375  max;  grid-No.  2  volts,  285  max;  plate 
dissipation,  8.5  max  watts;  grid-No.2  input,  2.7  max  watts.  Maximum  ratings  of  triode  unit  as  classAi 
amplifier:  plate  volts,  285  max;  plate  dissipation,  I.O  max  watt. This  type  is  used  principally  for  renewal 
purposes. 


LOW-MU  TRIODE 

Glass  octal  type  used  as  class  At  amplifier 
in  ac  /dc  radio  receivers.  Outline  14C,  OUT- 
LINES SECTION.  Heater  volts  (ac/dc),  6.3; 
amperes,  0.3.  Maximum  ratings  as  class  At  am- 
plifier: plate  volts,  300  max;  plate  dissipation, 
2.5  max  watts.  This  is  a  DISCONTINUED 
type  listed  for  reference  only. 


6AE5GT 


6AE6G 


6AE7GT 


TWIN-PLATE  CONTROL  TUBE 

Glass  octal  type  used  as  a  control  tube  for 
twin-indicator  type  electron-ray  tubes.  Outline 
22,  OUTLINES  SECTION.  Contains  two  tri- 
odes  with  different  cutoff  characteristics.  If  avc 
voltage  is  applied  to  the  common  control  grid  in 
suitable  circuit,  one  triode  section  operates  on 
weak  signals  while  the  other  operates  on  strong 
signals.  Heater  voltage  (ac/dc),  6.3;  amperes, 
0.15.  This  is  a  DISCONTINUED  type  listed 
for  reference  only. 

TWIN-INPUT  TRIODE 

Glass  octal  type  used  as  a  voltage  amplifier 
or  as  a  driver  for  two  type  6AC5-GT  tubes  in 
dynamic-coupled,  push-pull  amplifiers.  In  the 
latter  service,  type  6AE7-GT  replaces  two  tubes 
ordinarily  required  as  drivers.  Outlinel4C,  OUT- 
LINES SECTION.  Heater  volts  (ac/dc),  6.3; 
amperes,  0.5.  This  is  a  DISCONTINUED  type 
listed  for  reference  only. 

HALF-WAVE  VACUUM  RECTIFIER 

Miniature  type  used  as  a  damper 
tube  in  horizontal  deflection  circuits  of 
television  receivers.  Outline  9B,  OUT- 
LINES SECTION.  Tube  requires  min- 
iature nine-contact  socket  and  may  be 
mounted  in  any  position.  Socket  terminals  1,  2,  3,  6,  7,  and  8  should  not  be  used  as 
tie  points.  It  is  especially  important  that  this  tube,  like  other  power-handling 
tubes,  be  adequately  ventilated.  Heater  volts  (ac/dc),  6.3;  amperes,  1.2. 

DAMPER  SERVICE 

For  operation  in  a  5254ine,  30-frame  system 
Maximum  Ratings,  (Design- Maximum  Values): 

Peak  Inverse  Plate  Voltagb#  

Peak  Plate  Current  

Average  Plate  Current  

Peak  Heater  Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode   

Bulb  Temperature  (At  hottest  point)   

#  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  horizontal  scanning  cycle.  In 
525-line,  30-frame  system,  15  per  cent  of  one  horizontal  scanning  cycle  is  10  microseconds. 

*  The  dc  component  must  not  exceed  1000  volts. 
■  The  dc  component  must  not  exceed  100  volts. 


6AF3 

Related  type: 
12AF3 


4500  max 
750  max 
185  max 

4500*  max 
300"  max 

210  max 


volts 
ma 
ma 

volts 
volts 
"C 


139 


RCA  Receiving  Tube  Manual 


MEDIUM-MU  TRIODE 

Miniature  types  used  as  local 
oscillators  in  uhf  television  receivers 
covering  the  frequency  range  of  470  to 
890  megacycles  per  second.  6AF4  Out- 
line 7B,  6AF4-A  Outline  7A,  OUT- 
LINES SECTION.  Tubes  requires  miniature  seven-contact  socket  and  may  be 
mounted  in  any  position. 


6AF4 
6AF4A 

Reloted  types: 
2AF4B,  3AF4A 


Heater  Voltage  (ac/dc)  

Heater  Current  

Direct  Interelectrode  capacitances:* 

Grid  to  Plate  

Grid  to  Cathode  and  Heater  

Plate  to  Cathode  and  Heater  

Heater  to  Cathode**  


*  With  external  shield  connected  to  cathode,  except  as  noted. 
**  With  external  shield  connected  to  plate. 


Characteristics: 

Plate  Supply  Voltage  

Cathode-Bias  Resistor  

Amplification  Factor  

Plate  Resistance  (Approx.)  . 

Transconductance  

Plate  Current  


CLASS  Ai  AMPLIFIER 


UHF  OSCILLATOR 
Maximum  Ratings,  {Design-Maximum  Values): 

Plate  Voltage  

Grid  Voltage,  Negative-bias  value  

Grid  Current  

Plate  Dissipation  

DC  Cathode  Current  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  

Typical  Operation  as  Oscillator  at  1000  Mc: 

Plate  Supply  Voltage  

Plate  Resistor  

Grid  Resistor  

Plate  Current  

Grid  Current  (Approx.)  

Maximum  Circuit  Values: 

Grid-Circuit  Resistance: 

For  fixed-bias  operation  

For  cathode-bias  operation  

**The  dc  component  must  not  exceed  25  volts. 


AVERAGE    PLATE  CHARACTERISTICS 


6.3 
0.225 

1.9 
2.2 
1.4 

2.2 


80 
150 
13.5 
2100 
6500 
17.5 


150  max 
-50  max 
2  max 
2.5  max 
24  max 

50  max 
bOPmax 


100 
220 
10000 
17 

750 


volts 
ampere 

pf 
Pf 
Pf 
pf 


volts 
ohms 

ohms 
/Ltmhos 
ma 


volts 
volts 

ma 
watts 

ma 

volts 
volts 


volts 
ohms 
ohms 
ma 


Not  recommended 
0 . 5  max  megohm 


92CM-7756TI 


140 


6AF6G 


ELECTRON-RAY  TUBE 

Glass  octal  used  to  indicate  visually,  by 
means  of  two  shadows  on  the  fluorescent 
target,  the  effects  of  changes  in  the  controlling 
voltages.  It  is  a  twin-indicator  type  and  is  used 
as  a  convenient  means  of  indicating  accurate 
radio-receiver  tuning.  Maximum  over-all  length, 
2-5/16inches;maximumdiameter,l-5/16inches. 
This  type  may  be  supplied  with  pin  No.l 
omitted.  Tube  requires  octal  socket.  Heater  volts  (ac/dc),  6.3;  amperes,  0.15.  Maximum  ratings  in  in- 
dicator service;  fluorescent-target  volts,  250  max,  125  min;  ray-control-electrode  supply  volts,  250  max; 
peak  heater-cathode  volts,  90  max.  Typical  operation:  fluorescent-target  volts,  250;  fluorescent-target 
ma.,  3.75;  ray-contact-electrode  volts  (approx.  for  0*  shadow  angle),  155;  ray-control-electrode  volts 
(approx.  for  100°  shadow  angle),  0. 
KT2 
IS 


6AF11 

Related  type: 
15AF11 


DUAL  TRIODE— 

SHARP-CUTOFF  PENTODE 

Duodecar  type  used  in  a  variety 
of  applications  in  television  receivers. 
The  high-mu  triode  unit  is  used  for  age 
keyer  service,  the  medium-mu  triode 
unit  for  sync  separator  service,  and 
the  pentode  unit  for  video  amplifier  service.  Outline  12C,  OUTLINES  SECTION. 
Tube  requires  duodecar  twelve-contact  socket  and  may  be  mounted  in  any  posi- 
tion. Heater  volts  (ac/dc),  6.3;  amperes,  1.05. 

CLASS  Ai  AMPLIFIER 

Maximum  Ratings,  (Design-Maximum  Values): 

Plate  Voltage  

Grid-No  .  2  (screen-grid  Supply  Voltage  

Grid-No.2  Voltage  

Grid-No.  1  (control-grid)  Voltage,  Positive- 
bias  value  

Plate  Dissipation  

Grid-No. 2  Input: 

For  grid-No.2  voltages  up  to  165  volts  

For  grid-No.2  voltages  between  165  and  330 
volts  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode. . . . 
Heater  positive  with  respect  to  cathode .... 

Characteristics: 

Plate  Supply  Voltage  

Grid-No.2  Supply  Voltage  

Grid-No.l  Voltage  

Cathode-Bias  Resistor  

Amplification  Factor  

Plate  Resistance  (Approx)  

Transconductance  

Plate  Current  

Grid-No.2  Current  

Grid-No.l  Voltage  (Approx.)  for  plate  current 
of  100  /xa  


Maximum  Circuit  Values: 

Grid-No.l-Current  Resistance: 

For  fixed-bias  operation  

For  cathode-bias  operation  

■The  dc  component  must  not  exceed  100  volts. 


Triode 

Triode 

Pentode 

Unit  No.l 

Unit  No.  2 

Unit 

330  max 

330  max 

330  max 

volts 

330  max 

volts 

See  curve  page  70 

0  max 

0  max 

0  max 

volts 

1 . 1  max 

2  max 

5  max 

watts 

1.25  max 

watts 

See  curve  page  70 

200  max 

200  max 

200  max 

volts 

200'max 

200'max 

200"wax 

volts 

200 

200 

250 

volts 

150 

volts 

-2 

volts 

220 

100 

ohms 

68 

41 

12400 

9400 

68000 

ohms 

5500 

4400 

11000 

/xmhos 

7 

9.2 

24 

ma 

4.8 

ma 

-6.5 

-10 

volts 

0.5  max 

0 . 5  max 

0.25  max  megohm 

1  max 

1  max 

1  max 

megohm 

SHARP-CUTOFF  PENTODE 

Miniature  type  used  in  compact  A  ^  C 

radio  equipment  as  an  rf  or  if  amplifier         w A  w5 
up  to  400  megacycles  per  second. 
Outline  7B,  OUTLINES  SECTION, 
civ^  Tube  requires  miniature  seven-con- 

tact socket  and  may  be  mounted  in  any  position.  Except  for  slightly  different 


141 


RCA  Receiving  Tube  Manual 


characteristics,  this  type  is  similar  electrically  to  miniature  type  6BC5.  Heater 
volts  (ac/dc),  6.3;  amperes,  0.3.  For  typical  operation  as  a  resistance-coupled  amp- 
lifier, refer  to  RESISTANCE-COUPLED  AMPLIFIER  SECTION. 


POWER  PENTODE 

_  ^  ^  _  Metal  type  used  in  output  stage 

OA w#  video  amplifier  of  television  receiv- 

ers. Outline  5,  OUTLINES  SECTION. 
Tube  requires  octal  socket.  Heater 
volts  (ac/dc),  6.3;  amperes,  0.65.  Typi- 
cal operation  as  class  Ai  amplifier:  plate  volts,  300  max;  grid  No.3  connected  to 
cathode  at  socket;  grid-No.2  volts,  150  (300  max);  grid-No.l  volts,  -3  (0  max);  peak 
af  grid-No.l  volts,  3;  plate  ma.,  30  (zero  signal),  30.5  (maximum  signal);  grid-No.2 
ma.,  7  (zero  signal);  9  (maximum  signal);  plate  resistance  (approx.),  0.13  megohm; 
transconductance,  11000  junihos;  load  resistance,  10000  ohms;  maximum-signal 
power  output,  3  watts;  plate  dissipation,  9  max  watts;  grid-No.2  input,  1.5  max  watts. 


6AH4GT 


LOW-MU  TRIODE 

Glass  octal  type  having  high  perveance 
used  as  vertical  deflection  amplifier  in  television 
receivers.  Outline  14C,  OUTLINES  SECTION. 
Tube  requires  octal  socket  and  may  be  mounted 
in  any  position.  Heater  volts  (ac/dc),  6.3;  am- 
peres, 0.75.  Characteristics  as  class  Ai  amplifier: 
plate  volts,  250;  grid  volts,  -23;  amplification 
factor,  8;  plate  resistance  (approx.),  1780  ohms; 
transconductance,  4500  /umbos;  plate  ma.,  30. 
Maximum  ratings  as  vertical-deflection  amplifier  (for  operation  in  525-line,  30-frame  system) ;  dc  plate 
volts,  500  max;  peak  positive-pulse  plate  volts, 2000  max;  peak  niegative-pulse  grid  volts, -200  max;  peak 
cathode  ma.,  180  max;  average  cathode  ma.,  60  max;  plate  dissipation,  7.5  max  watts;  peak  heater- 
cathode  volts,  200  max  (the  dc  component  must  not  exceed  100  volts).  This  type  is  used  principally  for 
renewal  purposes. 

SHARP-CUTOFF  PENTODE 

Minature  type  used  as  if  amplifier  in  video 
stages  of  television  receivers.  Outline  7B,  OUT- 
LINES SECTION.  Tube  requires  miniature 
seven-contact  socket.  Heater  volts  (ac/dc),  6.3; 
amperes,  0.45.  Characteristics  as  class  Ai  am- 
plifier: plate  supply  volts,  300  max;  grid  No.3 
connected  to  cathode  at  socket;  grid-No.2  sup- 
ply volts,  150  (300  max);  cathode-bias  resistor, 
160  ohms;  plate  resistance  (approx.),  0.5  megohm;  transconductance,  9000  /xmhos;  plate  ma.,  10;  grid- 
No.2  ma.,  2.5;  plate  dissipation,  3.2  max  watts;  peak  heater-cathode  volts,  90  max.  This  type  is  used 
principally  for  renewal  purposes. 


6AH6 


6AK5 


SHARP-CUTOFF  PENTODE 

Miniature  type  used  as  an  rf  or  if 
amplifier  especially  in  high-frequency 
wide-band  applications.  It  is  useful  as 
an  amplifier  at  frequencies  up  to  400 
megacycles  per  second.  Outline  7A, 
OUTLINES  SECTION.  Tube  requires  miniature  seven-contact  socket  and  may 
be  mounted  in  any  position. 

Heater  Voltage  (ac/dc)   6.3  volts 

Heater  Current   0.175  ampere 

Direct  Interelectrode  Capacitances  (Approx.)  :■ 

Grid  No.l  to  Plate   0.02  max  pf 

Grid  No.l  to  Cathode,  Heater.  Grid  No.2.  Grid  No.3,  and  Internal  Shield. . .  4.0  pf 
Plate  to  Cathode,  Heater,  Grid  No.2,  Grid  No.3,  and  Internal  Shield   2.  8  pf 

142 


CLASS  At  AMPLIFIER 
Maximum  Ratings,  (Design-Center  Values): 

Plate  Voltage   180  max  volts 

Grid-No.2  (screen-grid)  Voltage   See  curve  page  70 

Grid-No.2  supply  Voltage   180  max  volts 

Grid-No.  1  Voltage,  Positive-bias  value   0  max  volts 

Plate  Dissipation   1.1  max  watts 

Grid-No.2  Input: 

For  grid-N 0.2  voltages  up  to  90  volts   0.5  max  watt 

For  grid-No.2  voltages  between  90  and  180  volts   See  curve  page  70 

Cathode  Current   18  max  ma 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   90  max  volts 

Heater  positive  with  respect  to  cathode   90  max  volts 

Characteristics: 

Plate  Supply  Voltage                                                                  120  180  volts 

Grid-No.2  Supply  Voltage                                                           120  120  volts 

Cathode-Bias  Resistor                                                                180  180  ohms 

Plate  Resistance  ( Approx.)                                                          0.3  0.5  megohm 

Transconductance                                                                    5000  5100  /imhos 

Grid-No.  1  Voltage  for  plate  current  of  10 /xa                                 -8.5  -8.5  volts 

Plate  Current                                                                            7.5  7.7  ma 

Grid-No.2  Current                                                                     2.5  2.4  ma 

■  With  external  shield  connected  to  pins  2  or  7. 


HALF-WAVE  VACUUM  RECTIFIER 

Miniature  type  used  as  damper  ^  a  ■  o 

tube  in  horizontal-deflection  circuits  of  O  AL3 

television  receivers.  Outline  9C,  OUT- 
LINES SECTION.  Tube  requires 
miniature  nine-contact  socket  and  may 
be  mounted  in  any  position.  Socket  terminals  1,  2,  3,  6,  7,  and  8  should  not  be  used 
as  tie  points.  It  is  especially  important  that  this  tube,  like  other  power-handling 
tubes,  be  adequately  ventilated.  Heater  volts  (ac/dc),  6.3;  amperes,  1.55. 

DAMPER  SERVICE 

For  operation  in  525-line,  30-frame  system 
Maximum  Ratings,  (Design-Center  Values): 

Peak  Inverse  Plate  Voltage "(AbsoiMfe  maximum)   7500°max  volts 

Peak  Plate  Current   550  max  ma 

DC  Plate  Current   220  max  ma 

Plate  Dissipation.   5  max  watts 

Peak  Heater-Cathode  Voltage   6600  max  volts 

°  Under  no  circumstances  should  this  absolute  value  be  exceeded. 

■  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  horizontal  scanning  cycle.  In  a 
525-line,  30-frame  system,  15  per  cent  of  one  horizontal  scanning  cycle  is  10  microseconds. 


TWIN  DIODE 

^Qjnp^I^^^^  Miniature,  high-perveance  type  X  A  ■  C 

(aI*— •» — I  Y)  used  as  detector  in  FM  and  television  OAL5 
P02®^A-^^4P^       circuits.  It  is  especially  useful  as  a  Reioied  type.: 

>H=^>^  ratio  detector  m  ac-operated  FM  re-  3Ai5,  12AL5 

Kbi  ceivers.  Each  diode  section  can  be  used 

independently  of  the  other,  or  the  two  sections  can  be  combined  in  parallel  or  full- 
wave  arrangement.  Resonant  frequency  of  each  unit  is  approximately  700  mega- 
cycles per  second.  Outline  7A,  OUTLINES  SECTION.  Tube  requires  miniature 
seven-contact  socket  and  may  be  mounted  in  any  position. 

Heater  Voltage  (ac/dc)   6.3  volts 

Heater  Current   0.3  ampere 

Direct  Interelectrode  Capacitances: 

Plate  No.l  to  Cathode  No.l,  Heater,  and  Internal  Shield   2.5  pf 

Plate  No.2  to  Cathode  No.2,  Heater,  and  Internal  Shield   2.5  pf 

Cathode  No.l  to  Plate  No.l,  Heater,  and  Internal  Shield   3.4  pf 

Cathode  No.2  to  Plate  No.2,  Heater,  and  Internal  Shield   3.4  pf 

Plate  No.  1  to  Plate  No.2   0.068  max  pf 


143 


RCA  Receiving  Tube  Manual 


HALF-WAVE  RECTIFIER 
Maximum  Ratings,  {Design-Center  Values): 

Peak  Inverse  Plate  Voltage  

Peak  Plate  Current  (Per  Plate)    

DC  Output  Current  (Per  Plate)  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  

Typical  Operation: 

AC  Plate  Voltage  per  Plate  (rms)  

Min.  Total  Effective  Plate-Supply  Impedance  per  Plate  

DC  Output  Current  per  Plate  


AVERAGE  CHARACTERISTICS 

HALF-WAVE  RECTIFICATION-SINGLE  DIODE 


330  max 

volts 

54  max 

ma 

9  max 

ma 

330  max 

volts 

330  max 

volts 

117 

volts 

300 

ohms 

9 

ma 

TYPE6AL5 

I — 

3  V 

— « 

/ 

h 

> 

B 

\— 
t 

h- 

/  v 

J»  s 

t 

■| 

— 

< 

oh 

ml 

TV 

%\ 

0 

0  /I  X 

POo  / 

|K<V 

1  joobocTt^ 

DJ2 


0J3 


6AL7GT 


-40      -30       -20      -10  0 
DC  VOLTS  DEVELOPED  BY  DIODE 
92CS-656IT 

ELECTRON-RAY  TUBE 

Glass  octal  type  used  to  indicate  visually 
on  a  pair  of  rectangular  fluorescent  patterns  the 
effects  of  changes  in  voltages  applied  to  its  grid 
and  three  deflecting  electrodes.  It  is  especially 
useful  in  meeting  the  requirements  for  accurate 
tuning  in  FM  receivers.  Maximum  dimensions: 
over-all  length,  3-1/16  inches;  seated  height, 
2-1/2  inches;  diameter,  1-9/32  inches.  Tube  re- 
quires octal  socket  and  may  be  mounted  in  any 
position.  Heater  volts  (ac/dc),  6.3;  amperes,  0.15.  Maximum  ratings  in  indicator  service:  fluorescent- 
target  volts,  365  max,  220  min;  peak  heater-cathode  volts,  90  maaj.Typical  operation  in  indicator  service: 
fluorescent-target  volts,  315;  deflecting  electrodes  Nos.1,2,  and  3  volts,  0;  cathode  resistor  (approx.), 
3300  ohms;  deflection  sensitivity  (approx),  1  mm/volt;  grid  volts  for  fluorescence  cutoff,  -7.  This  type 
is  used  principally  for  renewal  purposes. 

BEAM  POWER  TUBE^ 

SHARP-CUTOFF  PENTODE 

Duodecar  type  used  as  FM  detec- 
tor and  audio-frequency  output  am- 
plifier in  television  receivers.  Outline 
12B,  OUTLINES  SECTION.  Tube  re- 
quires duodecar  twelve-contact  socket 
and  may  be  mounted  in  any  position.  Heater  volts  (ac/dc),  6.3;  amperes,  0.9. 

BEAM  POWER  UNIT  AS  CLASS  Ai  AMPLIFIER 
Maximum  Ratings,  {Design-Maximum  Values) : 


6AL11 

Related  type: 
12AL11 


Plate  Voltage  

Grid-No.2  (screen-grid)  Voltage  . 

Plate  Dissipation  

Grid-No.2  Input  


275  max 
275  max 
10  max 
2  max 


volts 
volts 
watts 
watts 


144 


Technical  Data 


Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  max  volts 

Heater  positive  with  res^iect  to  cathode   200"wax  volts 

Typical  Operation: 

Plate  Voltage   250  volts 

Grid-No.2  Voltage   250  volts 

Grid-No.l  (Control-Grid)  Voltage   -8  volts 

Peak  AF  Grid-No.l  Voltage   8  volts 

Zero-Signal  Plate  Current   35  ma 

Maximum-Signal  Plate  Current   39  ma 

Zero-Signal  Grid-No.2  Current     2.5  ma 

Maximum-Signal  Grid-No.2  Current   7  ma 

Plate  Resistance  (Approx.)   0.1  megohm 

Transconductance   6500  /umhos 

Load  Resistance   5000  ohms 

Total  Harmonic  Distortion   10  percent 

Maximum-Signal  Power  Output   4.2  watts 

Maximum  Circuit  Values: 

Grid-No.  1-Circuit  Resistance: 

For  fixed-bias  operation   0 . 25  max  megohm 

For  cathode-bias  operation   0,5  max  megohm 

■  The  dc  component  must  not  exceed  100  volts. 

PENTODE  UNIT  AS  CLASS  Ai  AMPLIFIER 

Characteristics: 

Plate  Supply  Voltage   150  volts 

Grid-No.3  (Suppressor-Grid)  Voltage   0  volts 

Grid-No.2  (Screen-Grid)  Supply  Voltage   100  volts 

Cathode-Bias  Resistor   560  ohms 

Plate  Resistance  (Approx.)   0.15  niegohm 

Transconductance,  Grid  No.l  to  Plate   1000  /xmhos 

Transconductance,  Grid  No.3  to  Plate   400  /xmhos 

Plate  Current   1.3  ma 

Grid-No.2  Current   2.1  ma 

Grid-No.l  Voltage  (Approx.)  for  plate  current  of  30  ^a   -4.5  volts 

Grid-No.3  Voltage  (Approx.)  for  plate  current  of  50  /xa   -4.5  volts 

PENTODE  UNIT  AS  FM  DETECTOR 
Maximum  Ratings,  {Design-Maxitrium  Values): 

Plate  Voltage   330  max  volts 

Grid-No.3  Voltage     28  max  volts 

Grid-No.2  Supply  Voltage  ,   330  max  volts 

Grid-No.2  Voltage   See  curve  page  70 

Grid-No.  1  (control-grid)  Voltage,  Positive-bias  value   0  max  volts 

Plate  Dissipation   1.7  max  watts 

Grid-No.2  Input: 

For  grid-No.2  voltages  up  to  165  volts   1,1  max  watts 

For  grid-No.2  voltages  between  165  and  330  volts   See  curve  page  70 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  max  volts 

Heater  positive  with  respect  to  cathode   200 "max  volts 

■  The  dc  component  must  not  exceed  100  volts. 


6AM4 


HIGH-MU  TRrODE 

Miniature  type  used  as  mixer  and  rf  am- 
plifier in  cathode-drive  circuits  of  uhf  television 
receivers.  Outline  8A,  OUTLINES  SECTION. 
Tube  requires  miniature  nine-contact  socket 
and  may  be  mounted  in  any  position.  Heater 
volts  (ac/dc),  6.3;  amperes,  0.225.  Character- 
istics as  class  Ai  amplifier:  plate-supply  volts, 
200  max;  cathode-bias  resistor,  100  ohms;  am- 
plification factor,  85;  plate  resistance  (approx.), 
8700  ohms;  transconductance,  9800  ^umhos;  plate  ma.,  10;  plate  dissipation,  2  max  watts;  peak  heater- 
cathode  volts,  80  max.  This  type  is  used  principally  for  renewal  purposes. 

145 


RCA  Receiving  Tube  Manual 


DIODE-SHARP-CUTOFF 
PENTODE 

Miniature  types  used  in  diversified 
applications  in  television  receivers. 
Type  6AM8-A  has  a  controlled  heater 
warm-up  time  for  use  in  receivers  em- 
ploying series-connected  heater  strings. 
The  pentode  unit  is  used  as  an  if  amplifier,  video  amplifier,  or  age  amplifier.  The 
high-perveance  diode  is  used  as  an  audio  detector,  video  detector,  or  dc  restorer. 
Outline  8B,  OUTLINES  SECTION.  Tubes  require  miniature  nine-contact  socket 
and  may  be  mounted  in  any  position.  Type  6AM8  is  a  DISCONTINUED  type 
listed  for  reference  only. 


6AM8 

6AM8A 

Related  type: 
5AM8 


Heater  Voltage  (ac/dc)  

Heater  Current  

Heater  Warm-Up  Time  (Average)  for  6AM8-a'.  *.  *.*.'.*.*.* .*  V.  '.  '.  '.  V.  '.  '.  V.  '.  W 
Direct  Interelectrode  Capacitances: 
Diode  Unit: 

Plate  to  Cathode  and  Heater   

Cathode  to  Plate  and  Heater  

Pentode  Unit: 

Grid  No.l  to  Plate   

Grid  No.l  to  Cathode,  Heater,  Grid  No.2,  No.3  and  Internal  Shield .  . 

Plate  to  Cathode,  Heater,  Grid  No.2,  Grid  No.3,  and  Internal  Shield 

Pentode  Grid  No.l  to  Diode  Plate  

Pentode  Plate  to  Diode  Cathode  

Pentode  Plate  to  Diode  Plate  


6.3 
0.45 
11 


1.8 
3 


volts 
ampere 
seconds 


pf 
Pf 


PENTODE  UNIT  AS  CLASS  Ai  AMPLIFIER 
Maximum  Ratings,  {Design-Maximum  Values): 

Plate  Voltage  

Grid-No.3  (suppressor-grid)  Voltage,  Positive  value  

Grid-No.2  (screen-grid)  Supply  Voltage  

Grid-No.2  Voltage.  .  

Grid-No.1  (control-grid)  Voltage,  Positive-bias  value.  

Plate  Dissipation  

Grid-No.2  Input: 

For  grid-No.2  voltages  up  to  165  volts  

For  grid-No.2  voltages  between  165  and  330  volts  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  


0.015  max 

6.5 

2.6 
0 . 006  max 
0. 15  max 

0 . 1  max 


330  max 
0  max 
330  max 


pf 
pf 
pf 
pf 
pf 
pf 


volts 
volts 
volts 


See  curve  page  70 
0  max  volts 
3.2  max  watts 

0.55  max  watt 
See  curve  page  70 


200  max 
200°  max 


volts 
volts 


Characteristics: 

Plate  Supply  Voltage  

gri^  No.3  Connected 

Gnd-No.2  Supply  Voltage  

AVERAGE  CHARACTERISTICS 

PENTOPe  UNIT 


125  volts 
to  cathode  at  socket 
125  volts 


TYPE  6ArJl8-A|       1  1 

E^  s  f>.3  VOLTS  1         1  i 

%»HIU             ANU  INTbKNAl. 

CONNECTED  TO  CATHODE 
CRID>N£2  V0LTS=I50 

AT  S< 

 ^"l 

>CKE7 



C\'0 

\ 

-j  

-V- 

\ 

\ 

\ 

GRID 

•NA| 

volt 

I  EC| 

■-2 

3 

r 

W 

"  -1 

-4 

-a 

146 


42CM-e50ST2 


Cathode-Bias  Resistor                                                                                  56  ohms 

Plate  Resistance  (Approx.)   0.3  megohm 

Transconductance   7800  /xmhos 

Grid-No.l  Voltage  (Approx.)  for  plate  current  of  20                                               -6  volts 

Grid-No.l  Voltage  (Approx.)  for  plate  current  of  2  ma  and  cathode-bias 

resistor  of  0  ohms                                                                                      -3  volts 

Plate  Current   12.5  ma 

Grid-No.2  Current     3.2  ma 

Maximum  Circuit  Values: 

Grid-No.l-Circuit  Resistance: 

For  fixed-bias  operation   0.25  moa:  megohm 

For  cathode-bias  operation   1.0  max  megohm 

DIODE  UNIT 
Maximum  Ratings,  (Design-Maximum  Values): 

DC  Plate  Current  *   5  max  ma 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  max  volts 

Heater  positive  with  respect  to  cathode   200°  max  volts 

°The  dc  component  must  not  exceed  100  volts. 


6AN4 


HIGH-MU  TRIODE 

Miniature  type  used  as  mixer  or 
rf  amplifier  in  cathode-drive  circuits 
of  uhf  television  tuners  covering  the 
frequency  range  of  470  to  890  mega- 
cycles per  second.  Outline  7A,  OUT- 
LINES SECTION.  Tube  requires  miniature  seven-contact  socket  and  may  be 
mounted  in  any  position.  Heater  volts  (ac/dc),  6.3;  amperes,  0.225. 

CLASS  Ai  AMPLIFIER 
Maximum  Ratings,  (Design-Center  Values): 

Plate  Voltage  

Plate  Dissipation  

Cathode  Current  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  

Characteristics: 


300  max 
4  max 
30  max 

200  max 
200"max 


volts 
watts 
ma 

volts 
volts 


Plate-Supply  Voltage  

Cathode-Bias  Resistor  

Amplification  Factor  , 

Transconductance  

Plate  Current  , 

Grid  Voltage  (Approx.)  for  plate  current  of  20  ^a. 

Maximum  Circuit  Values: 

Grid-Circuit  Resistance; 

For  fixed-bias  operation  

For  cathode-bias  operation  

■  The  dc  component  must  not  exceed  100  volts. 


200 
100 
70 
10000 
13 
-7 


0.1  max 
0 . 5  max 


volts 
ohms 

Mmhos 
ma 

volts 


megohm 
megohm 


6AN8 

6AN8A 

Related  type: 
5AN8 


MEDIUM-MU  TRIODE— 
SHARP-CUTOFF  PENTODE 

Miniature  types  used  in  a  wide 
variety  of  applications  in  color  televi- 
sion receivers.  The  6AN8-A  has  a  con- 
trolled heater  warm-up  time  for  use  in 
receivers  employing  series-connected 
heater  strings.  The  pentode  unit  is  used  as  an  intermediate-frequency  amplifier,  a 
video  amplifier,  an  age  amplifier,  or  as  a  reactance  tube.  The  triode  unit  is  used  in 
low-frequency  oscillator,  sync-separator,  sync-clipper,  and  phase-splitter  circuits. 
Outline  8B,  OUTLINES  SECTION.  Tubes  require  miniature  nine-contact  socket 
and  may  be  mounted  in  any  position.  Type  6AN8  is  a  DISCONTINUED  type 
listed  for  reference  only. 


Heater  Voltage  (ac/dc)    

Heater  Current    

Heater  Warm-Up  Time  (Average)  6AN8-A . 


6.3 
0.45 
11 


volts 
ampere 
seconds 


147 


RCA  Receiving  Tube  Manual 


Direct  Intbrelectrodb  Capacitances: 
Triode  Unit: 

Grid  to  Plate   1.5 

Grid  to  Cathode  and  Heater   2.0 

Plate  to  Cathode  and  Heater   0.26 

Pentode  Unit: 

Grid  No.l  to  Plate   0.04  max 

Grid  No.l  to  Cathode,  Heater,  Grid  No.2,  Grid  No.3,  and  Internal  Shield ...  7 

Plate  to  Cathode,  Heater,  Grid  No.2,  Grid  No.3,  and  Internal  Shield   2.4 

Triode  Grid  to  Pentode  Plate  0.02 

Pentode  Grid  No.l  to  Triode  Plate  0.02 

Pentode  Plate  to  Triode  Plate  0.15 

CLASS  Ai  AMPLIFIER 
Maximum  Ratings,  {Design-Maximum  Values): 

Plate  Voltage  

Grid-No.2  Supply  Voltage  

Grid-No.2  (screen-grid)  Voltage    

Grid-No.  1  (control-grid)  VolTage,  Positive-bias  value . 

Plate  Dissipation  

Grid-No.2  Input: 

For  gridTNo.2  voltages  up  to  165  volts  

For  gri(]i-No.2  voltages  between  165  and  330  volts.  .  . . 
Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  


Triode  Unit 
330  max 


0  max 
2.8  max 


200  max 
2QQPmax 


Pentode  Unit 
330  max 
330  max 
See  curve 
0  max 
2 . 3  max 

0. 55  max 
See  curve 

200  max 
200°max 


Pf 
Pf 

pf 

H 


volts 
volts 
page  70 
volts 
watts 

watt 
page  70 

volts 
volts 


Characteristics: 

Plate  Supply  Voltage  

Grid-No.2  Supply  Voltage  

Grid-No.l  Voltage  

Cathode-Bias  Resistor  

Amplification  Factor  

Plate  Resistance  (Approx.)  

Transconductance  

Grid-No.l  Voltage  (Approx.)  for  plate  current  of  20na,  

Grid-No.l  Voltage  (Approx.)  for  plate  current  of  1.6  ma  and 

cathode-bias  resistor  of  0  ohms  

Plate  Current  

Grid-No.2  Current  


Triode  Unit       Pentode  Unit 


150 

-3 

21 
4700 
4500 
-17 


15 


125 
125 


170000 
7800 
-6 

-3 
12 
3.8 


volta 
volts 
volts 
ohms 

ohms 
/xmhos 
volts 

volts 
ma 
ma 


Maximum  Circuit  Values: 

Grid-No.l-Circuit  Resistance:* 

For  fixed-bias  operation   0.5  max  0 . 25  max  megohm 

For  cathode-bias  operation   1.0  max  1 . 0  max  megohm 

"The  dc  component  must  not  exceed  100  volts. 

*lf  either  unit  is  operating  at  maximum  rated  conditions,  grid-No.l-circuit  resistance  for  both  units 
should  not  exceed  the  stated  values. 


6AQ5 

6AQ5A 


BEAM  POWER  TUBE 


Related  types: 
5AQ5,  12AQ5 


Miniature  types  used  as  output 
amplifiers  primarily  in  automobile  re- 
ceivers and  in  ac-operated  receivers 
and,  tri ode-connected,  as  vertical  de- 
flection amplifiers  in  television  receiv- 
ers. Type  6AQ5-A  has  a  controlled  heater  warm-up  time  for  use  in  television 
receivers  employing  series-connected  heater  strings.  Outline  7C>  OUTLINES  SEC- 
TION. Tubes  require  miniature  seven-contact  socket  and  may  be  mounted  in  any 
position.  Within  their  maximum  ratings,  the  performance  of  these  types  is  equiva- 
lent to  that  of  larger  types  6V6  and  6V6-GTA.  Type  6AQ5  is  a  DISCONTINUED 
type  listed  for  reference  only. 


Heater  Voltage  (ac/dc)    6.3  volts , 

Heater  Current   0.45  ampere 

Heater  Warm-Up  Time  (Average)  for  6AQ5-A   11  seconds 

Direct  Interelectrode  Capacitances  (Approx.) : 

Grid  No.l  to  Plate   0.4  pf 

Grid  No.l  to  Cathode,  Heater,  Grid  No.2,  and  Grid  No.3  ,   8  pf 

Plate  to  Cathode,  Heater,  Grid  No.2,  and  Grid  No.3.   8.5  pf 

Amplification  Factor*   9.5 

Plate  Resistance  (Approx.)*     1970  ohms 

Transconductance*   4800  /tmhos 

Grid-No.1  Voltage  (Approx.)  for  plate  current  of  0.5  ma   -37  volts 

*  Grid  No.2  connected  to  plate;  plate  and  grid-No.2  volts,  250;  grid-No.  1  volts,  -12.5;  plate  ma.,  49.5. 

148 


CLASS  Ai  AMPLIFIER 
Maximum  Ratings,  (Design-Maximum  Values): 


Plate  Voltage   275  max  volts 

Grid-No.2  (screen-grid)  Voltage    275  max  volts 

Plate  Dissipation   12  max  watts 

Grid-No.2  Input  ,   2  max  watts 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  max  volts 

Heater  positive  with  respect  to  cathode    200 "wax  volts 

Bulb  Temperature  (At  hottest  point)    250  max  °C 


■  The  dc  component  must  not  exceed  100  volts. 

Typical  Operation: 

Same  as  for  type  6V6-GTA  within  the  limitations  of  the  maximum  ratings. 

Maximum  Circuit  Values: 

Grid-No.  1-Circuit  Resistance: 

For  fixed-bias  operation   0.1  max  megohm 

For  cathode-bias  operation   0.5  max  megohm 


RCA  Receiving  Tube  Manual 


VERTICAL  DEFLECTION  AMPLIFIER  (Triode  Connection)^ 

For  operation  in  a  525-line,  30-frame  system 
Maximum  Ratings,  (Design-Maximum  Values): 


DC  Plate  Voltage   275  max  volts 

Peak  Positive-Pulse  Plate  VoLTAGEf   1100  max  volts 

Peak  Negative-Pulse  Grid-No.1  (control-grid)  Voltage   -275  max  volts 

Peak  Cathode  Current   115  max  ma 

Average  Cathode  Current   40  max  ma 

Plate  Dissipation   10  max  watts 

Peak  Heater-cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  max  volts 

Heater  positive  with  respect  to  cathode   200"max  volts 

Bulb  Temperature  (At  hottest  point)    250  max  °C 

Maximum  Circuit  Value: 

Grid-No.  1-Circuit  Resistance: 

For  cathode-bias  operation   2.2  max  megohms 


°  Grid  No.2  connected  to  plate. 

t  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  vertical  scanning  cycle.  In  a  525- 
line,  30-frame  system,  15  per  cent  of  one  vertical  scanning  cycle  is  2.5  milliseconds. 

■  The  dc  component  must  not  exceed  100  volts. 


TWIN  diode— HIGH-MU  TRIODE 

Miniature  type  used  as  combined  detector, 
amplifier,  and  avc  tube  in  compact  radio  re- 
ceivers. Outline  7B,  OUTLINES  SECTION. 
Tube  requires  miniature  seven-contact  socket. 
Heater  volts  (ac/dc),  6.3;  amperes,  0.15.  Char- 
acteristics of  triode  unit  as  class  Ai  amplifier: 
plate  volts,  250  (300  max);  grid  volts,  -3;  am- 
plification factor,  70;  plate  resistance  (approx.), 
58000  ohms;  transconductance,  1200  /imhos; 
plate  ma.,  1 ;  peak  heater-cathode  volts,  90  max.  This  type  is  used  principally  for  renewal  purposes. 


6AQ6 


TWIN  DIODE— HIGH-MU  TRIODE 

Glass  octal  type  used  as  FM  detector  and  \j) 
audio  amplifier  in  circuits  which  require  diode        POi/^/*\  PN/Tn'^t 
and  triode  units  with  separate  cathodes.  Out-  *' 

diAf\7  flT     line  14C,  OUTLINES  SECTION.  Tube  requires        .  . 

w  AWjf  /  W  I       octal  socket.  Heater  volts  (ac/dc),  6.3;  amperes,  (2\ 

0.3.  Ratings  and  characteristics  of  triode  unit  as  w\\  <^^^^^K 

class  Ai  amplifier:  plate  volts,  250  max;  grid  (m"*  (a) 

volts,  -2;  amplification  factor,  70;  plate  resist-  P02 
ance  (approx.),  44000  ohms;  transconductance, 
1600  /imhos;  plate  ma.,  2.3.  This  type  is  used  principally  for  renewal  purposes. 

HIGH-MU  TWIN  TRIODE  "Q-^:::®''^ 
m  ^  Miniature  type  used  as  rf  ampli-  *^'r20,^2ln^^0*^'^» 

O-rV\j|0         fier    and   self-oscillating   mixer   in       Mof"  """jfL, 
FM/AM  radio  receivers.  Outline  8B,     -  /\]^(5Xt 
OUTLINESSECTION.Tuberequires      ^  0^^^^^^ 
nine-contact  socket  and  may  be  oper-  '*''"2^ 
ated  in  any  position.  Heater  volts  (ac/dc),  6.3;  amperes,  0.435.  With  plate  volts 
of  250  and  grid  volts  of  -2.3,  class  Ai  characteristics  of  each  unit  are:  plate  ma,  10; 
plate  resistance  (approx.),  9700  ohms;  transconductance,  5900  /xmhos;  amplifi- 
cation factor,  57. 

Maximum  Ratings,  (Design-Center  Values,  Each  Unit): 

Plate  Voltage  with  plate  ma  =  0   550  max  volts 

Plate  Voltage   300  max  volts 

Grid  Voltage,  Negative-bias  value   -100  max  volts 

Plate  Dissipation: 

For  either  plate   2.5  max  watts 

For  both  plates  with  both  units  operating   4.5  max  watts 

Cathode  Current   15  max  ma 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   90  max  volts 

Heater  positive  with  respect  to  cathode   90  max  volts 

150 


Technical  Data 


RF 

Typical  Operation,  (Each  Unit):                                           Amplifier  Converter 

Plate  Supply  Voltage                                                                  250  250 

Plate  Voltage   230 

Plate  Resistor                                                                          1800  12000 

Grid  Resistor                                                                                -  1 

Grid  Voltage   -2 

RMS  Oscillator  Voltage                                                                 -  3 

Cathode  Resistor   200 

Plate  Resistance  (Approx.)                                                         9700  22000 

Transconductance   6000 

Conversion  Transconductance                                                           -  2300 

Input  Resistance  at  frequency  (Mc)  =  100                                   6000  15000 

Plate  Current                                                                              10  5.2 

Equivalent  Noise  Resistance                                                        500  - 

Maximum  Circuit  Values,  (Each  Unit): 

Grid-Circuit  Resistance   1  max 

Resistance  between  Cathode  and  Heater   20000  max 


volts 
volts 
ohms 
megohm 
volts 
volts 
ohms 
ohms 
/Limhos 
/Ltmhos 
ohms 
ma 
ohms 


megohm 
ohms 


6AR5 


POWER  PENTODE 

Miniature  type  used  as  output  tube  prima- 
rily in  automobile  receivers  and  ac-operated  re- 
ceivers. Outline  7C,  OUTLINES  SECTION. 
Tube  requires  miniature  seven-contact  socket 
and  may  be  mounted  in  any  position.  Heater 
volts  (ac/dc),  6.3;  amperes,  0.4.  Maximum 
ratings  as  class  Ai  amplifier:  plate  and  grid-No.2 
(screen-grid)  volts,  250  max;  plate  dissipation, 
8.5  max  watts;  grid-No.2  input,  2.5  max  watts; 
peak  heater-cathode  volts,  90  max.  Within  its  maximum  ratings,  type  6AR5  is  equivalent  in  performance 
to  glass-octal  type  6K6-GT.  Type  6AR5  is  used  principally  for  renewal  purposes. 

SEMIREMOTE-CUTOFF 

TWIN  PENTODE 

Duodecar  type  used  as  if-ampli- 
fier  tube  in  television  receivers.  Out- 
line 12A,  OUTLINES  SECTION. 
Tube  requires  duodecar  twelve-con- 
tact-socket and  may  be  mounted  in 
any  position.  Heater  volts  (ac/dc),  6.3;  amperes,  0.8. 


6AR11 

Related  type: 
11AR11 


CLASS  Ai  AMPLIFIER 

Values  for  each  unit 
Maximum  Ratings,  (Design-Maximum  Values): 

Plate  Voltage   330  max  volts 

Grid-No.3  (suppressor-grid)  Voltage,  Positive  value   0  max  volts 

Grid-No.2  (SCREEN-GRID)  Supply  Voltage   330  wax  volts 

Grid-No.2  Voltage  See  curve  page  70 

Grid-No.1  (control-grid)  Voltage,  Positive-bias  value   0  max  volts 

Grid-No.2  Input: 

For  grid-No.2  voltages  up  to  165  volts   0.65  max  watt 

For  grid-No.2  voltages  between  165  and  330  volts  See  curve  page  70 

Plate  Dissipation   3.1  max  watts 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  max  volts 

Heater  positive  with  respect  to  cathode   200°max  volts 

Characteristics,  (Each  Unit): 

Plate  Supply  Voltage   125  volts 

Grid  No.3  Connected  to  cathode  at  socket 


Grid-No.2  Supply  Voltage  

Cathode-Bias  Resistor  

Plate  Resistance  (Approx.)  

Transconductance  

Plate  Current  

Grid-No.2  Current  

Grid-No.l  Voltage  (Approx.)  for  transconductance  of  50  /imhos. 
°  The  dc  component  must  not  exceed  100  volts. 


125 
56 

0.2 
10500 
11 

3.5 

-15 


volts 
ohms 
megohm 
/xmhos 
ma 
ma 
volts 


151 


RCA  Receiving  Tube  Manual 


6AS5 


BEAM  POWER  TUBE 

Miniature  type  used  as  output 
amplifier  primarily  in  automobile  and 
in  ac-operated  receivers.  Outline  7C, 
OUTLINES  SECTION.  Tube  re- 
quires miniature  seven-contact  socket 
and  may  be  mounted  in  any  position. 
For  curves  of  average  plate  charac- 
teristics, refer  to  type  35C5. 


Heater  Voltage  (ac/dc)  

Heater  Current  

Direct  Interelectrodb  Capacitances  (Approx.) : 

Grid  No.l  to  Plate  

Grid  No.l  to  Cathode,  Heater,  Grid  No.2,  and  Grid  No.3. 

Plate  to  Cathode,  Heater,  Grid  No.2,  and  Grid  No.3  


6.3 
0.8 

0.6 
12 
9.0 


CLASS  Ai  AMPLIFIER 
Maximum  Ratings,  {Design-Center  Values): 

Plate  Voltage   150  max 

Grid-No.2  (screen-grid)  Voltage   117  max 

Plate  Dissipation   5.5  max 

Grid-No.2  Input   1.0  max 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   100  max 

Heater  positive  with  respect  to  cathode   100  max 

Bulb  Temperature  (At  hottest  point)   250  max 

Typical  Operation: 

Plate  Voltage   150 

Grid-No.2  Voltage   110 

Grid-No.l  (Control-Grid)  Voltage   -8.5 

Peak  AF  Grid-No.  1  Voltage   8.5 

Zero-Signal  Plate  Current   35 

Maximum-Signal  Plate  Current   36 

Zero-Signal  Grid-No.2  Current  (Approx.)   2 

Maximum-Signal  Grid-No.2  Current  (Approx.)   6.5 

Transconductance   5600 

Load  Resistance   4500 

Total  Harmonic  Distortion   10 

Maximum-Signal  Power  Output   2.2 

Maximum  Circuit  Values: 

Grid-No.l-Circuit  Resistance: 

For  fixed-bias  operation   0.1  max 

For  cathode-bias  operation   0.5  max 


volts 
ampere 

Pf 
Pf 
pf 


volts 
volts 
watts 
watt 

volts 
volts 
"C 


volts 
volts 
volts 
volts 
ma 
ma 
ma 
ma 
Mmhos 
ohms 
per  cent 
watts 


megohm 
megohm 


DIODE-  H    ^  Po 

SHARP-CUTOFF  PENTODE  ^  Q^^^^^^ 

£LKQ^Ck                Miniature  type  used  in  diversified  c-"^^rr 

0/\D0          applications  in  television  and  radio  re-  (Ti(ur^  ^""^ks) 

Related  type:           ceivers.  The  pentode  unit  is  used  as  an  ^'p^njj^ 

if  amplifier,  video  amplifier,  or  age  ^2®^  ^® 
amplifier.  The  high-perveance  diode  is 
used  as  an  audio  detector,  video  detector,  or  dc  restorer.  Outline  8B,  OUTLINES 

SECTION.  Tube  requires  miniature  nine-contact  socket  and  may  be  mounted  in 
any  position. 

Heater  Voltage  (ac/dc)   6.3  volts 

Heater  Current   0.45  ampere 

Direct  Interelectrode  Capacitances: 
Diode  Unit: 

Plate  to  Cathode,  Heater,  Pentode  Grid  No.3,  and  Internal  Shield  3.0  pf 
Pentode  Unit: 

Grid  No.l  to  Plate   0 . 03  max  pf 

Grid  No.l  to  Cathode,  Heater,  Grid  No.2,  Grid  No.3,  and  Internal  Shield  7  pf 

Plate  to  Cathode,  Heater,  Grid  No.2,  Grid  No.3,  and  Internal  Shield   2.4  pf 

Pentode  Grid  No.l  to  Diode  Plate   0.005  moa;  pf 

Pfentode  Plate  to  Diode  Cathode   0. 15  max  pf 

Pentode  Plate  to  Diode  Plate   0.10  max  pf 

152 


PENTODE  UNIT  AS  CLASS  Ai  AMPLIFIER 
Maximum  Ratings,  (Design-Center  Values): 

Plate  Voltage  

Grid-No.3  (suppressor-grid)  Voltage,  Positive  value  

Grid-No.2  Supply  Voltage  

Grid-No.2  (screen-grid)  Voltage  

G  rid-No.  1  (control-grid)  Voltage,  Positive  bias  value  

Plate  Dissipation  

Grid-No.2  Input: 

For  grid-No.2  voltages  up  to  150  volts  

For  grid-No.2  voltages  between  150  and  300  volts  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  

Characteristics: 


300  max  volts 
0  max  volts 
300  max  volts 
See  curve  page  70 
0  max  volts 
2 . 5  max  watts 

0 . 5  max  watt 
See  curve  page  70 


200  max 
200°max 


volts 
volts 


Plate  Supply  Voltage  

Grid  No.3  and  Internal  Shield  

Grid-No.2  Supply  Voltage   150 

Cathode-Bias  Resistor   180 

Plate  Resistance  (Approx.)   300000 


200  volts 
Connected  to  cathode  at  socket 
volts 
ohms 


Transconductance . 
Grid-No.l  Voltage  (Approx.)  for  plate  current  of  10  n&. 

Plate  Current  

Grid-No.2  Current  


6200 
-8 
9.5 
3 


ohms 
/imhos 
volts 


megohm 
megohm 


330  max 

volts 

50  max 

ma 

5  max 

ma 

200  max 

volts 

2Q0**max 

volts 

Maximum  Circuit  Values: 

Grid-No.l-Circuit  Resistance: 

For  fixed-bias  operation   0 . 25  max 

For  cathode-bias  operation   1.0  max 

**  The  dc  component  must  not  exceed  100  volts. 

DIODE  UNIT 

Maximum  Ratings,  (Design-Center  Values): 

Peak  Inverse  Plate  Voltage  

Peak  Plate  Current  

DC  Plate  Current  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  

°  The  dc  component  must  not  exceed  100  volts. 

DUAL  TRIODE— 
SHARP-CUTOFF  PENTODE 

Duodecar  type  used  in  television  ^  -  « 

receivers.  High-mu  triode  is  used  in  OASi  I 

audio  if-amplifier  service;  medium- 
mu  triode  is  used  in  sync-separator 
service;  pentode  is  used  in  video  am- 
plifier service.  Outline  12B,  OUTLINES  SECTION.  Tube  requires  12-contact  sock- 
et and  may  be  mounted  in  any  position.  Heater  voltage  (ac/dc),  6.3;  amperes,  1.05. 


Maximum  Ratings,  (Design-Maximum  Vahies): 

Plate  Voltage  

Grid-No.2  (screen-grid)  Supply  Voltage  

Grid-No.2  Voltage  

Grid-No.  1  (control-grid)  Voltage, 

Positive-bias  value  

Grid-No.2  Input: 

For  grid-No.2  voltages  up  to  165  volts  

For  grid-No.2  voltages  between  165  and  330  volts 

Plate  Dissipation  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  


CLASS  Ai  AMPLIFIER 

Triode  Units 
No.l  No.2 
330  max  330  max 


Pentode 
Unit 

330  max  volts 
330  max  volts 
See  curve  page  70 


0  max     0  max 


1.5  max     2  max 


200  max  200  max 
200°»nax  200°»naa: 


0  max 


volts 


1 . 1  max  watts 
See  curve  page  70 
5  max  watts 


Characteristics: 

Plate  Supply  Voltage   200 

Grid-No.2  Supply  Voltage  

Grid  Voltage.   -2 

Cathode-Bias  Resistor   - 

Amplification  Factor   68 

Plate  Resistance  (Approx.) ,   12400 


200 


220 
41 
9400 


200  max 
2Q0°max 


200 
125 


68 
70000 


volts 
volts 


volts 
volts 
volts 
ohms 

ohms 

153 


RCA  Receiving  Tube  Manual 


Transconductance  

Plate  Current  

Grid-No.2  Current  

Grid-No.  1  Voltage  (Approx.): 

For  plate  current  of  10  ^ta  

For  plate  current  of  100  /ta  

Maximum  Circuit  Values,  {Each  Unit): 
Grid-No.  1-Circuit  Resistance: 

For  fixed-bias  operation  

For  cathode-bias  operation  

"  The  dc  component  must  not  exceed  100  volts. 


5500 
7 


4400 
9.2 


-6.5 


0.5  max  0.5  max 
1  max     1  max 


10500 
24 
5.2 


0.25  max 
1  max 


/umbos 
ma 
ma 

volts 
volts 


megohm 
megohm 


6AT6 

Related  type: 
12AT6 


TWIN  DIODE— HIGH-MU  TRIODE 

Miniature  type  used  as  a  com- 
bined detector,  amplifier,  and  avc  tube 
in  automobile  and  ac-operated  radio 
receivers.  Outline  7B,  OUTLINES 
SECTION.  Tube  requires  miniature 
seven-contact  socket  and  may  be  mounted  in  any  position.  For  typical  operation  as 
resistance-coupled  amplifier,  refer  to  RESISTANCE-COUPLED  AMPLIFIER 
SECTION. 

Heater  Voltage  (ac/dc)  

Heater  Current  

Direct  Interelectrodb  Capacitances: 

Triode  Grid  to  Triode  Plate  

Triode  Grid  to  Cathode  and  Heater  

Triode  Plate  to  Cathode  and  Heater  

Plate  of  Diode  Unit  No.2  to  Triode  Grid  

TRIODE  UNIT  AS  CLASS  A,  AMPLIFIER 
Maximum  Ratings,  {Design-Center  Values): 

Plate  Voltage  

Plate  Dissipation  

Grid  Voltage,  Positive-bias  value  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  

Characteristics: 

Plate  Voltage  

Grid  Voltage  

Amplification  Factor  

Plate  Resistance  

Transconductance  

Plate  Current  


6.3 
0.3 

2.0 
2.2 
0.8 
0.04  max 


volts 
ampere 

Pf 
pf 


300  max 
0 . 5  max 
0  max 

90  max 
90  wax 


volts 
watt 

volts 

volts 
volts 


100 
-1 
70 
54000 
1300 
0.8 


250 
-3 
70 
58000 
1200 
1.0 


volts 
volts 

ohms 
/xmhos 
ma 


DIODE  UNITS 

Maximum  Rating,  (Design-Center  Value): 

Plate  Current  (Each  Unit)   1.0  max  ma 

The  two  diode  plates  are  placed  around  a  cathode,  the  sleeve  of  which  is  common  to  the  triode  unit. 
Each  diode  jplate  has  its  own  base  pin.  For  diode  operation  curves,  refer  to  type  6AV6. 


6AT8 

6AT8A 


MEDIUM-MU  TRIODE- 
SHARP-CUTOFF  PENTODE 


Related  type: 
5AT8 


Miniature  types  used  as  combined 
oscillator  and  mixer  tubes  in  television 
receivers  utilizing  an  intermediate  fre- 
quency in  the  order  of  40  megacycles 
per  second.  Type  6AT8-A  has  a  con- 
trolled heater  warm-up  time  for  use  in  receivers  employing  series-connected  heater 
strings.  Outline  8B,0UTLINES  SECTI0N.  Except  for  interelectrode  capacitances 
and  basing  arrangement,  these  types  are  identical  with  miniature  type  6X8.  The 
basing  arrangement  of  the  6AT8  and  6AT8-A  is  particularly  suitable  for  connection 
to  the  coils  of  certain  designs  of  turret  tuners.  Type  6AT8  is  a  DISCONTINUED 
type  listed  for  reference  only. 


Heater  Voltage  (ac/dc)  

Heater  Current  

Heater  Warm-Up  Time  (Average)  for  6AT8-A . 

154 


6.3 
0.45 
11 


volts 
ampere 
seconds 


Technical  Data 


Without  Wiih 

Direct  Intbrblectrodb  Capacitances:  ^^f*''??'  ^^f^fJ^i 

Triode  Unit:  Shield  Shield' 

Grid  to  Plate                                                                     1.5  15  pf 

Grid  to  Cathode  and  Heater                                                 2.0  2.4  pf 

Plate  to  Cathode  and  Heater                                                0.5  1.0  pf 

Pentode  Unit: 

Grid  No.  1  to  Plate   0.06  max  0.03  wax  pf 

Grid  No.  1  to  Cathode,  Heater,  Grid  No.2,  and  Grid  No.3              4  .6  4  .8  pf 

Plate  to  Cathode,  Heater,  Grid  No.2,  and  Grid  No.3                  0.9  1.6  pf 

Pentode  Grid  No.l  to  Triode  Plate   0.05  max  0.04  max  pf 

Pentode  Plate  to  Triode  Plate   0.05  max  0.008  max  pf 

Heater  to  Cathode                                                                  6.0  6. Of  pf 

"  With  external  shield  connected  to  cathode  except  as  noted, 
t  With  external  shield  connected  to  plate. 

p 

HALF-WAVE  VACUUM  RECTIFIER 

^  Glass  octal  types  used  as  damper  AAU4GT 

tubes  in  horizontal-deflection  circuits  OMU**\JI 
ic^  V  VsT^        of  color  television  receivers  and  of  tele-    ^  A  |  T  A 

fuMs)         vision  receivers  utilizing  picture  tubes    OA\Unr\SP'  I  A\ 

having  wide-angle  deflection.  Outline 
14F,  OUTLINES  SECTION.  Tubes  require  octal  socket  and  may  be  mounted  in 
any  position.  These  types  may  be  supplied  with  pin  No.l  omitted.  Socket  terminals 
1,  2,  4,  and  6  should  not  be  used  as  tie  points.  It  is  especially  important  that  these 
tubes,  like  other  power-handling  tubes,  be  adequately  ventilated.  Type  6AU4-GT 
is  a  DISCONTINUED  type  listed  for  reference  only. 

Heater  Voltage  (AC/DC)   6.3  volts 

Heater  Current   1.8  amperes 

Direct  Interelectrode  Capacitances  (Approx.): 

Plate  to  Heater  and  Cathode   8.5  pf 

Cathode  to  Heater  and  Plate   11.5  pf 

Heater  to  Cathode    4.0  pf 

DAMPER  SERVICE 

For  operation  in  a  525-linet  SO-frame  system 

6AVU-GT  6AUU-GTA 
^    ,  Design-Center  Design-Maximum 

Maximum  Ratings:  Values'  Values 

Peak  Inverse  Plate  VoltageI   4500'*mox    4500  max  volts 

Peak  Plate  Current   1050  max    1300  max  ma 

DC  Plate  Current   175  max     210  max  ma 

Plate  Dissipation   6  max     6.5  max  watts 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   4500®*max    4500*  max  volts 

Heater  positive  with  respect  to  cathode   300#  max      300#  max  volts 

T Except  as  noted. 
The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  horizontal  scanning  cycle.  In  a 
525-line,  30-frame  system,  15  per  cent  of  one  horizontal  scanning  cycle  is  10  microseconds. 
°  Absolute  Maximum.  Under  no  circumstances  should  this  absolute  value  be  exceeded. 

♦  The  dc  component  must  not  exceed  900  volts. 
f  The  dc  component  must  not  exceed  100  volts. 

^--^  BEAM  POWER  TUBE 

^  G)Cp...   \  Glass  octal  type  used  as  horizon- 

tr^l  J-v  deflection  amplifier  in  low-cost,  high-       A  A I  I  ^  ^  T 

HvE^J/vi^^H     efficiency  deflection  circuits  of  televi-      0#\w3  w  I 
sion  receivers  employing  either  trans- 
^\  former  coupling  or  direct  coupling  to 

the  deflecting  yoke.  Outline  14C,  OUTLINES  SECTION.  Tube  requires  octal 
socket  and  may  be  mounted  in  any  position. 

heater  Voltage  (ac/dc)   6,3  volts 

Heater  Current   1 . 25  amperes 

Direct  Interelectrode  Capacitances  (Approx.): 

Grid  No.l  to  Plate   0.5  pf 

Grid  No.l  to  Cathode,  Heater,  Grid  No.2,  and  Grid  No.3   11.3  pf 

Plate  to  Cathode,  Heater,  Grid  No.2,  and  Grid  No.3   7.0  pf 

Transconductance#  i   5600  Mmhos 

Mu-Factor,  Grid  No.2  to  Grid  No.lf   5.9 

#  For  plate  volts,  115;  grid-No.2  volts,  175;  grid-No.l  volts,  -20. 
t  For  plate  volts,  100;  grid-No.2  volts,  100;  grid-No.l  volts,  -4.5. 

155 


RCA  Receiving  Tube  Manual 


HORIZONTAL  DEFLECTION  AMPLIFIER 

For  operation  in  a  525'line,  SO-frame  system 
Maximum  Ratings,  (Design-Center  Values): 

DC  Plate  Voltage   550  max  volts 

Peak  Positive-Pulse  Plate  Voltage*  ( Absolute  Maximum)   5500*>wtaaj  volts 

Peak  Negative-Pulse  Plate  Voltage     -1250  max  volts 

DC  Gbid-No.2  (screen-grid)  Voltage*   200  max  volts 

Peak  Negative-Pulse  Grid-No.1  (control-grid)  Voltage   -300  wax  volts 

Peak  Cathode  Current   400  max  iha 

Average  Cathode  Current   110  max  ma 

Grid-No.2  Input    2.5  max  watts 

Plate  Dissipation  ft  •   10  max  watts 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  max  volts 

Heater  positive  with  respect  to  cathode   200mmax  volts 

Bulb  Temperature  (At  hottest  point)   210  max  °C 

Maximum  Circuit  Value: 

Grid-No.l-Circuit  Resistance   0 . 47  max  megohm 

*  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  horizontal  scanning  cycle.  In  a 
525-line,  30-frame  system,  15  per  cent  of  one  horizontal  scanning  cycle  is  10  microseconds. 

°  Under  no  circumstances  should  this  absolute  value  be  exceeded. 

*  Obtained  through  a  series  dropping  resistor  of  sufficient  magnitude  to  limit  the  grid-No.2  input  to  the 
rated  maximum  value. 

ttAn  adequate  bias  resistor  or  other  means  is  required  to  protect  the  tube  in  the  absence  of  excitation. 

■  The  dc  component  must  not  exceed  100  volts. 

H  P 

6AU6  SHARP-CUTOFF  PENTODE  H^^y^M^^o^ 

X.  A  I  I  ^  A  Miniature  types  used  iii  compact  yf  r-i^^'p 

OAUOA       radio  equipment  as  rf  amplifier  espe-        riA  r*V^ 
R«iat«d  types:  cially  in  high-f  requency,  wide-band  ap-  ca^^^X^^TT^** 

4AU6, 12AU6  plications;  also  used  as  limiter  tube  in  ^T^^^^ 
FM  equipment.  Type  6AU6-A  has  a  ^« 
controlled  heater  warm-up  time  for  use  in  applications  employing  series-connected 
heater  strings.  Outline  7B,  OUTLINES  SECTION.  Tubes  require  miniature  seven- 
contact  socket  and  may  be  operated  in  any  position.  For  a  discussion  of  limiters, 
refer  to  ELECTRON  TUBE  APPLICATIONS  SECTION.  For  typical  oper- 
ation as  resistance-coupled  amplifier,  refer  to  RESISTANCE-COUPLED  AM- 
PLIFIER SECTION.  Type  6AU6  is  a  DISCONTINUED  type  listed  for  refer- 
ence only. 

Hbater  Voltage  (ac/dc)   6.3  volts 

Heater  Current   ....       0.3  ampere 

Heater  Warm-Up  Time  (Average)  for  6AU6'A   11  seconds 

Direct  Interelectrode  Capacitances:  Without  \Vith 

External  External 

Pentode  Connection:  ^^^^^^  Shield* 

Grid  No.l  to  Plate   0.0035  max   0.0035  max  pf 

Grid  No.l  to  Cathode,  Heater,  Grid  No.2,  Grid  No.3, 

and  Internal  Shield   5.5  5.5  pf 

Plate  to  Cathode,  Heater,  Grid  No.2,  Grid  No.3,  and 

Internal  Shield   5.0  5.0  pf 

Triode  Connection:^ 

Grid  No.l  to  Plate,  Grid  No.2,  Grid  No.3,  and 

Internal  Shield   2.6  2.6  pf 

Grid  No.l  to  Cathode  and  Heater   3.2  3.2  pf 

Plate,  Grid  No.2,  Grid  No.3,  and  Internal  Shield  to 

Cathode  and  Heater    1.2  8.5  pf 

■  With  external  shield  connected  to  cathode. 

t  Grid  No.2,  grid  No.3,  and  internal  shield  connected  to  plate. 

CLASS  Ai  AMPLIFIER  y^.^^,^  p,^^^^. 

Maximum  RaWngs,  {Design-Maximum  Values):  Connection  Connection 

Plate  Voltage     275  max  330  max  volts 

GiiiD-No.3  (suppressor-grid)  Voltage,  Positive  value   -  0  max  volts 

Grid-No.2  (screen-grid)  Voltage.  . . ,   -  See  curve  page  70 

Grid-No.2  Supply  Voltage   -  330  max  volts 

Plate  Dissipation   3.  5  mox  3.5  max  watts 

156 


Grid-No.2  Input: 

For  grid-No.2  voltages  up  to  165  volts   -  0.75  max  watt 

For  grid-No.2  voltages  between  165  and  330  volts   -  See  curve  page  70 

GRID-No.1  (CONTROL-GRID)  VOLTAGE: 

Positive-bias  value   0  max  0  max  volts 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  max  200  max  volts 

Heater  positive  with  respect  to  cathode   200^max  200^max  volts 

Characteristics:                                              clnnedion  Pentode  Connection 

Plate  Supply  Voltage                                                250  100        250  250  volts 

Grid  No.3                                                                  -  Connected  to  cathode  at  socket 

Grid-No.2  Supply  Voltage                                           -  100        125  150  volts 

Cathode-Bias  Resistor                                                330  150        100  68  ohms 

Amplification  Factor                                                   36  -  - 

Plate  Resistance  (Approx.)                                           -  0.5        1.5  1.0  megohms 

Transconductance                                                   4800  3900       4500  5200  /xmhos 

Grid-No.l  Voltage  for  plate  current  of  10  Ma                  -  -4.2      -5.5  -6.5  volts 

Plate  Current                                                        12.2  5.0        7.6  10.6  ma 

Grid-No.  2  Current                                                  -  2.1        3.0  4.3  ma 

t  Grid  No.2,  grid  No.3,  and  internal  shield  connected  to  plate. 
^  The  dc  component  must  not  exceed  1 00  volts. 


AVERAGE  CHARACTERISTICS 


TYPE  6AU(B  11 
Efs  6.3  VOLTS                 |  | 

CC 
CRIO 

NNECT 
-N»2  V 

:o  TO 

5LTSS 

:athod 

00 

E  at  S 

ocket. 

lb 

ECI  =  0 

—  0.5- 

f 

GRID-N 

tl  VOL 

TS  EC  I 

s-I.O 

ECl-O 

-1.5 

lb 

-2.0 

2.5 

 \^ 

KT2, 


GT2 


MEDIUM-MU  TWIN  TRIODE 

Miniature  type  used  as  phase  inverter  or 
amplifier  in  television  receivers  employing  series- 
connected  heater  strings.  Outline  8B,  OUT-  ,  «  ■  ■  — 
LINES  SECTION.  Heater  volts  (ac/dc),  6.3  6AU7 
(series),  3.15  (parallel);  amperes,  0.3  (series), 
0.6  (parallel) ;  warm-up  time  (average)  in  paral- 
lel arrangement,  11  seconds.  Except  for  heater 
and  heater-cathode  ratings,  this  type  is  identical 
with  miniature  type  12AU7.  The  6AU7  is  a 
DISCONTINUED  type  listed  for  reference  only. 


MEDIUM-MU  TRIODE— 

SHARP-CUTOFF  PENTODE  6AU8 

Miniature  types  used  in  television  ^  a  ■  ■  O  A 
receiver  applications.  Tubes  have  con-  W  AU  O  A 
trolled  heater  warm-up  time  for  use  in  Related  type: 

series-heater  strings.  Pentode  unit  is  saus 
used  as  video  amplifier,  if  amplifier, 
age  amplifier.  Triode  unit  is  used  in  sync-amplifier,  sync-separator,  sync-clipper, 
and  phase-inverter  circuits.  Outline  8D,  OUTLINES  SECTION.  Tubes  require 
nine-contact  socket  and  may  be  mounted  in  any  position.  Type  6AU8  is  a  DIS- 
CONTINUED type  listed  for  reference  only. 


157 


RCA  Receiving  Tube  Manual 


Heater  Voltage  (ac/dc)   6.3  volts 

Heater  Current   0.6  ampere 

Heater  Warm-up  Time  (Average)   11  seconds 

Direct  Interelectrode  Capacitances: 
Triode  Unit: 

Grid  to  Plate   2.2  pf 

Grid  to  Cathode  and  Heater   2.6  pf 

Plate  to  Cathode  and  Heater   0.34  pf 

Pentode  Unit: 

Grid  No.l  to  Plate   0.06  pf 

Grid  No.l  to  Cathode,  Heater,  Grid  No.2,  Grid  No.3,  and  Internal  Shield  7.5  pf 

Plate  to  Cathode,  Heater,  Grid  No.2,  Grid  No.3,  and  Internal  Shield   3.4  pf 

Triode  Grid  to  Pentode  Plate   0.022  max  pf 

Pentode  Grid  No.l  to  Triode  Plate   0 . 006  max  pf 

Pentode  Plate  to  Triode  Plate   0.12  max  pf 

Maximum  Ratings,  {Design-Maximum  Values):  Triode  Unit    Pentode  Unit 

Plate  Voltage                                                                       330  max  330  max  volts 

Grid-No.2  (screen-grid)  Supply  Voltage                                   -  330  max  volts 

Grid-No.2  Voltage.                                                                 -  See  curve  page  70 

Grid-No.  1  (control-grid)  Voltage,  Positive-bias  value                    0  max  0  max  volts 

Plate  Dissipation                                                                    2.^  max  3.3  max  watts 

Grid-No.2  Input 

For  grid-No. 2  voltages  up  to  165  volts                                      -  1  max  watt 

For  grid-No.2  voltages  between  165  and  330  volts                       -  See  curve  page  70 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode                                  200  max  200  max  volts 

Heater  positive  with  respect  to  cathode                                   200"/nax  200"max  volts 

Characteristics:                                                                       Triode  Unit  Pentode  Unit 

Plate  Supply  Voltage                                                                  150  200  volts 

Grid-No.2  Supply  Voltage                                                              -  125  volts 

Cathode-Bias  Resistor                                                                   150  82  ohms 

Amplification  Factor                                                                    43  - 

Plate  Resistance  (Approx.)                                                         8100  100000  ohms 

Transconductance                                                                     5300  8000  jumhos 

Grid-No.l  Voltage  (Approx.)  for  plate  current  of  100  Ata                 -6-5  -7.5  volts 

Plate  Current                                                                               9.5  17  ma 

Grid-No.2  Current                                                                           -  3.4  ma 

Maximum  Circuit  Values: 

Grid-No. 1-Circuit  Resistance: 

For  fixed-bias  operation                                                        0.5  max  0 . 25  max  megohm 

For  cathode-bias  operation                                                    1.0  max  1 . 0  max  megohm 

■  The  dc  component  must  not  exceed  100  volts. 


6AV5GA 

6AV5GT 

Related  types: 
12AV5GA,  25AV5GA 


BEAM  POWER  TUBE 

Glass  octal  types  used  as  hori- 
zontal deflection  amplifiers  in  tele- 
vision   receivers    employing  either 
transformer  coupling  or  direct  cou- 
pling to  the  deflecting  yoke.  6AV5-GA 
Outline  19B,  6AV5-GT  Outline  14C,  OUTLINES  SECTION.  Tubes  require  octal 
socket  and  may  be  mounted  in  any  position.  Type  6AV5-GT  is  a  DISCONTINUED 
type  listed  for  reference  only. 


Heater  Voltage  (ac/dc)   6.3 

Heater  Current  ^ .  1.2 

Transconductance*   5900 

Mu  Factor,  Grid  No.2  to  Grid  No.l**   4.3 

*  Plate  volts,  250;  grid-No.2  volts,  150;  grid-No.l  volts,  -22.5. 

**  Triode  connected;  plate  and  grid-No.2  volts,  150;  grid-No.l  volts,  -22.5. 


volts 
amperes 
jumhos 


HORIZONTAL  DEFLECTION  AMPLIFIER 

For  operation  in  a  525-line,  SO-frame  system 
Maximum  Ratings,  (Design-Center  Values): 


DC  Plate  Voltage   550  mox  volts 

Peak  Positive-Pulse  Plate  Voltage!  (Absolute  Maximum)   5500°waa;  volts 

Peak  Negative-Pulse  Plate  Voltage   -1250  max  volts 

DC  Grid-No.2  (screen-grid)  Voltage     175  max  volts 

Peak  Negative-Pulse  Grid-No.1  (control-grid)  Voltage   -300  max  volts 


158 


Peak  Cathode  Current   400  max  ma 

Average  Cathode  Current   110  max  ma 

Grid-No.2  Input   2.5  max  watts 

Plate  DiasiPATiONft   11  max  watts 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  max  volts 

Heater  positive  with  respect  to  cathode   200«ma»  volts 

Bulb  Temperature  (At  hottest  point)   210  max  ^C 

Maximum  Circuit  Value: 

Grid-No.l  Circuit  Resistance   0.47  max  megohm 


t  The  duration  of  the  voltage  pulse  must  not  exceed  16  per  cent  of  one  horizontal  scanning  cycle.  In  a 
525-line,  30-frame  system,  15  per  cent  of  one  horizontal  scanning  cycle  is  10  microseconds. 
°  Under  no  circumstances  should  this  absolute  value  be  exceeded. 

tt  An  adequate  bias  resistor  or  other  means  is  required  to  protect  the  tube  in  the  absence  of  excitation . 
■  The  dc  component  must  not  exceed  100  volts. 


TWIN  DIODE-HIGH-MU  TRIODE 

Miniature  type  used  as  combined 
detector,  amplifier,  and  avc  tube  in 
automobile  and  ac-operated  radio  re- 
ceivers. The  6AV6  may  be  substituted 
directly  for  the  6AT6  in  applications 


where  the  higher  amplification  of  the  6AV6  is  advantageous. 


Heater  Voltage  (ac/dc)  . 
Heater  Current  


6AV6 

Related  types: 
3AV6,  4AV6,  12AV6 


Without 
External 
Shield 
2.0 
2.2 
0.8 

0 . 04  max 


Direct  Interelectrode  Capacitances: 

Triode  Grid  to  Triode  Plate   

Triode  Grid  to  Cathode  and  Heater   

Triode  Plate  to  Cathode  and  Heater  , 

Plate  of  Diode  Unit  No.2  to  Triode  Grid  

■  With  external  shield  connected  to  cathode. 

TRIODE  UNIT  AS  CLASS  Ai  AMPLIFIER 
Maximum  Rating,  {Design-Maximum  Value): 

Plate  Voltage.  .  .*  , 

Grid  Voltage,  Positive-bias  value  

Plate  Dissipation  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  

Characteristics: 

Plate  Voltage  

Grid  Voltage  

Amplification  Factor  


AVERAGE  PLATE  CHARACTERISTICS 
TRIODE  UNIT 


100 

-1 

100 


6.3 
0.3 

With 
External 
Shield* 

2.0 

2.2 

1.2 
0 . 04  max 


330  max 
0  max 
0 . 55  max 

200  max 
200^wiox 


250 
-2 
100 


volts 
ampere 


Pf 
Pf 
pf 
pf 


volts 
volts 
watt 

volts 
volts 


volts 
volts 


159 


RCA  Receiving  Tube  Manual 


Plate  Resistance   80000     62500  ohms 

Transconductance   1250       1600  /xmhos 

Plate  Current   0-50        1.2  ma 

DIODE  UNITS 

Maximum  Rating,  {Design-Maximum  Value): 

Plate  Current  (Each  Unit)   1.0  max  ma 

^  The  dc  component  must  not  exceed  100  volts. 

The  two  diode  plates  are  placed  around  a  cathode,  the  sleeve  of  which  is  common  to  the  triode 
unit.  Each  diode  plate  has  its  own  base  pin.  Diode  biasing  of  the  triode  unit  is  not  recommended. 

AVERAGE  DIODE  CHARACTERISTICS 

HALF-WAVE  RECTIFICATION -SINGLE  DIODE  UNIT 

INSTALLATION  AND  APPLICATION 

Type  6AV6  requires  miniature  seven- 
contact  socket  and  may  be  mounted  in  any 
position.Outline7B,OUTLINESSECTION. 

The  triode  unit  of  the  6AV6  is  recom- 
mended for  use  only  in  resistance-coupled 
circuits.  Refer  to  the  RESISTANCE-COU- 
PLED AMPLIFIER  SECTION  for  typical 
operating  conditions. 

Grid  bias  for  the  triode  unit  of  the 
6AV6  may  be  obtained  from  a  fixed  source, 
such  as  a  fixed-voltage  tap  on  the  dc  power 
supply,  or  from  a  cathode-bias  resistor.  It 
should  not  be  obtained  by  the  diode-biasing 
method  because  of  the  probability  of  plate- 
current  cutoff,  even  with  relatively  small  sig- 
nal voltages  applied  to  the  diode  circuit. 


-.40      -30      -20  -10 
DC  VOLTS  DEVELOPED  BY  DIODE 

92CM-6875T 


6AW8 

6AW8A 


HIGH-MU  TRIODE— 
SHARP-CUTOFF  PENTODE 


Related  type: 
8AW8A 


Miniature  types  used  in  a  wide 
variety  of  applications  in  television 
receivers.  These  types  have  a  con- 
trolled heater  warm-up  time  for  use  in 
receivers  employing  series-connected 
heater  strings.  The  pentode  unit  is  used  as  an  if  amplifier,  video  amplifier,  age 
ampHfier,  or  reactance  tube.  The  triode  unit  is  used  in  low-frequency  oscillator, 
sync-separator,  sync-clipper,  and  phase-splitter  circuits.  Outline  8D,  OUTLINES 
SECTION.  Tubes  require  miniature  nine-contact  socket  and  may  be  mounted  in 
any  position.  Type  6AW8  is  a  discontinued  type  listed  for  reference  only. 

Heater  Voltage  (ac/dc)  

Heater  Cxjrrbnt  

Heater  Warm-Up  Time  (average)  

Direct  Interblectrode  Capacitances: 

Triode  Unit: 

Grid  to  Plate   

Grid  to  Cathode,  Pentode  Cathode,  Pentode  Grid  No.3, 
Internal  Shield,  and  Heater  

Plate  to  Cathode,  Pentode  Cathode,  Pentode  Grid  No.3.. 

Internal  Shield,  and  Heater  

Pentode  Unit: 

Grid  No.l  to  Plate  

Grid  No.l  to  Cathode,  Heater,  Grid  No.2,  Grid  No.3,  and 
Internal  Shield  

Plate  to  Cathode,  Heater,  Grid  No.2,  Grid  No.3,  and  In- 
ternal Shield.  


Pentode  Plate  to  Triode  Plate  

■  With  external  shield  connected  to  pins  4  and  5. 

160 


6.3 
0.6 
11 

volts 
ampere 
."seconds 

Without 
External 
Shield 
2.2 

With 
External 
Shield' 
2.2 

pf 

3.2 

3.4 

pf 

1.8 

3.0 

pf 

0.06  max 

0 . 05  max 

pf 

10 

10 

pf 

3.6 
0.008  max 
0.15  max 

4.5 
0.005  max 
0.025  max 

pf 
pf 
pf 

AVERAGE  CHARACTERISTICS 

TRIOOE  UNIT 


—  o  /■ 

1  1 

TYPE  6AW8-A 

Ep=6J  VOLTS 



*  / 

^  / 

•»  / 

<> 

-  (f/ 

T 

A 

0  too  200  300  400 

PLATE  VOLTS 

CLASS  A,  AMPLIFIER 
Maximum  Ratings,  {Deiign-MaximumValxies): 

Plate  Voltage  

Grid-No.2  (screen-grid)  Supply  Voltage  

Grid-No.2  Voltage  

Grid-No.  1  (control-grid)  Voltage: 

Positive  bias  value  

Plate  Dissipation  

Grid-No.2  Input: 

For  grid-No.2  voltages  up  to  165  volts  

For  grid-No.2  voltages  between  165  and  330  volts.  . . . 
Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  

Characteristics: 

Plate  Supply  Voltage  

Grid-No.2  Supply  Voltage  

Grid-No.l  Voltage  

Cathode-Bias  Resistor  

AmDlification  Factor  

Plate  Resistance  (Approx.)  

Transconductance  

Grid-No.l  Voltage  (Approx.)  for  plate  current  of  20  /la  

average  characteristics 

PENTODE  UNIT 


600  700 
92CM-ae44T 


Trxode  Unit 

Pentode  Unit 

330  max 

330  max 

volts 

330  max 

volts 

See  curve  page  70 

0  max 

0  max 

volts 

1.1  max 

3.75  max 

watts 

1.1  max 

watts 

See  curve  page  70 

200  max 

200  max 

volts 

200*mox 

200*»moa5 

volts 

Triode  Unit 

Pentode  Unit 

200 

150 

volts 

150 

volts 

-2 

volts 

150 

ohms 

70 

0.2 

megohm 

4000 

9500 

/^mhos 

-5 

-8 

volts 

1  1 

..J.n-M5t  VOL 

1          1  1 

TYPE  6AW8-A 

Er^=6.3  VOLTS 

GRIO- 

OLTS* 

ISO 

-1 

-2 



-3  

lb 

r 

E 

Cj_=0 

-4 

1 

150  200  250 

PLATE  VOLTS 


400 

92CM-9I73T 


161 


RCA  Receiving  Tube  Manual  = 


Plate  Current   4  15  ma 

Grid-No.2  Current   -  3.5  ma 

Maximum  Circuit  Values: 

Grid-No.l-Circuit  Resistance: 

For  fixed-bias  operation   0.5  max  0 . 25  max  megohm 

For  cathode-bias  operation   1.0  max  1 . 0  max  megohm 

"The  dc  component  must  not  exceed  100  volts. 

HALF-WAVE  VACUUM  RECTIFIER  'k^^-^^ 

^  «  ^  ^  Duodecar  type  used  as  damper  ®f- — 

OA/Vw  tube  in  horizontal-deflection  circvits  NcCsl  r--ijS[§)p 
Related  types:  of  television  receivers.  Outline  12C,  (2Sv/\>Ui) 

i2AX3,i7AX3         OUTLINES  SECTION.   Tube  re-  ^^^Q— 

quires  12-contact  socket  and  may  be  h  h 

mounted  in  any  position.  Socket  terminals  5,  6,  8,  and  9  should  not  be  used  as  tie 
points.  It  is  especially  important  that  this  tube,  like  other  power-handling  tubes, 
be  adequately  ventilated.  Heater  volts  (ac/dc),  6.3;  amperes,  1.2. 

DAMPER  SERVICE 

For  operation  in  a  525-line,  30-frame  system 
Maximum  Ratings,  (Design-Maximum  Values): 

Peak  Inverse  Plate  VoLTAGE°   5000  wax  volts 

Peak  Plate  Current   1000  max  ma 

DC  Plate  Current   165  max  ma 

Plate  Dissipation   5.3  max  watts 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   5000"wax  volts 

Heater  positive  with  respect  to  cathode   300  •wax  volts 

Characteristics,  Instantaneous  Value: 

Tube  Voltage  Drop  for  plate  current  of  250  ma    32  volts 

°  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  horizontal  scanning  cycle.  In  a 
525-line,  30-frame  system,  15  per  cent  of  one  horizontal  scanning  cycle  is  10  microseconds. 
■  The  dc  component  must  not  exceed  900  volts. 
•  The  dc  component  must  not  exceed  100  volts. 


6AX4GT 


HALF-WAVE  VACUUM  RECTIFIER 

.  A      il  Glass  octal  types  used  as  damper 

O  AX.4wTD  tube  in  horizontal  deflection  circuits  of 
television  receivers.  Outline  14C,  OUT- 
LINES SECTION.  May  be  supplied 
with  pin  No.  1  omitted.  Tubes  require 
be  operated  in  any  position.  Socket  terminals  1,  2,  4,  and  6 
tie  points.  It  is  especially  important  that  these  tubes,  like 
tubes,  be  adequately  ventilated. 


Related  types: 
12AX4GTA,  12AX4GTB, 
17AX4GT,  17AX4GTA, 
25AX4GT 

octal  socket  and  may 
should  not  be  used  as 
othel"  power-handling 


Heater  Voltage  (ac/dc)   6.3 

Heater  Current   1.2 

Direct  Interblectrode  Capacitances  (Approx.): 

Cathode  to  Plate  and  Heater .   8  5 

Plate  to  Cathode  and  Heater   5 

Heater  to  Cathode  ,   4 

DAMPER  SERVICE 
For  operation  in  a  525-line,  30-frame  system 

Maximum  Ratings,  {Design- Maximum  Values):                             6AXA-GT  GAXU-GTB 

Peak  Inverse  Plate  Voltage"                                                 4400  wax  5000  wax 

Peak  Plate  Current.                                                             825  max  1000  wax 

DC  Plate  Current.                                                                137  wax  165  wax 

Plate  Dissipation.                                                                  5  wax  5 . 3  wax 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode                                4400*wax  5000*wax 

Heater  positive  with  respect  to  cathode                                    300°max  300°max 

162 


VOltB 

amperes 


volts 
ma 
ma 

watts 

volts 
volts 


Technical  Data 


Characteristics,  Instantaneous  Test  Condition: 

Tube  Voltage  Drop  for  plate  current  of  250  ma   32  32  volts 

■  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  horizontal  scanning  cycle.  In 
a  5?5-line,  30-frame  system,  15  per  cent  of  one  horizontal  scanning  cycle  is  10  microseconds. 
eThe  do  component  must  not  exceed  900  volts. 
°The  dc  component  must  not  exceed  100  volts. 

p      ^     ^ FULL-WAVE  VACUUM  RECTIFIER 

Glass  octal  type  used  in  power      -  A  VCA^T 
supply  of  radio  equipment  having  mod-     O  A/\5 
erate  dc  requirements.  Outline  14  C, 
Ci)  OUTLINES  SECTION.  This  type 

*^         may  be  supplied  with  pin  No.  1  omitted. 
Tube  requires  octal  socket  and  may  be  mounted  in  any  position.  It  is  especially 
important  that  this  tube,  like  other  power-handling  tubes,  be  adequately  ventilated. 
Heater  volts  (ac),  6.3;  amperes,  1.2. 

FULL-WAVE  RECTIFIER 
Maximum  Ratings,  {Design-Center  Values): 

Peak  Inverse  Plate  Voltage   1250  max  volts 

Peak  Plate  Current  (Per  Plate)   375  max  ma 

Hot-Switching  Transient  Plate  Current 

B'or  duration  of  0.2  second  maximum   2.6  max  amperes 

AC  Plate  Supply  Voltage  (Per  Plate,  rms)   See  Rating  Chart 

DC  Output  Current  (Per  Plate,  rms)   See  Rating  Chart 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   450  max  volts 

Heater  positive  with  respect  to  cathode   450  max  volts 

Typical  Operation  with  Capacitor  Input  to  Filter: 

AC  Plate-to-Plate  Supply  Voltage  (rms)   700  900  volts 

Filter  Input  Capacitor*   10                 10  nt 

Effective  Plate-Supply  Impedance  Per  Plate   50  105  ohms 

DC  Output  Voltage  at  Input  to  Filter  (Approx.) : 

At  halMoad  current  of  I      5  ma   395                -  volts 

I    40  ma   -  540  volts 

At  full-load  current  of  ™* .on  ""^^IJ" 

(    80  ma   -                 490  volts 

Voltage  Regulation  (Approx.) : 

Half-load  to  full-load  current   45                50  volts 

Typical  Operation  with  Choke  Input  to  Filter: 

AC  Plate-to-Plate  Supply  Voltage  (rms)   700  900  volts 

Filter  Input  Choke                                                                    10  #              10  ##  henries 

DC  Output  Voltage  at  Input  to  Filter  (Approx.) : 

,          ^   ,   (    75  ma   270  volts 

At  half-load  current  of  {62.5  ma                                           -  365  volts 

At  full-load  current  of       J^?  ™* 250  ^  volts 

(  125  ma   -  350  volts 


RATING  CHART 


TYPE  6AX5-GT 
'  6.3  VOLTS 

MAXIMUM  OPERATING  VALUES  WITH: 
r  CHOKE- INPUT  FILTER 

p  CAPACITOR  -  INPUT  FILTER 

F  A 

l62 

.5 

C 

1 
1 
1 

r\ 
1  > 
1 

— [— 

1 
1 

D- 

— 1 — 
1 
1 

i35C 

G 

45C 

- 

0  100      200     300      400  500 

AC  PLATE  SUPPLY  VOLTS  (RMS)  PER  PLATE  (WITHOUT  LOAD) 

92CS-r3e3TI 


163 


RCA  Receiving  Tube  Manual 


Voltage  Regulation  (Approx.): 

Half-load  to  full-load  current     20  15  volts 

#  Higher  values  of  capacitance  than  indicated  may  be  used  but  the  effective  plate-supply  impedance 
may  have  to  be  increased  to  prevent  exceeding  the  maximum  rating  for  hot-switching  transient  plate 
current. 

#  This  value  is  adequate  to  maintain  optimum  regulation  provided  the  load  current  is  not  less  than  30 
ma.  For  load  currents  less  than  30  ma,  a  larger  value  of  inductance  is  required  for  optimum  regulation. 

#  #  This  value  is  adequate  to  maintain  optimum  regulation  provided  the  load  current  is  not  less  than  35 
ma.  For  load  currents  less  than  35  ma,  a  larger  value  of  inductance  is  required  for  optimum  regulation. 


6AX8 


MEDIUM-MU  TRIODE- 
SEMIREMOTE-CUTOFF  PENTODE 

Miniature  type  used  in  television- 
receiver  applications;  the  pentode  unit 
is  used  as  a  video  amplifier;  the  triode 
unit  is  used  as  a  sync  separator.  Out- 
line 8B,  OUTLINES  SECTION.Tube 


Kp,C3p 


Pt  Ct 

requires  miniature  nine-contact  socket  and  may  be  mounted  in  any  position. 


Heater  Voltage  (ac/dc)    6.3 

Heater  Current   0.45 

Direct  Interelectrode  Capacitances :° 
Triode  Unit: 

Grid  to  Plate   1.8 

Grid  to  Cathode  and  Heater   2.5 

Plate  to  Cathode  and  Heater   1 

Pentode  Unit: 

Grid  No.l  to  Plate   0 . 006  max 

Grid  No.l  to  Cathode,  Heater,  Grid  No.2,  Grid  No.3,  and 

Internal  Shield   5 

Plate  to  Cathode,  Heater,  Grid  No.2,  Grid  No.3  and  Internal  Shield  .  3.5 

Heater  to  Cathode  (Each  unit)   3.5« 


volts 
ampere 


Pf 
Pf 
pf 

pf 

pf 
pf 
pf 


CLASS  A,  AMPLIFIER 
Maximum  Ratings,  (Design-Center  Values):  Triode  Unit 

Plate  Voltage   300  max 

Grid-No.2  Supply  Voltage  

Grid-No.2  (screen-Grid)  Voltage  

Grid-No.1  (control-grid)  Voltage   0  max 

Plate  Dissipation   2.7  max 

Grid-No.2  Input 

For  grid-No.2  voltages  up  to  150  volts  

For  grid-No.2  voltages  between  150  and  300  volts  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   90  max 

Heater  positive  with  respect  to  cathode   90  max 

Characteristics: 

Plate  Supply  Voltage     150 

Grid-No.2  Supply  Voltage  

Cathode-Bias  Resistor  ,  56 

Amplification  Factor   40 

Plate  Resistance  (Approx.) .   0. 005 

Transconductance   8500 

Grid-No.l  Voltage  (Approx.)  for  plate  current  of  lO/xa   -12 

Plate  Current   18 

Grid-No.2  Current  

Maximum  Circuit  Values: 

Grid-No.l  Circuit  Resistance: 

For  fixed-bias  operation   0.1  max 

For  cathode-bias  operation   ,  0.5  wax 

°  With  external  shield  connected  to  cathode  of  unit  under  test  except  as  noted. 
•  V^ith  external  shield  connected  to  ground. 

164 


Pentode  Unit 
300  max  volts 
300  max  volts 
See  curve  page  70 
0  max  volts 
2 . 8  max  watts 

0 . 5  max  watt 
See  curve  page  70 


90  max 
90  max 


250 
110 
120 

0.4 
4800 
-12 
10 
3.5 


volts 
voits 


volts 
volts 
ohms 

megohm 
Mmhos 
volts 
ma 
ma 


0 . 1  max 
'0.5  max 


megohm 
megohm 


Technical  Data 


6AY3 

Related  type*: 
12AY3,  17AY3 


HALF-WAVE  VACUUM  RECTIFIER 

Novar  type  used  as  damper  tube 
in  horizontal  deflection  circuits  of  black- 
and-white  television  receivers.  Outline 
17B,  OUTLINES  SECTION.  Tube  re- 
quires novar  socket  and  may  be  oper- 
ated in  any  position.  Socket  terminals  1,  3,  6,  and  8  should  not  be  used  as  tie  points. 
It  is  especially  important  that  this  tube,  like  other  power-handling  tubes,  be 
adequately  ventilated. 

Heater  Voltage  (ac/dc)  

Heater  Current  

Direct  Intbrelectrode  Capacitances  (Approx.) : 

Plate  to  Cathode  and  Heater  

Cathode  to  Plate  and  Heater  

Heater  to  Cathode  


6.3 
1.2 

6.5 
9.0 
2.8 


volts 
amperes 

pf 


DAMPER  SERVICE 

For  operation  in  a  525-line,  30-frame  system 
Maximum  Ratings,  {Design-Maximum  Values): 

Peak  Inverse  Plate  Voltage"  

Peak  Plate  Current  

DC  Plate  Current  

Plate  Dissipation  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode.    

■  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  horizontal  scanning  cycle.  In  a 
525-line,  30-frame  system,  15  per  cent  of  one  horizontal  scanning  cycle  is  10  microseconds. 
•  The  dc  component  must  not  exceed  900  volts. 
°  The  dc  component  must  not  exceed  100  volts. 


5000  max 

volts 

1100  max 

ma 

175  max 

ma 

6 . 5  max 

watts 

5000 •wox 

volts 

300°maa; 

volts 

H.cap.is 


MEDIUM-MU  TRIODE— 
SHARP-CUTOFF  PENTODE 


6AZ8 


Miniature  type  used  in  a  wide 
variety  of  applications  in  television 
receivers.  The  pentode  unit  is  used  as 
an  if  amplifier,  video  amplifier,  age 
amplifier,  or  reactance  tube.  The  tri- 
ode  unit  is  used  in  low-frequency  oscillator,  sync-separator,  sync-clipper,  and  phase- 
splitter  circuit.  Outline  8B,  OUTLINES  SECTION.  Tube  requires  miniature 
nine-contact  socket  and  may  be  mounted  in  any  position. 

Heater  Voltage  (ac/dc)  

Heater  Current  

Direct  Intbrelectrode  Capacitances: 
Triode  Unit: 

Grid  to  Plate  

Grid  to  Cathode,  Heater,  Pentode  Grid  No.3,  and  Internal  Shield  

Plate  to  Cathode,  Heater,  Pentode  Grid  No.3,  and  Internal  Shield  

Pentode  Unit: 

Grid  No.l  to  Plate  

Grid  No.l  to  Cathode,  Heater,  Grid  No.2,  Grid  No.3,  and  Internal  Shield 

Plate  to  Cathode,  Heater,  Grid  No.2,  Grid  No.3,  and  Internal  Shield  

Triode  Grid  to  Pentode  Plate  

Pentode  Grid  No.l  to  Triode  Plate  

Pentode  Plate  to  Triode  Plate  


6.3 
0.45 


volts 
ampere 


1.7 
2 
1.7 

0 . 02  max 

6.5 

2  2 
0 . 027  max 
0.020  max 
0 . 045  max 


pf 
pf 

pf 
pf 
pf 
pf 
pf 
pf 


CLASS  Ai  AMPLIFIER 
Maximum  Ratings,  {Design-Center  Values): 

Plate  Voltage  

Grid-No.2  (screen-grid)  Supply  Voltage  

Grid-No.2  Voltage  

Grid-No.1  (control-grid)  Voltage,  Positive-bias  value. . 

Plate  Dissipation  

Grid-No.2  Input: 

For  grid-No.2  voltages  up  to  150  volts  

For  grid-No.2  voltages  between  150  and  300  volts.  . . . 
Peak  Heatbr-Cathodb  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  


Triode  Unit 
300  max 


0  max 
2.6  max 


200  max 
200Bmaa; 


Pentode  Unit 
300  max 
300  max 


volts 
volts 


See  curve  page  70 
0  max  volts 
2  max  watts 

0 . 5  max  watt 
See  curve  page  70 

*  volts 
^  volts 

165 


RCA  Receiving  Tube  Manual 


200 

200 

volts 

150 

volts 

-6 

volts 

180 

ohms 

19 

5750 

300000 

ohms 

3300 

6000 

/itmhos 

-19 

volts 

-12.5 

volts 

13 

9.5 

ma 

3 

ma 

0 . 5  max 

0.25  max 

megohm 

1 . 0  max 

1 . 0  max 

megohm 

Characteristics: 

Plate  Supply  Voltage  

Grid-No.2  Voltage  

Grid-No.  1  Voltage  

Cathode-Bias  Resistor  

Amplification  Factor  

Plate  Resistance  (Approx.)  

Transconductance  

Grid-No.l  Voltage  (Approx.)  for  plate  current  of  10  /ua  

Grid-No.  1  Voltage  (Approx.)  for  transconductance  of  100 

/tmhos  

Plate  Current  

Grid-No.2  Current  

Maximum  Circuit  Values: 

Grid-No.l-Circuit  Resistance:* 

For  fixed-bias  operation  

For  cathode-bias  operation  

■  The  dc  component  must  not  exceed  100  volts. 

^  The  heater-cathode  voltage  should  not  exceed  the  value  of  the  operating  cathode  bias.  If  the  heater- 
cathode  voltage  exceeds  the  operating  cathode  bias  value,  grid  No.3  will  be  made  negative  with  respect 
to  cathode,  and  thus  possibly  cause  a  change  in  tube  characteristics. 

*  If  either  unit  is  operating  at  maximum  rated  conditions,  grid-No.l-circuit  resistance  for  both  units 
should  not  exceed  the  stated  values. 

POWER  TRIODE 

Glass  octal  type  used  in  output  stage  of 
radio  receivers  and  amplifiers.  Maximum  di- 
mensions: over-all  length,  5-5/16  inches;  seated 
height,  4-3/4  inches;  diameter,  2-1/16  inches. 
6B40  Tube  requires  octal  socket.  For  typical  opera- 

tion as  a  single-tube  class  A  amplifier,  refer  to 
type  2A3.  Filament  volts  (ac /dc),  6.3;  amperes, 
1.0.  Maximum  ratings  as  push-pull  class  ABi 
amplifier:  plate  volts,  325;  plate  dissipation,  15 
watts.  Type  6B4-G  is  a  DISCONTINUED 
type  listed  for  reference  only. 


6B5 


DIRECT-COUPLED  POWER  TRIODE 

Glass  type  used  as  class  Ai  power  amplifier. 
One  triode,  the  driver,  is  directly  connected 
within  the  tube  to  the  second,  or  output,  triode. 
Outline  27,  OUTLINES  SECTION.  Tube  re- 
quires six-contact  socket.  Heater  volts  (ac/dc) , 
6.3;  amperes,  0.8.  Characteristics  of  input  and 
output  triodes  as  class  Ai  amplifier  follow.  Input 
triode:  plate  volts,  300  max;  grid  volts,  0;  plate 
ma.,  8.  Output  triode:  plate  volts,  300  wax;  plate  ma.,  45;  plate  resistance,  24000  ohms;  load  resistance, 
7000  ohms;  output  watts,  4.  This  is  a  DISCONTINUED  type  listed  for  reference  only. 

TWIN-DIODE— HIGH-MU  TRIODE 

Glass  octal  type  used  as  combined  detector, 
amplifier,  and  avc  tube.  Outline  23,  OUT- 
LINES SECTION.  Tube  requires  octal  socket. 
Heater  volts  (ac/dc),  6.3;  amperes,  0.3.  Within 
its  triode  maximum  plate-voltage  rating  of  250 
volts,  this  type  is  similar  electrically  to  type 
6SQ7  and  curves  under  that  type  apply  to  the 
6B6-G.  This  is  a  DISCONTINUED  type 
listed  for  reference  only. 


6B6G 


TWIN-DIODE— 
REMOTE-CUTOFF  PENTODE 

_  _  _  Glass  types  used  as  combined  detector,  am- 

OD/  plifier,  and  avc  tubes.  Outline  24B,  OUTLINES 

.  -J    ^  SECTION.  These  types  fit  the  small  seven-con- 

OB/ S  tact  (0.75-inch,  pin-circle  diameter)  socket.  Ex- 

cept for  interelectrode  capacitances,  the  elec- 
trical characteristics  of  the  6B7  are  identical 
with  those  of  type  6B8-G.  Type  6B7S  has  the 
external  shield  connected  to  the  cathode.  In 
general,  its  electrical  characteristics  are  similar  to  those  of  the  6B7,  but  the  two  types  are  usually  not 
directly  interchangeable.  These  are  DISCONTINUED  types  listed  for  reference  only. 

166 


6B8 

6B8G 


6B10 

Related  type: 
8B10 


TWIN  DIODE- 
SEMIREMOTE-CUTOFF  PENTODE 

Metal  type  6B8  and  glass  octal  type  6B8-G 
are  used  as  combined  detector,  amplifier,  and 
avc  tubes.  Outlines  3  and  23,  respectively, 
OUTLINES  SECTION.  Type  6B8  is  used 
principally  for  renewal  purposes;  6B8-G  is  a 
DISCONTINUED  type  listed  for  reference 
only.  Tubes  require  octal  socket.  Heater  volts 
(ac/dc),  6.3;  amperes,  0.3.  Maximum  ratings  of 
pentode  unit  as  class  Ai  amplifier:  plate  volts, 
300  max;  grid-No.2  volts,  125  max;  grid-No.2  supply  volts,  300  max;  grid-No.l  volts,  positive-bias 
value,  0  max;  plate  dissipation,  3.0  max  watts  (6B8),  2.25  max  watts  (6B8-G) ;  grid-No.2  input,  0.3  max 
watt. 

TWIN  DIODE— 

MEDIUM-MU  TWIN  TRIODE 

Duodecar  type  used  in  television 
receivers;  diode  units  are  used  in  hori- 
zontal-phase-detector circuits,  and  tri- 
ode  units  are  used  in  horizontal-oscil- 
lator circuits.Outline  12  A,  OUTLINES 
SECTION.  Tube  requires  duodecar  twelve-contact  socket  and  may  be  mounted  in 
any  position.  Heater  volts  (ac/dc),  6.3;  amperes,  0.6;  warm-up  time  (average),  11 
seconds. 

TRIODE  UNITS  AS  CLASS  Ai  AMPLIFIER 

Values  are  for  each  unit 
Maximum  Ratings,  (Design-Maximum  Values) : 

Plate  Voltage   330  max 

DC  Cathode  Current   20  max 

Plate  Dissipation   3  max 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  max  volts 

Heater  positive  with  respect  to  cathode   200°max  volts 

Characteristics: 

Plate  Voltage  

Grid  Voltage  

Amplification  Factor  

Plate  Resistance  (Approx.)  

Transconductance  

Plate  Current  

Grid  Voltage  (Approx.)  for  plate  current  of  50  /ua  

Maximum  Circuit  Values: 

Grid-Circuit  Resistance: 

For  fixed-bias  operation  

For  cathode-bias  operation  

DIODE  UNITS  (Each  Unit) 
Maximum  Rating,  (Design-Maximum  Value): 

Plate  Current  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  

Characteristics,  Instantaneous  Value: 

Tube  Voltage  Drop  for  plate  current  of  20  ma  

°  The  dc  component  must  not  exceed  100  volts. 


volts 
ma 
watts 


250 
-8 
18 
7200 
2500 
10 
-20 


0.25  max 
1  max 


200  max 
200°  max 


volts 
volts 

ohms 
/(mhos 
ma 
volts 


megohm 
megohm 


volts 
volts 


volts 


HALF-WAVE  VACUUM  RECTIFIER 

Novar  type  used  as  damper  tube 
in  horizontal-deflection  circuits  of  tele- 
vision receivers.  Outline  lOB,  OUT- 
LINES SECTION.  Tube  requires 
novar  nine-contact  socket  and  may  be 

1,  3,  6,  and  8  should  not  be  used  as  tie 


6BA3 


10 

mounted  in  any  position.  Socket  terminals 


167 


RCA  Receiving  Tube  Manual 


points.  It  is  especially  important  that  this  tube,  like  other  power-handling  tubes, 
be  adequately  ventilated, 

Hbater  Voltage  (ac  /dc)   6.3  volts 

Heater  Current   1.2  amperes 

Direct  Interelectrodb  Capacitances,  (Approx.) : 

Plate  to  Cathode  and  Heater   4.4  pf 

Cathode  to  Plate  and  Heater   6  pf 

Heater  to  Cathode   1.8  pf 

DAMPER  SERVICE 

For  operation  in  a  525-line,  30-frame  system 
Maximum  Ratings,  (Design- Maximum  Values): 

Peak  Inverse  Plate  Voltage   5000"max  volts 

Peak  Plate  Current   1000  max  ma 

DC  Plate  Current   165  max  ma 

Plate  Dissipation      5.3  max  watts 

Peak  Heater-Cathode  Voltage; 

Heater  negative  with  respect  to  cathode   5000*7nax  volts 

Heater  positive  with  respect  to  cathode   300°max  volts 

■  The  duration  of  the  voltage  pulse  must  not  exceed  1 5  per  cent  of  one  horizontal  scanning  cycle.  In  a 
525-line,  30-frame  system,  15  per  cent  of  one  horizontal  scanning  cycle  is  10  microseconds. 

•  The  dc  component  must  not  exceed  900  volts. 
°  The  dc  component  must  not  exceed  100  volts. 

REMOTE-CUTOFF  PENTODE  5M§ 

A  Miniature  type  used  as  rf  ampli- 

OBAw         fier  in  standard  broadcast  and  FM  re- 
Related  types:  ceivers,  as  Well  as  in  wide-band,  high-  cj-^yK^  >j  y^^. 

3BA6, 12BA6  frequency  applications.  This  type  is  's 

similar  in  performance  to  metal  type  cj 
6SG7.  The  low  value  of  grid-No.  1-to-plate  capacitance  minimizes  regenerative 
effects,  while  the  high  transconductance  makes  possible  high  signal-to-noise  ratio. 

Heater  Voltage  (ac/dc)   6.3  voltff 

Heater  Current   0.3  ampere 

Without  With 
External  External 

Direct  Interblectrode  Capacitances:  Shield  Shield' 

Grid  No.  1  to  Plate      0.0035  mox      0.0035  max  pf 

Grid  No.l  to  Cathode,  Heater,  Grid  No.2  Grid  No.3, 

and  Internal  Shield   5.5  5.5  pf 

Plate  to  Cathode,  Heater,  Grid  No.2,  Grid  No.3,  and 

Internal  Shield   5.0  5.5  pf 

■  With  external  shield  connected  to  cathode. 


CLASS  A,  AMPLIFIER 
Maximum  Ratings,  {Design-Maximum  Values): 

Plate  Voltage   330  wax  volts 

Grii>-No.3  (suppressor-grid)  Voltage,  Positive  value.   0  max  volts 

Grii>-No.2  (screen-grid)  Voltage   See  curve  page  70 

Grid-No.2  Supply  Voltage   330  wax  volts 

Plate  Dissipation   3.4  max  watts 

Grid-No.2  Input: 

For  grid-No.2  voltages  up  to  165  volts   0,7  max  watt 

For  grid-No.2  voltages  between  165  and  330  volts   See  curve  page  70 

Grid-No.  1  (control-grid)  Voltage: 

Negative  bias  value   -55  wax  volts 

Positive  bias  value   0  wax  volts 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode. .   200  wax  volts 

Heater  positive  with  respect  to  cathode   200*wax  volts 

*  The  dc  component  must  not  exceed  100  volts. 

Characteristics: 

Plate  Supply  Voltage                                                                 100  250  volts 

Grid  No.3  and  Internal  Shield                                                       Connected  to  cathode  at  socket 

Grid-No.2  Supply  Voltage                                                             100  100  volts 

Cathode-Bias  Resistor  .                                                                68  68  ohms 

Plate  Resistance  (Approx.)                                                        0.25  1.0  megohm 

Transconductance                                                                  4300  4400  /umhos 

Grid-No.  1  Voltage  (Approx.)  for  transconductance  of  40 jiimhos        -20  -20  volts 

Plate  Current                                                                       10.8  11  ma 

Grid-No.2  Current.                                                                 4.4  4.2  ma 

168 


INSTALLATION  AND  APPLICATION 

Type  6BA6  requires  miniature  seven-contact  socket  and  may  be  mounted  in 
any  position.  Outline  7B,  OUTLINES  SECTION. 

Control-grid  bias  variation  will  be  found  effective  in  changing  the  volume  of 
the  receiver.  In  order  to  obtain  adequate  volume  control,  an  available  grid-No.  1- 
bias  voltage  of  approximately  50  volts  will  be  required.  The  exact  value  will  depend 
upon  the  circuit  design  and  operating  conditions.  This  voltage  may  be  obtained, 
depending  on  the  receiver  requirements,  from  a  potentiometer  across  a  fixed  supply 
voltage,  from  a  variable  cathode-bias  resistor,  from  the  avc  system,  or  from  a 
combination  of  these  methods. 


The  grid-No.  2  (screen-grid)  voltage  may  be  obtained  from  a  potentiometer  or 
bleeder  circuit  across  the  B-supply  source,  or  through  a  dropping  resistor  from  the 
plate  supply.  The  use  of  series  resistors  for  obtaining  satisfactory  control  of  grid- 
No.2  voltage  in  the  case  of  four-electrode  tubes  is  usually  impossible  because  of 
secondary-emission  phenomena.  In  the  6BA6,  however,  because  grid  No.3  prac- 
tically removes  these  effects,  it  is  practical  to  obtain  grid-No.2  voltage  through  a 
series-dropping  resistor  from  the  plate  supply  or  from  some  high  intermediate 
voltage,  provided  the  soui^e  does  not  exceed  the  plate-supply  voltage.  With  this 
method,  the  grid-No. 2-to-cathode  voltage  will  fall  off  very  little  from  minimum  to 
maximum  value  of  the  resistor  controlling  cathode  bias.  In  some  cases,  it  may 
actually  rise.  This  rise  of  grid-No.2-to-cathode  voltage  above  the  normal  maximum 
value  is  allowable  because  both  the  grid-No.2  current  and  the  plate  current  are 
reduced  simultaneously  by  a  sufficient  amount  to  prevent  damage  to  the  tube.  It 
should  be  recognized  that,  in  general,  the  series-resistor  method  of  obtaining  grid- 
No.2  voltage  from  a  higher  voltage  supply  necessitates  the  use  of  the  variable 
cathode-resistor  method  of  controlling  volume  in  order  to  prevent  too  high  a  volt- 
age on  grid  No.2.  When  grid-No.2  and  control-grid  voltage  are  obtained  in  this 
manner,  the  remote  * 'cutoff"  advantage  of  the  6BA6  can  be  fully  realized.  How- 
ever, it  should  be  noted  that  the  use  of  a  resistor  in  the  grid-No.2  circuit  will  have 
an  effect  on  the  change  in  plate  resistance  with  variation  in  grid-No.3  (suppressor- 
grid)  voltage  in  case  grid  No.3  is  utilized  for  control  purposes. 

Grid  No.  3  (suppressor  grid)  may  be  connected  directly  to  the  cathode  or  it 
may  be  made  negative  with  respect  to  the  cathode.  For  the  latter  condition,  the 
grid-No.3.  voltage  may  be  obtained  from  a  potentiometer  or  bleeder  circuit,  or  from 
the  avc  system. 


169 


RCA  Receiving  Tube  Manual 


6BA7 

Related  type: 
12BA7 


PENTAGRiD  CONVERTER 

Miniature  type  used  as  converter 
in  superheterodyne  circuits  especially 
those  for  the  FM  broadcast  band.  Out- 
line 8D,  OUTLINES  SECTION.  Tube 
requires  miniature  nine-contact  socket 


and  may  be  mounted  in  any  position.  Heater  volts  (ac/dc),  6.3,  amperes,  0.3. 


CONVERTER  SERVICE 
Maximum  Ratings,  {Design-Center  Values): 

Plate  Voltage   300  max  volts 

Grid-No.5-and-Internal-shield  Voltage*   max  volts 

Grids-No.2-and-No.4  (screen-grid)  Voltage   100  max  volts 

Grids-No.2-and-No.4  Supply  Voltage   300  max  volts 

Plate  Dissipation   2.0  max  watts 

Grids-No.2-and-No.4  Input   \  .h  max  watts 

Total  Cathode  Current   22  max  ma 

Grid-No.3  Voltage: 

Negative  bias  value   -100  max  volts 

Positive  bias  value   0  max  volts 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   90  max  volts 

Heater  positive  with  respect  to  cathode   90  max  volts 

Characteristics  (Separate  Excitation) 

Plate  Voltage                                                                                 100  250  volts 

Grid  No.5  and  Internal  Shield*                                                         Connected  directly  to  ground 

Grids-No.2-and-No.4  (Screen-Grid)  Voltage                                     100  100  volts 

Grid-No.3  (Control-Grid)  Voltage                                                -1.0  -1.0  volt 

Grid-No.l  (Oscillator-Grid)  Resistor                                            20000  20000  ohms 

Plate  Resistance  (Approx.)                                                           0.5  1.0  megohm 

Conversion  Transconductance                                                       900  950  lumhos 

Conversion  Transconductance  (Approx.)**                                      3.6  3.5  ^/mhos 

Plate  Current                                                                                3.6  3.8  ma 

Grida-No  2-and-No.4  Current                                                        10.2  10  ma 

(Jrid-No  1  Current                                                                    0.35  0.35  ma 

Total  Cathode  Current                                                             14.2  14.2  ma 

NOTE:  The  transconductance  between  grid  No.l  and  grids  No.2  and  No.4  connected  to  plate  (not  oscil- 
lating) is  approximately  8000  ^mhos  under  the  following  conditions:  signal  applied  to  grid  No.l  at  zero 
bias;  grids  No.2  and  No.4  and  plate  at  100  volts;  grid  No.3  grounded.  Under  the  same  conditions,  the 
plate  current  is  32  milliamperes.  and  the  amplification  factor  is  16.5. 

♦  The  characteristics  shown  with  separate  excitation  correspond  very  closely  with  those  obtained  in  a 
self-excited  oscillator  circuit  operating  with  zero  bias. 

♦*  With  grid-No.3  bias  of  -20  volts. 

*  Internal  Shield  (pins  No.6  and  No.8)  connected  directly  to  ground. 


MEDIUM-MU  TRIODE-  A  , 

SHARP-CUTOFF  PENTODE 

^  n  A  A  A  Miniature  type  used  in  a  wide    ^^®frH  E^^O^^'^ 

wB Ao A        variety  of  applications  in  color  and      (^Vts~' '"!/?) 
Related  type:  black-and-white  television  receivers.     CT^-^\Ni£^  1/^g2p 

8BA8A  This  type  has  a  controlled  heater  ®pp 

warm-up  time  for  use  in  receivers  em- 
ploying series-connected  heater  strings.  The  pentode  unit  is  used  as  a  video  ampli- 
fier, an  age  amplifier,  or  a  reactance  tube.  The  triode  unit  is  used  in  low-frequency 
oscillator  and  phase-splitter  circuits.  Outline  8D,  OUTLINES  SECTION.  Tube 
requires  miniature  nine-contact  socket  and  may  be  mounted  in  any  position. 

Heater  Voltage  (ac/dc)   6.3  volts 

Heater  Current   0.6  ampere 

Heater  Warm-Up  Time  (Average)   11  seconds 

Without  With 

External  External 

Direct  Interelectrodb  Capacitances  (Approx.):              Shield  Shield' 
Triode  Unit: 

Grid  to  Plate                                                                  2.2  2.2  pf 

Grid  to  Cathode  and  Heater                                             2.5  2.7  pf 

Plate  to  Cathode  and  Heater                                             0.4  1.9  pf 

170 


Technical  Data 


Triode 
Unit 


Pentode  Unit: 

Grid  No.  1  to  Plate   0.06 

Grid  No.l  to  Cathode,  Heater,  Grid  No.2,  Grid  No.3,  and 

Internal  Shield   10 

Plate  to  Cathode,  Heater,  Grid  No.2,  Grid  No.3,  and  In- 
ternal Shield   3.6 

Triode  Grid  to  Pentode  Plate   0 . 016 

Pentode  Grid  No.l  to  Triode  Plate   0 . 006 

Pentode  Plate  to  Triode  Plate   0.16 

■  With  external  shield  connected  to  cathode  of  unit  under  test. 

CLASS  Ai  AMPLIFIER 

Maximum  Ratings,  (Design-Center  Values): 

Plate  Voltage  

Grid-No.2  (screen-grid)  Supply  Voltage  

Grid-No.2  Voltage  

G rid-No.  1  (control-grid)  Voltage: 

Negative  bias  value  

Positive  bias  value  

Plate  Dissipation  

GRiDrNo.2  Input: 

For  grid-No.2  voltages  up  to  150  volts  

For  grid-No.2  voltages  between  150  and  300  volts.  . 
Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  

Characteristics: 

Plate-Supply  Voltage  

Grid-No.2  Supply  Voltage  

Grid-No.  1  Voltage.;  

Cathode-Bias  Resistor  

Amplification  Factor  

Plate  Resistance  (Approx.)  

Transconductance  

Grid-No.l  Voltage  (Approx.)  for  plate  current  of  10  /xa. 

Plate  Current  

Grid-No.2  Current  

Maximum  Circuit  Values: 

Grid-No.  1-Circuit  Resistance: 

For  fixed-bias  operation  

For  cathode-bias  operation  

■  The  dc  component  must  not  exceed  100  volts. 
Pp,  G3p| 

Kp 

sis 


0.05 

10 

4.6 
0.006 
0.003 
0.023 


Pentode 
Unit 


Pf 

Pf 

pf 
pf 

pf 


300  max 

300  max 

volts 

- 

300  max 

volts 

See  curve  page  70 

-60  max 

volts 

0  max 

volts 

2  max 

3 . 26  max 

watts 

1  max 

watt 

See  curve  page  70 

200  max 

200  max 

volts 

200 "max 

200"wax 

volts 

200 

200 

volts 

160 

volts 

-8 

volts 

180 

ohms 

18 

6700 

400000 

ohms 

2700 

9000 

Mmhos 

-16 

-10 

volts 

8 

13 

ma 

3.5 

ma 

0 . 5  max 

0.25  max 

megohm 

1 . 0  max 

1 . 0  max 

megohm 

TRIODE— TWIN  PENTODE 

Duodecar  type  used  as  vertical 
deflection  oscillator  and  for  combined 
sync-age  applications  in  television  re- 
ceivers employing  series-connected 
heater  strings.  Outline  12B,  OUT- 


6BA11 


H  H 

LINES  SECTION.  Tube  requires  duodecar  twelve-contact  socket  and  may  be 
mounted  in  any  position.  Heater  volts  (ac/dc),  6.3;  amperes,  0.6;  warm-up  time 
(average),  11  seconds.  For  ratings  and  characteristics  of  pentode  units,  refer  to 
type  6HS8. 


TRIODE  UNIT  AS  CLASS  A,  AMPLIFIER 
Maximum  Ratings^  (Design-Center  Values): 

Plate  Voltage  

Average  Cathode  Current  

Plate  Dissipation  

Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  

Characteristics: 

Plate  Voltage  

Grid  Voltage  

Amplification  Factor  

Transconductance  

Plate  Current  

Grid  Voltage  (Approx.)  for  plate  current  of  100  na.  

Maximum  Circuit  Values: 

Grid-Circuit  Resistance: 

For  fixed-bias  operation  

For  cathode-bias  operation  

■  The  dc  component  must  not  exceed  100  volts. 


300  max 
20  max 
1 . 5  max 

200  max 
200"Twax 


250 
-11 
18 
1800 
5 

-18 


0.25  max 
1  max 


volts 
ma 
watts 

volts 
volts 


volts 
volts 

/xmhos 
ma 
volts 


megohm 
megohm 


171 


RCA  Receiving  Tube  Manual 


6BC4 


MEDIUM-MU  TRIODE 

Miniature  type  used  as  an  rf  am- 
plifier in  the  cathode-drive  circuits  of 
uhf  television  tuners  covering  the  fre- 
quency range  of  470  to  890  megacycles 
per  second.  Outline  8A,  OUTLINES 
SECTION.  Tube  requires  miniature  nine-contact  socket  and  may  be  mounted  in 
any  position. 


Heater  Voltage  (AC /DC)   6.3  volts 

Heater  Current   0.225  ampere 

Direct  Interelectrode  Capacitances  (Approx.) : 

Grid  to  Plate   1.6  pf 

Grid  to  Heater  and  Cathode   2.9  pf 

Plate  to  Heater  and  Cathode   0  .26  pf 

Heater  to  Cathode   2.7  pf 


CLASS  Ai  AMPLIFIER 


Maximum  Ratings,  {Design-Center  Values): 

Plate  Voltage   250  max  volts 

Plate  Dissipation  —  2.5  wax  watts 

Cathode  Current   25  max  ma 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   75  max  volts 

Heater  positive  with  respect  to  cathode   75  max  volts 


Characteristics: 

Plate  Supply  V  ol  tage   150  volts 

Cathode-Bias  Resistor   100  ohms 

Amplification  Factor   48 

Plate  Resistance  (Approx.)   4800  ohms 

Transconductance   10000  jumhos 

Grid  Voltage  (Approx.)  for  plate  current  of  10    -10  volts 

Plate  Current   14.5  ma 


Maximum  Circuit  Values: 

Grid-Circuit  Resistance: 

For  fixed-bias  operation   Not  recommended 

For  cathode-bias  operation   0.5  max  megohm 


SHARP-CUTOFF  PENTODE 

Miniature  type  used  in  compact 
radio  equipment  as  an  rf  or  if  amplifier 
at  frequencies  up  to  400  megacycles 
per  second.  Outline  7B,  OUTLINES 
SECTION.  Tube  requires  miniature 
seven-contact  socket  and  may  be  mounted  in  any  position.  For  typical  operation 
as  resistance-coupled  amplifier,  refer  to  RESISTANCE-COUPLED  AMPLI- 
FIER SECTION. 


6BC5 

Related  types: 
3BC5,  4BC5 


Heater  Volts  (ac/dc)    6.3  volts 

Heater  Current   0.3  ampere 

Direct  Interelectrode  Capacitances: 
Pentode  Connection: 

Grid  No.l  to  Plate   0.030  max  pf 

Grid  No.l  to  Cathode.  Heater.  Grid  No.2,  Grid  No.3,  and  Internal  Shield  6.5  pf 

Plate  to  Cathode.  Heater,  Grid  No.2,  Grid  No.3,  and  Internal  Shield  ...  1.8  pf 
Triode  Connection:* 

Grid  No.l  to  Plate  and  Grid  No.2   2.5  pf 

Grid  No.l  to  Cathode,  Heater,  Grid  No.3,  and  Internal  Shield   3.9  pf 

Plate  and  Grid  No.2  to  Cathode,  Heater,  Grid  No.3,  and  Internal  Shield .  .  3.0  pf 
*  Grid  No.2  connected  to  plate. 


172 


CLASS  Ai  AMPLIFIER 
Maximum  Ratings,  (Design-Center  Values): 

Plate  Voltage  

Grid-No.2  (screen-grid)  Supply  Voltage  

Grid-No.2  Voltage  

Grid-No.1  (control-grid)  Voltage,  Positive-bias  value.  . 

Plate  Dissipation  

Grid-No.2  Input: 

For  grid-No.2  voltages  up  to  150  volts  

For  grid-No.2  voltages  between  150  and  300  volts  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  

Characteristics: 

Plate  Supply  Voltage  

Grid-No.2  Supply  Voltage  

Cathode-Bias  Resistor  

Amplification  Factor  


Triode 

Pentode 

Connection* 

Connection 

300  max 

300  max 

volts 

300  max 

volts 

See  curve  page  70 

0  max 

0  max 

volts 

2.5  max 

2  max 

watts 

_ 

0.5  max 

watt 

_ 

See  curve  page  70 

90  max 

90  max 

volts 

90  max 

90  max 

volts 

180  250 

100 

125  250 

volts 

100 

125  150 

volts 

330  820 

180 

100  180 

ohms 

42  40 

0.006  0.009 

0.6 

0.5  0.8 

megohm 

6000  4400 

4900 

6100  5700 

/Limhos 

-5 

-6  -8 

volts 

8  6 

4.7 

8  7.5 

ma 

1.4 

2.4  2.1 

ma 

6BC7 


Grid-No.l  Voltage  (Approx.)  for  plate  current  of  10  fia. 

Plate  Current  

Grid-No.2  Current  

*  Grid  No.2  connected  to  plate. 
H 

TRIPLE  DIODE 

Miniature  type  containing  three 
high-perveance  diode  units  in  one  en- 
velope; used  in  dc  restorer  circuits  of 
color  television  receivers.  Also  used  in 
AM/FM  radio  receivers  as  a  combina- 
tion FM  discriminator  and  AM  detector  tube.  Outline  8B,  OUTLINES  SECTION. 
Tube  requires  nine-contact  miniature  socket  and  may  be  mounted  in  any  position. 

Heater  Voltage  (ac/dc)   6.3  volts 

Heater  Current   0.450  ampere 

Direct  Intbrelectrode  Capacitances  (Approx.): 

Diode-No.l  Plate  to  Diode-No.l  Cathode,  Heater,  and  Internal  Shield.  3.5  pf 

Diode-No.2  Plate  to  Diode-No.2  Cathode,  Heater,  and  Internal  Shield.  5.5  pf 

Diode-No.3  Plate  to  Diode-No.3  Cathode,  Heater,  and  Internal  Shield.  3.5  pf 

Maximum  Ratings^  (Design-Center  Values,  Each  Diode  Unit): 

Peak  Invsgrse  Plate  Voltage  

Peak  Plate  Current*  

DC  Output  Current  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode . 


330  max 
54  max 
12  max 

200  max 
200  max 


volts 
ma 
ma 

volts 
volts 


*  In  rectifier  service,  the  minimum  total  effective  plate-supply  impedance  per  plate  is  560  ohms. 

Hgv^^PT,         MEDIUM-MU  TWIN  TRIODE 

*^''"2(a^^^r^I^v2f'^'  Miniature  type  used  in  direct-  £Ln  K^Q 

"""f[T\      coupled  cathode-drive  rf  amplifier  cir-  ODCo 
/v^A^K-r,    cuits  of  vhf  television  tuners.  In  such  Related  type: 

(yV-— circuits,  one  triode  unit  is  used  as  the 
^"■■s  direct-coupled  grounded-cathode  driv- 

er for  the  other  unit.  This  type  is  also  used  in  push-pull  cathode-drive  rf  amplifiers. 
Outline  8B,  OUTLINES  SECTION.  Tube  requires  miniature  nine-contact  socket 
and  may  be  mounted  in  any  position. 

Heater  Voltage  (ac/dc)   6.3  volts 

Heater  Current   0.4  ampere 

Direct  Interelectrode  Capacitances*:  Unit  No. 1       Unit  No.2 

Grid  to  Plate   12  1.2  pf 

Grid  to  Cathode,  Heater,  and  Internal  Shield   2  .6  -  pf 

Cathode  to  Grid,  Heater,  and  Internal  Shield   -  5.5  pf 

Plate  to  Cathode,  Heater,  and  Internal  Shield    1.3  -  pf 

Plate  to  Grid,  Heater,  and  Internal  Shield   -  2.4  pf 

Plate  to  Cathode   -  0.12  pf 

Heater  to  Cathode    2.8  2.8  pf 

Plate  of  Unit  No.l  to  Plate  of  Unit  No.2  0  . 02  max  pf 

Plate  of  Unit  No.2  to  Plate  and  Grid  of  Unit  No.l   0 . 04  max  pf 

*  With  external  shield  connected  to  internal  shield. 

173 


RCA  Receiving  Tube  Manual 


CLASS  Ai  AMPUFIER  {Each  Unit) 


Maximum  Ratings,  {Design-Maximum  Values): 

Plate  Voltage  ,   250*mtta;  volts 

Plate  Dissipation   2.2  max  watts 

Cathode  Current   22  max  ma 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200*rnox  volts 

Heater  positive  with  respect  to  cathode   200"maa;  volts 

Characteristics: 

Plate  Supply  Voltage   150  volts 

Cathode-Bias  Resistor   220  ohms 

Plate  Resistance  (Approx.)    5300  ohms 

Amplification  Factor.   35 

Transconductance   6200  yumhos 

Grid  Voltage  (Aporox.)  for  transconductance  of  50  /imhos   -13  volts 

Plate  Current   10  ma 

Maximum  Circuit  Valua: 

Grid-Circuit  Resistance   0.5  max  megohm 


*  This  rating  may  be  as  high  as  300  volts  under  cutoff  conditions,  when  the  tube  is  used  as  a  cascode 
amplifier  and  the  two  units  are  connected  in  series. 
■  The  dc  component  must  not  exceed  100  volts. 


SHARP-CUTOFF  BEAM  TRIOOE 


6BD4 
6BD4A 


6BD6 

Relatad  type: 
12BD6 


Glass  octal  types  used  for  the  voltage  regu- 
lation of  high-voltage,  low-current  dc  power 
supplies  in  color  television  receivers.  Outline  25B, 
OUTLINES  SECTION.  Tubes  require  octal 
socket.  Heater  volts  (ac/dc),  6.3;  amperes,  0.6. 
Maximum  ratings  for  voltage-control  service:  dc 
plate  volts,  6BD4  20000  max,  6BD4-A  27000 
max;  unregulated  dc  supply  volts,  6BD4  40000  ^  • 

max,  6BD4-A  55000  max;  dc  grid  volts,  -125 
max;  peak  grid  volts,  -550  max;  dc  plate  ma.,  1.5  max;  plate  dissipation,  6BD4  20  max  watts,  6BD4-A 
25  max  watts;  peak  heater-cathode  volts,  180  max.  These  are  DISCONTINUED  types  listed  for 
reference  only. 

REMOTE-CUTOFF  PENTODE 

Miniature  type  used  as  rf  or  if  amplifier  in 
radio  receivers.  This  type  is  similar  in  perform- 
ance to  metal  type  6SK7.  Outline  7B,  OUT- 
LINES SECTION.  Tube  requires  miniature 
seven-contact  socket  and  may  be  mounted  in 
any  position.  Heater  volts  (ac/dc),  6.3;  am- 
peres, 0.3.  Characteristics  as  class  Ai  amplifier: 
plate  volts,  250  (300  max) ;  grid  No.3  connected 
to  cathode  at  socket;  grid-No.2  volts,  100  (125 
max);  grid-No.l  volts,  -3;  plate  resistance  (approx.),  0.8  megohm;  transconductance,  2000  /umhos;  plate 
dissipation,  3  max  watts;  grid-No.2  input,  0.65  max  watt;  plate  ma.,  9;  grid-No.2  ma.,  3;  total  cathode 
ma.,  14  max;  peak  heater-cathode  volts,  90  max.  This  type  is  used  principally  for  renewal  purposes. 

IC.  J< 

HALF-WAVE  VACUUM  RECTIFIER 

D  C  O  Duodecar  type  used  as  damper 

ODtw  tube  in  horizontal-deflection  circuits 

of  television  receivers.  Outline  12 D, 
OUTLINES   SECTION.   Tube  re- 
quires duodecar  twelve-contact  socket 
and  may  be  mounted  in  any  position.  Heater  volts  (ac/dc),  6.3;  amperes, 

DAMPER  SERVICE 

For  operation  in  a  525-line,  30-frame  system 
Maximum  Ratings,  {Design-Maximum  Values): 
Peak  Inverse  Plate  Voltagb#. 

Peak  Plate  Current.  

DC  Plate  Current  

Plate  Dissipation  


5000  max 
1200  max 
200  max 
6 . 5  max 


volts 
ma 
ma 

watts 


174 


Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   5000"waa;  volts 

Heater  positive  with  respect  to  cathode   300 °max  volts 

Characteristics,  Instantaneous  Value: 

Tube  Voltage  Drop  for  dc  plate  current  of  350  ma   25  volts 

*  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  horizontal  scanning  cycle.  In  a 
525-line,  30-frame  system,  15  per  cent  of  one  horizontal  scanning  cycle  is  10  microseconds. 

■  The  dc  component  must  not  exceed  900  volts. 
°  The  dc  component  must  not  exceed  100  volts. 

"^M^  PENTAGRID  CONVERTER 

"  i\\  l===5Ci  ^'          Miniature  type  used  as  converter  CZ. 

J^U^nXL      in  superheterodyne  circuits  in  both  the  OEl CO 

k(2A^^^L/^C3    standard  broadcast  and  FM  bands.The  Related  types: 

GT^^^^^           6BE6  is  similar  in  performance  to  3BE6,  12be6 
^'                   metal  type  6SA7.  For  general  discus- 
sion of  pentagrid  types,  see  Frequency  Conversion  in  ELECTRON  TUBE  AP- 
PLICATION SECTION. 

Heater  Voltage  (ac/dc)   6.3  volts 

Heater  Current   0.3  ampere 

Without  With 

External  External 

Direct  Interblectrode  Capacitances:                              Shield  Shield' 

Grid  No.3  to  Plate                                                             0.30  max  0.25  max  pf 

Grid  No.3  to  Grid  No.l                                                    0.15  max  0.15  max          -  pf 

Grid  No.l  to  Plate                                                           0.10  max  0 . 05  max  pf 

Grid  No.3  to  All  Other  Electrodes                                        7.0  7.0  pf 

Grid  No.l  to  All  Other  Electrodes                                        5.5  5.5  pf 

Plate  to  All  Other  Electrodes                                              8.0  13.0  pf 

Grid  No.l  to  Cathode  and  Grid  No.5                                    3.0  3.0  pf 

Cathode  and  Grid  No.5  to  All  Other  Electrodes  except 

Grid  No.l                                                                    15.0  20.0  pf 

■  With  external  shield  connected  to  cathode  and  grid  No.5. 

CONVERTER 
Maximum  Ratings,  (Design-Maximum  Values): 

Plate  Voltage   330  max  volts 

Grids-No.2-and-No.4  (screen-grid)  Voltage   110  max  volts 

GRIDS-N0.2-AND-N  0.4  Supply  Voltage   330  max  volts 

Plate  Dissipation   1.1  max  watts 

Grids-No  2-AND-N 0.4  Input   1.1  max  watts 

Cathode  Current   15.5  max  ma 

Grid-No.3  Voltage: 

Negative  bias  value   -55  max  volts 

Positive  bias  value   0  max  volts 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  max  volts 

Heater  positive  with  respect  to  cathode   200*max  volts 

Typical  Operation  (Separate  Excitation):* 

Plate  Voltage   100  250  volts 

Grids-No.2-and-No.4  (Screen-Grid)  Voltage   100  100  volts 

Grid-No.l  (Oscillator-Grid)  Voltage  (rms)   10  10  volts 

Grid-No.3  (Control-Grid)  Voltage   -1.5  -1.6  volts 

Grid-No.l  (Oscillator-Grid)  Resistor   20000  20000  ohms 

Plate  Resistance  (Approx.)   0.4  1.0  megohm 

Conversion  Transconductance   455  475  Mmhos 

Grid-No.  3  Voltage  for  conversion  transconductance  of  10  /umhos       -30  -30  volts 

Plate  Current    2.6  2.9  ma 

Grids-No.2-and-No.4  Current   7.0  6.8  ma 

Grid-No.l  Current   0.5  0.5  ma 

Cathode  Current .   10.1  10.2  ma 

Note:  The  transconductance  between  grid  No.l  and  grids  No.2  and  No.4  connected  to  plate  (not  oscil- 
lating) is  approximately  7250  umhos  under  the  following  conditions:  grids  No.l  and  No.3  at  0  volts; 
grids  No.2  and  No.4  and  plate  at  100  volts.  Under  the  same  conditions,  the  cathode  current  is  25  ma., 
and  the  amplification  factor  is  20.  Grid-No.l  voltage  (Approx.)  for  plate  current  of  10  /ua  is  -11  volts. 

*  The  dc  component  must  not  exceed  100  volts. 

*  The  characteristics  shown  with  separate  excitation  correspond  very  closely  with  those  obtained  in  a 
self-excited  oscillator  circuit  operating  with  zero  bias. 

INSTALLATION  AND  APPLICATION 

Type  6BE6  requires  miniature  seven-contact  socket  and  may  be  mounted  in 
any  position.  Outline  7B,  OUTLINES  SECTION. 

Because  of  the  special  structural  arrangement  of  the  6BE6,  a  change  in  signal- 

175 


RCA  Receiving  Tube  Manual 


grid  voltage  produces  little  change  in  cathode  current.  Consequently,  an  rf  voltage 
on  the  signal  grid  produces  little  modulation  of  the  electron  current  flowing  in  the 
cathode  circuit.  This  feature  is  important  because  it  is  desirable  that  the  impedance 
in  the  cathode  circuit  should  produce  little  degeneration  or  regeneration  of  the 
signal-frequency  input  and  intermediate-frequency  output.  Another  important 
feature  is  that,  because  signal-grid  voltage  has  very  little  effect  on  the  space  charge 
near  the  cathode,  changes  in  avc  bias  produce  little  change  in  oscillator  transcon- 
ductance  and  in  the  input  capacitance  of  grid  No.l.  There  is,  therefore,  little 
detuning  of  the  oscillator  by  avc  bias. 

A  typical  self-excited  oscillator  circuit  employing  the  6BE6  is  given  in  the 
CIRCUIT  SECTION. 

In  the  6BE6  operation  characteristics  curves  with  self-excitation,  E^  is  the 
voltage  across  the  oscillator-coil  section  between  cathode  and  ground;  E^  is  the 
oscillator  voltage  between  cathode  and  grid. 


OPERATION  CHARACTERISTICS 
WITH  SELF -EXCITATION 


OPERATION  CHARACTERISTICS 

WITH  SEPARATE  OSCILLATOR  EXCITATION 


TYPE  6BE6 

Ef =6.3  VOLTS       PLATE  VOLTS  =250  _ 
GRIDS-N«2  4.  N»4  VOLTS  =100 
GRID-N«3(C0NTR0L-GRID)V0LTS  =  -| 
GRID-N«I  RESIST0R-0HMS  =  20000 

P(»=  ^^TeT  ^         C^^^  """^^"^^ 

8  VOLTS 
RMS 


o600  <I2 


0.5        1.0  1.5 
ORID-N«l  MILLIAMPERES  (ICl) 

32CM-6625T 


TYPE  6BE6 

Ef  =  6.3  VOLTS 
PLATE  VOLTS  =  250 
GRIDS-N2  2  8,  N9  4  VOLTS  =  100 
GRID-  N9  3  (C0NTR0L-GRID)V0LTS»-I.5 
GRID-NSI  RESISTOR-OHMS  =  20000 
GRID-N9I  CURRENT  VARIED  BY 
ADJUSTMENT  OP  OSCILLATOR  VOLTAGE 


0.4  0.8  1.2 

GRID-N«I   MILLIAMPERES  (ICl) 

92CM-6624T 


6BF5 


BEAM  POWER  TUBE 

Miniature  type  used  in  audio  output  stage 
of  television  and  radio  receivers.  Triode-con- 
nected,  it  is  used  as  a  vertical  deflection  ampli- 
fier in  television  receivers.  Outline  7C,  OUT- 
LINES SECTION.  Tube  requires  miniature 
seven-contact  socket  and  may  be  mounted  in 
any  position.  Heater  volts  (ac/dc),  6.3;  am- 
peres, 1.2.  Typical  operation  as  class  Ai  ampli- 
fier: plate  volts,  110  (250  max)',  grid-No.2  volts, 
110  (117  wax);  grid-No.l  volts,  -7.5;  peak  af  grid-No.l  volts.  7.5;  plate  dissipation,  5.5  max  watts; 
grid-No.2  input,  1.25  max  watts;  plate  ma.,  36  (zero-signal),  39  (maximum-signal);  grid-No.2  ma.,  4 
(zero-signal),  10.5  (maximum-signal);  plate  resistance  (approx.),  12000  ohms;  transconductance,  7500 
/xmhos;  plate  load  resistance,  2500  ohms;^total  harmonic  distortion,  10  per  cent;  maximum-signal  power 
output,  1.9  watts;  peak  heater-cathode  volts,  200  max  (dc  component  100  max  when  heater  is  positive 
with  respect  to  cathode) .  This  type  is  used  principally  for  renewal  purposes. 


6BF6 

Related  type: 
12BF6 


TWIN  DIODE-- 
MEDIUM-MU  TRIODE 

Miniature  type  used  in  compact 
radio  equipment  as  combined  detector, 
amplifier,  and  avc  tube.  The  triode 
unit  is  particularly  useful  as  a  driver 
for  impedance-  or  transformer-coupled 


176 


output  stages  in  automobile  receivers.  It  is  equivalent  in  performance  to  metal 
type  6SR7.  Outline  7B,  OUTLINES  SECTION.  Tube  requires  miniature  seven- 
contact  socket  and  may  be  mounted  in  any  position. 

Heater  Voltage  (ac/dc)   6.3  volts 

Heater  Current   0.3  ampere 

Without  With 

External  External 

Direct  Interelectrode  Capacitances:                           Shield  Shield* 

Triode  Grid  to  Triode  Plate                                              1.9  1,9  pf 

Triode  Grid  to  Cathode  and  Heater                                    1.8  1.9  pf 

Triode  Plate  to  Cathode  and  Heater                                    0.7  1.2  pf 

Plate  of  Diode  Unit  No.l  to  Triode  Grid                           0.07  mox  0.06  max  pf 

Plate  of  Diode  Unit  No.2  to  Triode  Grid                           0 . 06  max  0 . 05  max  pf 

■  With  external  shield  connected  to  cathode. 

TRIODE  UNIT  AS  CLASS  Ai  AMPLIFIER 
Maximum  Ratings,  (Design-Center  Values): 

Plate  Voltage   300  max  volts 

Plate  Dissipation   2.5  max  watts 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   90  max  volts 

Heater  positive  with  respect  to  cathode   90  max  volts 

Typical  Operation: 

Plate  Voltage.  .   250  volts 

Grid  Voltage   -9  volts 

Amplification  Factor   16 

Plate  Resistance  (Approx.)   8500  ohms 

Transconductance   1900  utahoB 

Plate  Current   9.5  ma 

Load  Resistance   10000  ohms 

Total  Harmonic  Distortion   6.5  per  cent 

Power  Output   300  mw 

Maximum  Rating:  DIODE  UNITS 

Plate  Current  (Each  Unit)   1.0  max  ma 

The  two  diode  plates  and  the  triode  unit  have  a  common  cathode.  Diode  biasing  of  the  triode  unit 
of  the  6BF6  is  not  suitable.  For  diode  operation  curves,  refer  to  type  6AV6. 

#BEAM  POWER  TUBE  6BG6G 

Glass  octal  types  used  as  output  JiW%^Ji,f^  A 

amplifier  in  horizontal-deflection  cir-  OliwOwA 

H      cuits  of  television  equipment  and  other  Related  type: 

applications  where  high  pulse  voltages  19BG6GA 
"2  occur  during  short  duty  cycles.  Type 
6BG6-GA,  Outline  25A,  OUTLINES  SECTION.  Type  6BG6-G  maximum  dimen- 
sions: over-all  length,  5-11/16  inches;  seated  height,  5-1/8  inches;  diameter,  2-1/16 
inches.  Tubes  require  octal  socket.  They  may  be  supplied  with  pins  4  and  6  or  with 
pins  1,  4,  and  6  omitted.  Vertical  tube  mounting  is  preferred  but  horizontal  opera- 
tion is  permissible  if  pins  No.2  and  7  are  in  vertical  plane.  Type  6BG6-G  is  used 
principally  for  renewal  purposes. 

Heater  Voltage  (AC/DC)   6.3  volts 

Heater  Current   0.9  ampere 

Direct  Interelectrode  Capacitances:                                6BG6-G  6BG6-GA 

Grid  No.l  to  Plate                                                                 0.34  0.8  pf 

Grid  No.l  to  Cathode,  Heater,  Grid  No.2,  and  Grid  No.3  .  .          12  11  pf 

Plate  to  Cathode,  Heater,  Grid  No.2,  and  Grid  No.3                   6.5  6  pf 

Transconductance"   6000  /xmhos 

Mu-Factor,  Grid  No.2  to  Grid  No.l°   8.0 

°For  plate  and  grid-No.2  volts,  250;  grid-No.l  volts,  -15. 

HORIZONTAL  DEFLECTION  AMPLIFIER 
For  operation  in  a  525-line,  SO-frame  system 
Maximum  Ratings,  (Design-Center  Values): 

DC  Plate  Voltage   700  max  volts 

Peak  Positive-Pulse  Plate  Voltage*  (Absolute  Maximum)   6600*  max  volts 

Peak  Negativb-Pulsb  Plate  Voltage  ,  -1500  max  volts 

DC  Grid-No.2  (screen-grid)  Voltage   350  max  volts 

Peak  Negative-Pulse  Grid-No.I  (control-grid)  Voltage   -300  max  volts 

Peak  Cathode  Current   400  max  ma 

Average  Cathode  Current   110  wax  ma 

Plate  DissiPATiONff   20  max  watts 

Grid-No.2  Input   3.2  max  watts 


177 


RCA  Receiving  Tube  Manual 


Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode. 
Heater  positive  with  respect  to  cathode .  . 

Bulb  Temperature  (At  hottest  point) .... 


200  max 
200«max 

210  max 


volts 
volts 


Maximum  Circuit  Value: 

Grid-No.l-Circuit  Resistance   0.47  max  megohm 

*  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  horizontal  scanning  cycle.  In  a 
525-line,  30-frame  system,  15  per  cent  of  one  horizontal  scanning  cycle  is  10  microseconds. 

*  Under  no  circumstances  should  this  absolute  value  be  exceeded. 

ft  An  adequate  bias  resistor  or  other  means  is  required  to  protect  the  tube  in  the  absence  of  excitation. 
■  The  dc  component  must  not  exceed  100  volts. 


6BH3 

Related  types: 
17BH3,  22BH3 


HALF-WAVE  VACUUM  RECTIFIER 

Novar  type  used  as  damper  tube 
in  horizontal  deflection  circuits  of  black- 
and-white  television  receivers.  Outline 
17A,  OUTLINES  SECTION.  Tube  re- 
quires novar  socket  and  may  be  oper- 


ated in  any  position.  Socket  terminals  1,  3,  6,  and  8  should  not  be  used  as  tie 
points.  It  is  especially  important  that  this  tube,  like  other  power-handling  tubes, 
be  adequately  ventilated. 

Heater  Voltage  (ac/dc)  

Heater  Current  

Direct  Interelectrodb  Capacitances  (Approx.) : 

Plate  to  Cathode  and  Heater  

Cathode  to  Plate  and  Heater  

Heater  to  Cathode  


6.3 
1.6 

6.5 
9.0 
2.8 


volts 
amperes 

pf 
Pf 
pf 


DAMPER  SERVICE 

For  operation  in  a  525-line,  30-frame  system 
Maximum  Ratings,  {Design-Maximum  Values): 

Peak  Inverse  Plate  Voltage"  

Peak  Plate  Current  

DC  Plate  Current  

Plate  Dissipation  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  


5500  max 
1100  max 
180  max 
6 . 5  max 

5500  •max 
300  °max 


volts 
ma 
ma 

watts 

volts 
volts 


6BH6 


■  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  horizontal  scanning  cycle.  In  a 
525-line,  30-frame  system,  15  per  cent  of  one  horizontal  scanning  cycle  is  10  microseconds. 

•  The  dc  component  must  not  exceed  900  volts. 
°  The  dc  component  must  not  exceed  100  volts. 

SHARP-CUTOFF  PENTODE 

Miniature  type  used  as  rf  ampli- 
fier particularly  in  ac/dc  receivers  and 
in  mobile  equipment  where  low  heater- 
current  drain  is  important.  It  is  par- 
ticularly useful  in  high-frequency, 
wide-band  applications.  Outline  7B,  OUTLINES  SECTION.  Tube  requires  ; 
ture  seven-contact  socket  and  may  be  mounted  in  any  position. 

Heater  Voltage  (ac/dc)   6.3 

Heater  Current   0.15 

DiRtecT  Interelectrodb  Capacitances:" 

Grid  No.l  to  Plate   0.0035  max 

Grid  No.l  to  Cathode,  Heater,  Grid  No.2,  Grid  No.3,  and  Internal  Shield  .  5.4 

Plate  to  Cathode,  Heater,  Grid  No.2,  Grid  No.3,  and  Internal  Shield .....  4.4 

■  Without  external  shield,  or  with  external  shield  connected  to  cathode. 

CLASS  Ai  AMPLIFIER 
Maximum  Ratings,  {Design-Center  Values): 

Plate  Voltage  

Grid-No.2  (screen-grid)  Voltage  

Grid-No.2  Supply  Voltage  

Plate  Dissipation.  

Grid-No.2  Input; 

For  grid-No.2  voltages  up  to  150  volts   0.5  max 

For  grid-No.2  voltages  between  150  and  300  volts  

Grid-No.I  (control-grid)  Voltage: 

Negative-bias  value   -50  max 

Positive-bias  value   0  max 

178 


volts 
ampere 

pf 
pf 
pf 


300  max 

See  curve 
300  max 

3  max 


volts 
page  70 
volts 
watts 


watt 
See  curve  page  70 

volts 
volts 


Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode                                                       90  max  volts 

Heater  positive  with  respect  to  cathode                                                        90  max  volts 

Characteristics: 

Plate  Voltage                                                                                  100  250  volts 

Grid  No.3  and  Internal  Shield  Connected  to  cathode  at  socket 

Grid-No.2  Voltage                                                                           100  150  volts 

Grid-No.l  Voltage                                                                            -1          -1  volt 

Plate  Resistance  (Approx.)                                                                0.7  1.4  megohms 

Transconductance                                                                          3400  4600  A»mho8 

Grid-No.l  Voltage  (Approx.)  for  plate  current  of  10                                 -5  -7.7  volts 

Plate  Current                                                                                 3.6  7.4  ma 

Grid-No.2  Current                                                                           1.4  2.9  ma 


MEDIUM-MU  TRIODE--^ 
SHARP-CUTOFF  PENTODE 

Miniature  type  used  in  a  wide 
variety  of  applications  in  television 
receivers.  This  type  has  a  controlled 
heater  warm-up  time  for  use  in  re- 
ceivers   employing  series-connected 
heater  strings.  The  pentode  unit  is  used  as  an  if  amplifier,  a  video  amplifier,  or  an 
age  amplifier.  The  triode  unit  is  used  in  low-frequency  oscillator  circuits.  Outline 
8D,  OUTLINES  SECTION.  Tube  requires  miniature  nine-contact  socket  and  may 
be  mounted  in  any  position. 


6BH8 

Related  type: 
8BH8 


Heater  Voltage  (ac/dc)   6.3 

Heater  Current   0.6 

Heater  Warm-Up  Time  (Average)   11 

Direct  Interelectrode  Capacitances  (Approx.) : 
Triode  Unit: 

Grid  to  Plate   2.4 

Grid  to  Cathode  and  Heater   2.6 

Plate  to  Cathode  and  Heater   0 . 38 

Pentode  Unit: 

Grid  No.l  to  Plate   0 . 046 

Grid  No.l  to  Cathode,  Heater,  Grid  No.2,  Grid  No.3,  and  Internal  Shield  7 

Plate  to  Cathode,  Heater,  Grid  No.2,  Grid  No.3,  and  Internal  Shield. ...  2.4 

Triode  Grid  to  Pentode  Plate   0.016 

Pentode  Grid  No.l  to  Triode  Plate   0.004 

Pentode  Plate  to  Triode  Plate   0.095 


volts 
ampere 

seconds 


Pf 
Pf 
pf 


pf 
pf 
pf 
pf 
pf 
pf 


CLASS  Ai  AMPLIFIER 
Maximum  Ratings,  (Design-Center  Values):  Triode  Unit 

Plate  Voltage   300  max 

Grii>-No.2  (screen-grid)  Supply  Voltage  

Grid-N 0.2  Voltage  

Grid-No.  1  (control-grid)  Voltage,  Positive-bias  value.  . .  0  max 

Plate  Dissipation   2.5  max 

Grid-No.2  Input: 

For  grid-No.2  voltages  up  to  150  volts   - 

For  grid-No.2  voltages  between  150  and  300  volts  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  max 

Heater  positive  with  respect  to  cathode   200"max 

Characteristics: 

Plate  Supply  Voltage   1 50 

Grid-No.2  Supply  Voltage .  

Grid-No.l  Voltage   -5 

Cathode-Bias  Resistor   - 

Amplification  Factor   17 

Plate  Resistance  (Approx.)   5150 

Transconductance   3300 

Grid-No.l  Voltage  (Approx.)  for  plate  current  of  100  na,. .  .  -14 

Plate  Current   9.5 

Grid-No.2  Current  

Maximum  Circuit  Values: 

Grid-No.l-Circuit  Resistance: 

For  fixed-bias  operation   0.5  max 

For  cathode-bias  operation   1.0  max 

■  The  dc  component  must  not  exceed  100  volts. 


Pentode  Unit 

300  max  volts 
300  max  volts 
See  curve  page  70 

0  max  volts 
3  max  watts 

1  max  watt 
See  curve  page  70 


200  max 
200 "maa; 


volts 
volts 


200 

volts 

125 

volts 

volts 

82 

ohms 

50000 

ohms 

7000 

^mhos 

-8 

volts 

15 

ma 

3.4 

ma 

0.25  max 

megohm 

1 . 0  max 

megohm 

179 


RCA  Receiving  Tube  Manual 


REMOTE-CUTOFF  PENTODE 


1^                Miniature  type  used  as  rf  ampli-  ^^Cl/  rti^Xi^^^ 

ODJO          fier  in  high-frequency  and  wide-band  ^VU^1\l-v 

applications.  Features  high  transcon-  k®v^^^>/®g3 

ductance  and  low  grid-to-plate  capaci-  oT^^^^^ 

tance.  Outline  7B,  OUTLINES  SEC-  ^ 

TION.  Tube  requires  miniature  seven-contact  socket  and  may  be  mounted  in  any 
position. 

Heater  Voltage  (ac/dc)    6.3  volts 

Heater  Current   0.15  ampere 

Direct  Interelectrode  Capacitances:" 

Grid  No.l  to  Plate   0. 0035  max  pf 

Grid  No.l  to  Cathode,  Heater,  Grid  No.  2,  Grid  No.  3,  and  Internal  Shield  4.5  pf 

Plate  to  Cathode,  Heater,  Grid  No.  2,  Grid  No.  3,  and  Internal  Shield   5.5  pf 

■  Without  external  shield,  or  with  external  shield  connected  to  cathode. 


CLASS  A,  AMPLIFIER 


Maximum  Ratings,  {Design-Center  Values): 

Plate  Voltage.   300  max  volts 

Grid-No.2  (screen-grid)  Voltage   See  curve  page  70 

Grid-No.2  Supply  Voltage   300  wax  volts 

Plate  Dissipation   3  max  watts 

Grid-No.2  Input: 

For  grid-No.2  voltages  up  to  150  volts   0.6  max  watt 

For  grid-No.2  voltages  between  150  and  300  volts   See  curve  page  70 

Grid-No.1  (control-grid)  Voltage: 

Negative  bias  value   -50  max  volts 

Positive  bias  value   0  max  volts 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   90  max  volts 

Heater  positive  with  respect  to  cathode   90  max  volts 


Characteristics: 

Pl&te  Voltage  

100 

250 

volts 

GHd  No.3.  

Connected  to  cathode  at  socket 

brid-No.2  Voltage  

100 

100 

volts 

-1.0 

-1.0 

volt 

0.25 

1.3 

megohms 

Transconductance  

3650 

3600 

^mhos 

Grid-No.l  Voltage  (Approx.)  for  transconductance  of  10  /umbos 

-20 

-20 

volts 

9.0 

9.2 

ma 

Grid-No.2  Current  

3.5 

3.3 

ma 

6BJ7 


TRIPLE  DIODE 

Miniature  type  used  as  a  dc-re- 
storer  tube  in  each  of  the  three  signal 
channels  of  color-television  receivers. 
Each  diode  has  a  separate  cathode. 
Outline  8B,  OUTLINES  SECTION. 
Tube  requires  miniature  nine-contact  socket  and  may  be  mounted  in  any  position. 
Heater  volts,  6.3;  amperes,  0.45. 


DC  RESTORER  SERVICE 
MQ^imum  Ratings,  {Design-Center  Values,  Each  Diode  Unit): 


Peak  Inverse  Plate  Voltage   330  max  volts 

Peak  Plate  Current.  .......    10  wax  ma 

DC  OuTWT  Current    1  max  ma 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   330  max  volts 

Heater  positive  with  respect  ta  cathode   100  wax  volts 


180 


Technical  Data 


6BJ8 


TWIN  DIODE 
MEDIUM-MU  TRIODE 

Miniature  type  used  in  a  wide 
variety  of  applications  in  black-and- 
white  and  color  television  receivers. 
The  diode  units  are  used  in  phase- 
detector,  phase-comparator,  ratio-de- 
tector or  discriminator,  and  horizontal  afc  discriminator  circuits.  The  triode  unit 
is  used  in  phase-splitter,  audio-frequency  amplifier,  and  low-frequency  oscillator 
applications;  it  may  also  be  used  as  a  vertical-deflection  amplifier  in  compact  portable 
television  receivers.  This  type  has  a  controlled  heater  warm-up  time  for  use  in 
receivers  employing  series-connected  heater  strings.  Each  of  the  three  units  has  its 
own  cathode  with  individual  base-pin  terminal  to  provide  for  flexibility  of  circuit 
connections.  Outline  8D,  OUTLINES  SECTION.  Tube  requires  miniature  nine- 
contact  socket  and  may  be  mounted  in  any  position. 


Heater  Volts  (ac/dc)  

Heater  Current  

Heater  Warm-Up  Time  (Average)  

Direct  Interelectrode  Capacitances: 
Triode  Unit: 

Grid  to  Plate  

Grid  to  Cathode  and  Heater  

Plate  to  Cathode  and  Heater  

Diode  Units: 

Plate  to  Cathode  and  Heater  (Each  Unit)  

Cathode  to  Plate  and  Heater  (Each  Unit)  

Plate  of  Unit  No.l  to  Plate  of  Unit  No.2  

Plate  of  Diode  Unit  No.l  to  Triode  Grid  

Plate  of  Diode  Unit  No.2  to  Triode  Grid  

Plate  of  Either  Diode  Unit  to  All  Other  Electrodes .  .  .  . 
Cathode  of  Either  Diode  Unit  to  All  Other  Electrodes. 


TRIODE  UNIT  AS  CLASS  Ai  AMPLIFIER 
Maximum  Ratings,  {Design-Maximum  Values): 

Plate  Voltage  

Grid  Voltage,  Positive-bias  value  

Average  Cathode  Current  

Plate  Dissipation  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  

Characteristics: 


Plate  Voltage . 
Grid  Voltage.  . 


90 
0 


6.3 
0.6 
11 


2.6 
2.8 
0.31 

1.9 

4.6 
0.06  max 
0.07  max 
0.11  max 

3.0 

4.8 


330  max 
0  max 
22  max 
4  max 

200  max 
200  "maa; 


250 
-9 


volts 
ampere 
seconds 


Pf 
Pf 
pf 

pf 
pf 
pf 
pf 
pf 
pf 
pf 


volts 
volts 
ma 
watts 

volts 
volts 


volts 
volts 


AVERAGE  CHARACTERISTICS 

TRIODE  UNIT 


600  700 
S2CM-053IT 


181 


RCA  Receiving  Tube  Manual 


Amplification  Factor   22  20 

Plate  Resistance  (Approx.)   4700  7150  ohms 

Transconductance   4700  2800  Aimhos 

Grid  Voltage  (Approx.)  for  plate  current  of  10  /na   -7  -18  volts 

Plate  Current   13.5  8  ma 

Plate  Current  for  grid  voltage  of  -12.5  volts   -  1.7  ma 

Maximum  Circuit  Value: 

Grid-Circuit  Resistance .   1  max  megohm 

■  The  dc  component  must  not  exceed  100  volts. 

TRIODE  UNIT  AS  VERTICAL  DEFLECTION  AMPLIFIER 

For  operation  in  a  525-line,  30-frame  system 
Maximum  Ratings,  (Design-Maximum  Values): 

DC  Plate  Voltage   330  max  volts 

Peak  Positive-Pulse  Plate  Voltage  t   1200  max  volts 

Peak  Negative-Pulse  Grid  Voltage   -275  max  volts 

Peak  Cathode  Current   77  max  ma 

Average  Cathode  Current   22  max  ma 

Plate  Dissipation   4  max  watts 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  max  volts 

Heater  positive  with  respect  to  cathode   200"maa;  volts 

Maximum  Circuit  Value: 

Grid-Circuit  Resistance: 

For  cathode-bias  operation   2.2  max  megohms 

DIODE  UNITS 
Maximum  Ratings,  {Design-Maximum Values): 

Plate  Current  (Each  Unit) : 

Peak   54  max  ma 

Average   9  max  ma 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  max  volts 

Heater  positive  with  respect  to  cathode   200"max  volts 

t  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  vertical  scanning  cycle.  In  a  525- 
line,  30-frame  system,  15  per  cent  of  one  vertical  scanning  cycle  is  2.5  milliseconds. 

■  The  dc  component  must  not  exceed  100  volts. 


SHARP-CUTOFF  BEAM  TRIODE 

Glass  octal  type  used  for  the  volt-  0-&-© 
age  regulation  of  high-voltage,  low-  '^<<r/^llVr>'^ 
Qi^^  current  dc  power  supplies  in  color  tele- 

ODIxTT  vision  receivers.  Outline  25A,  OUT- 

LINES SECTION.  Tube  requires  oc- 
tal  socket  and  may  be  mounted  in  ^  ^ 

any  position. 

Heater  Voltage  (ac/dc)   6.3  volts 

Heater  Current   0,2  ampere 

Direct  Interelectrode  Capacitances  (Approx.) : 

Grid  to  Plate   0.03  pf 

Grid  to  Cathode  and  Heater   2.6  pf 

Plate  to  Cathode  and  Heater   1  pf 

Amplification  Factor  (Approx.)   2000 

VOLTAGE-CONTROL  SERVICE 
Maximum  Ratings,  {Design-Maximum  Values): 

DC  Plate  Voltage   27000  wax  volts 

Unregulated  DC  Supply  Voltage   60000  max  volts 

DC  Grid  Voltage   -135  max  volts 

Peak  Grid  Voltage"   -440  max  volts 

DC  Plate  Current   1.6  max  ma 

Plate  Dissipation   25  max  watts 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  wax  volts 

Heater  positive  with  respect  to  cathode   Not  recommended 

Maximum  Circuit  Value: 

Grid-Circuit  Resistance: 

For  use  with  "Flyback  Transformer"  high-voltage  supply   3  max  megohms 

■  For  interval  of  20  seconds  maximum  duration  during  equipment  warm-up  period. 

182 


AVERAGE  TRANSFER 
CHARACTERISTICS 


-20       -15  -10 

GRID  VOLTS 

92CS-8432TI 


BEAM  POWER  TUBE 

Miniature  type  used  in  audio  output  stages 
of  television  and  radio  receivers.  Outline  8D, 
OUTLINES  SECTION.  Tube  requires  minia- 
ture nine-contact  socket  and  may  be  mounted 
in  any  position.  Heater  volts  (ac/dc),  6.3;  am- 
peres, 1.2.  Typical  operation  as  class  Ai  ampli- 
fier: plate  and  grid-No.2  volts,  250  max;  grid- 
No.l  volts,  -5;  peak  af  grid-No.l  volts,  5;  plate 
dissipation,  9  max  watts;  grid-No.2  input,  2.5 
max  watts;  plate  ma.,  35  (zero-signal),  37  (maximum-signal);  grid-No.2  ma.,  3.5  (zero-signal),  10 
(maximum-signal);  plate  resistance  (approx.),  0.1  megohm;  transconductance,  8500  /umbos;  load 
resistance,  6500  ohms;  total  harmonic  distortion,  7  per  cent;  power  output,  3.5  watts;  peak  heater- 
cathode  volts,  100  max.  This  type  is  used  principally  for  renewal  purposes. 


6BK5 

Related  types: 
12BK5,  25BK5 


hq®^pt,        medium-mu  twin  triode  6BK7A 

^"r2(Ti^^Lr^^VT)^'^'  Miniature  types  used  in  direct-  Z^Dl^^D 
 coupled  cathode-drive  rf  amplifier  cir-         ODIv/  D 

(Tja^X"^!®       cuits  of  vhf  television  tuners.  In  such  Related  type: 

fn^CZ^TO  ci^c^i^S'       triode  unit  is  used  as  the  sbkza 

Pii^  Ms  direct-coupled  grounded-cathode  driv- 
er for  the  other  unit.  These  types  are  also  used  in  push-pull  cathode-drive  rf  amplifiers. 
Type  6BK7-B  has  a  controlled  heater  warm-up  time  for  use  in  receivers  employing 
series-connected  heater  strings.  Outline  8B,  OUTLINES  SECTION.  Tubes  require 
miniature  nine-contact  socket  and  may  be  mounted  in  any  position.  For  typical 
operation  as  a  resistance-coupled  amplifier,  refer  to  RESISTANCE-COUPLED 
AMPLIFIER  SECTION.  Type  6BK7-A  is  a  DISCONTINUED  type  listed  for 
reference  only. 

Heater  Voltage  (ac/dc)    ^  •  3  volts 

Heater  Current  • .  •  •        0  .45  ampere 

Heater  Warm-Up  Time  (Average)  for  6BK7-B   11  seconds 

Direct  Interelectrode  Capacitances:  ^^nit  No.  t     Unit  No.  2 

Grid  to  Plate   18  1.8  pf 

Grid  to  Cathode,  Heater,  and  Internal  Shield   3  3  pf 

Plate  to  Cathode,  Heater,  and  Internal  Shield   1  0.9  pf 

Cathode  to  Grid,  Heater,  and  Internal  Shield   6  6  pf 

Plate  to  Grid,  Heater,  and  Internal  Shield   2  .4  2  .4  pf 


183 


RCA  Receiving  Tube  Manual 


Plate  to  Cathode                                                              0.22  0.22  pf 

Heater  to  Cathode                                                               2.8  3  pf 

Grid  of  Unit  No.l  to  Grid  of  Unit  No.2   0 . 004  max  pf 

Plate  of  Unit  No.l  to  Plate  of  Unit  No.2    0 . 075  max  pf 

CLASS  Ai  AMPLIFIER  {Each  Unit) 
Maximum  Ratings,  (Design-Center  Values): 

Plate  Voltage   300  max  volts 

Grid  Voltage,  Negative-bias  value  ,   -50  max  volts 

Plate  Dissipation   2.7  max  watts 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200*max  volts 

Heater  positive  with  respect  to  cathode.   200"max  volts 

Characteristics: 

Plate  Supply  Voltage   150  volts 

Cathode-Bias  Resistor   56  ohms 

Amplification  Factor. ;   43 

Plate  Resistance  (Approx.)   4600  ohms 

Transconductance  ,   9300  /imhos 

Plate  Current  ,   18  ma 

Grid  Voltage  (Approx.)  for  plate  current  of  10    -11  volts 


*  In  cathode-drive  circuits  with  direct-coupled  drive,  it  is  permissible  for  this  voltage  to  be  as  high  as 

300  volts  under  cutoff  conditions. 

■  The  dc  component  must  not  exceed  100  volts. 


HALF-WAVE  VACUUM  RECTIFIER 

Glass  octal  type  used  as  a  damper  tube  in 

horizontal  deflection  circuits  of  color  television 

receivers. Maximum  dimensions:  over-all  length, 
ADI  ^  4-5/8  inches;  seated  height,  4-1/16  inches;  di- 

ameter,  1-5/8  inches.  Tube  requires  octal  socket. 

Heater  volts  (ac/dc),  6.3;  amperes,  3.  Maxi- 
mum ratings  for  damper  service:  peak  inverse 

plate  volts  (absolute  maximum),  4500  max; 

peak  plate  ma.,  1200  max;  dc  plate  ma.,  200 
max;  plate  dissipation,  8  max  watts;  peak  heater-cathode  volts,  4500  absolute  max  when  heater  is  nega- 
tive with  respect  to  cathode  (dc  component  must  not  exceed  900  volts) ;  300  max  when  heater  is  positive 
with  respect  to  cathode  (dc  component  must  not  exceed  100  volts).  This  is  a  DISCONTINUED  type 
listed  for  reference  only. 


MEDIUM-MU  TWIN  TRIODE 

Glass  octal  types  used  as  combined 
vertical  deflection  amplifier  and  ver- 
tical deflection  oscillator  in  television 
receivers.  When  so  operated,  it  is 
recommended  that  unit  No.l  (pins  4, 
5,  and  6)  be  used  as  the  oscillator.  Outline  14C,  OUTLINES  SECTION.  Tubes 
require  octal  socket  and  may  be  mounted  in  any  position.  Type  6BL7-GT  is  a 
DISCONTINUED  type  listed  for  reference  only. 


6BL7GT 

6BL7GTA 


Heater  Voltage  (ac/dc)  

6.3 

volts 

Heater  Current  

1.5 

amperes 

Direct  Interelectrode  Capacitances  (Approx.) : 

Unit  No.  1 

Unit  No.  2 

Grid  to  Plate  

6 

6 

pf 

Grid  to  Cathode  and  Heater  

4.2 

4.6 

pf 

Plate  to  Cathode  and  Heater  

0.9 

0.9 

pf 

Amplification  Factor*  

15 

Plate  Resistance  (Approx.)*  

2150 

ohms 

Transconductance*  

7000 

umhos 

*  Each  unit;  for  plate  volts,  250;  grid  volts,  -9;  plate  ma.,  40. 

VERTICAL  DEFLECTION  OSCILLATOR  OR  AMPLIFIER* 

For  operation  in  a  525-line,  30-frame  System 


Maximum  Ratings,  (Design-Center  Values): 

Oscillator 

A  ntpiifier 

DC  Plate  Voltage  

500  max 

500  max 

volts 

Peak  Positive-pulse  Plate  Voltage!  (Absolute  Maximum) . . 

2000  ^maa: 

volts 

Peak  Negative-Pulse  Grid  Voltage    

-400  max 

-250  max 

volts 

Peak  Cathode  Current  

210  max 

210  may 

ma 

Average  Cathode  Current  

60  max 

60  max 

ma 

184 


Plate  Dissipation: 

For  either  plate  

For  both  plates  with  both  units  operating . 
Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode .  . 

Heater  positive  with  respect  to  cathode.  .  . 


10  max 
12  max 


200  max 
200'max 


10  max 
12  max 


200  max 
200"mox 


watts 
watts 


volts 
volts 


A.l^max  megohms 


6BL8 

Related  type: 
4BL8 


Maximum  Circuit  Values: 

Grid-Circuit  Resistance   4.7  max 

•  Unless  otherwise  specified,  values  are  for  each  unit. 

t  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  vertical  scanning  cycle.  In  a 

525-line,  30-frame  system,  15  per  cent  of  one  vertical  scanning  cycle  is  2.5  milliseconds. 
^  Under  no  circumstances  should  this  absolute  value  be  exceeded. 
■  The  dc  component  must  not  exceed  100  volts. 

#  For  cathode-bias  operation. 

MEDIUM-MU  TRIODE— 
SHARP-CUTOFF  PENTODE 

Miniature  type  used  in  frequency- 
changer  service  in  television  receivers. 
Outline  8B,  OUTLINES  SECTION. 
Tube  requires  miniature  nine-contact 
socket  and  may  be  mounted  in  any 
position.  Heater  volts  (ac/dc),  6.3;  amperes,  0.45. 

CLASS  Ai  AMPLIFIER 

Maximum  Ratings,  (Design-Center  Values): 

Plate  Supply  Voltage  

Plate  Voltage  

Grid-No.2  (screen-grid)  Supply  Voltage  

Grid-No.2  Voltage; 

With  cathode  current  of  14  ma.  

With  cathode  current  less  than  10  ma  

Cathode  Current  

Grid-No.2  Input: 

With  plate  dissipation  greater  than  1.2  watts  

With  plate  dissipation  less  than  1.2  watts  

Plate  Dissipation  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  


Characteristics: 

Plate  Voltage  

Grid-No.2  Voltage  

Grid-No.l  Voltage  

Amplification  Factor  

Mu-Factor,  Grid  No.2  to  Grid  No.l .  .  .  . 

Plate  Resistance  (Approx.)  

Transconductance  

Plate  Current  

Grid-No.2  Current  

Input  Resistance  at  frequency  of  50  Mc  , 
Equivalent  Noise  Resistance  

Maximum  Circuit  Values: 

Grid-No.  1-Circuit  Resistance: 

For  fixed-bias  operation  

For  cathode-bias  operation  


Triode 

Pentode 

Unit 

Unit 

550  max 

550  max 

volts 

250  max 

250  max 

volts 

550  max 

volts 

175  max 

volts 

200  max 

volts 

14  max 

14  max 

ma 

0.5  max 

watt 

0.75  max 

watt 

1.5  max 

1.7  max 

watts 

100  max 

100  max 

volts 

100  max 

100  max 

volts 

100 

170 

volts 

170 

volts 

-2 

-2 

volts 

20 

47 

0.4 

megohm 

5000 

6200 

/umhos 

14 

10 

ma 

2.8 

ma 

0.01 

megohm 

1500 

ohms 

0 . 5  max 

0.5  max 

megohm 

0.5  max 

1  max 

megohm 

MEDIUM-MU  TRIODE 

Miniature  types  used  as  rf  ampli- 
fier tubes  in  grid-drive  circuits  of  vhf 
television  tuners.  The  double  base-pin 
connections  for  both  cathode  and  grid 
reduce  effective  lead  inductance  and 


6BN4 

6BN4A 

Related  types: 
2BN4A,  3BN4A 


185 


RCA  Receiving  Tube  Manual 


lead  resistance  with  consequent  reduction  in  input  conductance.  In  addition,  the 
basing  arrangement  facilitates  isolation  of  input  and  output  circuits  and  permits 
short,  direct  connections  to  base-pin  terminals.  Outline  7B,  OUTLINES  SECTION. 
Tubes  require  miniature  seven-contact  socket  and  may  be  mounted  in  any  position. 
Type  6BN4  is  a  DISCONTINUED  type  listed  for  reference  only. 


Heater  Voltage  (ac/dc)   6.3  volts 

Heater  Current.  .   0.2  ampere 

Direct  Interelectrode  Capacitances  (Approx.);* 

Grid  to  Plate   1.2  pf 

Grid  to  Cathode  and  Heater   3.2  pf 

Plate  to  Cathode  and  Heater   1.4  pf 

*  With  external  shield  connected  to  cathode. 

CLASS  Ai  AMPLIFIER 
Maximum  Ratings,  {Design-Center  Values): 

Plate  Voltage     275  max  volts 

Grid  Voltage,  Positive-bias  value   0  max  volts 

Plate  Dissipation   2.2  max  watts 

Cathode  Current   22  max  ma 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   100  max  volts 

Heater  positive  with  respect  to  cathode   100  max  volts 

Characteristics: 

Plate-Supply  Voltage   150  volts 

Cathode-Bias  Resistor   220  ohms 

Amplification  Factor   43 

Plate  Resistance  (Approx.)   5400  ohms 

Transconductance   7700  /xmhos 

Grid  Voltage  (Approx.)  for  plate  current  of  100  /la   -6  volts 

Plate  Current   9  ma 

Maximum  Circuit  Value: 

Grid-Circuit  Resistance   0.5  max  megohm 


BEAM  TUBE 

z.  nik  I Miniature  type  used  as  combined 
OqNO  limiter,  discriminator,  and  audio- volt- 
Reiated  types:  age  amplifier  in  inter  carrier  television 

3BN6, 4BN6  and  FM  receivers.  Outline  7C,  OUT- 

LINES SECTION.  Tube  requires 
miniature  seven-contact  socket  and  may  be  mounted  in  any  position.  Heater  volts 
(ac/dc),  6.3;  amperes,  0.3. 


LIMITER  AND  DISCRIMINATOR  SERVICE 
Maximum  Ratings,  {Design-MaximumValues): 

Plate-Supply  Voltage   330  max  volts 

Grid-No.2  Voltage    110  max  voits 

Grid-No.1  Voltage,  Positive  peak  value   60  max  volts 

Cathode  Current   13  max  ma 

Peak  Heater  Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  max  volts 

Heater  positive  with  respect  to  cathode   200°max  volts 

°  The  dc  component  must  not  exceed  100  volts. 

TWIN  DIODE— HIGH-MU  TRIODE  "Qc^^'*°' 

Miniature  type  used  in  a  wide  ^^^(z)/r^^^!^^^i^'^ 

ODIMo          variety  of  applications  in  color  and  ""rhll 

Related  type:           black-and-white  television  receivers.  v^o^S^f-^^^^/®^- 

8BN8              This  type  has  a  controlled  heater  ^  ^j-sli:::^^  ^ 
warm-up  time  for  use  in  receivers  em- 


ploying  series-connected  heater  strings.  The  triode  unit  is  used  in  burst-amplifier, 
af  amplifier,  and  low-frequency  oscillator  applications.  The  diode  units  are  used 


186 


in  phase-detector,  ratio-detector  or  discriminator,  and  horizontal  AFC  discrimin- 
ator circuits.  Outline  8D,  OUTLINES  SECTION.  Tube  requires  miniature  nine- 
contact  socket  and  may  be  mounted  in  any  position. 


Heater  Voltage  (ac/dc)   6.3 

Heater  Current   0.6 

Heater  Warm-Up  Time  (Average)   11 

Direct  Interelectrode  Capacitances: 

Triode  Grid  to  Triode  Plate   2.5 

Triode  Grid  to  Cathode  and  Heater   3.6 

Triode  Plate  to  Cathode  and  Heater   0 .25 

Plate  of  Diode  Unit  No.l  to  Triode  Grid   0 . 06  max 

Plate  of  Diode  Unit  No.2  to  Triode  Grid   0.1  max 

Plate  of  Diode  Unit  No.l  to  Plate  of  Diode  Unit  No.2   0 .07  max 

Diode  Cathode  to  All  Other  Electrodes  (Each  Diode  Unit)   5 

Diode  Plate  to  Diode  Cathode  and  Heater  (Each  Diode  Unit)   1.9 

Diode  Cathode  to  Diode  Plate  and  Heater  (Each  Diode  Unit)   4.8 

Diode  Plate  to  All  Other  Electrodes  (Each  Diode  Unit)   3 

TRIODE  UNIT  AS  CLASS  Aj  AMPLIFIER 
Maximum  Ratings,  {Design-Maximum  Values): 

Plate  Voltage   330  max 

Grid  Voltage,  Positive  bias  value   0  max 

Plate  Dissipation   1.7  max 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  max 

Heater  positive  with  respect  to  cathode   200 "max 

Characteristics: 

Plate  Voltage                                                                             100  250 

Grid  Voltage                                                                             -1  -3 

Amplification  Factor                                                                     75  70 

Plate  Resistance  (Approx.)                                                        21000  28000 

Transconductance                                                                     3500  2500 

Grid  Voltage  (Approx.)  for  plate  current  of  10                                -2.5  -5.5 

Plate  Current                                                                          1.5  1.6 

Maximum  Circuit  Value: 

Grid-Circuit  Resistance   1.0  max 


volts 
ampere 
seconds 

H 

H 

pf 
pf 


volts 
volts 
watts 

volts 
volts 


volts 
volts 

ohms 
/xmhos 
volts 
ma 


megohm 


DIODE  UNITS 
Maximum  Ratings,  {Design-Maximum  Values): 

Plate  Current  (Each  Unit) : 

Peak  

DC  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  

■  The  dc  component  must  not  exceed  100  volts. 

AVERAGE  CHARACTERISTICS 

  TRIODE  UNIT 


54  max 
9  max 


200  max 
200"mox 


ma 
ma 


volts 
volts 


900  400 
PLATE  VOLTS 


187 


RCA  Receiving  Tube  Manual 


POWER  PENTODE  „^  f? 

Miniature  type  used  in  the  output 

stage  of  audio-frequency  amplifiers.  ^^(3 
ReMedtyptr          Outline  8E,  OUTLINES  SECTION. 

*8BQ5  ^  '          Tube  requires  miniature  nine-contact  ^' 
socket  and  may  be  mounted  in  any 
position. 

Heater  Voltage  (ac/dc)   6.3 

Heater  C  urrent   0.76 

Direct  Interelectrode  Capacitances: 

Grid  No.l  to  Plate .     0.5  max 

Grid  No.l  to  Cathode.  Heater,  Grid  No.2,  and  Grid  No.3   10.8 

Plate  to  Cathode,  Heater,  Grid  No.2,  and  Grid  No.3   6.5 

Grid  No.l  to  Heater   0.25  max 


volts 
ampere 

Pf 
Pf 
pf 
pf 


CLASS  Ai  AMPLIFIER 


Maximum  Ratings,  {Design-Center  Values): 

Plate  Voltage   300  max  volts 

Grid-No.2  (screen-grid)  Voltage   300  max  volts 

Grid-No.1  (control-grid)  Voltage,  Positive-bias  value   0  max  volts 

Grid-No.2  Input   2  max  watts 

Plate  Dissipation   12  maa:  watts 

Cathode  Current   65  max  ma 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   100  max  volts 

Heater  positive  with  respect  to  cathode   lOO^woo;  volts 

^  The  dc  component  must  not  exceed  100  volts. 

Typical  Operation: 

Plate  Voltage   250  volts 

Grid-No.2  Voltage   250  volts 

Grid-No.l  (Control-Grid)  Voltage   ^7.3  volts 

Peak  AF  Grid-No.l  Voltage    6.2  volts 

Zero-Signal  Plate  Current   48  ma 

Maximum-Signal  Plate  Current   50 . 6  ma 

Zero-Signal  Grid-No.2  Current   5.5  ma 

Maximum-Signal  Grid-No.2  Current   10  ma 

Plate  Resistance  (Approx.)   38000  ohms 

Transconductance   11300  ^wihos 

Load  Resistance   4500  ohms 

Total  Harmonic  Distortion   10  per  cent 

Maximum-Signal  Power  Output   5.7  watts 

Maximum  Circuit  Values: 

Grid-No. l-Circuit  Resistance: 

For  fixed-bias  operation   0.3  wax  megohm 

For  cathode-bias  operation   1.0  max  megohm 


PUSH-PULL  CLASS  ABj  AMPLIFIER 
Maximum  Ratings:  (Same  as  for  single-tube  class  Ai  amplifier) 
Typical  Operation,  {Values  are  for  two  tubes): 

Plate  Supply  Voltage  

Grid-No.2  Supply  Voltage  

Cathode-Bias  Resistor  

Peak  AF  Grid-No.l-to-Grid-No.l  Voltage  

Zero-Signal  Plate  Current  

Maximum-Signal  Plate  Current  

Zero-Signal  Grid-No.2  Current  

Maximum-Signal  Grid-No.2  Current  

Effective  Load  Resistance  (Plate-to-plate)  ,  

Total  Harmonic  Distortion    

Maximum-Signal  Power  Output  

Maximum  Circuit  Values: 
Grid-No.l-Circuit  Resistance: 

For  fixed-bias  operation  

For  cathode-bias  operation  

188 


250 

300 

volts 

250 

300 

volts 

130 

130 

ohms 

22.6 

28.3 

volts 

62 

72 

ma 

75 

92 

ma 

7 

8 

ma 

15 

22 

ma 

8000 

8000 

ohms 

3 

4 

per  cent 

11 

17 

watts 

0.3  max  megohni 
1.0  max  megohm 


BEAM  POWER  TUBE  6BQ6GT 

Glass  octal  types  used  as  hori-  x^HANX^XD 
Nc    XI  I  T\         zontal  deflection  amplifiers  in  tele-  ODQOwTD 
|-L\\        vision  receivers.  Outline  15C,  OUT-  . 

LINES  SECTION.  Tubes  require  oc-  /6CU6 
tal  socket  and  may  be  mounted  in  any  Related  types: 

position.  These  types  may  be  supplied    i2bq6GTb/12cu6,  17BQ6. 
NC       K         with  pin  No*l  omitted.  Type  6BQ6-     gtb,  25bq6gtb/25CU6 
^3         GT  is  a  DISCONTINUED  type  listed 
for  reference  only. 

Heater  Voltage  (ac/dc)   6.3  volts 

Heater  Current   1.2  amperes 

Direct  Interblectrode  Capacitances  (Approx.,  6BQ6-GTB/6CU6): 

Grid  No.l  to  Plate   0.6  pf 

Grid  No.l  to  Cathode,  Heater,  Grid  No.2,  and  Grid  No.3   15  pf 

Plate  to  Cathode,  Heater,  Grid  No.2,  and  Grid  No.3   7  pf 

Transconductance*  (6BQ6-GTB/6CU6)  5900  ^mhos 

Mu-Factor,  Grid  No.2  to  Grid  No.l**   4.3 

*  For  plate  volts,  250;  grid-No.2  volts,  150;  grid-No.l  volts,  -22.5;  plate  ma.,  57;  grid-No.2  ma.,  2.1. 

For  plate  and  grid-No.2  volts,  150;  grid-No.l  volts,  -22.5. 

HORIZONTAL  DEFLECTION  AMPLIFIER 

For  operation  in  a  525-line,  SO-frame  system 

Maximum  Ratings^  (Design-Center  Values):  6BQ6-GT  6BQ6-GTB/6CU6 

DC  Plate  Voltage   550  max  600  max  volts 

Peak  Positive-Pulse  Plate  Voltage  •  (Absolute  Maximum)  5500twax  6000twoa;  volts 

Peak  Negative-Pulse  Plate  Voltage   -1250  max  -1250  max  volts 

DC  Grid-No.2  (screen-grid)  Voltage   175  max  200  max  volts 

Peak  Negative-Pulse  Grid-No.1  (control-grid)  Voltage  -300  wax  -300  max  volts 

Peak  Cathode  Current   400  wax  400  wax  ma 

Average  Cathode  Current   110  wax  110  wax  ma 

Grid-No.2  Input   2.5  wax  2.5  wax  watts 

Plate  Dissipation#   11  wax  11  wax  watts 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  wax  200  wax  volts 

Heater  positive  with  respect  to  cathode   200"wax  200"wax  volts 

Bulb  Temperature  (At  hottest  point) .   220  wax  220  wax  "C 

Maximum  Circuit  Value; 

Grid-No.l-Circuit  Resistance   0.47  wax  megohm 

•  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  horizontal  scanning  cycle.  In  a 
525-line,  30-frame  system,  15  per  cent  of  one  horizontal  scanning  cycle  is  10  microseconds. 

t  Under  no  circumstances  should  this  absolute  value  be  exceeded. 

#  An  adequate  bias  resistor  or  other  means  is  required  to  protect  the  tube  in  the  absence  of  excitation. 

•  The  dc  component  must  not  exceed  100  volts. 


"Q^^^**^'         MEDIUM-MU  TWIN  TRIODE  6BQ7 

^^20^^;ri]^^0^Ti  Miniature  types  used  in  direct-  XD^TA 

Z^r""  ""inX      coupled  cathode-drive  rf  amplifier  cir-       OD\ar#  A 
Km   /^K^^y^KTt    cuits  of  vhf  television  tuners.  In  such 

Related  types: 

Q-^--^.^^         circuits,  one  triode  unit  is  used  as  the         4BQ7a,  sbqza 
^"^^  direct-coupled  grounded-cathode  driv- 

er for  the  other  unit.  These  types  are  also  used  in  push-pull  cathode-drive  rf  amplifiers. 
Outline  8B,  OUTLINES  SECTION.  Tubes  require  miniature  nine-contact  socket 
and  may  be  mounted  in  any  position.  For  typical  operation  as  a  resistance-coupled 
amplifier,  refer  to  RESISTANCE-COUPLED  AMPLIFIER  SECTION.  Type 
6BQ7  is  a  DISCONTINUED  type  listed  for  reference  only. 

Heater  Voltage  (ac/dc)   6.3  volts 

Heater  Current   0.4  ampere 

Direct  Interblectrode  Capacitances  (GBQT-A):"  Unit  No.l        Unit  No.2 

Grid  to  Plate   1.2  1.2  pf 

Grid  to  Cathode,  Heater,  and  Internal  Shield   2.6  -  pf 

Cathode  to  Grid,  Heater,  and  Internal  Shield   -  5.0  pf 

Plate  to  Cathode,  Heater,  and  Internal  Shield   1.2  -  pf 

Plate  to  Grid,  Heater,  and  Internal  Shield   -  2.2  pf 

Plate  to  Cathode   0.12  0.12  pf 

Heater  to  Cathode  (6BQ7-A)   2.6  2.6  pf 

Plate  of  Unit  No.l  to  Plate  of  Unit  No.2   0. 010  max  pf 

Plate  of  Unit  No.2  to  Plate  and  Grid  of  Unit  No.l   0, 024  max  pf 

189 


RCA  Receiving  Tube  Manual 


CLASS  Ai  AMPLIFIER  {Each  Unit) 
Maximum  Ratings^  (Design-Center  Values): 

Plate  Supply  Voltage  

Plate  Dissipation  

Cathode  Current.  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  


250*max 
2  max 
20  max 

200*max 
200mnax 


volti 
watts 
ma 

volts 
volts 


6BQ7'A 
150 
220 
38 
5900 
6400 
9 

-6.5 


Characteristics:  6BQ7 

Plate  Supply  Voltage   150 

Cathode-Bias  Resistor   220 

Amplification  Factor   35 

Plate  Resistance  (Approx.)   5800 

Transconductance   6000 

Plate  Current   9 

Grid  Voltage  (Approx.)  ; 

For  plate  current  of  100 /Lia  

For  plate  current  of  10  /ua   -10 

Maximum  Circuit  Value: 

Grid-Circuit  Resistance  

"  With  external  shield  connected  to  internal  shield. 
*  In  cathode-drive  circuits  with  direct-coupled  drive,  it  is  permissible  for  this  voltage  to  be  as  high  as 
300  volts. 

■  The  dc  component  must  not  exceed  100  volts. 

AVERAGE  PLATE  CHARACTERISTICS 

FOR  EACH  UNIT 


volts 
ohms 


ohms 

/LimhoB 


volts 
volts 


0 . 5  max  megohm 


eoo 

92CM>753«RIT 

MEDIUM-MU  TRIODE— 

SHARP-CUTOFF  PENTODE 

Miniature  types  used  in  a  wide 
variety  of  applications  in  color  and 
black-and-white  television  receivers. 
Especially  useful  as  combined  triode 
oscillator  and  pentode  mixer  in  vhf 
television  tuners.  Type  6BR8-A  has  a  controlled  heater  warm-up  time  for  use  in 
receivers  employing  series-connected  heater  strings.  Outline  8B,  OUTLINES 
SECTION.  Except  for  basing  arrangement  and  grid-No.  1-to-plate  capacitance  of 
pentode  unit,  these  types  are  identical  with  miniature  types  6U8  and  6U8-A, 
respectively. 

HALF-WAVE  VACUUM  RECTIFIER 


6BR8 
6BR8A 

Related  type: 
5BR8 


H 

H 

(4Y, 

Pt(2)(t^ 

-H-i-yi^  Hp 

— J  IS 



M;ip 

6BS3 

Related  types: 
12BS3,  17BS3 


Novar  type  used  as  damper  tube 
in  horizontal-deflection  circuits  of 
black-and-white  television  receivers. 
Outline  lOD,  OUTLINES  SECTION. 
Tube  requires  novar  nine-contact  sock- 


190 


et  and  may  be  mounted  in  any  position.  Socket  terminals  1,  3,  6,  and  8  should  not 
be  used  as  tie  points;  it  is  recommended  that  socket  clips  for  these  pins  be  removed 
to  reduce  the  possibility  of  arc-over  and  to  minimize  leakage.  It  is  especially  impor- 
tant that  this  tube,  like  other  power-handling  tubes,  be  adequately  ventilated. 

Heater  Voltage  (ac  /dc)   6.3  volts 

Heater  Current   1.2  amperes 

Direct  Intbrelbctrode  CAPAcrTANCEs  (Approx.): 

Plate  to  Cathode  and  Heater   6.5  pf 

Cathode  to  Plate  and  Heater   9  pf 

Heater  to  Cathode   2.8  pf 

DAMPER  SERVICE 

For  operation  in  a  525-line,  30-frame  system 
Maximum  Ratings,  (Design-Maximum  Values): 

Peak  Inverse  Plate  Voltage"   5000  wax  volts 

Peak  Plate  Current   1100  max  ma 

DC  Plate  Current   200  max  ma 

Plate  Dissipation   6  max  watts 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   5000*waa;  volts 

Heater  positive  with  respect  to  cathode   300°max  volts 

Characteristics,  instantaneous  Value: 

Tube  Voltage  Drop  for  plate  current  of  140  ma   12  volts 

■  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  horizontal  scanning  cycle.  In  a 
525-line,  30-frame  system,  15  per  cent  of  one  horizontal  scanning  cycle  is  10  microseconds. 

•  The  dc  component  must  not  exceed  900  volts. 
°  The  dc  component  must  not  exceed  100  volts 

H 

a^,^^'''  MEDIUM-MU  TWIN  TRIODE 

*^'^2gv^p_  X/^^  Miniature  type  used  in  direct-  6BS8 

^mrtv      coupled  cathode-drive  rf  amplifier  cir-  Related  i  e- 

c  (?\f^V^^^5^      cuits  of  vhf  television  tuners.  In  such  *  "Ass^'** 

Or*— ^         circuits,  one  triode  unit  is  used  as  the 
^»        direct-coupled  grounded-cathode  driv- 
er for  the  other  unit.  This  type  is  also  used  in  push-pull  cathode-drive  rf  amplifiers. 
Outline  8B,  OUTLINES  SECTION.  Tube  requires  miniature  nine-contact  socket 
and  may  be  mounted  in  any  position.  Heater  volts  (ac/dc),  6.3;  amperes,  0.4. 

CLASS  A,  AMPLIFIER  (Each  Unit) 
Maximum  Ratings,  (Design-Center  Values): 

Plate  Voltage   150  max  volts 

Plate  Dissipation   2  max  watts 

Cathode  Current   20  max  ma 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  max  volts 

Heater  positive  with  respect  to  cathode   200  max  volts 

Characteristics: 

Plate-Supply  Voltage   150  volts 

Cathode-Bias  Resistor   220  ohms 

Amplification  Factor   36 

Plate  Resistance  (Approx.)   5000  ohms 

Transconductance   7200  /xmhos 

Plate  Current   10  ma 

Grid  Voltage  (Approx.)  for  plate  current  of  10  ^ta*   -7  volts 

Maximum  Circuit  Value: 

Grid-Circuit  Resistance   0.5  max  megohm 

*  This  value  applies  to  unit  No.2  only. 

H  SHARP-CUTOFF  TWIN  PENTODE 

(*>7'*Mi^  Miniature  type  used  as  combined 

pp2(2^^p-f^\^^^    sync  separator,  sync  clipper,  and  age 

l^^'^'^^Y^      amplifier  tube  in  television  receivers.  6 BUS 

c^(£KV\  L/®''^'  ^^^^^^^  8D,  OUTLINES  SECTION.  TliZXX 
's    Pjwli^         Tube  requires  miniature  nine-contact  3bu8,4BU8 
K  Gap  I      socket  and  may  be  mounted  in  any 

position. 

191 


RCA  Receiving  Tube  Manual 


Heater  Voltage  (ac/dc)   6.3  volts 

Heater  Curesnt       0.3  ampere 

Direct  Interelectrode  Capacitances: 

Grid  No.3  to  Plate  (Each  Unit)   1.9  pf 

Grid  No.  1  to  All  Other  Electrodes   6  pf 

Grid  No.3  to  All  Other  Electrodes  (Each  Unit)   3.6  pf 

Plate  to  All  Other  Electrodes  (Each  Unit)   3  pf 

Grid  No.3  of  Unit  No.l  to  Grid  No.3  of  Unit  No.2   0.015  max  pf 


CLASS  A,  AMPLIFIER 


Maximum  Ratings,  (Design-Maximum  Values): 

Plate  Voltage  (Each  Unit)   300  wax  volts 

Grid-No.3  (suppressor-grid)  Voltage  (Each  Unit): 

Peak  positive  value..   50  max  volts 

DC  negative  value   -50  max  volts 

DC  positive  value   S  max  volts 

Grid-No.2  (screen-grid)  Voltage   150  waa;  volts 

Grid-No.1  (control-grid)  Voltage,  Negative  bias  value.   -50  max  volts 

Cathode  Current.   12  max  ma 

Grid-No.2  Input  .       0 . 75  max  watt 

Plate  Dissipation  (Each  Unit)   1.1  max  watts 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  max  volts 

Heater  positive  with  respect  to  cathode   200"maa;  volts 


Characteristics:  With  Both  Units  Operating 

Plate  Voltage  (Each  Unit)   100  100  volts 

Grid-No.3  Voltage  (Each  Unit)   -10  0  volts 

Grid-No.2  Voltage   67  .5  67  .5  volts 

Grid-No.  1  Voltage   *  °  volts 

Plate  Current  (Each  Unit)   -  2.2  ma 

Grid-No.2  Current   6.5  3.3  ma 

Cathode  Current   6.6  7.8  ma 


With  One  Unit  Operating-^ 

Plate  Voltage   100  100  volts 

Grid-No.3  Voltage   0  0  volts 

Grid-No.2  Voltage     67 . 5  67 . 5  volts 

Grid-No.  1  Voltage     0  *  volts 

Grid-No.3  Transconductance   -  180  ^mhos 

Grid-No.  1  Transconductance   1500  -  /imhos 

Plate  Current   -  2.2  ma 

Grid-No.3  Voltage  (Approx.)  for  plate  current  of  100    -  -4.5  volts 

Grid- No.l  Voltage  (Approx.)  for  plate  current  of  100  Ma   -  -2.3  volts 


192 


Maximum  Circuit  Values; 

Grid-No.3-Circuit  Resistance  (Each  Unit)   0.5  max  megohm 

Grid-No.  1-Circuit  Resistance   0.5  max  megohm. 

■  The  dc  component  must  not  exceed  100  volts. 

*  Adjusted  to  give  a  dc  grid-No.  1  current  of  100  microamperes. 

t  With  plate  and  grid  No.3  of  the  other  unit  connected  to  ground. 


AVERAGE  CHARACTERISTICS 
/ITH  AS  VARIABLE 


H    @  TWIN  DIODE- 

MEDIUM-MU  TRIODE 

(fr — _p-vf)                Miniature  type  used  as  combined  AD\#0 

cj  (^^Z/K^®  *^02   synchronous  detector  and  chrominance  O  D  V  O 
r^^^^                  amplifier  in  color  television  receivers; 

also  used  as  combined  FM  detector 
and  af  voltage  amplifier.  Tube  has  con- 
trolled warm-up  time  for  use  in  series-connected  heater  strings.  Outline  8B,  OUT- 
LINES SECTION.  Tube  requires  miniature  nine-contact  socket  and  may  be  op- 
erated in  any  position.  Heater  volts  (ac/dc),  6.3;  amperes,  0.6;  warm-up  time 
(average),  11  seconds. 

TRIODE  UNIT  AS  CLASS  Ai  AMPLIFIER 
Maximum  Ratings,  (Design- Maximum  Values): 

Plate  Voltage   330  max  volts 

Grid  Voltage,  Positive-bias  value   0  max  volts 

Plate  Dissipation   2.7  max  watts 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  max  volts 

Heater  positive  with  respect  to  cathode   200°max  volts 

Characteristics: 

Plate  Voltage                                                                              75  200  volts 

Grid  Voltage.                                                                                0  -  volts 

Cathode  Resistor                                                                            -  330  ohms 

Amplification  Factor                                                                     -  33 

Plate  Resistance  (Approx.)                                                             -  5900  ohms 

Transconductance                                                                              -  5600  /tmhos 

Plate  Current                                                                              14  11  ma 

Grid  Voltage  (Approx.)  for  plate  current  of  100  Ata                             -  -11  volts 

Maximum  Circuit  Values: 

Grid-Circuit  Resistance: 

For  fixed-bias  operation   0.1  max  megohm 

For  cathode-bias  operation   0.5  max  megohm 

193 


RCA  Receiving  Tube  Manual 


DIODE  UNITS— TWO 

Values  are  for  each  unit 
Maximum  Ratings,  (Design-Maximum  Values): 

Plate  Current   10  max  ma 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  max  volts 

Heater  positive  with  respect  to  cathode   200°wax  volts 

Characteristics,  Instantaneous  Test  Condition: 

Tube  Voltage  Drop  for  plate  current  of  23  ma   5  volts 

°  The  dc  component  must  not  exceed  100  volts. 

H 

FULL-WAVE  VACUUM  RECTIFIER  ''©^-^v®"^ 
-     - -  -  -  Miniature  type  used  in  full-wave   ^'c/^wx.  .^^poi 

OBVy4         power  supplies  having  high  dc  out-  Zl\\r--\/Tl 
Related  type:  put  current  requirements.  Outline  8D,    nc(£\\  \aX  /2)nc 

12BW4  OUTLINES  SECTION.  Type  6BW4  G^--^ 

requires  miniature  nine-contact  socket  Pqz 
and  may  be  mounted  in  any  position.  It  is  especially  important  that  this  tube,  like 
other  power-handling  tubes,  be  adequately  ventilated.  Heater  volts  (ac/dc),  6.3; 
amperes,  0.9. 

FULL-WAVE  RECTIFIER 
Maximum  Ratings,  (Design-Center  Values): 

Peak  Inverse  Plate  Voltage   1275  max  volts 

AC  Plate  Supply  Voltage  (Per  Plate,  rms)   450  max  volts 

Steady-State  Peak  Plate  Current  (Per  Plate)   350  max  ma 

DC  Output  Current   62 . 5  max  ma 

Transient  Peak  Plate  Current  (Per  Plate)   2  max  amperes 

DC  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   450  max  volts 

Typical  Operation:        Filter  Input  Capacitor  Choke 

AC  Plate-To-Plate  Supply  Voltage  (rms)*   650  900  volts 

Filter  Input  Capacitor   40  -  /nf 

Total  Effective  Plate  Supply  Resistance  per  Plate   82  -  ohms 

Filter  Input  Choke   -  10  henries 

DC  Output  Current   100  100  ma 

DC  Output  Voltage  at  Input  to  Filter  ( Approx.)   330  360  volts 

*  AC  plate  supply  voltage  is  measured  without  load. 

TWIN  DIODE-  ^     H  ^ 

SHARP-CUTOFF  PENTODE  "Q.^-®'' 

Pn  ^/7/  I— §^/^'^P''^'^3p 

ARAA#Q               Miniature  type  used  in  television  '^<(3Vl^__.  zEz^u) 

O  D  W  O         receivers ;  diodes  are  used  as  horizontal  ^MJlL^  ^EEfjiL^ 

Related  type:           phase  detectors;  pentode  is  used  as  a  Kg^®^^Ni  JA^^^p 

sound  if  amplifier,  sound  limiter,  and  ^ 

age  keyer.  Outline  8B,  OUTLINES  Pp 

SECTION.  Heater  volts  (ac/dc),  6.3;  amperes,  0.45.  Tube  requires  nine-contact 
socket  and  may  be  operated  in  any  position. 

PENTODE  UNIT  AS  CLASS  Ai  AMPLIFIER 
Maximum  Ratings,  (Design-Maximum  Values): 

Plate  Voltage   330  wax  volts 

Grid-No.2  (screen-grid)  Supply  Voltage   330  max  volts 

Grid-No.2  Voltage   See  curve  page  70 

Grid-No.  1  (control-grid)  Voltage: 

Positive-bias  value   0  max  volts 

Negative-bias  value   -55  max  volts 

Grid-No.2  Input: 

For  grid-No.2  voltages  up  to  165  volts   0 . 55  max  watt 

For  grid-No.2  voltages  between  165  and  330  volts   See  curve  page  70 

Plate  Dissipation   3  max  watts 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode.   200  max  volts 

Heater  positive  with  respect  to  cathode   200**rnax  volts 

Characteristics: 

Plate  Voltage   250  volts 

Grid-No.2  Voltage   110  volts 

Cathode-Bias  Resistor   68  ohms 

Plate  Resistance  (Approx.)   0.25  megohm 

194 


Transconductance   5200  /tmhos 

Grid-No.l  Voltage  (Approx.)  for  plate  current  of  10/ia   -10  volts 

Plate  Current   10  ma 

Grid-No.2  Current   3.5  ma 

Maximum  Circuit  Values: 

Grid-No.l  Circuit  Resistance: 

For  fixed-bias  operation   0.1  max  megohm 

For  cathode-bias  operation   0.5  max  megohm 

DIODE  UNITS  (Each  Unit) 
Maximum  Ratings,  (Design-Maximum  Values): 

Plate  Current   5  max  ma 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  max  volts 

Heater  positive  with  respect  to  cathode   200°max  volts 

°  The  dc  component  must  not  exceed  100  volts. 

K  rV^^N^V-^  MEDIUM-MU  TWIN  TRIODE 

^'^^^flztjIIZ  /P*^^'           Glass  octal  type  used  as  combined  -  o  T 

J/V-Hi—^^^        vertical  deflection  amplifier  and  ver-  OB/V/ wT 
'^TsCiAX  ^V^^^AS*"       tical  deflection  oscillator  in  television 
Q^r^            receivers.  When  so  operated,  it  is 
^"^2        M            recommended  that  unit  No.l  (pins  4, 

5,  and  6)  be  used  as  the  oscillator.  Outline  14C,  OUTLINES  SECTION.  Tube 
requires  octal  socket  and  may  be  mounted  in  any  position. 

Heater  Voltage  (AC/DC)   6.3  volts 

Heater  Current   1.5  amperes 

Amplification  Factor*   10 

Plate  Resistance  (Approx.)*   1300  ohms 

Transconductance*   7600  /xmhos 

*  For  plate  volts,  250;  cathode-bias  resistor,  390  ohms;  plate  ma.,  42. 

VERTICAL  DEFLECTION  OSCILLATOR  OR  AMPLIFIER  (Each  Unit) 
For  operation  in  a  525'line,  SO-frame  system 

Maximum  Ratings,  (Design-Center  Values):  Oscillator  Amplifier 

DC  Plate  Voltage   500  max  500  max  volts 

Peak  Positive-Pulse  Plate  Voltage 

(Absolute  Maximum) #   -  2000*waa;  volts 

Peak  Negative-Pulse  Grid  Voltage   -400  waa;  -250  maa;  volts 

Peak  Cathode  Current   180  max  180  max  ma 

Average  Cathode  Current   60  max  60  max  ma 

Plate  Dissipation: 

For  either  plate   10  max  10  max  watts 

For  both  plates  with  both  units  operating   12  max  12  max  watts 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  max  200  max  volts 

Heater  positive  with  respect  to  cathode   200°wax  200°maa;  volts 

Maximum  Circuit  Values: 

Grid-Circuit  Resistance   2.2  max  2.2'max  megohms 

#  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  vertical  scanning  cycle.  In  a 
525-line,  30-frame  system,  15  per  cent  of  one  vertical  scanning  cycle  is  2.5  milliseconds. 

^  Under  no  circumstances  should  this  absolute  value  be  exceeded. 
°  The  dc  component  must  not  exceed  100  volts. 
■  For  cathode-bias  operation. 

FULL-WAVE  VACUUM  RECTIFIER 

t  jv     W  Octal  type  having  high  perveance  used  as  a 

ICO*/|      _L\  damper  tube  in  horizontal  deflection  circuits  of 

(^Y"^    ""^  \         television  receivers  or  as  a  rectifier  in  conven- 

(  r— I  r— 7  I         tional  power-supply  applications.  Outline  19A,        /L  P  WIT  A 
(^vVyV^t/T)      OUTLINES  SECTION.  Tube  requires  octal  1  ^  wr\ 

H^-'^VT"'''^'^/^*^    socket  and  may  be  mounted  in  any  position.  It 
"  Tq)  is  especially  important  that  this  tube,  like  other 

*^D2         '^Oi         power-handling  tubes,  be  adequately  ventilated. 

Heater  volts  (ac/dc),  6.3;  amperes,  1.6.  Maxi- 
mum ratings  for  damper  service  (each  unit):  peak  inverse  plate  volts  (absolute  maximum),  3000  max; 
peak  plate  ma.,  525  max;  dc  plate  ma.,  175  max.  Peak  heater-cathode  volts:  heater  negative  with  respect 
to  cathode,  450  max;  heater  positive  with  respect  to  cathode,  100  max.  This  type  is  used  principally  for 
renewal  purposes. 


195 


RCA  Receiving  Tube  Manual 


6BY6 

Related  type: 
3BY6 


PENTAGRID  AMPLIFIER 

Miniature  type  used  as  a  gated 
amplifier  in  color  television  receivers. 
In  such  service,  it  may  be  used  as  a 
combined  sync  separator  and  sync 
clipper.  Outline  7B,  OUTLINES  SEC- 
TION. Tube  requires  miniature  seven-contact  socket  and  may  be  mounted  in 
any  position. 

Heater  Voltage  (ac/dc)  

Heater  Current  

Direct  Interelectrode  Capacitances: 

Grid  No.l  to  Plate  

Grid  No.3  to  Plate  

Grid  No.l  to  Grid  No.3  

Grid  No.l  to  All  Other  Electrodes  

Grid  No.3  to  All  Other  Electrodes  

Plate  to  All  Other  Electrodes  


Characteristic,:  CLASS  A,  AMPLIFIER 

Plate  Voltage  

Grids-No.2-and-No.4  Voltage  

Grid-No.3  Voltage  

Grid-No.l  Voltage  

Grid-No.3-to-Plate  Transconductance  

Grid-No.l-to-Plate  Transconductance  

Plate  Current  

Grids-No.2-and-No.4  Current  

Grid-No.3  Volts  (Approx.)  for  plate  current  of  35 /ua  and  grid-No.l  volts  =-4 
Grid-No.l  Volts  (Approx.)  for  plate  current  of  35 Ma  and  grid-No.3  volts  =0. . 

GATED  AMPLIFIER 

Maximum  Ratings,  (Design-Maximum  Values): 

Plate  Voltage  

Grids-No.2-and-No.4  Voltage  

Grids-No.2-and-No.4  Supply  Voltage  

Grid-No.3  Voltage: 

Negative  bias  value  

Positive  bias  value  

Positive  peak  value  

Grid-No.1  Voltage,  Negative  bias  value  

Plate  Dissipation  

Grid-No.3  Input  

Grids-No.2-and-No.4  Input: 

For  grids-No.2-and-No.4  voltages  up  to  165  volts  

For  grids-No.2-and-No.4  voltages  between  165  and  330  volts  

AVERAGE  OPERATION  CHARACTERISTICS 


6.3 

volts 

0.3 

ampere 

0.08  max 

Pf 

0.35  max 

Pf 

0 . 22  max 

pf 

5.4 

pf 

6.9 

pf 

7.6 

pf 

250 

volts 

100 

volts 

-2.5 

volts 

-2.5 

volts 

500 

/Ltnihos 

1900 

/Ltmhos 

6.5 

ma 

9 

ma 

-15 

volts 

-12 

volts 

330  max 

volts 

See  curve  page  70 

330  max 

volts 

-55  max 

volts 

0  max 

volts 

27  max 

volts 

-110  max 

volts 

2.3  max 

watts 

0.1  max 

watt 

1.1  max 

watts 

See  curve  page  70 

196 


Grid-No.1  Input  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  

Characteristics  as  Sync  Separator  and  Sync  Clipper: 

Plate  Voltage  

Grid-No.3  Voltage  

Grids-No.2-and-No.4  Voltage  

Grid-No.  1  Voltage  

Plate  Current  

Grids-No.2-and-No.4  Current  

Grid-No.3  Volts  (Approx.)  for  plate  voltage  of  25  volts,  grids-No.2-and-No.4 

voltage  of  25  volts,  grid-No.l  voltage  of  0  volts,  and  plate  current  of  50  n& 
Grid-No.l  Volts  (Approx.)  for  plate  voltage  of  25  volts,  grids-No.2-and-No.4 

voltage  of  25  volts,  grid-No.3  voltage  of  0  volts,  and  plate  current  of  50  na 

Maximum  Circuit  Values: 

Grid-No.l  or  Grid-No.S-Circuit  Resistance: 

For  fixed-bias  operation  

For  cathode-bias  operation  

°  The  dc  component  must  not  exceed  100  volts. 


0 . 1  tncix 

watt 

200  max 

volts 

200°max 

volts 

10 

volts 

0 

volts 

25 

volts 

0 

volts 

1.4 

ma 

3.5 

ma 

-2.5 

volts 

-2.3 

volts 

0 . 5  max 
1 . 0  max 


megohm 
megohm 


©  r^Po  DIODE- 

SHARP-CUTOFF  PENTODE 

K5^^S|     z||^T(iV  Miniature  type  used  in  diversified  ARYfi 

(iA\yC~^yfe      applications  in  television  receivers.  The  OO  T  O 

*is^  \^^^(^^^p  pentode  unit  is  used  as  an  rf  amplifier 
vi^Kp       and  the  high-perveance  diode  as  a 
limiter  or  detector.  This  type  has  a 
controlled  heater  warm-up  time  for  use  in  receivers  employing  series-connected 
heater  strings.  Outline  8D,  OUTLINES  SECTION.  Tube  requires  miniature  nine- 
contact  socket  and  may  be  mounted  in  any  position.  Heater  volts  (ac/dc),  6.3; 
amperes,  0.6;  warm-up  time  (average),  11  seconds. 

PENTODE  UNIT  AS  CLASS  Ai  AMPLIFIER 
Maximum  Ratings,  (Design-Center  Values): 

Plate  Volt  AGE   300  max  volts 

Grid-No.3  (suppressor-grid)  Voltage,  Positive  value   0  max  volts 

Grid-No.2  (screen  grid)  Supply  Voltage   300  max  volts 

Grid-No.2  Voltage   See  curve  page  70 

G rid-No.  1  (control-grid)  Voltage: 

Negative  bias  value   -50  max  volts 

Positive  bias  value   0  max  volts 

Plate  Dissipation   3  max  watts 

Grid-No-2  Input: 

For  grid-No.2  voltages  up  to  150  volts   0.65  max  watt 

For  grid-No.2  voltages  between  150  and  300  volts   See  curve  page  70 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  max  volts 

Heater  positive  with  respect  to  cathode   200"max  volts 

Characteristics: 

Plate  Supply  Voltage   100  250  volts 

Grid  No.3   Connect  to  cathode  at  socket 

Grid-No.2  Supply  Voltage   100  150  volts 

Cathode-Bias  Resistor   150  68  ohms 

Plate  Resistance  (Approx.)   0.5  1  megohm 

Transconductance   3900  5200  /imhos 

Grid-No.l  Voltage  (Approx.)  for  plate  current  of  10  /na   -4.2  -6.5  volts 

Plate  Current   5  10.6  ma 

Grid-No.2  Current   2.1  4.3  ma 

Maximum  Circuit  Values: 

Grid-No.l-Circuit  Resistance: 

For  fixed-bias  operation   0.25  max  megohm 

For  cathode-bias  operation   1.0  max  megohm 

■  The  dc  component  must  not  exceed  100  volts. 

DIODE  UNIT 

Maximum  Ratings,  (Design-Center  Values): 

Peak  Inverse  Plate  Voltage   430  wax  volts 

Peak  Plate  Current   180  max  ma 

DC  Plate  Current   45  wax  ma 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  wax  volts 

Heater  positive  with  respect  to  cathode   200"wax  volts 

■  The  dc  component  must  not  exceed  100  volts. 

197 


RCA  Receiving  Tube  Manual 


6BZ6 

Related  types: 
3BZ6,  4BZ6,  12BZ6 


330  max 
0  max 
330  max 


volts 
volts 
volts 


SEMIREMOTE-CUTOFF  PENTODE 

Miniature  type  used  in  gain-con- 
trolled video  if  stages  of  television 
receivers.  Outline  7B,  OUTLINES 
SECTION.  Tube  requires  miniature 
seven-contact  socket  and  may  be 
mounted  in  any  position. 

Heater  Voltage  (ac/dc)  

Heater  Current  

Without 

External 

Direct  Interelectrode  Capacitances:  Shield 

Grid  No.l  to  Plate   0.025  wmx 

Grid  No.l  to  Cathode,  Heater,  Grid  No.2,  Grid  No.3,  and 

Internal  Shield   7 

Plate  to  Cathode,  Heater,  Grid  No.2,  Grid  No.3,  and  In- 
ternal Shield   2 

*  With  external  shield  connected  to  cathode. 

CLASS  Ai  AMPLIFIER 
Maximum  Ratings,  (Design- Maxim  urn  Values): 

Plate  Voltage  

Grid  No.3  (suppressor-grid)  Voltage,  Positive  Value  

Grid-No.2  (screen-grid)  Supply  Voltage  

Grid-No.2  Voltage  

Grid-No.1  (control-grid)  Voltage,  Positive  bias  value  

Plate  Dissipation  

Grid-No.2  Input: 

For  grid-No.2  voltages  up  to  165  volts   0.55  max  watt 

For  grid-No.2  voltages  between  165  and  330  volts   See  curve  page  70 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  

Characteristics: 

Plate  Supply  Voltage  

Grid  No.3   Connected  to  cathode  at  socket 

Grid-No.2  Supply  Voltage   125  volts 

Cathode-Bias  Resistor   56  ohms 

Plate  Resistance  (Approx.)     0^26  megohm 

Transconductance  

Grid-No.l  Voltage  (Approx.)  for  transconductance  of  50  Atrahos  

Grid  No.l  Voltage  (Approx.)  for  transconductance  of  700  /xmhos  and 

cathode  resistor  of  0  ohms  

Plate  Current  

Grid-No.2  Current  

Maximum  Circuit  Values: 

Grid-No.  1-Circuit  Resistance: 

For  fixed-bias  operation   0.25  wax 

For  cathode-bias  operation   1.0  max 

■  The  dc  component  must  not  exceed  100  volts. 

AVERAGE  CHARACTERISTICS 


See  curve  page  70 
0  max  volts 
2.3  max  watts 


200  max 
20Qmmax 


125 


8000 
-19 

-4.5 
14 
3.6 


volts 
volts 


volts 


/xmhos 
volts 

volts 
ma 
ma 


megohm 
megohm 


200 
PLATE  VOLTS 


TYPE  6BZ6 

lb 

— 1 

0 

£■£  s  6.3  VOLTS 

cmONaa  AND  inti 

SHIELD  CONNEC 
TO  CATHODE  AT 
SOCKET. 
CRI0-N*2  VOLTS  s 

RNAL 

-0.25 

TEOy 

129 

f- 

-0.75 

-  GRID 

-N*l  V 

olts 

ECF- 

lb 

— -1.! 

\ 

\ 

i- 

-2 

IC2 

-3 

1 

lb 

-4 

\  

1 

-6 

-10 
"'^1 

198 


92CM-8508T3 


KT2, 


MEDIUM-MU  TWIN  TRIODE 


6BZ7 

Related  type: 
4BZ7 


Miniature  type  used  in  direct- 
coupled  cathode-drive  rf  amplifier  cir- 
cuits of  vhf  television  tuners.  In  such 
circuits,  one  triode  unit  is  used  as  the 
direct-coupled  grounded-cathode  driv- 
er for  the  other  unit.  This  type  is  also  used  in  push-pull  cathode-drive  rf  amplifiers. 
Outhne  8B,  OUTLINES  SECTION.  Tube  requires  miniature  nine-contact  socket 
and  may  be  mounted  in  any  position.  For  typical  operation  as  a  resistance-coupled 
amplifier,  refer  to  RESISTANCE-COUPLED  AMPLIFIER  SECTION.  Heater 
volts  (ac/dc),  6.3;  amperes,  0.4. 

CLASS  Ai  AMPLIFIER  (Each  Unit) 
Maximum  Ratings,  (Design-Center  Values): 

Plate  Voltage  

Plate  Dissipation  

Cathode  Current  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  

*  In  cathode-drive  circuits  with  direct-coupled  drive,  it  is  permissible  for  this  voltage  to  be  as  high  as 

300  volts  under  cutoff  conditions. 

■  The  dc  component  must  not  exceed  100  volts. 

Characteristics: 

Plate  Supply  Voltage  

Cathode-Bias  Resistor  

Amplification  Factor  

Plate  Resistance  (Approx.)  

Transconductance  

Plate  Current  

Grid  Voltage  (Approx.)  for  plate  current  of  100  hb,  

Maximum  Circuit  Value: 

Grid-Circuit  Resistance  

AVERAGE  CHARACTERISTICS 

EACH  UNIT 


260*wax 
2.0  max 
20  max 

200*?nax 
200Bmax 


150 
220 
36 
5300 
6800 
10 
-7 


volts 
watts 
ma 

volts 
volts 


volts 
ohms 

ohms 
/xmhos 
ma 
volts 


0.5  max  megohm 


PLATE  VOUTS 

MEDIUM-MU  TWIN  TRIODE 

Miniature  type  used  in  direct-coupled,  cath- 
ode-drive, rf  amplifier  circuits  in  vhf  television 
tuners.  In  such  circuits,  one  triode  unit  is  used 
as  the  direct-coupled,  grounded-cathode  driver 
for  the  other  unit.  Outline  8B,  OUTLINES  SEC- 
TION. Tube  requires  miniature  nine-contact 
socket.  Heater  volts  (ac  /dc),  6.3;  amperes,  0.4. 
Characteristics  as  class  Ai  amplifier  (each  unit) : 
plate  supply  volts,  125  (250  max) ;  cathode-bias 


600  700 
92CM  -923IT 


6BZ8 


199 


RCA  Receiving  Tube  Manual 


resistor,  100  ohms;  amplification  factor,  45;  plate  resistance  (approx.),  5600  ohms;  transconductance, 
8000  /xmhos;  plate  ma.,  10;  cathode  ma.,  20  max;  plate  dissipation,  2.2  max  watts;  peak  heater-cathode 
volts,  200  max.  Type  6BZ8  is  used  principally  for  renewal  purposes. 

POWER  TRIODE 

Miniature  type  used  in  compact 
Jy^A  radio  equipment  as  a  local  oscillator 

in  FM  and  other  high-frequency  cir- 
cuits. It  may  also  be  used  as  a  class  C 
rf  amplifier.  In  such  service,  it  delivers 
a  power  output  of  5.5  watts  at  moderate  frequencies,  and  2.5  watts  at  150  mega- 
cycles per  second.  Outline  7B,  OUTLINES  SECTION.  Tube  requires  miniature 
seven-contact  socket  and  may  be  mounted  in  any  position.  For  typical  operation 
as  a  resistance-coupled  amplifier,  refer  to  RESISTANCE-COUPLED  AMPLI- 
FIER SECTION.  For  additional  curve  of  plate  characteristics,  refer  to  type 
12AU7-A. 


Heater  Voltage  (ac/dc)  . 
Heater  Current  


Direct  Interelectrode  Capacitances  (Approx.): 

Grid  to  Plate  

Grid  to  Cathode  and  Heater  

Plate  to  Cathode  and  Heater  

^  With  external  shield  connected  to  cathode. 

CLASS  Ai  AMPLIFIER 
Maximum  Ratings^  (Design-Center  Values): 

Plate  Voltage  

Plate  Dissipation  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  

Characteristics: 

Plate  Voltage  ,.  

Grid  Voltage*    

Amplification  Factor  

Plate  Resistance  (Approx.)  

Transconductance  

Plate  Current  

Grid  Voltage  (Approx.)  for  plate  current  of  10  . 


6.3 

0.15 

Without 

With 

External 

External 

Shield 

Shield'' 

1.6 

1.4 

1.8 

1.8 

1.3 

2.5 

300  max 
3 . 5  max 


200  max 
200*max 


volts 
ampere 


Pf 
pf 


volts 
watts 


volts 
volts 


100 
0 

19.5 
6250 
3100 
11.8 
-10 


250 
-8.5 
17 
7700 
2200 
10.5 

-25 


volts 
volts 

ohms 
/Ltmhos 
ma 
volts 

*  Transformer-  or  impedance-type  input  coupling  devices  are  recommended  to  minimize  resistance  in 
the  grid  circuit. 

Maximum  Circuit  Values: 

Grid-Circuit  Resistance: 

For  fixed  bias  operation   0.25  inax  megohm 

For  cathode-bias  operation   1.0  max  megohm 

*  The  dc  component  must  not  exceed  100  volts. 

AVERAGE  PLATE  CHARACTERISTICS 


300  400 
PLAte . VOLTS 


200 


6C5 

6C5GT 


RF  POWER  AMPLIFIER  AND  OSCIUATOR—Class  C  Telegraphy 
Maximum  Ratings^  (Design-Center  Values): 

Plate  Voltagia    300  max  volts 

GuiD  Voltage   -50  max  volts 

Plate  Current   25  max  ma 

Grid  Current   S  max  ma 

Plate  Dissipation   5  max  watts 

Typical  Operation  at  frequencies  up  to  50  Mc: 

Plate  Voltage   300  volts 

Grid  Voltage     -27  volts 

Plate  Current     25  ma 

Grid  Current  (Approx.)   7  ma 

Driving  Power  (Approx.)   0.35  watt 

Power  Output  (Approx.) •   5.5  watts 

•  Approximately  2.5  watts  power  output  can  be  obtained  when  the  6C4  is  used  at  150  megacycles  as 
an  oscillator  with  grid  resistor  of  10,000  ohms  and  with  maximum  rated  input. 

MEDIUM-MU  TRIODE 

Metal  type  6C5  and  glass  octal  type  6C5-GT 
used  as  audio  amplifier,  oscillator,  or  detector 
tubes.  Outlines  3  and  24,  respectively,  OUT- 
LINES SECTION.  Tubes  require  octal  socket. 
Heater  volts  (ac/dc),  6.3;  amperes,  0.3.  Typical 
operation  as  class  A;  amplifier:  plate  volts,  250 
(300  max);  grid  volts,  -8  (0  max);  amplification 
factor,  20;  plate  resistance,  10000  ohms;  trans- 
conductance,  2000  /Limhos;  plate  ma.,  8;  plate 
dissipation,  2.5  max  watts.  Type  6C5-GT  is  a  DISCONTINUED  type  listed  for  reference  only.  Type 
6C5  is  used  principally  for  renewal  purposes. 

SHARP-CUTOFF  PENTODE 

Glass  type  used  as  biased  detector  and  as  a 
high-gain  amplifier  in  radio  equipment.  Outline 
24  A,  OUTLINES  SECTION.  Tube  requires  six- 
contact  socket.  Heater  volts  (ac/dc),  6.3;  am- 
peres, 0.3.  For  ratings  and  typical  operation 
data,  refer  to  type  6J7.  Type  6C6  is  used  prin- 
cipally for  renewal  purposes. 

TWIN  DIODE— 
MEDIUM-MU  TRIODE 

Glass  type  used  as  combined  detector,  am- 
plifier, and  avc  tube.  Outline  24B,  OUTLINES 
SECTION.  Heater  volts  (ac/dc),  6.3;  amperes, 
0.3.  This  type  is  similar  to,  but  not  interchange- 
able with,  type  85.  The  6C7  is  a  DISCON- 
TINUED type  listed  for  reference  only. 

MEDIUM-MU  TWIN  TRIODE 

Glass  octal  type  used  as  a  voltage  amplifier 
and  phase  inverter  in  radio  equipment.  Outline 
23,  OUTLINES  SECTION.  Tube  requires 
octal  socket.  Heater  volts  (ac/dc),  6.3;  amperes, 
0.3.  Maximum  ratings  for  each  triode  unit  as 
class  Ai  amplifier:  plate  volts,  250  max;  grid 
volts,  positive-bias  yalue,  0  max;  plate  dissi- 
pation, 1.0  max  watt.  Typical  operation:  plate 
volts,  250;  grid  volt^,  -4.5;  plate  ma.,  3.2;  plate 
resistance,  22500  ohms;  amplification  factor,  36;  transconductance,  1600  /xmhos.  This  type  is  used  prin- 
cipally for  renewal  purposes. 


6C6 


6C7 


6C8G 


-'"'SHARP-CUTOFF  DUAL  TETRODE 

Miniature  type  used  as  vhf  rf-am-  m 
plifier  and  autodyne  mixer  tube.  Out-  OC9 
line  8B,  OUTLINES  SECTION,  ex-  Related  lype: 

cept  center  pin  is  added  to  base.  Tube  i7C9 
requires  miniature  ten-contact  socket 
and  may  be  mounted  in  any  position.  Heater  volts  (ac/dc),  6.3;  amperes,  0.4. 


201 


RCA  Receiving  Tube  Manual 


CLASS  Ai  AMPLIFIER  {Each  Unit) 
Maximum  Ratings,  {Design-Maximum  Values): 

Plate  Voltage   250  max  volts 

Grid-No.2  (SCREEN-GRID)  Supply  Voltage   180  max  volts 

Grid-No.2  Voltage   See  curve  page  70 

Cathode  Current   20  max  ma 

Plate  Dissipation: 

Either  plate   1.5  max  watts 

Both  plates  (both  units  operating)   2.5  wax  watts 

Grid-No.2  Input: 

For  grid-No.2  voltages  up  to  90  volts   0.5  max  watt 

For  grid-No.2  voltages  between  90  and  180  volts   See  curve  page  70 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   100  max  volts 

Heater  positive  with  respect  to  cathode   100  wax  volts 

Characteristics: 

Plate  Voltage   125  volts 

Grid-No.2  Voltage   80  volts 

Grid-No.  1  Voltage   -1  volt 

Plate  Resistance  (Approx.)   0.1  megohm 

Transconductance   8000  ^mhos 

Plate  Current   10  ma 

Grid-No.2  Current   1.5  ma 

Grid-No.l  Voltage  (Approx.)  for  plate  current  of  20  ixa   -6  volts 


FULL-WAVE  VACUUM  RECTIFIER 

Miniature  type  used  in  power- 
supply  of  compact,  audio  equipment 
f%C/yjL         having  moderate  dc  requirements.  Out- 
^  line  8E,  OUTLINES  SECTION.  Tube 

requires  miniature  nine-contact  socket 
and  may  be  mounted  in  any  position.  It  is  especially  important  that  this  tube,  like 
other  power-handling  tubes,  be  adequately  ventilated.  Heater  volts  (ac/dc),  6.3; 
amperes,  1. 

FULL-WAVE  RECTIFIER 
Maximum  Ratings^  {Design-Center  Values): 

Peak  Inverse  Plate  Voltage   1000  max  volts 

Peak  Plate  Current  (Per  Plate)   450  max  ma 

AC  Plate  Supply  Voltage  (Per  Plate,  rms)  with  Capacitor  Input  to  Filter         350  max  volts 


OPERATION  CHARACTERISTICS 
rULL-WAVE  ClRCUtT    CAPACfTOR  INPUT  TO  FILTER 


I    I    I    i    1    \  r 

TYPE6CA4     E^«6.»  VOLTS 

•  SUPPLY  rREQUCNCY  (CP3)s60   

CAPACITOR  INPUT  TO  FILTER  :SO/i^ 

—  TOTAL  EFFECTIVE  PLATE-SUPPLY  IMPEDANCE 

PER  PLATE      CURVE  I  A  I  B  |  C 
rtw  ruATt       nwu«  1 150  200  240 


100  ISO 
DC  LOAD  MILLIAMPERES 


92CS-I0379TI 


202 


Technical  Data 


DC  Output  Current   150  max  ma 

Hot  Switching  Transient  Plate  Current  (Per  Plate)   # 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   500  max  volts 

Typical  Operation  with  Capacitor  Input  to  Filter: 

AC  Plate-to-Plate  Supply  Voltage  (rms)                         500            600  700  volts 

Filter-Input  Capacitor                                                  50              50  50  tii 

Total  Effective  Plate  Supply  Impedance  per  Plate.  .  150  200  240  ohms 
DC  Output  Voltage  at  Input  to  Filter  (Approx.) 

For  dc  output  current  of  150  ma                              245             293  347  volts 

#  When  capacitor-input  circuits  are  used,  a  maximum  peak  current  value  per  plate  of  1  ampere  during 
the  initial  cycles  of  the  hot-switching  transient  should  not  be  exceeded. 


BEAM  POWER  TUBE 

Miniature  type  used  in  af  power 
output  stage  of  radio  and  television 
receivers.  Outline  7C,  OUTLINES 
SECTION.  Tube  requires  miniature 
seven-contact  socket  and  may  be  op- 
erated in  any  position.  Heater  volts 
(ac/dc),  6.3;  amperes,  1.2. 

CLASS  Ai  AMPLIFIER 
Maximum  Ratings,  {Design-Center  Values): 

Plate  Voltage  

Grid-No.2  (screen-grid)  Voltage  

Grid-No.  1  (control-grid)  Voltage,  Positive-bias  value  

Plate  Dissipation  

Grid-No.2  Input  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  

Bulb  Temperature  (At  hottest  point)  


Typical  Operation: 

Plate  Voltage  

Grid-No.2  Voltage  

Grid-No.l  (Control-Grid)  Voltage  

Peak  AF  Grid-No.l  Voltage  

Zero-Signal  Plate  Current  

Maximum-Signal  Plate  Current  

Zero-Signal  Grid-No.2  Current  (Approx.)  

Maximum-Signal  Grid-No.2  Current  (Approx.) . 

Plate  Resistance  (Approx.)  

Transconductance  

Load  Resistance  

Total  Harmonic  Distortion  

Maximum-Signal  Power  Output  


Maximum  Circuit  Values: 

Grid-No.l-Circuit  Resistance: 

For  fixed-bias  operation  

For  cathode-bias  operation  

°  The  dc  component  must  not  exceed  100  volts. 


BEAM  POWER  TUBE 


6CA5 

Related  types: 
12CA5,  25CA5 


130  max 
130  max 
0  max 
5  max 
1 . 4  max 

200  max 
20(fmax 
180  max 


volts 
volts 
volts 
watts 
watts 

volts 
volts 
°C 


110 

125 

volts 

110 

125 

volts 

-4 

-4.5 

volts 

4 

4.5 

volts 

32 

37 

ma 

31 

36 

ma 

3.5 

4 

ma 

7.5 

11 

ma 

16000 

15000 

ohms 

8100 

9200 

/xmhos 

3500 

4500 

ohms 

5 

6 

per  cent 

1.1 

1.5 

watts 

0 . 1  max 
0 . 5  max 


megohm 
megohm 


6CB5 

6CB5A 


Glass  octal  types  used  as  hori- 
zontal deflection  amplifiers  in  color 
television  receivers.  Type  6CB5-A, 
Outline  25A,  OUTLINES  SECTION. 
Type  6CB5  maximum  dimensions: 
over-all  length,  5-1/8  inches;  seated  height,  4-19/32  inches;  diameter,  2-1/16  inches. 
Tubes  require  octal  socket  and  may  be  mounted  in  any  position.  Type  6CB5  is  a 
DISCONTINUED  type  listed  for  reference  only. 


Heater  Voltage  (ac/dc)  . . . :  

Heater  Current  

Direct  Interelectrodb  Capacitances  (Approx.) : 

Grid  No.l  to  Plate  

Grid  No.l  to  Cathode,  Heater,  Grid  No.2,  and  Grid  No.3 . 

Plate  to  Cathode,  Heater,  Grid  No.2.  and  Grid  No.3  


6.3 
2.5 

0.4 
22 
10 


volts 
amperes 

Pf 
Pf 
pf 

203 


RCA  Receiving  Tube  Manual 


Transconductance*   8800  /umbos 

Mu-F ACTOR,  Grid  No.2  to  Grid  No.l*   3.8 

♦For  plate  and  grid-No.2  volts,  175;  grid-No.l  volts,  -30;  plate  ma.,  90;  grid-No.2  ma.,  6. 

HORIZONTAL  DEFLECTION  AMPLIFIER 

For  operation  in  a  525-line,  SO-frame  system 

Maximum  Ratings: 

DC  Plate  Voltage  

Peak  Positive-Pulse  Plate  Voltage#  

Peak  Negative-Pulse  Plate  Voltage  

DC  Grid-No.2  (screen-grid)  Voltage  

DC  Grid-No.1  (control-grid)  Voltage  

PEAk  Negative-Pulse  Grid-No.1  Voltage   

Peak  Cathode  Current   

Average  Cathode  Current   

Grid-No.2  Input  

Plate  DissiPATiONf  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  

Bulb  Temperature  (At  hottest  point)  

Maximum  Circuit  Value; 

Grid-No.l-Circuit  Resistance  

^  Except  as  noted. 

#  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  horizontal  scanning  cycle.  In  a 

525-line,  30-frame  system,  15  per  cent  of  one  horizontal  scanning  cycle  is  10  microseconds. 

°  Absolute-Maximum  Value.  Under  no  circumstances  should  this  absolute  value  be  exceeded. 

t  An  adequate  bias  resistor  or  other  means  is  required  to  protect  the  tube  in  the  absence  of  excitation. 

■The  dc  component  must  not  exceed  100  volts. 


6CB5 

6CB5-A 

Design-Center 

Design-Maximum 

Values^ 

Values 

700  max 

880  max 

volts 

6800°wax 

6800  max 

volts 

-1500  max 

-1650  max 

volts 

200  max 

220  max 

volts 

-50  max 

-55  max 

volts 

-200  max 

-220  max 

volts 

-  max 

850  max 

ma 

200  max 

240  max 

ma 

3.6  max 

4  max 

watts 

23  max 

26  max 

watts 

200  max 

200  max 

volts 

200"max 

200 "wax 

volts 

210  max 

220  max 

°C 

0.47  max  megohm 


6CB6 
6CB6A 

Related  types: 
3CB6,  4CB6 


SHARP-CUTOFF  PENTODE 

Miniature  types  used  in  television 
receivers  as  intermediate-frequency 
amplifier  at  frequencies  up  to  about  45 
megacycles  per  second  and  as  rf  am- 
plifier in  vhf  television  tuners.  Tubes 
feature  very  high  transconductance  combined  with  low  interelectrode  capacitance 
values,  and  are  provided  with  separate  base  pins  for  grid  No.3  and  the  cathode  to 
permit  the  use  of  an  unbypassed  cathode  resistor  to  minimize  the  effects  of  regenera- 
tion. Type  6CB6-A  has  a  controlled  heater  warm-up  time  for  use  in  television  re- 
ceivers employing  series-connected  heater  strings.  Outline  7B,  OUTLINES  SEC- 
TION. Tubes  require  miniature  seven-contact  socket  and  may  be  mounted  in  any 
position.  For  typical  operation  as  a  resistance-coupled  amplifier,  refer  to  RESIST- 
ANCE-COUPLED AMPLIFIER  SECTION. 


Heater  Volts  (ac/dc)  

Heater  Current  

Heater  Warm-up  Time  (Average)  for  6CB6-A. 


Direct  Interelectrode  Capacitances: 

Grid  No.l  to  Plate  

Grid  No.l  to  Cathode,  Heater,  Grid  No.2,  Grid  No.3, 

and  Internal  Shield  

Plate  to  Cathode,  Heater,  Grid  No.2,  Grid  No.3,  and 

Internal  Shield  

*  With  external  shield  connected  to  cathode. 

CLASS  Ai  AMPLIFIER 
Maximum  Ratings,  {Design-Maximum  Values): 

Plate  Voltage  

Grid-No.3  (suppressor-grid)  Voltage,  Positive  value  

Grid-No.2  (screen-grid)  Voltage  

Grid-No.2  Supply  Voltage  

Grid-No.  1  (control-grid)  Voltage,  Positive-bias  value  

Plate  Dissipation  

Grid-No.2  Input: 

For  grid-No.2  voltages  up  to  165  volts  

For  grid-No.2  voltages  between  165  and  330  volts  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  

204 


Without 
External 

Shield 
0.025  max 

6.5 

2 


6.3 

0.3 
11 
With 
External 
Shield*^ 
0.015  max 

6.5 

3 


volts 
ampere 

seconds 


Pf 
Pf 
pf 


330  max 
0  max 
See  curve  page  70 


volts 
volts 


330  max 
0  max 
2.3  max 

0.55  max 


volts 
volts 
watts 

watt 


See  curve  page  70 


200  max 
200°max 


volts 
volts 


Technical  Data 


Characteristics: 

Plate  Supply  Voltage   125  volts 

Grid  No.3  Connected  to  cathode  at  socket 

Grid-No.2  Supply  Voltage   125  volts 

Cathode-Bias  Resistor   56  ohms 

Plate  Resistance  ( Approx.)   0 . 28  megohm 

Transconductance   8000  /imhos 

Grid-No.l  Voltage  (Approx.)  for  plate  current  of  20  /ua   -6.5  volts 

Grid-No.  1  Voltage  (Approx.)  for  plate  current  of  2.8  ma  and  cathode-bias 

resistor  of  0  ohms   -3  volts 

Plate  Current   13  ma 

Grid-No.2  Current   3.7  ma 

°  The  dc  component  must  not  exceed  100  volts. 

AVERAGE  CHARACTERISTICS 


 1  \  \  1  1  T" 

TYPE  6CB6-A  C.f>s6.3  VOLTS 
CRiO  N*3  AND  INTERNAL  SHIELD 

CONNECTED  TO  CATHODE  AT  SOCKET. 
CRID-Na2  V0LTS=I25 


7f 


CRIO-N»l  VOLTS  EC|=0 


IC2 


0  50        100       ISO      200      250       300      350  400 

PLATE  VOLTS 

92CM-9S54TI 

/^^l^   Nc  ^^'^'^  POWER  TUBE 

G3@C_rr:  I  Glass  octal  types  used  as  horizon-  6CD6G 

(  1  tal  deflection  amplifiers  in  high-effi-      A^l^ A 

H(iA^^--^\-?y^        ciency  deflection  circuits  of  television  Ov#l^OV!JA% 
^Jvt^  receivers  employing  either  transformer  "  25cd6GB*" 

coupling  or  direct  coupling  to  the  de- 
flection yoke.  Type  6CD6-GA,  Outline  25A,  OUTLINES  SECTION.  Tubes  re- 
quire octal  socket.  Type  6CD6-GA  may  be  supplied  with  pins  1,  4,  and  6  omitted. 
Vertical  tube  mounting  is  preferred  but  horizontal  operation  is  permissible  if  pins 
No.2  and  7  are  in  vertical  plane.  Type  6CD6-G  has  a  maximum  peak  positive- 
pulse  pi  ate- voltage  rating  {Absolute  Maximum)  of  6600  volts,  a  maximum  plate- 
dissipation  rating  of  15  watts,  and  a  maximum  bulb-temperature  rating  (at  hottest 
point)  of  210''C.  Type  6CD6-G  is  a  DISCONTINUED  type  listed  for  reference  only. 

Heater  Voltage  (ac/dc;   6.3  volts 

Heater  Current   2.5  amperes 

Direct  Intbrelectrode  Capacitances  (Approx.) : 

Grid  No.l  to  Plate   1.1  pf 

Grid  No.  1  to  Cathode,  Heater,  Grid  No.2,  and  Grid  No.3                                 22  pf 

Plate  to  Cathode,  Heater,  Grid  No.2,  and  Grid  No.3   8.5  pf 

Transconductance®   7700  Mmhos 

Plate  Resistance  ( Approx.)°   7200  ohms 

Mu-Factor,  Grid  No.2  to  Grid  No.l*»     3.9 

"For  plate  and  grid-No.2  volts,  175;  grid-No.l  volts,  -30;  plate  ma.,  75;  grid-No.2  ma.,  5.5. 

HORIZONTAL  DEFLECTION  AMPLIFIER 

For  operation  in  a  525~lin€,  SO-frame  system 
Maximum  Ratings,  (Design-Center  Values): 

DC  Plate  Voltage   700  max  volts 

Peak  Positive-Pulse  Plate  Voltage*  (Absolute  Maximum)   7000"maa;  volts 

Peak  Negative-Pulse  Plate  Voltage   -1500  max  volts 

DC  Grid-No.2  (screen-grid)  Voltage   175  max  volts 

Peak  Negative-Pulse  Grid-No.1  Voltage   -200  max  volts 

Peak  Cathode  Current   700  waa:  ma 

Average  Cathode  Current   200  max  ma 


205 


RCA  Receiving  Tube  Manual 


Plate  Dissipation  f  

Grid-No.2  Input  

Peak  HEATERrCATHOOB  Voltage: 

Heater  negative  with  respect  to  cathode . 

Heater  positive  with  respect  to  cathode.  . 
Bulb  Temperature  (At  hottest  point)  


20  max 

watts 

3  max 

watts 

200  max 

volts 

200°max 

volts 

225  max 

0.47  max  megohm 


Maximum  Circuit  Value: 

Grid-No. 1-Circuit  Resistance: 

For  grid-resistor-bias  operation . 
♦  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  horizontal  scanning  cycle.  In 
a  525-line,  30-frame  system,  15  per  cent  of  one  horizontal  scanning  cycle  is  10  microseconds. 
■  Under  no  circumstances  should  this  absolute  value  be  exceeded. 

t  An  adequate  bias  resistor  or  other  means  is  required  to  protect  the  tube  in  the  absence  of  excitation. 
°  The  dc  component  must  not  exceed  100  volts. 

AVERAGE  CHARACTERISTICS 


1  ,  ,  

TYPE  6CD6-GA 

=  6.3  VOLTS 
CRIO-NtI  VOLTS  =  0 

_  EC2 

=176 



^  1^ 

25  

200  «)l 
M 

ST 

150  t 
u 
a. 

too  3 

ifti  TS  CC2 

75 

50 

i 

N 

50  ^ 
a 

0  § 

125 
100 

PLATE  VOLTS 
AVERAGE  CHARACTERISTICS 


6CE5 

Related  type: 
3CE5 


SHARP-CUTOFF  PENTODE 

Miniature  type  used  as  rf  and  if 
amplifier  in  vhf  television  receivers 
employing  series-connected  heater 
strings.  Outline  7B,  OUTLINES  SEC- 
TION. Tube  requires  miniature  seven- 
contact  socket  and  may  be  operated 
in  any  position. 


206 


Heater  Volts  (ac/dc)   6.3 

Heater  Current   0.3 

Heater  Warm-Up  Time  (Average)   11 

Direct  Interelectrode  Capacitances: 

Grid  No.l  to  Plate   0 . 03  max 

Grid  No.l  to  Cathode,  Heater,  Grid  No.2, 

Grid  No.3,  and  Internal  Shield   6.5 

Plate  to  Cathode,  Heater,  Grid  No.2, 

Grid  No.3,  and  Internal  Shield   1.9 

CLASS  Ai  AMPLIFIER 
Maximum  Ratings^  {Design-Center  Values): 

Plate  Voltage   300  max 

Grid-No.2  (screen-grid)  Voltage   150  max 

Grid-No.1  (control-grid)  Voltage,  Positive-bias  value   0  max 

Grid-No.2  Input   0.5  max 

Plate  Dissipation   2  max 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  max 

Heater  positive  with  respect  to  cathode   200"mox 

■  The  dc  component  must  not  exceed  100  volts. 
Characteristics: 

Plate  Voltage   125 

Grid-No.2  Voltage   125 

Grid-No.  1  Supply  Voltage   -1 

Grid-No.l  Resistor  (Bypassed)   1 

Plate  Resistance  (Approx.)   0.3 

Transconductance   7600 

Grid-No.l  Voltage  (Approx.)  for  plate  current  of  35  /ta   -5 

Plate  Current   11 

Grid-No.2  Current   2.3 


volts 
ampere 
seconds 

Pf 

Pf 

pf 


volts 
volts 
volts 
watt 
watts 

volts 
volts 


volts 
volts 
volt 
megohm 
megohm 
/tmhos 
volts 
ma 
ma 


6CF6 

Related  type: 
3CF6 


SHARP-CUTOFF  PENTODE 

Miniature  type  used  in  television 
receivers  as  an  intermediate-frequency 
amplifier  at  frequencies  up  to  about  45 
megacycles  per  second  ,and  as  an  rf 
amplifier  in  vhf  television  tuners.  Be- 
cause of  its  plate-current  cutoff  characteristic,  this  type  is  used  in  gain-controlled 
stages  of  video  if  amplifiers.  This  type  is  electrically  similar  to  miniature  type 
6CB6.  Outline  7B,  OUTLINES  SECTION.  Heater  volts  (ac/dc),  6.3;  amperes,  0.3. 

Characteristics: 

Plate  Supply  Voltage   125  volts 

Grid  No.3  Connected  to  cathode  at  socket 

Grid-No.2  Supply  Voltage   125  volts 

Cathode-Bias  Resistor     56  ohms 

Plate  Resistance  (Approx.)   0.3  megohm 

Transconductance   7800  /umhos 

Grid-No  1  Voltage  (Approx.)  for  plate  current  of  20  jua   -6  volts 

Grid-No.l  Voltage  (Approx.)  for  plate  current  of  2.2  ma  and  cathode-bias 

resistor  of  0  ohms   -3  volts 

Plate  Current   12.5  ma 

Grid  No.2  Current   3.7  ma 


KT2 


GT2^ 


MEDIUM-MU  TWIN  TRIODE 


6CG7 

Related  type: 
8CG7 


Miniature  type  used  as  combined 
vertical  deflection  and  horizontal  de- 
flection oscillator  in  television  re- 
ceivers. Also  used  as  phase  inverter, 
sync  separator  and  amplifier,  and  re- 
sistance-coupled amplifier  in  radio  receivers.  This  type  has  a  controlled  heater 
warm-up  time  for  use  in  receivers  employing  series-connected  heater  strings.  Except 
for  the  common  heater,  each  triode  unit  is  independent  of  the  other.  Outline  8D, 
OUTLINES  SECTION.  Tube  requires  miniature  nine-contact  socket  and  may  be 
mounted  in  any  position.  For  typical  operation  as  a  resistance-coupled  amplifier, 
refer  to  RESISTANCE-COUPLED  AMPLIFIER  SECTION. 


Heater  Voltage  (ac/dc)  . 
Heater  Current  


6.3 
0.6 


volts 
ampere 


207 


RCA  Receiving  Tube  Manual 


Heater  Warm-Up  Time  (Average)   11 

Direct  Intbrelectrodb  Capacitances  (Each  Unit,  Approx.): 

Grid  to  Plate   4.0 

Grid  to  Cathode,  Heater,  and  Internal  Shield   2.3 

Plate  to  Cathode,  Heater,  and  Internal  Shield   2.2 

CLASS  Ai  AMPLIFIER  {Ecu^h  Unit) 
Maximum  Ratings,  (Design-Maximum  Values): 

Plate  Voltage   330  max 

Grid  Voltage,  Positive-bias  value   0  max 

Plate  Dissipation: 

For  either  plate   4  max 

For  both  plates  with  both  units  operating   5.7  max 

Cathode  Current   22  max 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  max 

Heater  positive  with  respect  to  cathode   200"m.ax 

Characteristics: 

Plate  Voltage                                                                       90  250 

Grid  Voltage                                                                          0  -8 

Amplification  Factor                                                             20  20 

Plate  Resistance  (Approx.)                                                  6700  7700 

Transconductance                                                              3000  2600 

Grid  Voltage  (Approx.)  for  plate  current  of  10  hb.                       -7  -18 

Plate  Current  for  grid  voltage  of  -12.5  volts                              -  1.3 

Plate  Current                                                                       10  9 

Maximum  Circuit  Value: 

Grid-Circuit  Resistance: 

For  fixed-bias  operation   1.0  max 

■  The  dc  component  must  not  exceed  100  volts. 


Pf 
Pf 
pf 


volts 
volts 

watts 
watts 
ma 

volts 
volts 


volts 
volts 

ohms 
/xmhos 
volts 
ma 
ma 


megohm 


AVERAGE  PLATE  CHARACTERISTICS 
rOR  EACH  UNIT 


•2CM-e442T 


OSCILLATOR 

For  operation  in  a  525-line,  30-frame  system 

Vertical 
Deflection 

Maximum  Ratings,  {Design- Maximum  Values,  Each  Unit):  Oscillator 

DC  Plate  Voltage   330  max 

Peak  Negative-Pulse  Grid  Voltage   -440  max 

Peak  Cathode  Current    77  max 

Average  Cathode  Current   22  max 

Plate  Dissipation: 

For  either  plate   4  max 

For  both  plates  with  both  units  operating   5.7  max 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  max 

Heater  positive  with  respect  to  cathode   200"woa; 

Maximum  Circuit  Value: 

Grid-Circuit  Resistance   2.2  max 

■  The  dc  component  must  not  exceed  100  volts. 

208 


Horizontal 
Deflection 
Oscillator 

330  max 
-660  max 

330  max 
22  max 

4  max 
5.7  max 

200  max 
200"max 


volts 
volts 
ma 
ma 

watts 
watts 

volts 
volts 


2.2  max  megohms 


MEDiUM-MU  TRIODE— 
SHARP-CUTOFF  PENTODE 


6CG8 

6CG8A 


Related  type: 
5CG8 


Miniature  types  used  as  combined 
oscillator  and  mixer  tubes  in  television 
receivers  utilizing  an  intermediate  fre- 
quency in  the  order  of  40  megacycles 
per  second.  When  used  in  an  AM/FM 
receiver,  the  triode  unit  is  used  as  an  oscillator  for  both  sections.  In  the  AM  section, 
the  pentode  unit  is  used  as  a  high-gain  pentode  mixer;  in  the  FM  section,  the 
pentode  unit  is  used  either  as  a  pentode  mixer  or  as  a  triode-connected  mixer  de- 
pending on  signal-to-noise  considerations.  Type  6CG8-A  has  a  controlled  heater 
warm-up  time  for  use  in  television  receivers  employing  series-connected  heater 
strings.  Outline  8B,  OUTLINES  SECTION.  Tubes  require  miniature  nine-contact 
socket  and  may  be  mounted  in  any  position.  Heater  volts  (ac/dc),  6.3;  amperes, 
0.45;  warm-up  time  (average)  for  6CG8-A,  11  seconds.  Maximum  ratings,  char- 
acteristics, and  typical  operating  values  are  the  same  as  those  of  miniature  type 
6X8.  For  curves  of  average  characteristics,  see  type  6X8.  The  6CG8  is  a  DISCON- 
TINUED type  listed  for  reference  only. 

Without  With 
Direct  Interelectrode  Capacitances:  ^^K*"??^  ^^^^^^^ 

Triode  Unit:  Shield  Shield? 

Grid  to  Plate   1.5  1.5  pf 

Grid  to  Cathode,  Heater,  and  Pentode  Grid  No.  3   2  2.4  pf 

Plate  to  Cathode,  Heater,  and  Pentode  Grid  No. 3   0.5  1  pf 

Pentode  Unit: 

Grid  No.l  to  Plate   0.04  war  0.02  woa;  pf 

Grid  No.l  to  Cathode,  Heater,  Grid  No.2,  and  Grid  No.3        4.6  4.8  pf 

Plate  to  Cathode,  Heater,  Grid  No.2,  and  Grid  No.3. . .         0.9  1.6  pf 

Pentode  Grid  No.l  to  Triode  Plate   0.05  max  0.04  max  pf 

Pentode  Plate  to  Triode  Plate   0.05  woa;  0.008  wax  pf 

Heater  to  Cathode   6.5  6.5*  pf 

°  With  external  shield  connected  to  cathode,  except  as  noted. 
•  With  external  shield  connected  to  plate. 


6CH8 


MEDIUM-MU  TRIODE- 
SHARP-CUTOFF  PENTODE 

Miniature  type  used  in  a  wide 
variety  of  applications  in  television 
receivers.  The  pentode  unit  is  used  as 
an  if  amplifier,  video  amplifier,  age 
amplifier,  or  reactance  tube.The  triode 
unit  is  used  in  low-frequency  oscillator,  sync-separator,  sync-clipper,  and  phase- 
splitter  circuits.  Outline  8B,  OUTLINES  SECTION.  Tube  requires  miniature 
nine-contact  socket  and  may  be  mounted  in  any  position.  For  curves  of  average 
plate  characteristics,  refer  to  type  6AN8.  The  pentode-unit  curve  for  the  6AN8 
applies  for  this  type  except  that  grid  No.3,  heater,  and  internal  shield  (pin  5)  are 
connected  to  ground. 


Heater  Voltage  (ac/dc)   6.3  volts 

Heater  Current   0.45  ampere 

Direct  Interelectrode  Capacitances: 
Triode  Unit: 

Grid  to  Plate   1.6  pf 

Grid  to  Cathode,  Heater,  Pentode  Grid  No.3,  and  Internal  Shield   1.9  pf 

Plate  to  Cathode,  Heater,  Pentode  Grid  No.3,  and  Internal  Shield   1.6  pf 

Pentode  Unit: 

Grid  No.l  to  Plate   0.025  pf 

Grid  No.l  to  Cathode,  Heater,  Grid  No.2,  Grid  No.3,  and  Internal  Shield  7  pf 

Plate  to  Cathode,  Heater,  Grid  No.2,  Grid  No.3,  and  Internal  Shield,  .  2.25  pf 

Triode  Grid  to  Pentode  Plate   0 . 005  pf 

Pentode  Grid  No.l  to  Triode  Plate   0 . 02  pf 

Pentode  Plate  to  Triode  Plate   0 . 04  pf 

209 


RCA  Receiving  Tube  Manual 


CLASS  Ai  AMPLIFIER 

Maximum  Ratings,  {Design-Center  Values):  Triode  Unit    Pentode  Unit 

Plate  Voltage   300  max        300  max  volts 

Grid-No.3  (suppressor-grid)  Voltage,  Positive  value   -                 0  max  volts 

Grid-No.2  Supply  Voltage   -              300  max  volts 

Grid-No.2  (screen-grid)  Voltage   -               See  curve  page  70 

Grid-No.1  (control-grid)  Voltage,  Positive-bias  value   0  max           0  max  volts 

Plate  Dissipation   2.6  waa;           2  max  watts 

Grid-No.2  Input: 

For  grid-No.2  voltages  up  to  150  volts   -               0.5  max  watt 

For  grid-No  2  voltages  between  150  and  300  volts   -                See  curve  page  70 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  max           *  max  volts 

Heater  positive  with  respect  to  cathode   200°max           0  max  volts 

Characteristics: 

Plate  Supply  Voltage   200               200  volts 

Grid  No.3   -Connected  to  ground  atsocket 

Grid-No.2  Supply  Voltage   -               150  volts 

Grid  Voltage   -6                ~  volts 

Cathode-Bias  Resistor   -               180  ohms 

Amplification  Factor   19 

Plate  Resistance  (Approx.)   5750          300000  ohms 

Transconductance   3300             6200  /imhos 

Grid-No.l  Voltage  (Approx.)  for  plate  current  of  lO/xa   -19                -8  volts 

Plate  Current.   13               9.5  ma 

Grid-No.2  Current   -              2.8  ma 

Maximum  Circuit  Values: 

Grid-No.l-Circuit  Resistance:* 

For  fixed-bias  operation   0.5  max      0 . 25  max  megohm 

For  cathode  bias  operation   1.0  max        1 . 0  max  megohm 

°  The  dc  component  must  not  exceed  100  volts. 

*  The  heater-cathode  voltage  should  not  exceed  the  value  of  the  operating  cathode  bias  because  the 
voltage  between  the  heater  and  cathode  is  also  applied  between  the  cathode  and  grid  No.3.  The  net 
result  is  to  make  grid  No.3  negative  with  respect  to  cathode  with  possible  change  in  tube  characteristics. 

*  If  either  unit  is  operating  at  maximum  rated  conditions,  grid  No.l-circuit  resistance  for  both  units 
should  not  exceed  the  stated  values. 


6CK4 


LOW-MU  TRIODE 

Glass  octal  type  used  as  a  vertical-deflec- 
tion-amplifier tube  in  television  receivers.  Out- 
line 14E,  OUTLINES  SECTION.  Tube  requires 
octal  socket.  Heater  volts  (ac  /dc),  6.3;  amperes, 
1.25.  Characteristics  as  class  Ai  amplifier:  plate 
volts,  250;  grid  volts,  -28;  plate  ma.,  40;  am- 
plification factor,  6.6;  plate  resistance  (approx.), 
1200  ohms;  transconductance,  5500  /liiwhos. 
Maximum  ratings  as  vertical  deflection  ampli- 
fier (for  operation  in  a  525-line,  30-frame  system):  de  plate  volts,  550  max;  peak  positive-pulse  plate 
volts,  2000  max;  peak  negative-pulse  grid  volts,  250  max;  peak  cathode  ma.,  350  max;  average  cathode 
ma.,  100  max;  plate  dissipation,  12  max  watts;  peak  heater-cathode  volts,  200  max  (the  dc  component 
must  not  exceed  100  volts).  This  type  is  used  principally  for  renewal  purposes. 

POWER  PENTODE 

Miniature  type  used  in  output  ^^(^  \r:r^> 
^          stage  of  video  amplifier  of  television 

receivers  and  as  wide-band  amplifier  G^^\k'^>  U^^z 

tube  in  industrial  and  laboratory  equip-  ' 

ment.  Outline  8D.  OUTLINES  SEC-  ~c, 

TION.  Tube  requires  miniature  nine-contact  socket  and  may  be  mounted  in  any 
position. 

Heater  Voltage  (ac/dc)   6.3  volts 

Heater  Current   0 . 65  ampere 

Direct  Interelectrode  Capacitances  (Approx.) : 

Grid  No.l  to  Plate   0.12  pf 

Grid  No.l  to  Cathode,  Heater,  Grid  No.2,  Grid  No.3,  and  Internal  Shield  11  pf 

Plate  to  Cathode,  Heater,  Grid  No.2,  Grid  No.3,  and  Internal  Shield. ...  5.5  pf 

CLASS  Ai  AMPLIFIER 
Maximum  Ratings,  (Design-Center  Values) : 

Plate  Voltage   300  wax  volts 


210 


Grid-No.3  (suppressor-grid)  Voltage,  Positive  Value. 

Grid-No.2  (screen-grid)  Supply  Voltage  

Grid-No.2  Voltage  

Grid-No.  1  (control-grid)  Voltage: 

Negative-bias  value  

Positive-bias  value  

Plate  Dissipation  

Grid-No.2  Input  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  

Bulb  Temperature  (At  hottest  point)  

Typical  Operation: 
Plate  Voltage . 


0  max 
300  max 
150  max 

-50  max 
0  max 
7 . 5  max 
1 . 7  max 

100  max 
100  max 
200  max 


volts 
volts 
volts 

volts 
volts 
watts 
watts 

volts 
volts 


250  volts 

Grid  No.3  and  Internal  Shield  Connected  to  cathode  at  socket 

volts 
volts 
volts 


Grid-No.2  Voltage. 
Grid-No.  1  Voltage. 

Peak  AF  Grid-No.l  Voltage  

Zero-Signal  Plate  Current  

Maximum-Signal  Plate  Current  

Zero-Signal  Grid-No.2  Current  , 

Maximum-Signal  Grid-No.2  Current  

Plate  Resistance  (Approx.)  

Transconductance  

Grid-No.l  Voltage  (Approx.)  for  plate  current  of  lO^a.  .  . 

Load  Resistance  

Total  Harmonic  Distortion  

Maximum-Signal  Power  Output.  

Typical  Operation  in  4-Mc-Bandwidth  Video  Amplifier- 
Plate  Supply  Voltage. 


150 
-3 
3 
30 
31 
7 

7.2 
0.09 
11000 
-14 
7500 
8 

2.8 
300 


ma 
ma 
ma 
megohm 
/imhos 
volts 
ohms 
per  cent 
watts 


volts 

Grid  No.3' and  Internal  Shield  Connected  to  cathode  at  socket 

300  volts 
-2  volts 
3  volts 
24000  ohms 
0 . 1  megohm 
3900  ohms 
30  ma 
7.0  ma 
132  volts 


Grid-No.2  Supply  Voltage . 

Grid-No.l  Bias  Voltage  

Grid-No.l  Signal  Voltage  (Peak  to  Peak). 

Grid-No.2  Resistor  

Grid-No.l  Resistor  

Load  Resistor  

Zero-Signal  Plate  Current  

Zero-Signal  Grid-No.2  Current  

Voltage  Output  (Peak  to  Peak)  

Maximum  Circuit  Values: 

Grid-No.l  Circuit  Resistance: 

For  fixed-bias  operation  

For  cathode-bias  operation  


AVERAGE  CHARACTERISTICS 


0.1  max 
0 . 5  max 


megohm 
megohm 


uj  TYPE  6CL6 
a       =  6.3  VOLTS 
30  \  GRID  N93  AND  INTERNAL  SHIELD 
<     CONNECTED  TO  CATHODE  AT 
SOCKET. 


92CM-7602n 


f2TR 


MEDIUM-MU  TRIODE- 
SHARP-CUTOFF  TETRODE 

Miniature  types  used  as  combined 
vhf  oscillator  and  mixer  in  television 
receivers  employing  series-connected 
heater  strings.  Outline  8B,0UTLINES 
SECTION.  Tubes  require  miniature 


6CL8 

6a8A 


Related  types: 
5CL8A,  19CL8A 


211 


RCA  Receiving  Tube  Manual 


nine-contact  socket  and  may  be  mounted  in  any  position.  For  maximum  ratings 
as  class  A,  amplifier,  see  type  6U8-A.  Type  6CL8  is  a  DISCONTINUED  type 
listed  for  reference  only.  Heater  volts  (ac/dc),  6.3;  amperes,  0.45;  warm-up  time 
(average),  11  seconds. 

CLASS  Aj  AMPLIFIER 

Characteristics:  Triode  Unit    Tetrode  Unit 

Plate  Supply  Voltage   125  125  volts 

Grld-No.2  (Screen-Grid)  Voltage   -  125  volts 

Grid-No.  1  Voltage   -1  -1  volt 

Amplitication  Factor   40  - 

Plate  Resistance  (Approx.)   0 . 005  0 . 2  megohm 

Transconductance   8000  6500  ftmhos 

Grid-No.  1  Voltage  (Approx.)  for  plate  current  of  20  /*»   -9  -9  volts 

Plate  Current   14  12  ma 

Grid-No.2  Current   -  4  ma 

Maximum  Circuit  Values: 

Grid-No.  1-Circuit  Resistance: 

For  fixed-bias  operation   0.5  max      0 . 25  max  megohm 

For  cathode-bias  operation   1  max  1  max  megohm 


BEAM  POWER  TUBE 

Miniature  type  used  as  vertical  ci^-^/] 
f%dUif%         deflection  amplifier  in  television  re- 

ceivers  and  as  audio  power  amplifier  (zXlj 
in  radio  and  television  receivers.  Out-  "^^^^iLl^^iJ^ 
line  8D,0UTLINES  SECTION.  Tube  ck^ 
requires  miniature  nine-contact  socket  and  may  be  mounted  in  any  position.  For 
typical  operation  and  maximum  circuit  values  as  class  Ai  amplifier,  refer  to  type 
6V6-GT.  For  curves  of  average  plate  characteristics,  refer  to  type  6AQ5-A. 

Heater  Voltage  (ac/dc)   6  .3  volts 

Heater  Current   0.45  ampere 

Amplification  Factor*   9.8 

Plate  Resistance  (Approx.)*   I960  ohms 

Transconductance*   5000  fimhos 

*  Grid  No.2  connected  to  plate;  plate  and  grid-No.2  volts,  250;  grid-No.l  volts,  -12.5;  plate  and  grid- 
No.2  ma;,  49.5. 

CLASS  A,  AMPLIFIER 
Maximum  Ratings^  (Design-Center  Values): 

Plate  Volt  AGE   315  max  volts 

Grid-No.2  (screen-grid)  Voltage   285  max  volts 

Grid-No.2  Input   2  max  watts 

Plate  Dissipation   12  max  watts 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  max  volts 

Heater  positive  with  respect  to  cathode   200"wttaj  volts 

VERTICAL  DEFLECTION  AMPLIFIER 

For  operation  in  a  5254ine,  SO-ftame  system 
.        _    .         ^        ^        ,        ^  Triode  Pentode 

MOXimum  Ratings,  (Design-Center  Values):  Connection"  Connection 

DC  Plate  Voltage  ,   315  max  315  max  volts 

Peak  Positive-Pulse  Plate  VoLTAGEf  (Absolute  Maximum) . .  2000*maa:  2000*wax  volts 

DC  Grid-No.2  (screen-grid)  Voltage   -  285  max  volts 

Peak  Negative-Pulse  Grid-No.  1  (control-grid)  Voltage  .  -250  max  -250  max  volts 

Peak  Cathode  Current   120  max  120  max  ma 

Average  Cathode  Current   40  max  40  max  ma 

Plate  Dissipation   9  max  8  max  watts 

Grid-No.2  Input   -  1.75  max  watts 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  max  200  max  volts 

Heater  positive  with  respect  to  cathode   200"m,ax  200"max  volts 

Maximum  Circuit  Values: 

Grid-No.l-Circuit  Resistance: 

For  cathode-bias  operation   2.2  max  2  . 2  max  megohms 

°  Grid  No.2  connected  to  plate. 

t  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  vertical  scanning  cycle.  In  a  525- 
line,  30-frame  system,  15  per  cent  of  one  vertical  scanning  cycle  is  2.5  milliseconds. 

*  Under  no  circumstances  should  this  absolute  value  be  exceeded. 
■  The  dc  component  must  not  exceed  100  volts. 

212 


Technical  Data 


MEDIUM-MU  DUAL  TRIODE 

Miniature  type  used  as  combined 
vertical  deflection  oscillator  and  vertical 
deflection  amplifier  in  television  receiv- 
ers employing  series-connected  heater 
strings.  Unit  No.l  is  used  as  a  conven- 


6CM7 


Related  type: 
•CM7 

PT2  ^KT2 

tional  blocking  oscillator  in  vertical  deflection  circuits,  and  unit  No.2  as  a  vertical 
deflection  amplifier.  Outline  8D,  OUTLINES  SECTION.  Tube  requires  miniature 
nine-contact  socket  and  may  be  mounted  in  any  position. 


Heater  Voltage  (ac/dc)  

Heater  Current  

Heater  Warm-up  Time  (Average)  

Direct  Interelbctrode  Capacitances  (Approx.): 

Grid  to  Plate  

Grid  to  Cathode  and  Heater  

Plate  to  Cathode  and  Heater  


Unit  No.l 
3.8 
2 

0.5 


CLASS  Ai  AMPLIFIER 

Characteristics: 

Plate  Voltage  

Grid  Voltage  

Amplification  Factor  

Plate  Resistance  (Approx.)  

Transconductance  

Grid  Voltage  (Approx.)  for  plate  current  of  10  /na  

Plate  Current  

Plate  Current  for  grid  voltage  of  -10  volts  


6.3 
0.6 
11 

Vnit  No.2 
3 

3.5 
0.4 


volts 
ampere 
seconds 


Pf 
pf 


Unit  No.l 

Unit  No.2 

200 

250 

volts 

-7 

-8 

volts 

21 

18 

10500 

4100 

ohms 

2000 

4400 

MmhoB 

-14 

volts 

5 

20 

ma 

1 

ma 

AVERAGE  CHARACTERISTICS 

UNIT  Nil 


900  400 
PLATE  VOLTS 


•tCM-MITT 


VERTICAL  DEFLECTION  OSCILLATOR  AND  AMPLIFIER 

For  operation  in  a  525-line,  SO-frame  ayalem 


Maximum  Ratings,  (Design-Maximum  Values): 

DC  Plate  Voltage  

Peak  Positive-Pulse  Plate  Voltage  #  

Peak  Negative-pulse  Grid  Voltage  

Peak  Cathode  Current  

Average  Cathode  Current   

Plate  Dissipation  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode.  ,  . 

Heater  positive  with  respect  to  cathode. . . . 

Maximum  Circuit  Values: 

Grid-Circuit  Resistance: 

For  fixed-bias  operation  


Unit  No.l 

Unit  No.2 

Oscillator 

Amplifier 

550  max 

550  max 

VOltB 

2200  max 

volts 

-220  max 

-220  max 

volts 

77  max 

77  max 

ma 

17  max 

22  max 

ma 

1.45  max 

6  max 

watts 

200  max 

200  max 

volts 

200*max 

200^max 

volts 

2.2  max 

1 . 0  max 

megohms 

213 


RCA  Receiving  Tube  Manual 


For  cathode-bias  operation   2.2  max  2 . 5  max  megohms 

For  grid-resistor-bias  operation   2.2  max  -  megohms 

#  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  vertical  scanning  cycle.  In  a  525- 
line,  30-frame  system,  15  per  cent  of  one  vertical  scanning  cycle  is  2.5  milliseconds. 

*  The  dc  component  must  not  exceed  100  volts. 


AVERAGE  CHARACTERISTICS 

UNIT  Nt2 


HIGH-MU  TRIODE— . 
SHARP-CUTOFF  PENTODE 

Miniature  type  used  in  variety  of 
applications  in  television  receivers.  The 
pentode  unit  is  used  as  an  intermedi- 
ate-frequency-amplifier, a  video-am- 
plifier, an  age-amplifier,  or  as  a  react- 
ance tube.  The  triode  unit  is  used  in  sweep-oscillator,  sync-separator,  syn  .-clipper, 
and  phase-splitter  circuits.  Outline  8B,  OUTLINES  SECTION.  Tube  requires 
miniature  nine-contact  socket  and  may  be  mounted  in  any  position.  Heater  volts 
(ac/dc),  6.3;  amperes,  0.45;  warm-up  time  (average),  11  seconds. 


6CM8 

Related  type: 
5CM8 


CLASS  Aj  AMPLIFIER 

Maximum  Ratings^  {Design-Center  Values): 

Plate  Voltage  

Grid-No.2  (screen-grfd)  Supply  Voltage  

Grid-No.2  Voltage  

Grid-No.1  (control-grid)  Voltage,  Positive-bias  value  

Plate  Dissipation  

Grid-No.2  Input: 

For  grid-No.2  voltagies  lip  to  150  volts  

For  grid-No.2  voltages  between  150  and  300  volts  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  

Characteristics: 

Plate  Supply  Voltage ,  ,  

Grid-No.2  Supply  Voltage  

Grid  Voltage  

Cathode-Bias  Resistor  

Amplification  Factor. ,  

Plate  Resistance  (Approx.)  

Transconductance  

Grid-No.  1  Voltage  (Approx.)  for  plate  current  of  10  pia  

Plate  Current  

Grid-No.2  Current  

214 


Triode  Unit    Pentode  Unit 


300  max 

300  max 

volts 

300  max 

volts 

See  curve 

page  70 

0  max 

0  max 

volts 

1  max 

2  max 

watts 

0 . 5  max 

watt 

See  curve 

page  70 

200  max 

200  max 

volts 

200"/naa; 

200"max 

volts 

250 

250 

volts 

150 

volts 

-2 

volts 

180 

ohms 

100 

0.05 

0 . 6  megohm 

2000 

6200 

/xmhos 

-8 

volts 

1.8 

9.5 

ma 

2.8 

ma 

Maximum  Circuit  Values: 

Grid-No.l-Circuit  Resistance:  ^^^^^^^           Pentode  Unit 

For  fixed-bias  operation   0.25  max      0.2b  max  megohm 

For  cathode-bias  operation   1  max           1  max  megohm 

■  The  dc  component  must  not  exceed  100  volts. 

H 

KD.fcoa"^!--^^^'^      TWIN-DIODE-HIGH-MU  TRIODE 

*^  ^^^^n  iflM^^  Miniature  type  used  as  combined  ^    1  ^ 

/gV^r-^  r-^  horizontal  phase  detector  and  react-  OdM# 

'*'**^^*^^^^^S^''^  ance  tube  in  television  receivers  em-  Related  type: 

P02  '^^M  ploying  series-connected  heater  strings.  8CN7 
The  triode  unit  is  used  in  sync-sepa- 
rator, sync-amplifier,  or  audio  amplifier  circuits.  Outline  8B,  OUTLINES  SEC- 
TION. Tube  requires  miniature  nine-contact  socket  and  may  be  mounted  in  any 
position.  For  typical  operation  of  triode  unit  as  resistance-coupled  amplifier,  refer 
to  RESISTANCE-COUPLED  AMPLIFIER  SECTION.  For  curve  of  average 
plate  characteristics  for  triode  unit,  refer  to  type  6T8-A.  Heater  volts  (ac/dc),  6.3 
(series),  3.15  (parallel);  amperes,  0.3  (series),  0.6  (parallel);  warm-up  time  (aver- 
age), 11  seconds. 

TRIODE  UNIT  AS  CLASS  Ai  AMPLIFIER 
Maximum  Ratings,  {Design-Maximum  Values): 

Plate  Voltage   330  max  volts 

Grid  Voltage,  Positive-bias  value   0  max  volts 

Plate  Dissipation   1.1  max  watt 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  max  volts 

Heater  positive  with  respect  to  cathode     200"rwax  volts 

Characteristics: 

Plate  Voltage   100  250  volts 

Grid  Voltage   -1  -3  volts 

Amplification  Factor   70  70 

Plate  Resistance  ^Approx.)   54000  58000  ohms 

Transconductance   1300  1200  /^mhos 

Plate  Current   0.8  1  ma 

DIODE  UNITS 
Maximum  Ratings,  {Design-Maximum  Values): 

Plate  Current  (Each  Unit)   5.5  max  ma 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  max  volts 

Heater  positive  with  respect  to  cathode   200"rnax  volts 

■  The  dc  component  must  not  exceed  100  volts; 

P 

^^^""^K      HALF-WAVE  VACUUM  RECTIFIER 

]  Octal  type  used  as  damper  tube  ^  A^^N  A 

(\         ^^Jti)      ill  horizontal-deflection  circuits  of  tele-  Ow(il4 
vision  receivers.  Outline  14F,  OUT- 
^ir^  LINESSECTION.Tuberequiresoctal 
"  socket  and  may  be  mounted  in  any 

position.  Socket  terminals  1,  2,  4,  and  6  should  not  be  used  as  tie  points.  It  is  espe- 
cially important  that  this  tube,  like  other  power-handling  tubes,  be  adequately 
ventilated.  Heater  volts  (ac/dc),  6.3;  amperes,  1.6. 

DAMPER  SERVICE 

For  operation  in  a  525-line,  30-frame  system 
Maximum  Ratings,  {Design-Maximum  Values): 

Peak  Inverse  Plate  Current"   5500  max  volts 

Peak  Plate  Current   1200  max  ma 

DC  Plate  Current   190  max  ma 

Plate  Dissipation   6.5  max  watts 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode     5500*wax  volts 

Heater  positive  with  respect  to  cathode   300°max  volts 


215 


RCA  Receiving  Tube  Manual 


Characteristics,  Instantaneous  Value: 

Tube  Voltage  Drop  for  plate  current  of  250  ma   25  volts 

■  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  horizontal  scanning  cycle.  In  a 
525-line,  30-frame  system,  15  per  cent  of  one  horizontal  scanning  cycle  is  10  microseconds. 
•  The  dc  component  must  not  exceed  900  volts. 
°  The  dc  component  must  not  exceed  100  volts. 


MEDIUM-MU  TRIODE-  h 

SHARP-CUTOFF  TETRODE  ''^^V^;:::^'' 

Miniature  type  used  in  a  wide  ^^'^^©kA^^ 

OCCjIO          variety  of  applications  in  color  and  -JS™|;z^^L 

Related  type:           black-and-white  television  receivers  CiTR^i^^_y^^^^KT 
5CQ8              employing  series-connected  heater 

strings.  Especially  useful  as  combined  '*t  ct 
vhf  oscillator  and  mixer  in  tuners  of  television  receivers  utilizing  an  intermediate 
frequency  in  the  order  of  40  megacycles  per  second.  The  tetrode  unit  is  used  as  a 
mixer,  video  if  amplifier,  or  sound  if  amplifier  tube.  The  triode  unit  is  used  in  vhf 

oscillator,  phase-splitter,  sync-clipper,  sync-separator,  and  rf  amplifier  circuits. 

Outline  8B,  OUTLINES  SECTION.  Tube  requires  miniature  nine-contact  socket 
and  may  be  mounted  in  any  position. 

Heater  Voltage  (ac/dc)   6.3  volts 

Heater  Current   0.45  ampere 

Heater  Warm-Up  Time  (Average)   11  seconds 

Without  With 

External  External 

Direct  Interelectrode  Capacitances:                           Shield  Shield' 
Triode  Unit: 

Grid  to  Plate                                                                  1.8  1.8  pf 

Grid  to  Cathode  and  Heater                                              2.7  2.7  pf 

Plate  to  Cathode  and  Heater                                             0.4  1.2  pf 

Tetrode  Unit: 

Grid  No.l  to  Plate                                                        0.019  max  0.015  max  pf 

Grid  No.l  to  Cathode,  Heater,  Grid  No.2  and  Internal 

Shield                                                                        5.0  5.0  pf 

Plate  to  Cathode,  Heater,  Grid  No.2,  and  Internal  Shield       2.5  3.3  pf 

Tetrode  Plate  to  Triode  Plate                                               0.07  max  0.01  max  pf 

Heater  to  Cathode  (Each  Unit)                                               3.0  3 .  Ot  pf 

■  With  external  shield  connected  to  cathode  of  unit  under  test, 
t  With  external  shield  connected  to  ground. 

CLASS  Ai  AMPLIFIER 

Maximum  Ratings,  (Design- Maximum  Values):                    Triode  Unit  Tetrode  Unit 

Plate  Voltage                                                                 330  max  330  max  volts 

Grid-No.2  (screen-grid)  Supply  Voltage                               -  330  max  volts 

Grid-No.2  Voltage                                                              -  See  curve  page  70 

Grid-No.I  (control-grid)  Voltage,  Positive-bias  value.  .            0  max  Omax  volts 

Plate  Dissipation                                                        3.1  max  3 . 2  max  watts 

Grid-No.2  Input: 

For  grid-No.2  voltages  up  to  165  volts                                   -  0.7  max  watt 

For  grid-No.2  voltages  between  165  and  330  volts    ....          -  See  curve  page  70 

Grid  Input                                                                  0.55  max  -  watt 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode                              200  max  200  max  volts 

Heater  positive  with  respect  to  cathode                               200*  wax  200*  max  volts 

Characteristics: 

Plate-Supply  Voltage                                                               125  125  volts 

Grid-No.2  Supply  Voltage                                                         -  125  volts 

Grid-No.  1  Voltage                                                                 -  -1  volts 

Cathode-Bias  Resistor                                                          56  -  ohms 

Amplification  Factor   40 

Plate  Resistance  (Approx.)                                                   5000  140000  ohms 

Transconductance                                                               8000  5800  /nmhos 

Grid-No.  1  Voltage  (Approx.)  for  plate  current  of  100  na.  . .         -7  -7  volts 

Plate  Current                                                                        15  12  ma 

Grid-No.2  Current .                                                                   -  4.2  ma 

Maximum  Circuit  Values: 

Grid-No.  1 -Circuit  Resistance: 

For  fixed-bias  operation                                                      0.5  max  0  .25  max  megohm 

For  cathode-bias  operation                                                1.0  max  1 . 0  max  megohm 

*  The  dc  component  must  not  exceed  100  volts. 

216 


Technical  Data 


"G—©""  DIODE- REMOTE-CUTOFF 

"(3/5?Ve)=.p  PENTODE 

ziz^^^j  Miniature  type  used  as  combined  Owlvw 

/^^^r-i^^^T^  detector  and  audio  amplifier  in  auto-  Related  type: 

PD^"^v^^i/M;ip      mobile  and  ac-operated  radio  receivers.  i 2CR6 

(v  The  diode  unit  is  used  as  an  AM  de- 

^'^^^  tector,  and  the  pentode  unit  as  an 

automatic-volume-controlled  audio  amplifier.  Outline  7B,  OUTLINES  SECTION. 
Tube  requires  miniature  seven-contact  socket  and  may  be  mounted  in  any  position. 
Heater  volts  (ac/dc),  6.3;  amperes,  0.3. 

PENTODE  UNIT  AS  CLASS  Ai  AMPLIFIER 
Maximum  Ratings,  {Design-Center  Values): 

Plate  Voltage   300  wax  volts 

Grid-No.2  (screen-grid)  Voltage   See  curve  page  70 

Grid-No.2  Supply  Voltage   300  max  volts 

Grid-No.  1  (control-grid)  Voltage,  Positive-bias  value   0  max  volts 

Plate  Dissipation   2.5  max  watts 

Grid-No.2  Input: 

For  grid-No.2  voltages  up  to  150  volts   0.3  max  watt 

For  grid-No.2  voltages  between  150  and  300  volts   See  curve  page  70 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   100  max  volts 

Heater  positive  with  respect  to  cathode   100  wax  volts 

Characteristics: 

Plate  Voltage   250  volts 

Grid-No.2  Voltage   100  volts 

Grid-No.l  Voltage   -2  volts 

Plate  Resistance  ( Approx.)   0.8  megohm 

Transconductance   2200  /xmhos 

Plate  Current   9.6  ma 

Grid-No.2  Current   2.6  ma 

Grid-No.l  Voltage  (Approx.)  for  transconductance  of  10  ^nihos   -32  volts 

Maximum  Circuit  Values: 
Grid-No.l-Circuit  Resistance: 

For  fixed-bias  operation   0 . 25  wax  megohm 

For  cathode-bias  operation   1.0  wax  megohm 

DIODE  UNIT 

Maximum  RaWng,  (Design-Center  Value): 

Plate  Current   1  wax  ma 

PPENTAGRID  AMPLIFIER 

ll            Miniature  type  used  as  a  gated  Z^^CX. 

amplifier  in  television  receivers.  In  Ow50 

G3     such  service,  it  may  be  used  as  a  com-  Related  types: 

bined  sync  separator  and  sync  clipper.  3CS6, 4CS6 
Outline  7B,  OUTLINES  SECTION. 
Tube  requires  miniature  seven-contact  socket  and  may  be  mounted  in  any  position. 
Heater  volts  (ac/dc),  6.3;  amperes,  0.3. 

CLASS  Ai  AMPLIFIER 

Characteristics: 

Plate  Voltage                                                                    100  100  volts 

Grids-No.2-and-No.4  Voltage                                                30  30  volts 

Grid-No.3  Voltage                                                              -1  0  volt 

Grid-No.l  Voltage                                                                0  -1  volt 

Plate  Resistance  (Approx.)                                                  0.7  1  megohm 

Grid-No.3-to-Plate  Transconductance                                   1 500  -  /tmhos 

Grid-No.l-to-Plate  Transconductance                                     -  1100  /ixmhos 

Plate  Current                                                                   0.8  1.0  ma 

Grids-No.2-and-No.4  Current                                              5.5  1.3  ma 

Grid-No.3  Voltage  (Approx.)  for  plate  current  of  50 /ta            -2.2  -  volts 

Grid-No.l  Voltage  (Approx.)  for  plate  current  of  50  ^a               -  -2.5  volts 

GATED  AMPLIFIER  SERVICE 
Maximum  Ratings,  (Design-Center  Values): 

Plate  Voltage   300  max  volts 

GRIDS-N0.2-AND-N0.4  Supply  Voltage   SOO  max  volts 

Grids-No.2-and-No.4  Voltage   See  curve  page  70 

Plate  Dissipation  ,   I  max  watt 

Grids-No.2-and-No.4  Input: 

For  grids-No.2-and-No.4  voltages  up  to  150  volts   1  max  watt 

For  grids-No.2-and-No.4  voltages  between  150  and  300  volts   See  curve  page  70 

Cathode  Current   14  max  ma 

217 


RCA  Receiving  Tube  Manual 


Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  max 

Heater  positive  with  respect  to  cathode   200"waa; 

Maximum  Circuit  Values: 

Grid-No. 1-Circuit  Resistance   0.47  max 

Grid-No.3-Circuit  Resistance   2.2  max 

■The  dc  component  must  not  exceed  100  volts. 


volts 
volts 


megohm 
megohms 


6CS7 

Related  type: 
8CS7 


MEDIUM-MU  DUAL  TRIODE 

Miniature  type  used  as  combined 
vertical  deflection  oscillator  and  verti- 
cal deflection  amplifier  in  television  re- 
ceivers employing  series-connected 
heater  strings/Unit  No.l  is  used  as  a 
conventional  blocking  oscillator  in  vertical  deflection  circuits,  and  unit  No.2  as  a 
vertical  deflection  amplifier.  Outline  8D,  OUTLINES  SECTION.  Tube  requires 
miniature  nine-contact  socket  and  may  be  mounted  in  any  position.  Heater  volts 
(ac/dc),  6.3;  amperes,  0.6;  warm-up  time  (average),  11  seconds. 

CLASS  Ai  AMPLIFIER 

Characteristics:                                                            Unit  No.  1  Unit  No.  2 

Plate  Voltage   250  250 

Grid  Voltage   -8.5  -10 . 5 

Amplification  Factor   17  15  .5 

Plate  Resistance  (Approx.)   7700  3450 

Transconductance   2200  4500 

Grid  Voltage  (Approx.)  for  plate  current  of  10  /za   -24  - 

Grid  Voltage  (Approx.)  for  plate  current  of  50  /*»   -  -22 

Plate  Current   10.5  19 

Plate  Current  for  grid  voltage  of  -16  volts   -  3 


volts 
volts 

ohms 
/imhos 
volts 
volts 
ma 
ma 


VERTICAL  DEFLECTION  OSCILLATOR  AND  AMPLIFIER 

For  operation  in  a  525-line,  30-frame  system 

Unit  No.  1  Unit  No.  2 

Maximum  Ratings^  {Design-Center  Values):                              Oscillator  Amplifier 

DC  Plate  Voltage                                                             500  max  500  max  volts 

Peak  Positive-Pulse  Plate  VoLTAGBf  {Absolute  Maximum)        -  2200 *max  volts 

Peak  Negative-Pulse  Grid  Voltage                                  -400  max  -250  max  volts 

Peak  Cathode  Current                                                     70  max  105  mox  ma 

Average  Cathode  Current                                                20  max  30  max  ma 

Plate  Dissipation                                                            1.25  max  6 . 5  max  watts 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode                                200  max  200  max  volts 

Heater  positive  with  respect  to  cathode                                200"max  200"max  volts 

Maximum  Circuit  Values: 

Grid-Circuit  Resistance                                                          2.2  max  2 . 2  max  megohms 

t  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  vertical  scanning  cycle.  In  a 
525-line,  30-frame  system,  15  per  cent  of  one  vertical  scanning  cycle  is  2.5  milliseconds. 
^  Under  no  circumstances  should  this  absolute  value  be  exceeded. 
■  The  dc  component  must  not  exceed  100  volts. 

BEAM  POWER  TUBE 


6CU5 

Related  types: 
12CU5/12C5,  17CU5 


Miniature  type  used  in  the  audio 
output  stage  of  television  receivers. 
Outline  7C,  OUTLINES  SECTION. 
Tube  requires  miniature  seven-contact 
socket  and  may  be  mounted  in  any 
position. 


Heater  Voltage  (ac/dc)  

Heater  Current  

Direct  Interelectrode  Capacitances  (Approx.) : 

Grid  No.l  to  Plate   .   

Grid  No.l  to  Cathode,  Heater,  Grid  No.2,  and  Grid  No.3 .  . 

Plate  to  Cathode,  Heater,  Grid  No.2,  and  Grid  No.3  

CLASS  Ai  AMPLIFIER 
Maximum  Ratings,  (Design-Maximum  Values): 
Plate  Voltage  

218 


150  max 


volts 


Grid-No.2  (screen-grid)  Voltage   130  max 

Grid-No.1  (control-grid)  Voltage,  Positive-bias  value   0  max 

Plate  Dissipation   1  max 

Grid-No.2  Input     I A  max 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  max 

Heater  positive  with  respect  to  cathode   200'mox 

Bulb  Temperature  (At  hottest  point)   220  max 

■  The  dc  component  must  not  exceed  100  volts. 

Typical  Operation: 

Plate  Voltage   120 

Grid-No.2  Voltage   110 

Grid-No.l  Voltage   -8 

Peak  AF  Grid-No.  1  Voltage   8 

Zero-Signal  Plate  Current   49 

Maximum-Signal  Plate  Current   50 

Zero-Signal  Grid-No.2  Current   4 

Maximum-Signal  Grid-No.2  Current   8.5 

Plate  Resistance  (Approx.)   10000 

Transconductance   7500 

Load  Resistance   2500 

Total  Harmonic  Distortion   10 

Maximum-Signal  Power  Output   2.3 

Maximum  Circuit  Values: 

Grid-No.l-Circuit  Resistance: 

For  fixed-bias  operation   0.1  max 

For  cathode-bias  operation   0.5  max 


volts 
volts 
watts 
watts 

volts 
volts 
'C 


volts 
volts 
volts 
volts 
ma 
ma 
ma 
ma 
ohms 
umhos 
ohms 
per  cent 
watts 


megohm 
megohm 


Refer  to  type  6BQ6GTB/6CU6 


6CU6 


6CU8 


MEDIUM-MU  TRIODE- 
SHARP-CUTOFF  PENTODE 

Miniature  type  used  in  a  wide 
variety  of  applications  in  color  and 
black-and-white  television  receivers 
employing  series-connected  heater 
strings.  The  pentode  unit  is  used  as  an 
if  amplifier,  a  video  amplifier,  an  age  amplifier,  and  a  reactance  tube.  The  triode 
unit  is  used  in  low-frequency  oscillator,  sync-separator,  sync-clipper,  and  phase- 
splitter  circuits.  Outline  8B,  OUTLINES  SECTION.  Tube  requires  miniature 
nine-contact  socket  and  may  be  mounted  in  any  position.  For  curves  of  plate 
characteristics  for  pentode  unit,  refer  to  type  6AN8. 

Heater  Voltage  (ac/dc)  

Heater  Current  

Heater  Warm-up  Time  (Average)  

Direct  Intbrelectrodb  Capacitances; 
Triode  Unit: 

Grid  to  Plate  

Grid  to  Cathode,  Heater,  Pentode  Grid  No.3,  and  Internal  Shield  

Plate  to  Cathode,  Heater,  Pentode  Grid  No.3,  and  Internal  Shield  

Pentode  Unit: 

Grid  No.l  to  Plate  

Grid  No.l  to  Cathode,  Heater,  Grid  No.2,  Grid  No.3,  Triode  Cathode,  and 

Internal  Shield  

Plate  to  Cathode,  Heater,  Grid  No.2,  Grid  No.3,  Triode  Cathode,  and  In- 
ternal Shield  

Pentode  Grid  No.l  to  Triode  Plate  

Pentode  Plate  to  Triode  Plate  


6.3 
0.45 
11 


1  6 
1.9 
1.6 


volts 
ampere 
seconds 


Pf 
Pf 
pf 


0 . 025  max 


2.4 

0 . 03  max 
0 . 07  max 


pf 

pf 

pf 
pf 
pf 


CLASS  Ai  AMPLIFIER 
Maximum  Ratings,  (Design-Maximum  Values): 

Plate  Voltage  

Grid-No.2  Supply  Voltage  

Grid-No.2  (screen-grid)  Voltage  

Grid-No.  1  (control-grid)  Voltage,  Positive-bias  value  

Plate  Dissipation  

Grid-No.2  Input: 

For  grid-No.2  voltages  up  to  165  volts  

For  grid-No.2  voltages  between  165  and  330  volts  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode.  

Heater  positive  with  respect  to  cathode  , . 


Triode  Unit    Pentode  Unit 


330  max 


0  max 
2.8  max 


200  max 
200*'waa; 


volts 
volts 


330  max 
330  max 
See  curve  page  70 
0  max  volts 
2 . 3  max  watts 


0 . 55  max  watt 
See  curve  page  70 


200  max 
200*'mox 


volts 
volts 

219 


RCA  Receiving  Tube  Manual 


Characteristics:  Triode  Unit 

Plate  Supply  Voltage   125 

Grid-No.2  Supply  Voltage  

Grid-No.  1  Voltage   -1 

Cathode-Bias  Resistor  

Amplification  Factor   24 

Plate  Resistance  (Approx.)   4100 

Transconductance   5800 

Grid-No.l  Voltage  (Approx.)  for  plate  current  of  20  ^ta   -19 

Plate  Current   17 

Plate  Current  for  grid-No.  1  voltage  of  -3  volts  and  cathode- 
bias  resistor  of  0  ohms    - 

Grid-No.2  Current  

°  The  dc  component  must  not  exceed  100  volts. 


HIGH-MU  TRIODE 


6CW4 

Related  types: 
2CW4,  13CW4 


Nuvistor  type  used  as  a  grounded- 
cathode,  neutralized  rf  amplifier  in  vhf 
tuners  of  television  and  FM  receivers. 
Outline  1,  OUTLINES  SECTION. 
Tube  requires  nuvistor  socket  and  may 
be  operated  in  any  position. 


Pentode  Unit 
125 
125 

56 

170000 
7800 
-8 
12 

-1.6 
3.8 


volts 
volts 
volts 
ohms 

ohms 
/imhos 
volts 
ma 

ma 

ma 


INDEX  =  LARGE  LUC 
e  =  PIN  CUT  OFF 


Heater  Voltage  (ac/dc)   6.3 

Heater  Current   0.135 

Direct  Interelectrode  Capacitances  (Approx.): 

Grid  to  Plate   0 . 92 

Grid  to  Cathode,  Heater,  and  Shell   4.3 

Plate  to  Cathode,  Heater,  and  Shell   1.8 

Plate  to  Cathode   0.18 

Heater  to  Cathode   1.6 

CLASS  Ai  AMPLIFIER 
Maximum  Ratings,  {Design-Maximum  Values): 

Plate  Supply  Voltage   300°maa; 

Plate  Voltage   135  max 

Grid  Voltage: 

Negative-bias  value   55  max 

Peak  positive  value   0  max 

Plate  Dissipation   1.5  max 

Cathode  Current   15  max 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  ,  100  max 

Heater  positive  with  respect  to  cathode   100  max 


volts 
amp 

pf 
Pf 
Pf 
pf 


volts 
volts 

volts 
volts 
watt 
ma 

volts 
volts 


Characteristics  and  Typical  Operation: 

Plate  Supply  Voltage                                                                  110  70  volts 

Grid  Supply  Voltage                                                                      0  0  volts 

Cathode-Bias  Resistor                                                                 130  -  ohms 

Grid  Resistor                                                                                -  47000  ohms 

Amplification  Factor                                                                    65  68 

Plate  Resistance  (Approx.)                                                         6600  5440  ohms 

Transconductance                                                                     9800  12500  /xmhos 

Grid  Voltage  (Approx.)  for  plate  current  of  10  Aia                              -4  -  volts 

Plate  Current                                                                                  7  7.2  ma 

Maximum  Circuit  Values: 

Grid-Circuit  Resistance:' 

For  fixed-bias  operation   0.5  max  megohm 

For  cathode-bias  operation   2.2  max  megohms 

°  A  plate  supply  voltage  of  300  volts  may  be  used  provided  that  a  sufficiently  large  resistor  is  used  in 
the  plate  circuit  to  limit  the  plate  dissipation  to  1.5  watts  under  any  condition  of  operation. 
■  For  operation  at  metal-shell  temperatures  up  to  135°  C. 


MEDIUM-MU  TRIODE— 

"©^^^^'^''^.s''      SHARP-CUTOFF  PENTODE 

^^©^-1  rf^O©^'^  Miniature  type  used  in  television  V O 

^J/|tz:;  receiver  applications.  Pentode  unit  is  O^TVO 

ct^A^^  L^^zp    ^^^^     video  amplifier;  triode  unit  is  Related  type: 

Vj^ — ^  used  in  sound  intermediate-frequency  scxs 

amplifier,  sweep-oscillator,  sync-sep- 
arator, sync-amplifier,  and  sync-clipper  circuits.  Outline  8D,  OUTLINES  SEC- 
TION. Tube  requires  miniature  nine-contact  socket  and  may  be  mounted  in  any 
position.  Heater  volts  (ac/dc),  6.3;  amperes,  0.75. 

CLASS  Ai  AMPLIFIER 

Maximum  Ratings,  (Design-Maximum  Values):  Triode  Unit  Pentode  Unit 

Plate  Voltage   330  max  330  max  volts 

Grid-No.2  (SCREEN-GRID)  Supply  Voltage   -  330  max  volts 

Grid-No.2  Voltage   -  See  curve  page  70 

Grid-No.1  (control-grid)  Voltage,  Positive-bias  value   0  max  0  max  volts 

Plate  Dissipation   2  max  5  max  watts 

Grid-No.2  Input: 

For  grid-No.2  voltages  up  to  165  volts   -  11  wax  watts 

For  grid-No.2  voltages  between  165  and  330  volts   See  curve  page  70 

Peak  Heater-Cathode  Voltage: 

Heaternegative  with  respect  to  cathode   200  max  200  wax  volts 

Heater  positive  with  respect  to  cathode   200 "max  200 "max  volts 

Characteristics: 

Plate  Supply  Voltage   150  200  volts 

Grid-No.2  Supply  Voltage   -  125  volts 

Cathode-Bias  Resistor   150  68  ohms 

Amplification  Factor   40 

Plate  Resistance  (Approx.)   8700  70000  ohms 

Transconductance   4600  10000  /imhos 

Grid-No.l  Voltage  (Approx.)  for  plate  current  of  100 /xa   -5  -8.5  volts 

Plate  Current   9.2  24  ma 

Grid-No.2  Current   -  5.2  ma 

Maximum  Circuit  Values: 

Grid-No.  1-Circuit  Resistance:  ^  ^ 

For  fixed-bias  operation   0.5  wax       0.25  max  megohm 

For  cathode-bias  operation   1  max  1  max  megohm 

■  The  dc  component  must  not  exceed  100  volts. 


SHARP-CUTOFF  TETRODE 

Miniature  type  used  as  rf  ampli- 
fier in  vhf  tuners  of  television  receivers. 
Outline  7B,  OUTLINES  SECTION. 
Tube  requires  miniature  seven-contact 
socket  and  may  be  mounted  in  any 
position. 


6CY5 

Related  types: 
2CY5,  3CY5,  4CY5 


221 


RCA  Receiving  Tube  Manual 


Heateh  Voltage  (ac/dc)  

Heater  Current   

Direct  Interelectrode  Capacitances  (Approx.)°: 

Grid-No.  1  to  Plate  

Grid-No.l  to  Cathode,  Heater,  Grid  No.2,  and  Internal  Shield. 

Plate  to  Cathode,  Heater,  Grid  No.2,  and  Internal  Shield  

°  With  external  shield  connected  to  cathode. 

CLASS  Ai  AMPLIFIER 
Maximum  Ratings,  {Design-Maximum  Values): 

Plate  Voltage  

Grid-No.2  (screen-grid)  Supply  Voltage  

Grid-No.2  Voltage  

G rid-No.  1  (control-grid)  Voltage,  Positive-bias  value  

Cathode  Current  

Grid-No.2  Input: 

For  grid-No.2  voltages  up  to  90  volts  

For  grid-No.2  voltages  between  90  and  180  volts  

Plate  Dissipation  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  

Characteristics: 

Plate  Voltage  

Grid-No.2  Voltage  

Grid-No.l  Voltage  

Plate  Resistance  (Approx.)  

Transconductance  

Plate  Current  

Grid-No.2  Current  

Grid-No.l  Voltage  (Approx.)  for  plate  current  of  20  /ua  

Maximum  Circuit  Value: 

Grid-No.  1-Circuit  Resistance  


6.3 
0.2 

0.03 
4.5 
3 


volts 
ampere 

Pf 
Pf 
pf 


180  max 

volts 

180  max 

volts 

See  curve 

page  70 

0  max 

volts 

20  max 

ma 

0.5  max 

watt 

See  curve 

page  70 

2  max 

watts 

100  max 

volts 

100  max 

volts 

125 
80 
-1 

0.1 
8000 
10 

1.5 


volts 
volts 
volt 
megohm 
Mmhos 
ma 
ma 
volts 


0 . 5  max  megohm 


AVERAGE  CHARACTERISTICS 


-0. 

5 

TYpe'eCYs'  1 

s  e.3  VOLTS  ' 

GRID- 

NJt2  V 

5LT$  >l 

0 

G 

1  VOLT 

5  Ecr 

-1.0 

-1.5 

*0 

lb 

cc 

,=-2.0 

-  -2.5 

-3.0 

120  160 
PLATE  VOLTS 


240  200 
92CM-»5ltT 


6CY7 

Related  type: 
11CY7 


DUAL  TRIODE 

Miniature  type  used  as  combined 
vertical  oscillator  and  vertical  de- 
flection amplifier  in  television  receiv- 
ers. Unit  No.l  is  a  high-mu  triode 
unit  used  as  a  blocking  oscillator  in 
vertical  deflection  circuits,  and  unit  No.2  is  a  low-mu  triode  unit  used  as  a  vertical 
deflection  amplifier.  Outline  8D,  OUTLINES  SECTION.  Tube  requires  miniature 
nine-contact  socket  and  may  be  mounted  in  any  position.  Heater  volts  (ac/dc), 
6.3;  amperes,  0.75. 

222 


CLASS  Ai  AMPLIFIER 


Characteristics: 

Plate  Supply  Voltage  

Grid  Voltage  

Cathode-Bias  Resistor  

Amplification  Factor  

Plate  Resistance  (Approx.)  

Transconductance  

Grid  Voltage  (Approx.)  for  plate  current  of  10  /na.  . 
Grid  Voltage  (Approx.)  for  plate  current  of  200  fxa. . 

Plate  Current  

Plate  Current  for  grid  voltage  of  -30  volts  


Unit  No.l 

Unit  No.2 

250 

150 

volts 

-3 

volts 

620 

ohms 

68 

5 

52000 

920 

ohms 

1300 

5400 

/^mhos 

-5.5 

volts 

-40 

volts 

1.2 

30 

ma 

3.5 

ma 

VERTICAL  DEFLECTION  OSCILLATOR  AND  AMPLIFIER 

For  operation  in  a  525-line,  SO-frame  system 

Unit  No.l 
Oscillator 
  350  ^ax 


Maximum  Ratings,  {Design-Maximum  Values): 

DC  Plate  Voltage  

Peak  Positive-Pulse  Plate  Voltage#  

Peak  Negative-Pulse  Grid  Voltage  

Peak  Cathode  Current  

Average  Cathode  Current  

Plate  Dissipation  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode. . . 

Heater  positive  with  respect  to  cathode .  .  . 


-400  max 


200  max 
200"max 


Unit  No.2 
Amplifier 

350  max 
1800  max 
-250  max 

120  max 
35  max 

5 . 5  max 

200  max 
200"max 


volts 
volts 
volts 
ma 
ma 
watts 

volts 
volts 


Maximum  Circuit  Values: 

Grid-Circuit  Resistance   2.2  max        2. 2 1 wax  megohms 

#  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  vertical  scanning  cycle.  In  a 
525-line,  30-frame  system,  15  per  cent  of  one  vertical  scanning  cycle  is  2.5  milliseconds. 
■  The  dc  component  must  not  exceed  100  volts, 
t  For  cathode-bias  operation. 


BEAM  POWER  TUBE 


6CZ5 

Related  type: 
5CZ5 


Miniature  type  used  as  a  vertical 
deflection  amplifier  in  high-efficiency 
deflection  circuits  of  television  receiv- 
ers utilizing  picture  tubes  having  diag- 
onal deflection  angles  of  110  degrees 
and  operating  at  ultor  voltages  up  to  18  kilovolts.  Also  used  in  the  audio  output 
stage  of  television  and  radio  receivers.  This  type  has  a  controlled  heater  warm-up 
time  for  use  in  receivers  employing  series-connected  heater  strings.  Outline  8E, 
OUTLINES  SECTION.  Tube  requires  miniature  nine-contact  socket  and  may  be 
mounted  in  any  position. 

Heater  Voltage  (ac/dc)   6.3  volts 

Heater  Current   0 . 45  ampere 

Heater  Warm-Up  Time  (Average)   11  seconds 

Direct  Interelectrode  Capacitances: 

Grid  No.l  to  Plate   0.4  max  pf 

Grid  No.l  to  Cathode,  Heater,  Grid  No.2,  and  Grid  No.3   9  pf 

Plate  to  Cathode,  Heater,  Grid  No.2,  and  Grid  No.3   6  pf 

Plate  Resistance  (Approx.)*   0.073  megohm 

Transconductance*   4800  /umhos 


VERTICAL  DEFLECTION  AMPLIFIER 

For  operation  in  a  525-line,  SO-frame  system 
Maximum  Ratings,  (Design-Maximum  Values): 

DC  Plate  Voltage  

Peak  Positive-Pulse  Plate  Voltage#  

Grid-No.2  (screen-grid)  Voltage  

Peak  Negative-Pulse  Grid-No.  1  (control-grid)  Voltage  

Peak  Cathode  Current  

Average  Cathode  Current  

Plate  Dissipation  

Grid-No.2  Input  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  

Bulb  Temperature  (At  hottest  point)  


350  max 
2200  max 
315  max 
-275  max 
155  max 
45  max 
10  max 
2.2  max 

200  max 
200^maa; 
250  max 


volts 
volts 
volts 
volts 
ma 
ma 
watts 
watts 

volts 
volts 
*C 

223 


RCA  Receiving  Tube  Manual 


Maximum  Circuit  Values: 

Grid-No.l-Circuit  Resistance: 

For  fixed-bias  operation   0  5  max  megohm 

For  cathode-bias  operation   1.0  max  megohm 

#  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  vertical  scanning  cycle.  In  a 
525-line,  30-frame  system,  15  per  cent  of  one  vertical  scanning  cycle  is  2.5  milliseconds. 
The  dc  component  must  not  exceed  100  volts. 


REMOTE-CUTOFF  PENTODE  "'(7) 

Glass  type  used  in  rf  and  if  stages  of  radio  re-  /a^— i  I'V^^'i 
cei  vers  employing  a  vc.  Outline  24  A,  OUTLINES 
^r\^  SECTION.  Tube  requires  six-contact  socket.  pC^^ 

^  Except  for  interelectrode  capacitances,  this  type 

is  identical  electrically  with  type  6U7-G.  Refer   

to  type  6SK7  for  application  information.  (j)  (6) 

Heater  volts  (ac/dc),  6.3;  amperes,  0.3.  This  "  ' 

type  is  used  principally  for  renewal  purposes. 

SHARP-CUTOFF  PENTODE  <i2(3y^^s®" 

Glass  type  used  as  detector  or  amplifier  in  ^A/O-.  I 

6D7  radio  receivers.  Outline  24A,  OUTLINES  SEC-  ^-V^EErJ  >^ 

TION.  Heater  volts  (ac/dc),  6.3;  amperes,  0.3.  p(i\  — /®K 
For  electrical  characteristics,  refer  to  type  6 J 7. 
Type  6D7  is  a  DISCONTINUED  type  listed  (TV — 
for  reference  only. 

PENTAGRID  CONVERTER 

Glass  octal  type  used  in  superheterodyne         P/'js/j*-^   I  /Vr\*'2 
circuits.  Outline  23,  OUTLINES  SECTION. 
6D80  Tube  requires  octal  socket.  Heater  volts  (ac/dc) , 

6.3;  amperes,  0.15.  Except  for  interelectrode  H^£Ar^^>W^H 
capacitances  and  heater  rating,  the  6D8-G  is 
similar  electrically  to  type  6A8-G.  Type  6D8-G 
is  a  DISCONTINUED  type  listed  for  reference  nc  k 

only.  P 

HALF-WAVE  VACUUM  RECTIFIER 

M.W\  A  A  Glass  octal  type  used  as  damper 

ODA4         tube  in  horizontal-deflection  circuits  ^  ^^7) 

Related  fype:  of  television  receivers.  Outline  14C,  ic^ 

17D4  OUTLINES  SECTION.  Tube  re-  (V) 

quires  octal  socket  and  may  be  mounted  " 
in  any  position.  May  be  supplied  with  pin  No.l  omitted.  Socket  terminals  1,  2,  4, 
and  6  should  not  be  used  as  tie  points.  It  is  important  that  this  tube,  like  other 
power-handling  tubes,  be  adequately  ventilated.  Heater  volts  (ac/dc),  6.3;  am- 
peres, 1.2. 

DAMPER  SERVICE 

For  operation  in  a  525-line,  SO-frame  system 
Maximum  Ratings,  (Design-Maximum  Values): 

Peak  Inverse  Plate  Current*   4400  max  volts 

Peak  Plate  Current   900  max  ma 

DC  Plate  Current   155  max  ma 

Plate  Dissipation   5.5  max  watts 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   4400"max  volts 

Heater  positive  with  respect  to  cathode   SOO^max  volts 

•  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  horizontal  scanning  cycle.  In  a 
525-line,  30-frame  system,  15  per  cent  of  one  horizontal  scanning  cycle  is  10  microseconds. 
■  The  dc  component  must  not  exceed  900  volts. 
^  The  dc  component  must  not  exceed  100  volts. 

BEAM  POWER  TUBE  "(ii::^^ 

£^m\n  r                 Miniature  type  used  as  vertical-  ^ '(3^/"^-^-^^*^*^^ 

ODB3          deflection-amplifier  tube  in  television  |y^Eiz7|[T^ 

receivers.   Outline  8D,  OUTLINES  Kfiz(^)^f/\J^/®ic 

SECTION,  except  all  vertical  dimen-  ' 

si ons  of  this  type  are  1/8  inch  greater.  G2  ^ 

224 


6DC6 


Tube  requires  miniature  nine-contact  socket  and  may  be  operated  in  any  position. 
Heater  volts  (ac/dc),  6.3;  amperes,  1.2.  Except  for  heater  ratings,  this  type  is  iden- 
tical with  miniature  type  12DB5. 

SHARP-CUTOFF  PENTODE 

Miniature  type  used  in  the  gain- 
controlled  picture  if  stages  of  color  tele- 
vision receivers.  It  is  also  used  as  a 
radio-frequency  amplifier  in  the  tuners 
of  such  receivers.  Outline  7B,  OUT- 
LINES SECTION.  Tube  requires  seven-contact  miniature  socket  and  may  be 
mounted  in  any  position. 

Heater  Voltage  (ac/dc)  

Heater  Current  

Direct  Inter  electrode  Capacitances: 

Grid  No.l  to  Plate  

Grid  No.l  to  Cathode,  Heater,  Grid  No.2,  Grid  No.3,  and  Internal  Shield 

Plate  to  Cathode,  Heater,  Grid  No.2,  Grid  No.3,  and  Internal  Shield  

CLASS  AiAMPLIFIER 
Maximum  Ratings,  (Design-Center  Values): 

Plate  Voltage  

Grid-No.3  (suppressor-grid)  Voltage,  Positive  value  

Grid-No.2  Supply  Voltage  

Grid-No.2  (screen-grid)  Voltage  

Grid-No.1  (control-grid)  Voltage,  Positive-bias  value  

Plate  Dissipation  

Grid-No.2  Input: 

For  grid-No.2  voltages  up  to  150  volts  

For  grid-No.2  voltages  between  150  and  300  volts  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  


6.3 
0.3 

0 . 02  max 
6.5 
2 


volts 
ampere 

Pf 
Pf 
pf 


300  max 
0  max 
300  max 


volts 
volts 
volts 


See  curve  page  70 
0  max  volts 
2  max  watts 

0 . 5  max  watt 
See  curve  page  70 


200  max 
20Q''max 


volts 
volts 


Characteristics: 

Plate  Supply  Voltage   200  volts 

Grid  No.3  Connected  to  cathode  at  socket 

Grid-No.2  Supply  Voltage    150  volts 

Cathode-Bias  Resistor   180  ohms 

Plate  Resistance  ( Approx.)   0.5  megohm 

Transconductance   5500  umbos 

Grid-No.l  Voltage  (Approx.)  for  transconductance  of  50  /umbos   -12. 5  volts 

Plate  Current   9  ma 

Grid-No.2  Current   3  ma 

Maximum  Circuit  Values: 

Grid-No.l-Circuit  Resistance: 

For  fixed-bias  operation  

For  cathode-bias  operation  

°  The  dc  component  must  not  exceed  100  volts. 

AVERAGE  PLATE  CHARACTERISTICS 


0.25  max 
1 . 0  max 


megohm 
megohm 


s 

y  10 


0 

1         1         1  1 

6.3  VOLTS 

CR 

0-Nt 

2  VOL 

rs«i5 

0 

VOL" 

3  Ec 

CRI 

0-NCI 

-2 

-3 

-4 

-6 

-10 

100  150  200  250  300  350 

PLATt  VOLTS  92CM-e330Tl 


225 


RCA  Rece wing  Tube  Manual 


TWIN  DIODE—  „     H  p 

SEMIREMOTE-CUTOFF  PENTODE  ^  Sv^^'po, 

£^w\^^  Miniature  type  used  as  rf-  and  ^^®k\/zzz-\J^ 

ODWO  if-amplifier  tubes  in  radio  and  tele-  (ncv^*~is48> 

vision  receivers.  Outline  8D,  OUT-  6|Jr^^^^*^^^P02 
LINESSECTION.Tuberequiresnine-  ClT— ^ 
contact  socket  and  may  be  mounted 
in  any  position.  Heater  volts  (ac/dc),  6.3;  amperes,  0.3. 

PENTODE  UNIT  AS  CLASS  Ai  AMPLIFIER 
Maximum  Ratings,  {Design-Center  Values) : 

Plate  Supply  Voltage   550  max  volts 

Plate  Voltage   300  max  volts 

Grid-No.2  Voltage: 

With  plate  current  greater  than  8  ma   \2h  max  volts 

With  plate  current  less  than  4  ma   300  max  volts 

Cathode  Current   16.5  wax  ma 

Grid-No.2  Input   0^45  wax  watts 

Plate  Dissipation   2.2b  max  watts 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   100  max  volts 

Heater  positive  with  respect  to  cathode   100  wax  volts 

Characteristics: 

Plate  Voltage                                                                               200  250  volts 

Grid  No.3   Connected  to  cathode  at  socket 

Grid-No.2  Voltage                                                                   100  100  volts 

Grid-No.l  Voltage. . .  .  :   -1.5  -2  volts 

M/i-Factor,  Grid  No.2  to  Grid  No.l                                                20  20 

Plate  Resistance  (Approx.)                                                         0  .6  1  megohm 

Transconductance   4500  3800  /xmhos 

Plate  Current                                                                           11  9  ma 

Grid-No,2  Current                                                                     3.3  2.7  ma 

Transconductance,  at  grid-No.  1  voltage  of -20  volts                        120  200  /umhos 

Maximum  Circuit  Values: 

Grid-No.  1-Circuit  Resistance   3  max  megohms 

DIODE  UNITS  {Each  Unit) 
Maximum  Ratings,  {Design-Center  Values): 

Peak  Inverse  Plate  Voltage   200  wax  volts 

Peak  Plate  Current   5  wax  ma 

Average  Plate  Current.   0.8  wax  ma 

p 

HALF-WAVE  VACUUM  RECTIFIER  — ^ 

M^W^^A  Glass  octal  type  used  as  damper 

ODe4  tube  in  horizontal-deflection  circuits 

Related  types:  of  television  receivers.  Outline  14F,  ^^^"^^^u 

17DE4,22DE4  OUTLINES  SECTION.  Tube  re-  ^^TO 

quires  octal  socket  and  may  be  oper-  h 

ated  in  any  position.  Socket  terminals  1, 2,.  4,  and  6  should  not  be  used  as  tie  points. 

It  is  important  that  this  tube,  like  other  power-handling  tubes,  be  adequately 

ventilated. 


Heater  Voltage  (AC/DC)   6.3  volts 

Heater  Current    1.6  amperes 

Direct  Interblbctrode  Capacitances  (Approx.): 

Plate  to  Cathode  and  Heater   8.5  pf 

Cathode  to  Plate  and  Heater   11.5  jrf 

Heater  to  Cathode   4  pf 


DAMPER  SERVICE 

For  operation  in  a  525-Une,  SO-frame  system 
Maximum  Ratings,  {Design-Maximum  Values): 

Peak  Inverse  Plate  Voltage#   5500  wax  volts 

Peak  Plate  Current   1100  wax  ma 

DC  Plate  Current   180  wax  ma 

Plate  Dissipation   6.5  wax  watts 


226 


Technical  Data 


Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   5500"max  volts 

Heater  positive  with  respect  to  cathode  •   ZOO*max  volts 

Characteristics,  Instantaneous  Value: 

Tube  Voltage  Drop  for  plate  current  of  350  ma   34  volts 

#  the  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  horizontal  scanning  cycle.  In 
a  525-linc,  30-frame  system,  15  per  cent  of  one  horizontal  scanning  cycle  is  10  microseconds. 

■  The  dc  component  must  not  exceed  900  volts. 

•  The  dc  component  must  not  exceed  100  volts, 

SHARP-CUTOFF  PENTODE 

)oz         Miniature  type  used  in  the  gain-  £^W\^£^ 
controlled  picture  if  stages  of  television  O  D  CO 

receivers  utilizing  an  intermediate  fre-  Related  type: 

Ts  quency  in  the  order  of  40  megacycles  4DE6 
gT"  per  second.  Also  used  as  an  rf  amplifier 

in  vhf  television  tuners.  This  tube  features  very  high  transconductance  combined 
with  low  interelectrode  capacitance  values,  and  is  provided  with  separate  base  pins 
for  grid  No.3  and  cathode  to  permit  the  use  of  an  unbypassed  cathode  resistor  to 
minimize  the  effects  of  regeneration.  Outline  7B,  OUTLINES  SECTION.  Tube 
requires  miniature  seven-contact  socket  and  may  be  mounted  in  any  position. 


Heater  Voltage  (ac/dc)  . 
Heater  Current  


Without 
External 
Shield 
0 . 025  max 


6.3 
0.3 

With 
External 
Shield'' 
0.015  max 


6.5 


Direct  Interelectrode  Capacitances: 

Grid  No.l  to  Plate  

Grid  No.l  to  Cathode,  Heater,  Grid  No.2,  Grid  No.3, 

and  Internal  Shield   6.5 

Plate  to  Cathode,  Heater,  Grid  No.2,  Grid  No.3,  and  In- 
ternal Shield   2 

^  With  external  shield  connected  to  cathode. 

CLASS  Ai  AMPLIFIER 
Maximum  Ratings,  (Design-Maximum  Values): 

Plate  Voltage  

Grid-No.3  (suppressor-grid)  Voltage,  Positive  value  

Grid-No.2  (screen-grid)  Supply  Voltage  

Grid-No.2  Voltage  

Grid-No.  1  (control-grid)  Voltage,  Positive-bias  value  

Plate  Discipation  

Grid-No.2  Input: 

For  grid-No.2  voltages  up  to  165  volts   0.55  max 

For  grid-No.2  voltages  between  165  and  330  volts  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  

Characteristics: 

Plate  Supply  Voltage  

Grid  No.3  


volts 
ampere 


Pf 
Pf 


330  max 
0  max 
330  max 


volts 
volts 
volts 

See  curve  page  70 
0  max  volts 
2.3  max  watts 

watt 

See  curve  page  70 


200  max 
200«maa: 


125 


volts 
volts 


volts 


  Connected  to  cathode  at  socket 

AVERAGE  PLATE  CHARACTERISTICS 


TYPE  6DE6 

Ef  =  6.3  VOLTS  ' 
GRID  NS  3  AND  INTERNAL  SHIELD 

CONNECTED  TO  CATHODE  AT  SOCKET 
CRID-Na2  VOLTS  =  125 


92CM-857eTI 


227 


RCA  Receiving  Tube  Manual 


VOlt3 

ohms 
megohm 
/xmhos 
/xmhos 
volts 
ma 
ma 


Grid-No.2  Supply  Voltage   125 

Cathode-Bias  Resistor   56 

Plate  Resistance  (Approx.)   0.25 

Transconductance   8000 

Transconductance  for  grid-No.l  volts  of  -5.5  and  cathode  resistor  of  0  ohms  700 

Grid-No.l  Voltage  (Approx.)  for  plate  current  of  20  /ua   -9 

Plate  Current   15.5 

Grid-No.2  Current   4.2 

■  The  dc  component  must  no^  exceed  100  volts 

DUAL  TRIODE 

Miniature  type  used  as  combined 
vertical  oscillator  and  vertical-de- 
flection amplifier  in  television  receiv- 
ers. Unit  No.l  is  a  medium-mu  triode 
unit  used  as  a  blocking  oscillator  in 
vertical-deflection  circuits,  and  unit  No.2  is  a  low-mu  triode  unit  used  as  a  vertical- 
deflection  amplifler.  Outline  8D,  OUTLINES  SECTION.  Tube  requires  miniature 
nine-contact  socket  and  may  be  mounted  in  any  position.  For  curve  of  average 
plate  characteristics,  Unit  No.2,  refer  to  type  6DR7. 

Heater  Voltage  (ac/dc)  

Heater  Current  

Direct  Interelectrode  Capacitances  (Approx.): 

Grid  to  Plate  

Grid  to  Cathode  and  Heater  

Plate  to  Cathode  and  Heater  


6DE7 

Related  types: 
10DE7,  13DE7 


Characteristics. 

Plate  Voltage.  .  . 


CLASS  A,  AMPLIFIER 


Unit  No.l 
4 

2.2 
C.52 


Grid  Voltage . 

Amplification  Factor  

Plate  Resistance  (Approx.)  

Transconductance  

Plate  Current  

Plate  Current  for  grid  voltage  of  -24  volts  

Grid  Voltage  (Approx.)  for  plate  current  of  10  )ua. 
Grid  Voltage  (Approx.)  for  plate  current  of  50  /xa. 


Unit  No.l 
250 
-11 
17.5 
8750 
2000 
5.5 

-20 


6.3 

volts 

0.9 

ampere 

Unit  No.2 

8.5 

Pf 

5.5 

Pf 

1 

pf 

Unit  No.2 

150 

volts 

-17.5 

volts 

6 

925 

ohms 

6500 

//mhos 

35 

ma 

10 

ma 

volts 

-44 

volts 

VERTICAL-DEFLECTION  OSCILLATOR  AND  AMPLIFIER 

For  operation  in  a  525-line,  SO-frame  system 

Maximum  Ratings,  {Design-Maximum  Values):  Oscillator- 
DC  Plate  Voltage   330  max 

Peak  Positive-Pulse  Plate  Voltage#  

Peak  Negative-Pulse  Grid  Voltage.   -400  max 

Peak  Cathode  Current   77  max 

Average  Cathode  Current   22  max 

228 


92CM-<)q88T 


Unit  No.2 
Amplifier 

275  max 
1500  max 
-250  max 

175  max 
50  max 


volts 
volts 
volts 
ma 
ma 


Plate  Dissipation  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode. 

Heater  positive  with  respect  to  cathode .  . 


1.5  max 


200  max 
200'max 


7  max 


200  max 
200"moa; 


volts 
volts 


Maximum  Circuit  Values: 

Grid-Circuit  Resistance: 

For  grid-resistor  bias  or  cathode-bias  operation   2.2  max        2 . 2  max  megohms 

#  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  vertical  scanning  cycle.  In  a 
525-line,  30-frame  system,  15  per  cent  of  one  vertical  scanning  cycle  is  2.5  milliseconds. 
■  The  dc  component  must  not  exceed  100  volts. 

BEAM  POWER  TUBE 


Glass  octal  type  used  as  output 
tube  in  audio-amplifier  applications. 
Outline  14C,  OUTLINES  SECTION. 
Tube  requires  octal  socket  and  may 
be  mounted  in  any  position.  This  type 
may  be  supplied  with  pin  1  omitted. 


6DG6GT 


Heater  Voltage  (ac/dc)  

Heater  Current  

Direct  Interelectrode  Capacitances  (Approx.): 

Grid  No.l  to  Plate  

Grid  No.l  to  Cathode,  Heater,  Grid  No.2,  and  Grid  No.3 . 

Plate  to  Cathode,  Heater,  Grid  No.2,  and  Grid  No.3  


6.3 
1.2 

0.6 
15 
10 


volts 
amperes 

Pf 
pf 


CLASS  Ai  AUDIO-FREQUENCY  POWER  AMPLIFIER 
Maximum  Ratings^  (Design-Center  Values): 

Plate  Voltage  

Grid-No.2  (screen-grid)  Voltage  

Plate  Dissipation  

Grid-No.2  Input  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  

Typical  Operation: 

Plate  Supply  Voltage   110 

Grid-No.2  Supply  Voltage   110 

Grid-No.l  (Control-Grid)  Supply  Voltage   -7.5 

Peak  AF  Grid-No.l  Voltage   7 .  5 

Cathode-Bias  Resistor   - 

Zero-Signal  Plate  Current   49 

Maximum-Signal  Plate  Current   50 

Zero-Signal  Grid-No.2  Current   4 

Maximum-Signal  Grid-No.2  Current   .  10 


8000 
2000 
10 
2.1 


200  max 

volts 

125  max 

volts 

10  max 

watts 

1 . 25  max 

watts 

200  max 

volts 

200 *max 

volts 

200 

volts 

125 

volts 

volts 

8.5 

volts 

180 

ohn^s 

46 

ma 

47 

ma 

2.2 

ma 

8.5 

ma 

28000 

ohms 

8000 

/iimhos 

4000 

ohms 

10 

per  cent 

3.8 

watts 

0 . 1  max 

megohm 

0.5  max 

megohm 

Plate  Resistance  (Approx.)   13000 

Transconductance  

Load  Resistance  

Total  Harmonic  Distortion  

Maximum-Signal  Power  Output  

Maximum  Circuit  Values: 

Grid-No.l-Circuit  Resistance: 

For  fixed-bias  operation  

For  cathode-bias  operation  

^  The  dc  component  must  not  exceed  100  volts, 

SHARP-CUTOFF  PENTODE 

Miniature  type  used  as  interme- 
diate-frequency amplifier  tube  in  tele- 
vision receivers.  This  tube  features 
high  transconductance  at  low  plate  and 
grid-No.2  voltages,  combined  with  low 
interelectrode  capacitances.  Outline  7B,  OUTLINES  SECTION.  Tube  requires 
miniature  seven-contact  socket  and  may  be  mounted  in  any  position. 

6 . 3  volts 


6DK6 

Related  types: 
3DK6,  12DK6 


Heater  Voltage  (ac/dc)  

Heater  Current  

Direct  Interelectrode  Capacitances: 

Grid  No.l  to  Plate  

Grid  No.l  to  Cathode,  Heater,  Grid  No.2,  Grid  No.3,  and 

Internal  Shield  

Plate  to  Cathode,  Heater,  Grid  No.2,  Grid  No.3,  and  In- 
ternal Shield  


0.3 
0 . 025  max 
6.3 


pf 
pf 
pf 
229 


RCA  Receiving  Tube  Manual 


CLASS  Ai  AMPLIFIER 
Maximum  Ratings,  {Design-Maximum  Values): 

Plate  Voltage  

Grid-No.3  (suppressor-grid)  Voltage,  Positive  value  

Grid-No.2  (screen-grid)  Supply  Voltage  

Grid-No.2  Voltage  

Grid-No.1  (control-grid)  Voltage,  Positive-bias  value  

Plate  Dissipation  

Grid-No.2  Input: 

For  grid-No.2  voltages  up  to  165  volts  

For  grid-No.2  voltages  between  165  and  330  volts  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  

Characteristics: 

Plate  Supply  Voltage  

Grid  No.3  Connected 

Grid-No.2  Supply  Voltage  

Cathode-Bias  Resistor  

Plate  Resistance  (Approx.)  

Transconductance  

Grid-No.l  Voltage  (Approx.)  for  plate  current  of  20  /xa  

Plate  Current  

Grid-No  2  Current  

■  The  dc  component  must  not  exceed  100  volts. 


AVERAGE  CHARACTERISTICS 


330  max  volts 
0  max  volts 
330  max  volts 
See  curve  page  70 
0  max  volts 
2 . 3  max  watts 

0 . 55  max  watt 
See  curve  page  70 


200  max 
200"moa; 


volts 
volts 


125  volts 
to  cathode  at  socket 

125  volts 

56  ohms 

0.35  megohm 

9800  Mmhos 

-6 . 5  volts 

12  ma 

3.8  ma 


300  400 
PLATE  VOLT* 


f2CM-9d»ITl 


HALF-WAVE  VACUUM  RECTIFIER  -f^) 

^  1^  -  -  m  Glass  octal  type  used  as  damper  ^^^^ 

wDfVl4         tube  in  horizontal-deflection  circuits 
Related  types:  of  television  receivers.  Outline  14F.  C2> 

12DM4, 17DM4         OUTLINES  SECTION.  Tube  re-  ^^3^ 
quires  octal  socket  and  may  be  oper- 
ated in  any  position.  Socket  terminals  1,  2,  4,  and  6  should  not  be  used  as  tie  points. 
It  is  important  that  this  tube,  like  other  power-handling  tubes,  be  adequately 
ventilated. 

Heater  Voltage  (ac/dc)   6.3  volts 

Heater  Current   1.2  amperes 

Direct  Interelectrode  Capacitances  (Approx.) : 

Plate  to  Cathode  and  Heater   8.5  pf 

Cathode  to  Plate  and  Heater     11.5  pf 

Heater  to  Cathode   4  pf 

DAMPER  SERVICE 

For  operation  in  a  525-line,  30-frame  system 
Maximum  Ratings^  (Design-Maximum  Values): 

Peak  Inverse  Plate  Voltage"     5000  max  volts 

Peak  Plate  Current   1100  max  ma 

DC  Plate  Current   175  wax  ma 


230 


Plate  Dissipation   6.5  max  watts 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   5000  "max  volts 

Heater  positive  with  respect  to  cathode   300 •mox  volts 

°  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  horizontal  scanning  cycle.  In 

a  525-line,  30-frame  system,  15  per  cent  of  one  horizontal  scanning  cycle  is  10  microseconds. 

■  The  dc  component  must  not  exceed  900  volts. 

•  The  dc  component  must  not  exceed  100  volts. 

BEAM  POWER  TUBE 

vpiJTUk^  Glass  octal  type  used  as  horizontal-deflec- 

\^r~\/  PX/^NC  ^^^^  amplifier  tube  in  television  receivers  hav- 

G3\^.^W_riZ  I  ing  low  B-supply  voltages.  Outline  25A,  OUT- 

I  \  j         lines  section.  Tube  requires  octal  socket. 

I^^aT)      Vertical  mounting  is  preferred,  but  horizontal  x  [  jr 

n^\.       ^T/^-^H     mounting  is  permissible  if  pins  1  and  3  are  in  ^^^^iNI^/ 
OyTTsS  vertical  plane.  Heater  volts  (ac/dc),  6.3;  am-  Related  type* 

NC  peres,  2.5.  Except  for  heater  ratings,  this  type  is  osoma 

identical  with  miniature  type  25DN6.  Type 
6DN6  is  used  principally  for  renewal  purposes. 

rV^T^nK     medium-mu  dual  triode 

^^^^^^^yCl^     yt^^^'        Glass  octal  type  used  as  combined  r%  K I  "T 

,^-%r~~' "^^J^     vertical-deflection-oscillator  and  ver-  ODIM/ 
^T2{iX\^C!^;<^^^/^^    tical-deflection-amplifier  tube  in  tele- 
rN~rTO  vision  receivers.  Outline  14B,  OUT- 

LINES  SECTION.  Tube  requires  octal 
socket  and  may  be  mounted  in  any  position.  Heater  volts  (ac/dc),  6.3;  amperes,0.9. 

CLASS  A,  AMPLIFIER 

Characteristics:  Unit  No.l  Unit  No.2 

Plate  Voltage   250  250  volts 

Grid  Voltage   -8  -9.5  volts 

Amplification  Factor   22 . 5  15.4 

Plate  Resistance  (Approx.)   9000  2000  ohms 

Transconductance   2500  7700  /nmhos 

Plate  Current                                                                     .  8  41  ma 

Grid  Voltage  (Approx.)  for  plate  current  of  10  Ata   -18  -  volts 

Grid  Voltage  (Approx.)  for  plate  current  of  50    -  -23  volts 

VERTICAL-DEFLECT!ON  OSCILLATOR  AND  AMPLIFIER 

For  operation  in  a  525-line,  30-frame  system 

Unit  No.l  Unit  No.2 

Maximum  Ratings,  (Design-Maximum  Values):                           Oscillator  Amplifier 

DC  Plate  Voltage                                                                 350  max  550  max  volts 

Peak  Positive-Pulse  Plate  Voltage#                                         -  2500  max  volts 

Peak  Negative-Pulse  Grid  Voltage                                       400  max  250  max  ma 

Peak  Cathode  Current                                                           -  150  max  ma 

Average  Cathode  Current                                                      -  50  max  ma 

Plate  Dissipation                                                                   1  max  10  max  watts 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode                                     200  max  200  max  volts 

Heater  positive  with  respect  to  cathode                                    200"wax  200"max  volts 

Maximum  Circuit  Values: 

Grid-Circuit  Resistance: 

For  fixed-bias  operation   2.2  max        2 . 2  max  megohms 

For  cathode-bias  operation   2.2  max         -  megohms 

#  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  vertical  scanning  cycle.  In  a 
525-line,  30-frame  system,  15  per  cent  of  one  vertical  cycle  is  2.5  milliseconds. 

■  The  dc  component  must  not  exceed  100  volts. 

P 

,    ,    fl       HALF-WAVE  VACUUM  RECTIFIER 

C^Y      r  \ 

Glass  octal  type  used  as  damper 
tube  in  horizontal-deflection  circuits  of         A  A. 
^Ci<^H      television  receivers.  Outline  14E, OUT-  O l/\rf ^ 

LINES  SECTION.  Tube  requires  oc- 
H  tal  socket  and  may  be  mounted  in  any 

position.  Socket  terminals  1,  2,  4,  and  6  should  not  be  used  as  tie  points.  Heater 
volts  (ac/dc),  6.3;  amperes,  1.2. 


231 


RCA  Receiving  Tube  Manual 


DAMPER  SERVICE 

For  operation  in  a  525-line,  30-frame  system 
Maximum  Ratings,  (Design-Maximum  Values): 

Peak  Inverse  Plate  Voltage#  

Peak  Plate  Current  

DC  Plate  Current  

Plate  Dissipation  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  


5500  max 

volts 

1000  max 

ma 

175  max 

ma 

6  max 

watts 

5500"maa; 

volts 

300°mox 

volts 

32 

volts 

Characteristics,  Instantaneous  Value: 

Tube  Voltage  Drop  for  plate  current  of  250  ma  

#  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  horizontal  scanning  cycle.  In  a 
525-line,  30-frame  system,  15  per  cent  of  one  horizontal  scanning  cycle  is  10  microseconds. 
■  The  dc  component  must  not  exceed  900  volts. 
°  The  dc  component  must  not  exceed  100  volts. 


6DQ5 


BEAM  POWER  TUBE 

Glass  octal  type  used  as  horizon- 
tal deflection  amplifier  in  color  televi- 
sion receivers.  Outline  25A,  OUT- 
LINES SECTION.  Tube  requires  oc- 
tal socket  and  may  be  mounted  in  any 
position. 

Heater  Voltage  (ac/dc)  

Heater  Current  

Direct  Interelectrode  Capacitances  (Approx): 

Grid  No.l  to  Plate  

Grid  No.l  to  Cathode,  Heater,  Grid  No.2,  and  Grid  No.3  

Plate  to  Cathode,  Heater,  Grid  No.2,  and  Grid  No.3  

Plate  Resistance  (Approx.)*  

Transconductance*  

Mu-Factor,  Grid  No.2  to  Grid  No.l**  

*  For  plate  volts,  175;  grid-No.2  volts,  125;  grid-No.l  volts,  -25;  plate  ma.,  110;  grid-No.2  ma.,  5. 
**  For  plate  and  grid-No.2  volts,  125;  grid-No.l  volts,  -25. 

AVERAGE  CHARACTERISTICS 


6.3 
2.5 

0.5 
23 
11 
5500 
10500 
3.3 


volts 
amperes 

H 
pf 

ohms 
/xmhos 


300  400 
PLATE  VOLTS 

HORIZONTAL  DEFLECTION  AMPLIFIER 

For  operation  in  a  525-line,  30-frame  system 
Maximum  Ratings,  (Design-Maximum  Values): 

DC  Plate  Voltage  

Peak  Positive-Pulse  Plate  VoLTAGEf  

Peak  Negative-Pulse  Plate  Voltage  

DC  Grid-No.2  (screen-grid)  Voltage  

Peak  Negative-Pulse. Grid-No.  1  (control-grid)  Voltage  

Peak  Cathode  Current  

Average  Cathode  Current  

232 


02CM-9309T 


990  max 
6500  max 
-1100  max 

190  max 
-250  max 
1100  max 

315  max 


volts 
volts 
volts 
volts 
volts 
ma 
ma 


3  .2  max 

watts 

24  max 

watts 

200  max 

volts 

200°max 

volts 

220  max 

Grid-No.2  Input  

Plate  Dissipation  #  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode . 

Heater  positive  with  respect  to  cathode . 
Bulb  Temperature  (At  hottest  point) .... 

Maximum  Circuit  Value: 

Grid-No.  1-Circuit  Resistance: 
For  grid-resistor-bias  operation  

t  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  horizontal  scanning  cycle.  In  a 
525-line,  30-frame  system,  15  per  cent  of  one  horizontal  scanning  cycle  is  10  microseconds. 
#  An  adequate  bias  resistor  or  other  means  is  required  to  protect  the  tube  in  the  absence  of  excitation. 
**  The  dc  component  must  not  exceed  100  volts. 

AVERAGE  CHARACTERISTICS 


0 . 47  max  megohm 


600 
400 

TYPE  60Q5 
t^*%.%  VOLTS 
GRID-N*  1  VOUTSsO 

1 

125 

»oo^ 

250 

hi 

200  a! 

T» 

I 

a 

< 

150  d 

a 

50 

200 

25 

100  ^ 

M 

a 
m 

0 

■-4- 

CC2- 

7l-l 

25 

r 

SOO  400 
PL  ATI  VOLTS 


BEAM  POWER  TUBE 

Glass  octal  types  used  as  horizon- 
tal-deflection-amplifier tubes  in  high- 
efficiency  deflection  circuits  of  tele- 
vision receivers.  Outline  21,  OUT- 
''''      c'a        LINES  SECTION.  Tubes  require 
octal  socket  and  may  be  mounted  in  any  position.  These  types  may  be  supplied 
with  pin  1  omitted.  Type  6DQ6-A  is  used  principally  for  renewal  purposes. 


6DQ6A 
6DQ6B 

Related  types: 
12DQ6A,  12DQ6B, 
17DQ6A,  17DQ6B 


Heater  Voltage  (ac/dc)  

Heater  Current  

Direct  Interelectrode  Capacitances  (Approx.) 

Grid  No.l  to  Plate  

Grid  No.l  to  Cathode,  Heater,  Grid  No.2,  and  Grid  No.3. 

Plate  to  Cathode,  Heater,  Grid  No.2,  and  Grid  No.3  

CLASS  Ai  AMPLIFIER 


6.3 
1.2 

0.5 
15 
7 


Characteristics: 

Plate  Voltage  

Grid-No.2  Voltage  

Grid-No.  1  Voltage  

Plate  Resistance  (Approx.)  

Transconductance  

Plate  Current  

Grid-No.2  Current  

Grid-No.l  Voltage  (Approx.)  for 

grid-No.2  volts=150,  plate  ma=l^ 

plate  volts =250  

plate  volts =5000  


60 
150 
0 


315' 
25' 


6DQ6-A 

250 
150 
-22.5 
20000 
6600 
55 
1.5 


-40 
-100 


60 
150 
0 


345° 
27° 


6DQ6'B 


250 
150 
-22.5 
18000 
7300 
65 
1.8 


-42 
-100 


volts 
amperes 

Pf 
Pf 
pf 


volts 
volts 
volts 
ohms 

ma 
ma 


HORIZONTAL-DEFLECTION  AMPLIFIER 

For  operation  in  a  525-line,  SO-frame  system 
Maximum  Ratings,  (Design-Maximum  Values):  6DQ6-A 

DC  Plate-Supply  Voltage   770  max 

Peak  Positive-Pulse  Plate  Voltage"   6000  max 


6DQ6-B 
770  max 
6500  max 


volts 
volts 


volts 
volts 


233 


RCA  Receiving  Tube  Manual 


Peak  Negative-Pulse  Plate  Voltage.  . .  . . 

DC  Grid-No.2  (screen-grid)  Voltage  

Peak  Negative-Pulse  Grid-No.1  Voltage. 

Peak  Cathode  Current  

Average  Cathode  Current  

Grid-No.2  Input  

Plate  Dissipation*  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode. 

Haater  positive  with  respect  to  cathode .  . 
Bulb  Temperature  (At  hottest  point)  


—1500  max 

—1500  max 

220  max 

220  max 

volts 

-330  max 

-330  max 

volts 

540  max 

610  max 

ma 

155  max 

175  max 

ma 

3 . 6  max 

3 . 6  max 

watts 

18  max 

18  max 

watts 

200  max 

200  max 

volts 

200  °max 

200°max 

volts 

220  max 

220  max 

^'C 

1  max 

1  max 

megohm 

Maximum  Circuit  Values: 

Grid-No. l-Circuit  Resistance  for  grid-resistor-bias  operation . 

"  This  value  can  be  measured  by  a  method  involving  a  recurrent  waveform  such  that  the  maximum 
ratings  of  the  tube  will  not  be  exceeded. 

■  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  horizontal  scanning  cycle.  In  a 
525-line,  30-frame  system,  15  per  cent  of  one  horizontal  scanning  cyjle  is  10  microseconds. 
•  An  adequate  bias  resistor  or  other  means  is  required  to  protect  the  tube  in  the  absence  of  excitation. 
°  The  dc  component  must  not  exceed  100  volts. 

AVERAGE  CHARACTERISTICS 


TYPE 
GRID 

6DC 
}>.3  vc 
-NS2 

i6-B 

LTS 
VOL! 

0 

6DR7 

R*laled  types: 
10DR7,  13DR7 


DUAL  TRIODE 

Miniature  type  containing  high- 
mu  and  low-mu  triodes;  used  as  com- 
bined vertical-deflection-oscillator  and 
vertical-deflection-amplifier  tube  in 
television  receivers.  Outline  8D,  OUT- 
LINES SECTION.  Tube  requires  min- 
iature nine-contact  socket  and  may  be 
operated  in  any  position. 


92CM-I0555T 


Heater  Voltage  (ac/dc)  

Heater  Current    

DiREicT  Intbrblectrodb  Capacitances  (Approx.) : 

Grid  to  Plate  

Grid  to  Cathode  and  Heater  

Plate  to  Cathode  and  Heater  


CLASS  A,  AMPLIFIER 

Characteristics: 

Plate  Voltage  

Grid  Voltage  

Amplification  Factor  

Plate  Resistance  (Approx.)  

Transconductance  

Grid  Voltage  (Approx.)  for  plate  current  of  10  /xa  

Grid  Voltage  (Approx.)  for  plate  current  of  50  /xa.  . 

Plate  Current   

Plate  Current  for  grid  voltage  of  -24  volts.  

234 


6.3 

volts 

0.9 

ampere 

Unit  No.l 

Unit  No.2 

4.5 

8.5 

Pf 

2.2 

5.5 

Pf 

0.34 

1 

pf 

Unit  No.l 

Unit  No.2 

250 

150 

volts 

-3 

-17.5 

volts 

68 

6 

40000 

925 

ohms 

1600 

6500 

Aimhos 

-5.5 

volts 

-44 

volts 

1.4 

35 

ma 

10 

raa 

Technical  Data 


AVERAGE  PLATE  CHARACTERISTICS 
UNIT  Ntl 


TYPI 

6DRT 
6.3  vol 

.TS 

J/ 

/ 

100       ISO      200  250 


300  350 
PLATE  VOLTS 


92CM-99I2T 


VERTICAL-DEFLECTION  OSCILLATOR  AND  AMPLIFIER 

For  operation  in  a  525-line,  30-frame  system 

.        -                 .           .            ,     .  UnitNo.l  UnitNo.2 

Maximum  Ratings,  {Design-Maximum  Values):  Oscillator  Amplifier 

DC  Plate  Voltage   330  waa:  21b  max  volts 

Peak  Positive-Pulse  Plate  Voltage#   -  1500  max  volts 

Peak  Negative-Pulse  Grid  Voltage   -400  max  -250  max  volts 

Peak  Cathode  Current   10  max  lib  max  ma 

Average  Cathode  Current   20  max  50  max  ma 

Plate  Dissipation   1  max  1  max  watts 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  max  200  max  volts 

Heater  positive  with  respect  to  cathode   200^max  200^rnax  volts 

Maximum  Circuit  Value: 

Grid-Circuit  Resistance: 

For  grid-resistor-bias  or  cathode-bias  operation   2.2  max        2.2  max  megohms 

#  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  vertical  scanning  cycle.  In  a  525- 
line,  30-frame  system,  15  per  cent  of  one  vertical  scanning  cycle  is  2.5  milliseconds. 

*  The  dc  component  must  not  exceed  100  volts. 


235 


RCA  Receiving  Tube  Manual 


HIGH-MU  TRIODE 

Nuvistor  type  used  as  grounded- 
cathode,  neutralized  rf  amplifier  in  vhf 
tuners  of  television  and  FM  receivers. 
Because  of  its  cutoff  characteristics, 
the  6DS4  is  used  in  circuits  to  reduce 
cross-modulation  distortion.  Outline  1,  OUTLINES  SEC- 
TION. Tube  requires  nuvistor  socket  and  may  be  operated 
in  any  position. 


6DS4 

Related  type: 
2DS4 


INDEX  =  LARGE  LUG 
e  =  PIN  CUT  OFF 


Heater  Voltage  (ac/dc)  

Heater  Current  

Direct  Interelectrode  Capacitances  (Approx.) : 

Grid  to  Plate  

Grid  to  Cathode,  Heater,  and  Shell  

Plate  to  Cathode,  Heater,  and  Shell  

Plate  to  Cathode  

Heater  to  Cathode  


6.3 
0.135 

0.92 
4.3 
1.8 

0.18 
1.6 


volts 
ampere 


CLASS  Ai  AMPLIFIER 


Characteristics: 

Plate  Supply  Voltage  

Grid  Supply  Voltage  

Cathode-Bias  Resistor  

Amplification  Factor  

Plate  Resistance  (Approx.)  

Transconductance  

Plate  Current  

Grid  Voltage  (Approx.)  for  plate  current  of  100  /ta . 
Grid  Voltage  (Approx.)  for  plate  current  of  10  Ma  •  • 


Maximum  Ratings,  {Design-Maximum  Values): 

Plate  Supply  Voltage  

Plate  Voltage  

Grid  Voltage,  Negative-bias  value  

Grid  Voltage,  Peak  positive  value  

Plate  Dissipation  

Cathode  Current  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode, . . 

Heater  positive  with  respect  to  cathode .  .  , 


Typical  Operation: 

Plate  Voltage  

Grid  Supply  Voltage  

Grid  Resistor  

Amplification  Factor  

Plate  Resistance  (Approx.) . 

Transconductance  

Plate  Current  


AVERAGE  PLATE  CHARACTERISTICS 


110 

volts 

0 

volts 

130 

ohms 

63 

7000 

ohms 

9000 

/Ltmhos 

6.5 

ma 

-5 

volts 

-6.8 

volts 

300°maa; 

volts 

135  max 

volts 

55  max 

volts 

0  max 

volts 

1 . 5  max 

watt 

15  max 

ma 

100  max 

volts 

100  max 

volts 

70 

volts 

0 

volts 

47000 
68 
5440 
12500 
7 


ohms 

ohms 
/umhos 
ma 


236 


Maximum  Circuit  Values: 

Grid-Circuit  Resistance:' 

For  fixed-bias  operation   0.5  max  megohm 

For  cathode-bias  operation   2.2  max  megohms 

°  A  plate  supply  voltage  of  300  volts  may  be  used  provided  a  sufficiently  large  resistor  is  used  in  the  plate 

circuit  to  limit  the  plate  dissipation  to  1 . 5  watts  under  any  condition  of  operation. 

■  For  operation  at  metal-shell  temperatures  up  to  125°C. 


BEAM  POWER  TUBE 

Miniature  type  used  in  the  audio 
output  stages  of  television  and  radio 
receivers.  Outline  7C,  OUTLINES 
SECTION.  Tube  requires  miniature 
seven -contact  socket  and  may  be 
mounted  in  any  position. 

Heater  Voltage  (ac/dc)  

Heater  Current  

Direct  Interelectrode  Capacitances  (Approx.): 

Grid  No.l  to  Plate  

Grid  No.l  to  Cathode,  Heater,  Grid  No.2,  and  Grid  No.3  

Plate  to  Cathode,  Heater,  Grid  No.2,  and  Grid  No.3  


6DS5 


CLASS  Ai  AMPLIFIER 
Maximum  Ratings,  (Design-Maximum Values): 

Plate  Voltage  

Grid-No.2  (screen-grid)  Voltage  

Grid-No.  1  (control-grid)  Voltage,  Positive  bias  value  

Plate  Dissipation  

Grid-No.2  Input  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  

Bulb  Temperature  (At  hottest  point)  


6.3 
0.8 

0.19 
9.5 
6.3 


275  max 
275  max 
0  max 
9  max 
2 . 2  max 

200  max 
200*wax 
250  max 


volts 
ampere 

Pf 
Pf 


volts 
volts 
volts 
watts 
watts 

volts 
volts 

°C 


Typical  Operation  and  Characteristics: 

Plate  Supply  Voltage  

Grid-No.2  Supply  Voltage  

Grid-No.  1  Voltage  

Cathode-Bias  Resistor  

Peak  AF  Grid-No.  1  Voltage  

Zero-Signal  Plate  Current  

Maximum-Signal  Plate  Current  

Zero-Signal  Grid-No.2  Current  

Maximum-Signal  Grid-No.2  Current  .  ,  .  . 

Plate  Resistance  (Approx.)  

Transconductance  

Load  Resistance  

Total  Harmonic  Distortion  

Maximum-Signal  Power  Output  


Cathode-Bias 

Fixed-Bias 

Operation 

Operation 

200 

250 

200 

250 

volts 

200 

200 

200 

200 

volts 

-7.5 

-8.5 

volts 

180 

270 

ohms 

7.5 

9.2 

7.5 

8.5 

volts 

34.5 

27 

35 

29 

ma 

32.5 

25 

36 

32 

ma 

3.5 

3 

3 

3 

ma 

9 

9 

9 

10 

ma 

28000 

28000 

28000 

28000 

ohms 

6000 

5800 

6000 

5800 

/imhos 

6000 

8000 

6000 

8000 

ohms 

10 

10 

9 

10 

per  cent 

2.8 

3.6 

3 

3.8 

watts 

AVERAGE  CHARACTERISTICS 


TYPE  60S5 
Ef»  6.3  VOLTS  I 
GRIO-NS  2  VOLTS « 


RCA  Receiving  Tube  Manual 


Maximum  Circuit  Values: 

Grid-No.  1-Circuit  Resistance: 

For  fixed-bias  operation   0.1  max  megohm 

For  cathode-bias  operation   1.0  max  megohm 

*■  The  dc  component  must  not  exceed  100  volts. 

P 

HALF-WAVE  VACUUM  RECTIFIER  ,  — ^ 

(3}( 

-  Glass  octal  type  used  as  damper 

ODT4         tube  in  horizontal-deflection  circuits 

of  color  television  receivers.  Outline     ic^^v. '^^^^[/Mi 
14F,  OUTLINES  SECTION.  Tube 
requires  octal  socket  and  may  be 
mounted  in  any  position.  Socket  terminals  1,  2,  4,  and  6  should  not  be  used  as 
tie  points.  Heater  volts  (ac/dc),  6.3;  amperes,  1.2. 

DAMPER  SERVICE 

For  operation  in  a  525-line,  30-frame  system 
Maximum  Ratings,  (Design-Maximum  Values) 

Peak  Inverse  Plate  Voltage*   5500  max  volts 

Peak  Plate  Current   1450  max  ma 

DC  Plate  Current   235  max  ma 

Plate  Dissipation   7.5  max  watts 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   5500"wax  volts 

Heater  positive  with  respect  to  cathode   300^wax  volts 

Characteristics,  Instantaneous  Value: 

Tube  Voltage  Drop  for  plate  current  of  350  ma   28  volts 

•  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  horizontal  scanning  cycle.  In  a 
525-line,  30-frame  system,  15  per  cent  of  one  horizontal  scanning  cycle  is  10  microseconds. 

■  The  dc  component  must  not  exceed  900  volts. 

*  The  dc  component  must  not  exceed  100  volts. 


6DT5 

Related  type: 
12DT5 


BEAM  POWER  TUBE 

Miniature  type  used  as  a  vertical- 
deflection-amplifier  tube  in  television 
receivers  employing  110-degree  pic- 
ture-tube systems.  Outline  8D,  OUT- 
LIN  ES  SE  CT  ION .  Tube  requires  min- 
iature nine-contact  socket  and  may 
be  operated  in  any  position. 

Heater  Voltage  (ac/dc)   6.3  volts 

Heater  Current   1.2  amperes 

Transconductance*   6200  Mmhcs 

*  For  plate  and  grid-No.2  volts,  250;  grid-No. 1  volts,  -16.5;  plate  ma.,  44;  grid-No.2  ma.,  1.5. 

VERTICAL-DEFLECTION  AMPLIFIER 

For  operation  in  a  525-line,  30-frame  system 
Maximum  Ratings,  (Design- Maximum  Values): 

DC  Plate  Voltage  

Peak  Positive-Pulse  Plate  Voltage#  

Grid-No.2  (screen-grid)  Voltage  

Peak  Negative-Pui-se  Grid-No.I  (control-grid)  Voltage  

Peak  Cathode  Current  

Average  Cathode  Current  

Plate  Dissipation  

Grid-No.2  Input  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  

Maximum  Circuit  Values: 

Grid-No. 1-Circuit  Resistance: 

For  fixed-bias  operation  

For  cathode-bias  operation  

*  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  vertical  scanning  cycle, 
line,  30-frame  system,  15  per  cent  of  one  vertical  scanning  cycle  is  2.5  milliseconds. 

*  The  dc  component  must  not  exceed  100  volts. 

238 


315  max 
2200  max 
285  max 
-250  max 
190  max 
55  max 
9  max 
2  max 

200  max 
200*max 


0 . 5  max 
1  max 


volts 
volts 
volts 
volts 
ma 
ma 
watts 
watts 

volts 
volts 


megohm 
megohm 

In  a  525- 


SHARP-CUTOFF  PENTODE 

Miniature  type  used  as  FM  de- 
tector in  television  receivers.  Outline 
7B,  OUTLINES  SECTION.  Tube  re- 
quires miniature  seven-contact  socket 
and  may  be  mounted  in  any  position. 


6DT6 

6DT6A 


Related  types: 
3DT6A,  4DT6A 


Type  6DT6  is  a  DISCONTINUED  type  listed  for  reference  only. 


Heater  Voltage  (ac/dc)  

Heater  Current  

Direct  Interelectrode  Capacitances  (Approx.)* 

Grid  No.l  to  Plate  

Grid  No.l  to  Cathode,  Heater,  Grid  No.2,  Grid  No.3,  and  Internal  Shield 

Grid  No.3  to  Plate  

Grid  No.l  to  Grid  No.3  

Grid  No.3  to  Cathode,  Heater,  Grid  No.l,  Grid  No.2,  and  Internal  Shield 
♦External  shield  connected  to  cathode.  fFor  type  6DT6-A,  value  is  1.7  nni. 
Characteristics:                              CLASS  Ai  AMPLIFIER  6DT6'A 
Plate  Supply  Voltage  150 

Grid  No.3  (Suppressor  Grid)  Connected  to  cathode  at  socket 

Grid-No.2  (Screen-Grid)  Supply  Voltage  100        ^"'^  *' 

Cathode-Bias  Resistor  560 

Plate  Resistance  (Approx.)  0.15 

Transconductance,  Grid  No.l  to  Plate  1350 

Transconductance,  Grid  No.3  to  Plate  515 

Plate  Current  1,55 

Grid-No.2  Current  1.8 

Grid-No.l  Voltage  (Approx.)  for  plate  current  of  10  i*a   -5.2 

Grid-No.3  Voltage  (Approx.)  for  plate  current  of  10  /la  -4.2 

FM  DETECTOR 

Maximum  Ratings,  (Design-Maximum  Values): 

Plate  Voltage  

Grid-No.3  Voltage  

Grid-No.2  Supply  Voltage  

Grid-No.2  Voltage  

Grid-No.  1  (control-grid)  Voltage,  Positive-bias  value  

Plate  Dissipation  

Grid-No.2  Input: 

For  grid-No.2  voltages  up  to  165  volts  ;  

For  grid-No.2  voltages  between  165  and  330  volts  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  

Maximum  Circuit  Values: 

Grid-No.  1-Circuit  Resistance: 

For  fixed-bias  operation  

For  cathode-bias  operation  

■  The  dc  component  must  not  exceed  100  volts. 

AVERAGE  PLATE  CHARACTERISTICS 


6.3 

volts 

0.3 

ampere 

0.02 

5.8 

pf 

1.4t 

Pf 

0.1 

pf 

6.1 

pf 

6DT6 

150 

volts 

d  to  cathode  at  socket 

100 

volts 

560 

ohms 

0.15 

megohm 

800 

/imhos 

515 

Mmhos 

1.1 

ma 

2.1 

ma 

-4.5 

volts 

-3.5 

volts 

330  max 

volts 

28  max 

volts 

330  max 

volts 

See  curve  page  70 
0  max  volts 
1 . 7  max  watts 

1 . 1  max  watts 
See  curve  page  70 


200  max 
200'max 


0 . 25  max 
0 . 5  max 


volts 
volts 


megohm 
megohm 


r 

3* 

TYPE  6DT6-A  ' 

E^«6.3  VOLTS 

GRID  No.3  CONNECTED  TO 

\ 

C 

GRID 

ATHODE 
-No.2  V 

AT  so 
rOLTS«l 

:ket. 

00 

-4 

-1 

-2 

-3 

300  400 
PLATE  VOLTS 


239 


RCA  Receiving  Tube  Manual 


AVERAGE  CHARACTERISTICS 


»2CM-M2STt 


6DT8 

Related  type: 
12DT8 


HIGH-MU  TWIN  TRIODE  ^  /vaw;t. 

Miniature  type  used  in  a  wide 
variety  of  applications  in  radio  and 
television  receivers.  Especially  useful 
in  push-pull  rf  amplifiers  or  as  fre- 
quency  converter  in  FM  tuners.  Outline  8B,  OUTLINES  SECTION.  Tube  re- 
quires miniature  nine-contact  socket  and  may  be  mounted  in  any  position.  Heater 
volts  (ac/dc),  6.3;  amperes,  0.3.  Peak  heater-cathode  volts:  heater  negative  with 
respect  to  cathode,  200  max;  heater  positive  with  respect  to  cathode,  200  max;  (the 
dc  component  must  not  exceed  100  volts).  Except  for  heater  and  heater-cathode 
ratings,  interelectrode  capacitances,  and  basing  arrangement,  this  type  is  identical 
with  miniature  type  12AT7. 

Direct  Interelectrode  Gapacitances  (Approx.,  Each  Unit  Except  as  Noted): 

Grid  to  Plate  

Grid  to  Cathode,  Heater,  and  Internal  Shield  

Plate  to  Cathode,  Heater,  and  Internal  Shield  

Heater  to  Cathode  

Cathode  to  Grid,  Heater,  and  Internal  Shield  (Unit  No.2)  

Plate  to  Grid,  Heater,  and  Internal  Shield  (Unit  No.2)  

*  With  external  shield  connected  to  cathode  of  unit  under  test. 

•  With  external  shield  connected  to  ground, 
t  With  external  shield  connected  to  grid  of  unit  under  test. 


MEDIUM-MU  TRIODE 

Nuvistor  type  used  at  frequencies 
MfWMM  up  to  1000  megacycles  in  uhf  oscillator 

OD  V4         stages  of  television  receivers.  Outline 
p.:  1,  OUTLINES  SECTION.  Tube  re- 

2DV4  quires  nuvistor  socket  and  may  be 

mounted  in  any  position. 


INDEX*LAR6E  LUd 
••SHORT  PINi  IC-00  NOT  USE 


Heater  Voltage  (ac  /dc)  

Heater  Current  

Direct  Interelectrode  Capacitances  (Approx.): 

Grid  to  Plate  

Grid  to  Cathode,  Heater,  and  Shell  

PUte  to  Cathode,  Heater,  and  Shell.  .  . 

Plate  to  Cathode  

Heater  to  Cathode  

Grid  to  Cathode  


6  3 
0.135 

1.8 
4.4 
19 
0.25 
1.4 
3.7 


volts 
ampere 

^\ 


240 


CLASS  Ai  AMPLIFIER 


Maximum  Ratings,  (Design-Maximum  Values): 

Plate  Supply  Voltage  

Plate  Voltage  

Grid  Voltage: 

Negative-bias  value  

Peak  positive  value  

Plate  Dissipation  

Cathode  Current  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode. . . 

Heater  positive  with  respect  to  cathode .  .  . 


Characteristics: 

Plate  Supply  Voltage  

Cathode-Bias  Resistor  

Amplification  Factor  

Plate  Resistance  (Approx.)  

Transconductance  

Grid  Voltage  (Approx.)  for  plate  current  of  10  /xa . 
Plate  Current  


Typical  Operation  as  Oscillator  at  950  Mc: 

Plate  Voltage  

Grid  Voltage  

Grid  Resistor  

Plate  Current  

Grid  Current  


Maximum  Circuit  Values: 

Grid-Circuit  Resistance:** 

For  fixed-bias  operatioli  

For  cathode-bias  operation  

**  For  operation  at  metal-shell  temperatures  up  to  135  °C. 


AVERAGE  PLATE  CHARACTERISTICS 


300  max 
125  max 

-55  max 
2  max 
1  max 
15  max 

100  max 
100  max 


75 
100 
35 
3100 
11500 
-7 
10.5 


60 
-2 
5600 
8 

350 


0 . 1  max 
0.2  max 


volts 
volts 

volts 
volts 
watt 
ma 

volts 
volts 


volts 
ohms 

ohms 
/imhos 
volts 


volts 
volts 
ohms 
ma 
;ta 


megohm 
megohm 


120        140  160 
PLATE  VOLTS 


240  260 

92CM-II78IT 


HALF-WAVE  VACUUM  RECTIFIER 

Novar  type  used  as  damper  tube         A^WWki  A 
in  horizontal-deflection  circuits  of  col-         ODW 4 
or  and  black-and-white  television  re- 
ceivers. Outline  lOD,  OUTLINES 
SECTION.  Tube  requires  novar  nine- 
contact  socket  and  may  be  mounted  in  any  position.  Socket  terminals  1,  3,  6,  and  8 
should  not  be  used  as  tie  points;  it  is  recommended  that  socket  clips  for  these  pins 
be  removed  to  reduce  the  possibility  of  arc-over  and  to  minimize  leakage.  It  is 
especially  important  that  this  tube,  like  other  power-handling  tubes,  be  adequately 
ventilated. 


241 


RCA  Receiving  Tube  Manual 


Heater  Voltage  (ac  /dc)  

Heater  Current  

Direct  Interelectrode  Capacitances  (Approx.) : 

Plate  to  Cathode  and  Heater  

Cathode  to  Plate  and  Heater  

Heater  to  Cathode  


6.3 
1.2 


6.5 
9 

2.8 


volts 
amperes 

pf 


DAMPER  SERVICE 

For  operation  in  a  525-linef  30-frame  system 
Maximum  Ratings,  (Design-Maximum  Values): 

Peak  Inverse  Plate  Voltage®   5000  max  volts 

Peak  Plate  Current   1300  woa?  ma 

DC  Plate  Current       250  max  ma 

Plate  Dissipation    8.5  max  watts 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   5000  "maa:  volts 

Heater  positive  with  respect  to  cathode   300 •wax  volts 

Characteristics,  Instantaneous  Value: 

Tube  Voltage  Drop  for  plate  current  of  350  ma   25  volts 

°  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  horizontal  scanning  cycle.  In  a 
525-line,  30-frame  system,  15  per  cent  of  one  horizontal  scanning  cycle  is  10  microseconds. 
■  The  dc  component  must  not  exceed  900  volts. 
•  The  dc  component  must  not  exceed  100  volts. 


BEAM  POWER  TUBE 


6DW5 


Miniature  ctype  used  in  vertical 
deflection  amplifier  service  in  television 
receivers  employing  110-degree  deflec- 
tion systems.  Outline  8E,  OUTLINES 
SECTION.  Tube  requires  miniature 
nine-contact  socket  and  may  be  operated  in  any  position.  Heater  volts  (ac/dc), 
6.3;  amperes,  1.2. 

CLASS  Ai  AMPLIFIER 

Characteristics: 

Plate  Voltage   60  200 

Grid-No.2  Voltage   150  150 

Grid-No.l  Voltage   0  -22.5 

Amplification  Factor   -  - 

Plate  Resistance  (Approx.)   -  15000 

Transconductance   -  5500 

Plate  Current   260"  55 

Grid-No.2  Current   20"  2 

Grid-No.l  Voltage  (Approx.)  for  plate  current  of  0 . 1  ma     -  -55 


Pentode 
Connection 


Triode 
Connection^ 
150 

-22.5 
4.3 


volts 
volts 
volts 

ohms 
/xmhos 
ma 
ma 
volts 


VERTICAL  DEFLECTION  AMPLIFIER 

For  operation  in  a  525-line,  30-frame  system* 
Maximum  Ratings,  {Design-Maximum  Values): 

DC  Plate  Voltage   330  wax  volts 

Peak  Positive-Pulse  Plate  Voltage*   2200  max  volts 

DC  Grid-No.2  (screen-grid)  Voltage   220  max  volts 

Peak  Negative-Pulse  Grid-No.1  (control-grid)  Voltage   -250  max  volts 

Peak  Cathode  Current   225  max  ma 

Average  Cathode  Current   65  max  ma 

Plate  Dissipation   11  max  watts 

Grid-No.2  Input   2.5  max  watts 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  max  volts 

Heater  positive  with  respect  to  cathode   200*wax  volts 

Maximum  Circuit  Values: 

Grid-No.l  Circuit  Resistance: 

For  cathode-bias  operation   2.2  max  megohms 

°  With  grid  No.2  connected  to  plate. 

■  This  value  can  be  measured  by  a  method  involving  a  recurrent  waveform  such  that  the  maximum 
ratings  of  the  tube  will  not  be  exceeded. 

•  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  vertical  scanning  cycle.  In  a 
525'-line,  30-frame  system,  15  per  cent  of  one  vertical  scanning  cycle  is  2 . 5  milliseconds. 

♦  The  dc  component  must  not  exceed  100  volts. 

242 


H     ^  HIGH-MU  TRIODE— 

Q^^®**  Kp      SHARP-CUTOFF  PENTODE 

^(IVa--.  ™^0^is*          Miniature  type  used  in  television-  X.  1%  V  O 

JSp:;  ™gLL       receiver  applications.  The  triode  unit  ODJvO 

pISAML/V---^^  ®ip    is  used  as  a  sync-separator,  sync-am-  Related  type: 

Qj^  0          plifier,  keyed-age,  or  noise-suppressor  lODXS 

tube.  The  pentode  unit  is  used  as  a 

video-output  tube.  Outline  8D,  OUTLINES  SECTION.  Tube  requires  miniature 
nine-contact  socket  and  may  be  mounted  in  any  position.  Heater  volts  (ac/dc), 
6.3;  amperes,  0.72. 

CLASS  Ai  AMPLIFIER 

Triode  Pentode 

hKaximum  Ratings,  (Design-Center  Values) :                                     Unit  Unit 

Plate  Supply  Voltage                                                            550  max  550  max  volts 

Peak  Plate  Voltage,  with  maximum  plate  current  of  0.1  ma°       600  max  -  volts 

Plate  Voltage.                                                                    300  max  300  max  volts 

Grid-No.2  (screen-grid)  Supply  Voltage                                   -  550  max  volts 

Grid-No.2  Voltage                                                                    -  300  max  volts 

Cathode  Current                                                                  12  max  40  max  ma 

Grid-No.2  Input                                                                     -  1.7  max  watts 

Plate  Dissipation                                                                   1  max  4  max  watts 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode                                  200  max  200  max  volts 

Heater  positive  with  respect  to  cathode                                   200  max  200  max  volts 

Triode 

Characteristics:  Unit  Pentode  Unit 

Plate  Voltage                                                       200         170         200  220  volts 

Grid-No.2  Voltage                                                    -         170         200  220  volts 

Grid-No.l  Voltage                                               -1.7       -2.1        -2.9  -3.4  volts 

Amplification  Factor                                               65            -            -  - 

M/Lt-Factor,  Grid-No.2  to  Grid-No.l                            -           36           36  36 

Plate  Resistance  (Approx.)                                          -         0.1        0.13  0.15  megohm 

Transconductance .  .                                             4000      11000      10400  10000  /zmhos 

Plate  Current                                                          3           18           18  18  ma 

Grid-No.2  Current                                                    -            3            3  3  ma 

Typical  Operation  of  Pentode  Unit  as  Video  Output  Tube: 

Plate  Supply  Voltage                                                     170            200  220  volts 

Series  Plate  Resistor                                                      3000           3000  3000  ohms 

Grid-No.2  Voltage                                                         170            200  220  volts 

Grid-No.l  Voltage                                                            -2           -2.8  -3.3  volts 

Transconductance                                                      10400          10000  9700  Mmhos 

Plate  Current                                                                 18              18  18  ma 

Grid-No.2  Current                                                        3.2            3.1  3.1  ma 

Maximum  Circuit  Values:                                                               Triode  Pentode 

Grid-No.l-Circuit  Resistance:                                                          ^^^^  ^^^^ 

Fcr  fixed-bias  operation                                                            1  max  1  max  megohm 

For  cathode-bias  operation                                                          3  max  2  max  megohms 

°  With  maximum  duty  factor  of  0.18  and  maximum  pulse  duration  of  18  microseconds. 


MEDIUM-MU  TRIODE 

Miniature  type  used  as  a  local- 
oscillator  tube  in  uhf  television  re- 
ceivers covering  the  frequency  range 
from  470  to  890  megacycles.  Outline 
7A,  OUTLINES  SECTION.  Tube  re- 
quires miniature  seven-contact  socket  and  may  be  mounted  in  any  position.  For 
curve  of  average  plate  characteristics,  refer  to  type  6AF4-A. 


6DZ4 

Related  types: 
2DZ4,  3DZ4 


Heater  Voltage  (ac  /do)  

Heater  Current  

Direct  Interelectrode  Capacitances  (Approx.) :° 

Grid  to  Plate  

Grid  to  Cathode  and  Heater  

Plate  to  Cathode  and  Heater  

°  With  external  shield  connected  to  cathode. 


6.3 
0.225 

1.8 
2  2 
13 


volts 
ampere 

Pf 
Pf 
pf 


24.3 


RCA  Receiving  Tube  Manual 


CLASS  Ai  AMPLIFIER 

Characteristics: 

Plate  Supply  Voltage   80  volts 

Plate  Resistor   2700  ohms 

Amplification  Factor   14 

Plate  Resistance  (Approx.) .   2000  ohms 

Transconduetance   6700  /nmhos 

Plate  Current   15  ma 

Grid  Voltage  (Approx.)  for  plate  current  of  20  /na   -11  volts 

UHF  OSCILLATOR 
Maximum  Ratings,  {Design-Maximum  Values): 

Plate  Voltage   135  max  volts 

Grid  Voltage,  Negative-bias  value   -50  max  volts 

Grid  Current   2  max  ma 

Cathode  Current   20  max  ma 

Plate  Dissipation   2.3  max  watts 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   50  max  volts 

Heater  positive  with  respect  to  cathode   50"waa;  volts 

Typical  Operation  as  Oscillator  at  1000  Mc: 

Plate  Supply  Voltage   135  volts 

Plate-Circuit  Resistance   2700  ohms 

Grid  Resistor   10000  ohms 

Plate  Current   15.5  ma 

Grid  Current  (Approx.)   800  ^a 

Maximum  Circuit  Values: 

Grid-Circuit  Resistance: 

For  fixed-bias  operation   Not  recommended 

For  cathode-bias  operation   0.5  max  megohm 

■  The  dc  component  must  not  exceed  25  volts. 

G2  Gip, 

TWIN  POWER  PENTODE 

JLT\yT                Glass  octal  type  used  as  power  (  '-rEFEEEJll 
OU^/           amplifier  tube  in  high-fidelity  audio  rK^^~^~^lJ(^ 
equipment.  Outline  19A,  OUTLINES  h^^^^^V^^-^^ 

SECTION.  Tube  requires  octal  socket  GT^^ 

and  may  be  operated  in  any  position.  ^'pz 
It  is  especially  important  that  this  tube,  like  other  power-handling  tubes,  be  ad- 
equately ventilated.  Heater  voltage  (ac/dc),  6.3;  amperes,  1.52. 

CLASS  Ai  AMPLIFIER 

Characteristics,  {Each  Unit): 

Plate  Voltage   250  volts 

Grid-No.2  (Screen-Grid)  Voltage   250  volts 

Grid-No.l  (Control-Grid)  Voltage   -7.3  volts 

Plate  Resistance  (Approx.)   38000  ohms 

Transconduetance   11300  /xmhos 

Plate  Current   48  ma 

Grid-No.2  Current   5.5  ma 

PUSH-PULL  CLASS  ABi  AMPLIFIER 
Maximum  Ratings,  {Design-Maximum  Values^  Per  Tube): 

Plate  Voltage   440  max  volts 

Grid-No.2  Voltage   300  maa;  volts 

Grid-No.2  Input  (Total)     4  max  watts 

Plate  Dissipation   13.2  max  watts 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  max  volts 

Heater  positive  with  respect  to  cathode   200°max  volts 

Fixed  Cathode 

Typical  Operation,  (Per  Tw66):                                                  Bias  Bias 

Plate  Voltage                                                                             400  300  volts 

Grid-No.2  Voltage                                                                       250  250  volts 

Grid-No.l  Voltage                                                                        -11  -  volts 

Cathode-Bias  Resistor                                                                   -  120  ohms 

Peak  AF  Grid-No.l-to-Grid-No.l  Voltage                                        22  22  volts 

244 


Technical  Data 


Zero-Signal  Plate  Current   40  66  ma 

Maximum-Signal  Plate  Current   100  80  ma 

Zero-Signal  Grid-No.2  Current   4  7  ma 

Maximum-Signal  Grid-No.2  Current   13  15  ma 

Effective  Load  Resistance  (Plate-to-Plate)   9000  9000  ohms 

Total  Harmonic  Distortion   2.5  3.5  per  cent 

Maximum-Signal  Power  Output   18  12  watts 

Maximum  Circuit  Values,  {Each  Unit): 

Grid-No.l-Circuit  Resistance   0 .21  max  megohm 

°  The  dc  component  must  not  exceed  100  volts. 

(3l^4j  ELECTRON-RAY  TUBE 

p^™^-  "S-HCs>  Glass  type  used  to  indicate  visu-  ^  C  C 

'T^^'l^      ally  by  means  of  a  fluorescent  target  Oc5 
the  effects  of  a  change  in  a  controlling  Related  type: 

\  • )      C  y         voltage.  It  is  used  as  a  convenient  2E5 
"         means  of  indicating  accurate  radio- 
receiver  tuning.  Maximum  dimensions:  over-all  length,  4-3/16  inches;  seated  height, 
3-9/16  inches;  diameter,  1-3/16  inches.  Tube  requires  six-contact  socket.  Heater 
volts  (ac/dc),  6.3;  amperes,  0.3.  For  additional  considerations,  refer  to  Tuning  Indi- 
cationwitkElectron-Ray  TuhesmELF.CTR01^TVBEAFFhlCATI0^S  SECTION. 

TUNING  INDICATOR 
Maximum  and  Minimum  Ratings/  {Design-Center  Values): 

Plate-Supply  Voltage   250  waa;  volts 

Target  Voltage   (250  max  volts 

( 125  win  volts 

Typical  Operation: 

Plate  and  Target  Supply  Voltage   200  250  volts 

Series  Triode-Plate  Resistor   1  1  megohm 

Target  Current*!   3  4  ma 

Triode-Plate  Current*   0.19  0.24  ma 

Triode-Grid  Voltage  (Approx.): 

For  shadow  angle  of  0°   -6.5  -8.0  volts 

For  shadow  angle  of  90°   0  0  volts 

*  For  zero  triode-grid  voltage.      t  Subject  to  wide  variations. 


6E6 


TWIN  POWER  TRIODE 

Glass  type  used  as  class  Ai  amplifier  in 
either  push-pull  or  parallel  circuits.  Outline  27, 
OUTLINES  SECTION.  Heater  volts  (ac/dcj , 
6.3;  amperes,  0.6.  With  plate  volts  of  250  and 
grid  volts  of  -27.5,  characteristics  for  each  unit 
are:  plate  ma.,  18;  plate  resistance,  3500  ohms; 
transconductance,  1700  /umhos;  amplification 
factor,  6.  With  plate-to-plate  load  resistance 
of  14000  ohms,  output  for  two  tubes  is  1.6  watts.  This  is  a  DISCONTINUED  type  listed  for  ref- 
erence only. 

REMOTE-CUTOFF  PENTODE 

Glass  type  used  in  rf  and  if  stages  of  radio 
receivers  employing  avc.  Outline  24A,  OUT- 
LINES SECTION.  Except  for  interelectrode 
capacitances,  this  type  is  identical  electrically 
with  type  6U7-G.  Heater  volts  (ac/dc),  6.3; 
amperes,  0.3.  This  is  a  DISCONTINUED  type 
listed  for  reference  only. 

SHARP-CUTOFF  TETRODE 

Miniature  type  used  as  rf  ampli- 
fier in  vhf  tuners  of  television  receivers. 
Outline  7B,  OUTLINES  SECTION. 
Tube  requires  miniature  seven-contact 
socket  and  may  be  operated  in  any 
position. 


Heater  Voltage  (ac/dc)  . 
Heater  Current  


6E7 


6EA5 

Related  type: 
3EA5 


6.3 
0.2 


volts 
ampere 

245 


RCA  Receiving  Tube  Manual 


Direct  Interelectrodb  Capacitances: 

Grid  No.l  to  Plate  

Grid  No.l  to  Cathode,  Heater,  Grid  No.2,  and  Internal  Shield .  . 

Plate  to  Cathode,  Heater,  Grid  No.2,  and  Internal  Shield  

**  With  external  shield  connected  to  cathode. 


Without 
External 
Shield 
0 . 06  max 
3.8 
2.3 


With 
External 

Shield" 
0.05  max 
4.5 
3 


Pf 
Pf 
pf 


CLASS  Ai  AMPLIFIER 


Maximum  Ratings,  (Design-Maximum  Values): 

Plate  Voltage   250  max  volts 

Grid-No.2  (screen-grid)  Voltage   150  max  volts 

Grid-No.  1  (control-grid)  Voltage,  Positive-bias  value   0  max  volts 

Cathode  Current   20  max  ma 

Grid-No.2  Input   0.5  maa;  watt 

Plate  Dissipation   S. 25  max  watts 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  max  volts 

Heater  positive  with  respect  to  cathode   200  "waa;  volts 

Characteristics: 

Plate  Voltage   250  volts 

Grid-No.2  Voltage   140  volts 

Grid-No.l  Voltage   -1  volt 

Plate  Resistance  (Approx.)   0.15  megohm 

Transconductance   8000  /tmhos 

Plate  Current   10  ma 

Grid-No.2  Current   0.95  ma 

Grid-No.l  Voltage  (Approx.)  for  transconductance  of  100  /xmhos  or  less.  ...  -6  volts 


■  The  dc  component  must  not  exceed  100  volts. 


DUAL  TRIODE 

Glass  octal  type  containing  high- 
£^  C  A  7  triode  and  high-perveance,  low-mu 

triode  in  same  envelope.  Used  as  a 
combined  vertical  deflection  oscillator 
and  vertical  deflection  amplifier  in  tele- 
vision receivers.  Outline  14B,  OUTLINES  SECTION.  Tube  requires  octal  socket 
and  may  be  operated  in  any  position.  Heater  volts  (ac/dc),  6.3;  amperes,  1.05. 


Characteristics:                                CLASS  Ai  AMPLIFIER  Unit  No.l  Unit  No.2 

Plate  Voltage   250  60  175 

Grid  Voltage   -3  0  -25 

Amplification  Factor   66  -  5.5 

Plate  Resistance  (Approx.)   30000  -  920 

Transconductance   2200  -  6000 

Grid  Voltage  (Approx.) : 

For  plate  current  of  20    -5.3  -  - 

,For  plate  current  of  200  /na   -  -  -45 

Plate  current   2  100*  40 


volts 
volts 

ohms 
/umhos 

volts 
volts 
ma 


VERTICAL-DEFLECTION  OSCILLATOR  AND  AMPLIFIER 

For  operation  in  a  525-line,  30-frame  system 

Unit  No.l  Unit  No.2 

Maximum  Ratings,  (Design-Maximum  Values):                               Oscillator  Amplifier 

be  Plate  Voltage                                                                 350  max  550  max 

Peak  Positive-Pulse  Plate  Voltage®                                         -  1500  max 

Peak  Negative-Pulse  Grid  Voltage                                      -400  max  -250  max 

Peak  Cathode  Current                                                           -  max  175  max 

Average  Cathode  Current                                                      -  max  50  max 

Plate  Dissipation                                                                     1  max  10  max 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode                                   200  max  200  max 

Heater  positive  with  respect  to  cathode                                   200"rnax  200"max 

Maximum  Circuit  Values: 

Grid-Circuit  Resistance: 

For  grid-resistor-bias  operation                                                    1  max  1  max 

For  cathode-bias  operation                                                      2.2  max  2 . 2  max 

°  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  vertical  scanning  cycle. 

line,  30-frame  system,  1 5  per  cent  of  one  vertical  scanning  cycle  is  2 .  5  milliseconds. 

■  The  dc  component  must  not  exceed  100  volts. 

246 


volts 
volts 
volts 
ma 
ma 
watts 

volts 
volts 


megohm 
megohms 
In  a  525- 


Technical  Data 


H    A     pp  MEDIUM-MU  TRIODE- 

SHARP-CUTOFF  PENTODE 

^QC— -r  r-.  vZ)  's        Miniature  type  used  as  combined  6EA8 

oscillator  and  mixer  in  television  re-  Related  typet: 

'^\p^^y\y^  ^r^^T    ceivers  utilizing  an  intermediate  fre-  seas,  19EA8 

ClT  ^  quency  in  the  order  of  40  megacycles 

per  second.  Outline  8B,  OUTLINES 
SECTION.  Tube  requires  miniature  nine-contact  socket  and  may  be  mounted  in 
any  position. 

Heater  Voltage  (ac/dc)   6,3  volts 

Heater  Current   0.45  ampere 

Heater  Warm-up  Time  (Average)   11  seconds 

Without  With 

Direct  Interelectrode  Capacitances:                                  External  External 

Triode  Unit:                                                                           Shield  Shield° 

Grid  to  Plate                                                                         1.7  1.7  pf 

Grid  to  Cathode,  Heater,  Pentode  Cathode, 

Pentode  Grid  No.3,  and  Internal  Shield                                   3  3.2  pf 

Plate  to  Cathode,  Heater,  Pentode  Cathode, 

Pentode  Grid  No.3,  and  Internal  Shield                                1.4  1.9  pf 

Cathode  to  Heater                                                                     3  3"  pf 

Pentode  Unit: 

Grid  No.l  to  Plate                                                                0.02  max       0.01  max  pf 

Grid  No.l  to  Cathode,  Heater,  Grid  No.2,  Grid  No.3,  and 

Internal  Shield                                                                       5  5  pf 

Plate  to  Cathode,  Heater,  Grid  No.2,  Grid  No.3,  and 

Internal  Shield                                                                    2.6  3.4  pf 

Heater  to  Cathode                                                                     3  3"  pf 

°  With  external  shield  connected  to  cathode  of  unit  under  test  except  as  noted. 
■  With  external  shield  connected  to  ground. 

CLASS  A,  AMPLIFIER 

.         «    .  .  .         -rr  ,     V  Triode  Pentode 

Maximum  Ratings,  {Design-Maximum  Values):  Unit  Unit 

Plate  Voltage   330  max  330  max  volts 

Grid-No.2  (SCREEN-GRID)  Supply  Voltage   -  330  max  volts 

Grid-No.2  Voltage   -  See  curve  page  70 

GaiD-No.l  (control-grid)  Voltage,  Positive-bias  value   0  max  0  max  volts 

Plate  Dissipation   2.5  max  3.1  wax  watts 

Grid-No.2  Input: 

For  grid-No.2  voltages  up  to  165  volts   -  0.55  max  watt 

For  grid-No.2  voltages  between  165  and  330  volts   -  See  curve  page  70 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode.   200  max  200  max  volts 

Heater  positive  with  respect  to  cathode  ,.   200*wax  200*wax  volts 

•  The  dc  component  must  not  exceed  100  volts. 


AVERAGE  PLATE  CHARACTERISTICS 
 TRIODE  UNIT  


TYPE  6EA8 


0  SO  100  150  200  250  300  350  400 

PLATE  VOLTS 

92CM-9e66T 


247 


RCA  Receiving  Tube  Manual 


Characteristic: 

Plate  Supply  Vol tage   150 

Grid-No.2  Voltage  

Grid-No.l  Voltage  

Cathode-Bias  Resistor   56 

Amplification  Factor   40 

Plate  Resistance  (Approx.)   5000 

Transconductance   8500 

Plate  Current   18 

Grid-No.2  Current   

Grid-No.l  Voltage  for  plate  current  of  10  /xa   "12 


Pentode 
Unit 
125 
125 
-1 


200000 
6400 
12 
4 
-9 


volts 
volts 
volt 
ohms 

ohms 
Mmhos 
ma 
ma 
volts 


AVERAGE  CHARACTERISTICS 

PENTODE  UNIT 


TYPE  6EA8 
E^sb.3  VOLTS 
.  CRID-Na2  V0LTS  =  I25 


HIGH-MU  TRIODE-  h 

SHARP-CUTOFF  PENTODE  ""(^^M^^'^sT 

6EB8               Miniature  type  used  in  color  and  ^^©flf^  if3l Yz) 

Related  type:          black-and-wWte  television  receivers.  iWrp^^^M^ 

Pentode  unit  is  used  as  video  output  gt®^^!!^  J/^ozp 

amplifier;  triode  unit  is  used  in  sync-  — 

separator,  sync-clipper,  and  phase-in-  ^'^ 
verter  circuits.  Outline  8D,  OUTLINES  SECTION.  Tube  requires  miniature  nine- 
contact  socket  and  may  be  mounted  in  any  position. 

Heater  Voltage  ( ac /dc)   6.3  volts 

Heater  Current   0.75  ampere 

Direct  Interelectrode  Capacitances; 
Triode  Unit: 

Grid  to  Plate   4.4  pf 

Grid  to  Cathode  and  Heater   2.4  pf 

Plate  to  Cathode  and  Heater   0. 36  pf 

Pentode  Unit: 

Grid  No.l  to  Plate   0.1  max  pf 

Grid  No.l  to  Cathode,  Heater,  Grid  No.2,  Grid  No.3,  and  Internal  Shield .  11  pf 

Plate  to  Cathode,  Heater,  Grid  No.2,  Grid  No.3,  andlnternal  Shield   4.2  pf 

Triode  Grid  to  Pentode  Plate   0.018  max  pf 

Pentode  Grid  No.l  to  Triode  Plate   0 . 005  max  pf 

Pentode  Plate  to  Triode  Plate   0. 17  max  pf 


CLASS  AMPLIFIER 

..     .        ^    ,                                           ^  Triode  Pentode 

Maximum  Ratings,  {Design-Maximum  Values):  Unit  Unit 

Plate  Voltage   330  max  330  max  volts 

Grid-No.2  (screen-grid)  Supply  Voltage   -  330  max  volts 

Grid-No.2  Voltage   -  See  curve  page  70 

Grid-No.1  (CONTROL-GRID)  Voltage,  Positive-bias  value   0  max  0  max  volts 

Plate  Dissipation   1  max  5  max  watts 


248 


Technical  Data 


AVERAGE  PLATE  CHARACTERISTICS 
TRIODE  UNIT 


Grid-No.2  Input: 

For  grid-No.2  voltages  up  to  165  volts  

For  grid-No.2  voltages  between  165  and  330  volts. 
Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  

"  The  dc  component  must  not  exceed  100  volts. 

Characteristics: 

Plate  Supply  Voltage . 


92CM-9907TI 

1 . 1  max  watts 
See  curve  page  70 


200  max 
200°maa; 


200  max 
200°  waa; 


Grid-No.2  Supply  Voltage  

Grid  Voltage  

Cathode-Bias  Resistor  

Amplification  Factor  

Plate  Resistance  (Approx.)  

Transconductance  

Grid  Voltage  (Approx.)  for  plate  current  of  20  /xa  

Grid-No.  1  Voltage  (Approx.)  for  plate  current  of  100  /xa. 

Plate  Current  

Grid-No.2  Current  


Triode 

Pentode 

Unit 

Unit 

250 

200 

125 

-2 

68 

100 

37000 

75000 

2700 

12500 

-5 

-9 

2 

25 

7 

Maximum  Circuit  Values: 

Grid-No.  1-Circuit  Resistance: 
For  fixed-bias  operation . . .  . 
For  cathode-bias  operation . 


AVERAGE  CHARACTERISTICS 

PENTODE  UNIT 


0 . 5  max 
1 . 0  max 


0.25  max 
1 . 0  max 


volts 
volts 


volts 
volts 
volts 
ohms 

ohms 
/xmhos 
volts 
volts 
ma 
ma 


megohm 
megohm 


TYPE  6EB8 

Ef.=  6.3  VOLTS 
GRID-N2  2V0LTS=I2 

5 

r 

\  I 

\  L 
\j 

-2 

\  

 3 

5RID-N1 

I^OLTJ 

LcL=2 

lb  

-4 

-5 

300  400 
PLATE  VOLTS 


^?CM-<)906T 


249 


RCA  Receiving  Tube  Manual 


POWER  PENTODE 

Miniature  type  used  in  the  audio 
output  stage  of  radio  and  television 
receivers  and  in  phonographs.  This 
type  has  unusually  high  power  sensi- 
tivity and  is  capable  of  providing  rel- 
atively high  power  output  at  low  plate  and  screen-grid  voltages  with  a  low  af  grid- 
No.l  driving  voltage.  Outline  7C,  OUTLINES  SECTION.  Tube  requires  miniature 
seven-contact  socket  and  may  be  mounted  in  any  position. 


6EH5 

Related  types: 
12EH5,  25EH5, 50EH5 


Heater  Voltage  (ac/dc)  

Heater  Current  

Direct  Interelectrode  Capacitances  (Approx.) : 

Grid  No.l  to  Plate  

Grid  No.l  to  Cathode,  Heater,  Grid  No.2,  and  Grid  No.3 .  . 

Plate  to  Cathode,  Heater,  Grid  No.2,  and  Grid  No.3  

CLASS  Ai  AMPLIFIER 
Maximum  Ratings,  {Design-Maximum  Values) : 

Plate  Voltage  

Grid-No.2  (screen-grid)  Voltage   

Plate  Dissipation  

Grid-No.2  Input.  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  

Bulb  Temperature  (At  hottest  point)  

Typical  Operation: 

Plate  Supply  Voltage  

Grid-No.2  Supply  Voltage  

Cathode-Bias  Resistor  

Peak  AF  Grid-No.  1  Voltage  

Zero-Signal  Plate  Current .  

Maximum-Signal  Plate  Current  

Zero-Signal  Grid-No.2  Current  

Maximum-Signal  Grid-No.2  Current  

Plate  Resistance  (Approx.)  

Transconductance  

Load  Resistance  

Total  Harmonic  Distortion  

Maximum-Signal  Power  Output  


Maximum  Circuit  Values: 

Grid-No.  1-Circuit  Resistance: 

For  fixed-bias  operation  

For  cathode-bias  operation  

■  The  dc  component  must  not  exceed  100  volts. 


AVERAGE  CHARACTERISTICS 


6.3 
1.2 

0.65 
17 
9 


150  max 
130  max 
5 . 5  max 
2  max 

200  max 
200"maa: 

220  max 


110 
115 
62 
3 
42 
42 
11.5 
14.5 
11000 
14600 
3000 
7 

1.4 


0 . 1  max 
0 . 5  max 


volts 
amperes 

Pf 
Pf 
pf 


volts 
volts 
watts 
watts 

volts 
volts 
°C 


volts 
volts 
ohms 
volts 
ma 
ma 
ma 
ma 
ohms 
Mmhos 
ohms 
per  cent 
watts 


megohm 
megohm 


PLATE  VOLTS 


92CM-9623T 


250 


PUSH-PULL  CLASS  ABx  AUDIO-FREQUENCY  POWER  AMPLIFIER 
Maximum  Ratings:  (Same  as  for  class  Ai  audio-frequency  power  amplifier) 


Typical  Operation,  (Values  are  for  2  tubes): 

Plate  Supply  Voltage   140  volts 

Grid-No.2  Supply  Voltage   120  volts 

Cathode-Bias  Resistor   68  ohms 

Peak  AF  Grid-No.  1  Voltage   9.4  volts 

Zero-Signal  Plate  Current   47  ma 

Maximum-Signal  Plate  Current   51  ma 

Zero-Signal  Grid-No.2  Current   11  ma 

Maximum-Signal  Grid-No.2  Current   17.7  ma 

Effective  Load  Resistance  (Plate-to-plate)   6000  ohms 

Total  Harmonic  Distortion   5  per  cent 

Maximum-Signal  Power  Output   3.8  watts 

Maximum  Circuit  Values: 

Grid-No. 1-Circuit  Resistance: 

For  fixed-bias  operation   0.1  max  megohm 

For  cathode-bias  operation   0.5  max  megohm 


SEMIREMOTE-CUTOFF  PENTODE 

Miniature  type  used  as  if-ampli- 
fier  tube  in  television  receivers.  Out- 
line 8C,  OUTLINES  SECTION.  Tube 
requires  nine-contact  socket  and  may- 
be mounted  in  any  position.  Heater 
volts  (ac/dc),  6.3;  amperes,  0.3. 


6EH7 

Related  types: 
3EH7,  4EH7 


CLASS  Ai  AMPLIFIER 


Maximum  Ratings,  (Design-Center  Values): 

Plate  Supply  Voltage   550  max  volts 

Plate  Volt  AGE   250  max  volts 

Grid-No.3  (suppressor-grid)  Voltage,  Positive  value   0  max  volts 

Grid-No.2  (screen-grid)  Supply  Voltage   550  max  volts 

Grid-No.2  Voltage   250  max  volts 

Cathode  Current     20  max  ma 

Grid-No.2  Input   0.65  maa;  watt 

Plate  Dissipation   2.5  max  watts 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   150  max  volts 

Heater  positive  with  respect  to  cathode   150  max  volts 


Characteristics: 

Plate  Voltage   200  volts 

Grid  No.3  Connected  to  cathode  at  socket 

Grid-No.2  Voltage   90  volts 

Grid-No.  1  Voltage   -2  volts 

Plate  Resistance  ( Approx.)   0.5  megohm 

Transconductance   12500  /xmhos 

Plate  Current   12  ma 

Grid-No.2  Current   4.5  ma 


Typical  Operation: 

Plate  Voltage  

Grid  No.3  

Grid-No.2  Supply  Voltage  

Grid-No.2  Series  Resistor  

Grid-No.  1  Voltage  

Transconductance  

RMS  Grid-No.l  Voltage,  for  cross-modulation 
factor  of  0.01    


200 

200 

200 

200 

volts 

Connected  to  cathode  at 

socket 

200 

200 

200 

200 

volts 

22000 

22000 

22000 

22000 

ohms 

-19.5 

-9.5 

-6.5 

-2 

volts 

125 

625 

1250 

12500 

Atmhos 

450 

160 

100 

mv 

Maximum  Circuit  Values: 

Grid-No. l-Circuit  Resistance 


1  max  megohm 

251 


RCA  Receiving  Tube  Manual 


6EH8 


Kp,G3p,IS 


MEDiUM-MU  TRIODE- 
SHARP-CUTOFF  PENTODE 

Miniature  type  used  as  combined  oscillator 
and  mixer  tube  in  vhf  tuners  of  television  re- 
ceivers having  series-connected  heater  strings. 
Outline  8B,  OUTLINES  SECTION.  Tube  re- 
quires nine-contact  socket.  Heater  volts  (ac/dc), 
6.3;  amperes,  0.45;  warm-up  time  (average),  11 
seconds.  Characteristics  as  class  Ai  amplifier: 
plate  and  grid-No.2  volts,  125  (300  max);  grid- 
No.l  volts, -1(0  max)  \  amplification  factor  (tri- 
ode  unit),  40;  plate  resistance  (pentode  unit,  approx,),  0.17  megohm;  transconductance,  7500  /imhos 
(triode  unit),  6000  umbos  (pentode  unit);  plate  ma.,  13.5  (triode  unit),  12  (pentode  unit);  grid-No.2 
ma.  (pentode  unit) ,  4 ;  peak  heater-cathode  volts,  200  max  (the  dc  component  must  not  exceed  100  volts) . 
This  type  is  used  principally  for  renewal  purposes. 

SHARP-CUTOFF  PENTODE 

Miniature  type  used  as  if-ampli- 
fier  tube  in  television  receivers.  Out- 
line 8C,  OUTLINES  SECTION.  Tube 
requires  miniature  nine-contact  socket 
and  may  be  mounted  in  any  position. 
Heater  volts  (ac/dc),  6.3;  amperes,0.3. 

CLASS  Ai  AMPLIFIER 
Maximum  Ratings,  {Design-Center  Values): 

Plate  Supply  Voltage  ,  

Plate  Voltage  

Grid-No.2  (screen-grid)  Supply  Voltage  

Grid-No.2  Voltage  

Cathode  Current  

Grid-No.2  Input  

Plate  Dissipation  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  

Characteristics: 

Plate  Voltage  

Grid  No.3  

Grid-No.2  Voltage  

Grid-No.  1  Voltage  

Plate  Resistance  (Approx.)  

Transconductance  

Plate  Current  

Grid-No.2  Current  


6EJ7 

Related  types: 
3EJ7,  4EJ7 


190 


550  max 
250  max 
550  max 
250  max 
25  max 
0.9  max 
2 . 5  max 

150  max 
150  max 

200 


Connected  to  cathode 

190  200 

-2.35  -2.5 

0.35  0.35 

15000  15000 

10  10 

4.1  4.1 


volts 
volts 
volts 
volts 
ma 
watt 
watts 

volts 
volts 

volts 
at  socket 
volts 
volts 
megohm 
/Ltmhos 
ma 
ma 


Maximum  Circuit  Values: 

Grid-No. 1-Circuit  Resistance. 


BEAM  POWER  TUBE 


6EM5 

Related  type: 
8EM5 


Miniature  type  used  as  vertical 
deflection  amplifier  in  television  re- 
ceivers utilizing  picture  tubes  having 
diagonal  deflection  angles  of  110  de- 
grees. Outline  8E,  OUTLINES  SEC- 
TION. Tube  requires  miniature  nine-contact  socket  and  may  be  mounted 
position. 

Heater  Voltage  (ac/dc)  

Heater  Current  

Direct  Interelbctrode  Capacitances: 

Grid  No.  1  to  Plate   

Grid  No.l  to  Cathode,  Heater,  Grid  No.2,  and  Grid  No.3  

Plate  to  Cathode,  Heater,  Grid  No.2,  and  Grid  No.3  

Plate  Resistance  (Approx.)*  

Transconductance*  

*  For  plate  and  grid-No.2  volts,  250;  grid-No.l  volts,  -18;  plate  ma.,  40;  grid-No.2  ma.,  3. 

252 


6.3 
0.8 

0.7  max 
10 

5.1 
0.05 
5100 


m  any 

volts 
ampere 

Pf 
Pf 
pf 

megohm 
Mmhos 


AVERAGE  CHARACTERISTICS 


TYPE  6EM5  1  1 

Ef=  6.3  VOLTS  1  1 

RRin-N9  9  VOLTSs 

of 

0  — 

 IJ 

_  -5 

\ 

V 

^\ 

-15 

V 

ic 

2 

-20 

Lci=0 

-25 

200  250 
PLATE  VOLTS 


VERTICAL  DEFLECTION  AMPLIFIER 

For  operation  in  a  525-line,  30-frame  system 
Maximum  Ratings^  {Design-Center  Values): 

DC  Plate  Voltage  

Peak  Positive-Pulse  Plate  VoLTAGEf  {Absolute  Maximum)  

Grid-No.2  (screen-grid)  Voltage  

Peak  Negative-Pulse  Grid-No.1  (control-grid)  Voltage  

Peak  Cathode  Current  

Average  Cathode  Current  

Plate  Dissipation  

Grid-No.2  Input  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  

Bulb  Temperature  (At  hottest  point)    


92CM-9797TI 


315  max 
2200^rnaa; 

285  max 
-250  max 
210  max 
60  max 
10  max 
1 . 5  max 

200  max 
200"waa: 

250  max 


volts 
volts 
volts 
volts 
ma 
ma 
watts 
watts 

volts 
volts 
°C 


Maximum  Circuit  Values: 

Grid-No.  1-Circuit  Resistance   2.2  max  megohm 

t  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  vertical  scanning  cycle.  In  a 
525-line,  30-frame  system,  15  per  cent  of  one  vertical  scanning  cycle  is  2.5  milliseconds. 
^  Under  no  circumstances  should  this  absolute  value  be  exceeded. 
■  The  dc  component  must  not  exceed  100  volts. 

AVERAGE  CHARACTERISTICS 
WITH  EC2  AS  VARIABLE 


'type'6EM5  1 

Ef  =  6.3  VOLTS 

 2 

50 

GRID 

-N2  1 

VOLTS 

=  0 

200 

i 

GRID 

-N2  2 

VOLTS 

^£2  = 

150 

IOC 

) 

50 

150  200 

PLATE  VOLTS 


400 
92CM-9672T 


253 


HCA  Receiving  Tube  Manual  = 

DUAL  TRIODE  ,^   ^  ^ 

M^m./k'^  Glass  octal  type  containing  high- 

OElVl/           mu triode and high-perveance, low-mu  .  ^.    >^  ^ry)^ 
Related  types:          triode  in  Same  envelope.  Used  as  com-  ^'^^^ 

10EM7, 13EM7  bined  vertical-deflection  amplifier  and  ^ 
vertical-deflection  oscillator  in  tele- 
vision  receivers  employing  picture  tubes  having  110-degree  deflection  angles  and 
high  ultor  voltages.  Outline  14A,  OUTLINES  SECTION.  Tube  requires  octal 
socket  and  may  be  mounted  in  any  position.  For  curve  of  average  plate  characteris- 
tics, Unit  No.l,  refer  to  type  6DR7  (Unit  No.l). 

Heater  Voltage  (ac/dc)   6.3  volts 

Heater  Current   0 . 925  ampere 

Direct  Interelectrode  Capacitances  (Approx.) :                  Unit  No.l  Unit  No.2 

Grid  to  Plate                                                                       4.8  10  pf 

Grid  to  Cathode  and  Heater                                                  2.2  7  pf 

Plate  to  Cathode  and  Heater                                                 0.6  1.8  pf 

CLASS  Ai  AMPLIFIER 

Characteristics:                                                                  Unit  No.l  Unit  No.2 

Plate  Voltage                                                                            250  150  volts 

Grid  Voltage                                                                               -3  -20  volts 

Amplification  Factor                                                                    64  5.4 

Plate  Resistance  (Approx.)                                                       40000  750  ohms 

Transconductance                                                                     1600  7200  yumhos 

Grid  Voltage  (Approx.) : 

For  plate  current  of  lO/ta                                                     -5.5  -  volts 

For  plate  current  of  100  Aia                                                       -  -45  volts 

Plate  Current                                                                             1.4  50  ma 

Plate  Current,  for  plate  voltage  of  60  volts  and  zero  grid  voltage         -  95  ma 

Plate  Current,  for  irid  voltage  of  -28  volts                                       -  10  ma 

#  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  vertical-scanning  cycle.  In  a  525- 
line,  30-frame  system,  15  per  cent  of  one  vertical-scanning  cycle  is  2.5  milliseconds. 
■  The  dc  component  must  not  exceed  100  volts. 

VERTICAL-DEFLECTION  OSCILLATOR  AND  AMPLIFIER 
For  operation  in  a  525-line,  30-frame  system 

.        „                                                                             Unit  No.l  Unit  No.2 

Maximum  Ratings,  {Design-Maximum  Values):                              Oscillator  Amplifier 

DC  Plate  Voltage                                                                 330  wax  330  max  volto 

Peak  Positive-Pulse  Plate  Voltage#                                       -  1500  max  volts 

Peak  Negative-Pulse  Grid  Voltage                                     -400  max  -250  max  volts 

Peak  Cathode  Current                                                          77  max  175  max  ma 

Average  Cathode  Current                                                   22  wax  50  wax  ma 

Plate  Dissipation                                                                  1.5  wax  10  wax  watts 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode                                  200  wax  200  wax  volts 

Heater  positive  with  respect  to  cathode                                   200  wax"  200  wax"  volts 


AVERAGE  PLATE  CHARACTERISTICS 

UNIT  N8  2 


300  350  400 
PLATE  VOLTS 


92CM-I0466T 


254 


Technical  Data 


Maximum  Circuit  Values: 

Grid-Circuit  Resistance: 

For  grid-resistor-bias  operation . 
For  cathode-bias  operation .... 


Unit  No.l 
2 . 2  max 
2 . 2  max 


DIODE-REMOTE-CUTOFF 
PENTODE 

Miniature  type  used  as  combined 
if  amplifier  and  AM  detector  in  AM 
and  AM/FM  radio  receivers.  Outline 
8D,  OUTLINES  SECTION.  Tube  re- 
quires miniature  nine-contact  socket 
and  may  be  operated  in  any  position. 


Unit  No.2 

2 . 2  max  megohms 

2 . 2  max  megohms 


6EQ7 

Related  types: 
12EQ7,  20EQ7 


6.3 
0.3 


300  max 


Heater  Voltage  (ac/dc)  

Heater  Current  

Direct  Interelectrodb  Capacitances: 
Pentode  Unit: 

Grid  No.l  to  Plate   0 . 002  max 

Grid  No.l  to  Cathode,  Heater,  Grid  No.2,  Grid  No.3,  and  Internal  Shield  5.5 
Plate  to  Cathode,  Heater,  Grid  No.2,  Grid  No.3,  and  Internal  Shield  .  .  5 

Pentode  Grid  No.l  to  Diode  Plate   0 . 0015  max 

Pentode  Plate  to  Diode  Plate   0 . 095 

PENTODE  UNIT  AS  CLASS  Ai  AMPLIFIER 
Maximum  Ratings,  (Design-Maximum  Values): 

Plate  Voltage  

Grid-No.3  (suppressor-grid)  Voltage: 

Positive  value  '  

Negative  value  

Grid-No.2  (screen-grid)  Supply  Voltage  

Grid-No.2  Voltage  

Grid-No.1  (control-grid)  Voltage: 

Positive-bias  value  

Negative-bias  value  

Plate  Dissipation  

GriD-No.3  Input  

Grid-No.2  Input: 

For  grid-No.2  voltages  up  to  150  volts  

For  grid-No.2  voltages  between  150  and  300  volts  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  

Bulb  Temperature  (At  hottest  point)  


volts 
ampere 


Pf 
Pf 


volts 


300  max  volts 
-300  max  volts 
300  max  volts 
.  .See  curve  page  70 


0  max 
-50  max 

3  max 
0 . 2  max 


volts 
volts 
watts 
watt 


0 . 6  max  watt 
.  .  See  curve  page  70 


200  max 
200 "wax 

150  max 


volts 
volts 
°C 


Characteristics: 

Plate  Voltage   100  volts 

Grid  No.3  Connected  to  cathode  at  socket 

Internal  Shield  Connected  to  cathode  at  socket 

Grid-No.2  Voltage   100  volts 

Grid-No.  1  Supply  Voltage   0  volts 

Grid-No.  1  Resistor  (Bypassed)   2.2  megohms 

AVERAGE  CHARACTERISTICS 


1   1    i  1 

TYPE  bEQ7 

Ef  =  6.3  VOLTS 

GRID  No.3  AND  INTERNAL  SHIELD 

CONNECTED  TO  CATHODE  AT  SOC 
GRIO-No.  2  VOLTS  =  IOO 

KET. 

GRID-No 

1  VOLTJ 

>  EcrO 

lb 

-1 

-2 

IC2 

ECrO 

-3 

-4 

-2 

-5 
-10 

-zo 

255 


RCA  Receiving  Tube  Manual 


Plate  Resistance  (Approx.)  

Transconductance  

Plate  Current  

Grid-No.2  Current  

Grid-No.l  Voltage  (Approx.)  for  transconductance  of  40  /imhos. 

DIODE  UNIT 
Maximum  Ratings,  {Design-Maximum  Values): 
Plate  Current  

Characteristics,  Instantaneous  Value: 

Tube  Voltage  Drop  for  plate  current  of  2  ma  

■  The  dc  component  must  not  exceed  100  voltis. 


HIGH-MU  TRIODE 

Miniature  type  with  frame  grid 
used  in  vhf  tuners  of  television  receiv- 
ers. Outline  7B,  OUTLINES  SEC- 
TION. Tube  requires  miniature  seven- 
contact  socket  and  may  be  mounted 
in  any  position.  Heater  volts  (ac/dc), 
6.3,  amperes,  0.18. 


6ER5 

Related  types: 
2ER5,  3ER5 


CLASS  Ai  AMPLIFIER 
Maximum  Ratings,  {Design-Center  Values): 

Plate  Voltage  

Grid  Voltage,  Negative-bias  value  

Cathode  Current  

Plate  Dissipation  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  

Characteristics: 

Plate  Voltage  

Grid  Voltage  

Amplification  Factor  

Plate  Resistance  (Approx.)  

Transconductance  

Plate  Current  

Grid  Voltage  (Approx.)  for  transconductance  of  500  /imhos .  .  .  . 
Grid  Voltage  (Approx.)  for  transconductance  of  100  /tmhos.  .  . . 

Maximum  Circuit  Value: 

Grid  Circuit  Resistance  


0.25 
3800 
9 

3.5 
-20 


1  max 
10 


megohm 
Atmhos 
ma 
ma 
volts 


volts 


250  max 

volts 

-50  max 

volts 

20  max 

ma 

2 , 2  max 

watts 

100  max 

volts 

100  max 

volts 

200 

volts 

-1.2 

volts 

80 

8000 

ohms 

10500 

jumhos 

10 

ma 

-3.8 

volts 

-5.6 

volts 

1  max 

megohm 

6ES5 


HIGH-MU  TRIODE 

Miniature  type  used  as  grounded- 
cathode  rf  amplifier  in  vhf  television 
receivers.  Outline  7B,  OUTLINES 
SECTION.  Tube  requires  miniature 
seven-contact  socket  and  may  be  op- 
erated in  any  position.  Heater  volts 
(ac/dc),  6.3;  amperes,  0.2. 

CLASS  Ai  AMPLIFIER 
Maximum  Ratings,  {Design-Maximum  Values): 

Plate  Voltage  

Grid  Voltage,  Positive-bias  value  

Cathode  Current  

Plate  Dissipation  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  

Characteristics: 

Plate  Voltage  

Grid  Voltage  

Amplification  Factor  

Plate  Resistance  (Approx.)  

Transconductance  

Plate  Current  

Grid  Voltage  (Approx.)  for  plate  current  of  100  /xa  

Maximum  Circuit  Values: 

Grid-Circuit  Resistance  

256 


250  max 

volts 

0  max 

volts 

22  max 

ma 

2.2  max 

watts 

100  max 

volts 

100  max 

volts 

200 

volts 

-1 

volt 

75 

8000 

ohms 

9000 

/umhos 

10 

ma 

-6 

volts 

1  max 

megohm 

VARIABLE-MU  TWIN  TRIODE 

Miniature  type  with  high  trans- 
conductance,  variable  mu,  and  low 
noise;  used  as  cascode-type  amplifier 
in  tuners  of  television  receivers.  Out- 
line 8B,  OUTLINES  SECTION.  Tube 
requires  miniature  nine-contact  socket  and  may  be  operated  in  any  position.  Heater 
volts  (ac/dc),  6.3;  amperes,  0.365. 


6ES8 

Related  type: 
4ES8 


Characteristics: 

Plate  Voltage.  . . 
Grid  Voltage  


CLASS  Ai  AMPLIFIER  (Each  Unit) 


Plate  Current  

CASCODE-TYPE  AMPLIFIER 
Maximum  Ratings,  (Design-Center  Values): 

Plate  Supply  Voltage  with  plate  current  of  0  ma  

Plate  Voltage  (Each  unit)  

Grid  Voltage,  Negative-bias  value  (Each  unit)  

Cathode  Current  (Each  unit)  

Plate  Dissipation  (Each  unit)  

Heater-Cathode  Voltage: 
Unit  No.l:<> 

RMS  voltage  between  cathode  and  heater  

Unit  No.2:" 

RMS  voltage  between  cathode  and  heater*  

DC  voltage  between  cathode  and  heater*.  


90 

90 

90 

volts 

-1.2 

-5 

-9 

volts 

2500 

ohms 

12500 

625 

125 

/imhos 

15 

ma 

550  max 
130  max 
-50  max 
22  max 
1 . 8  max 


50  max 


50  max 
130  max 


volts 
volts 
volts 
ma 
watts 

volts 

volts 
volts 


In  a  cascode-type  circuit  with  the  grid  of  the 
output  unit  connected  to  a  voltage  divider^ 


Typical  Operation: 

Supply  Voltage  

Plate  Current  

Transconductanee  

Noise  Figure*  

Grid  Voltage  (Approx.)  for  transconductanee  of  125  ^mhos 
Input  Voltage  for  cross-modulation  factor  of  0.01  and 

transconductanee  of  125  /umbos  


180 
15 
12500 
6.5 
-9 

500 


volts 
ma 
/imhos 
db 
volts 

mv 


Maximum  Circuit  Values: 

Grid-Circuit  Resistance  (Each  unit)   1  max  meghom 

°  Grounded-cathode  input  unit — pins  6,  7,  and  8. 
■  Grounded-grid  output  unit — pins  1,  2,  and  3. 

•  Cathode  positive  with  respect  to  heater. 

°  In  order  not  to  exceed  the  maximum-rated  plate  voltage  when  the  cascode-type  amplifier  is  controlled 
it  is  necessary  to  use  a  voltage  divider  for  the  grid  of  the  grounded-grid  output  unit. 

*  Measured  with  tube  operating  in  a  television  tuner. 

HIGH-MU  TWIN  TRIODE 

Miniature  type  used  in  high-gain,  ^Cl  IT 

resistance-coupled,  low-level  audio-  OcU/ 
amplifier  applications  where  low-hum 
and  non-microphonic  characteristics 
are  important  considerations,  such  as 
in  microphone  amplifiers  and  in  preamplifiers  for  mono-  and  stereophonic  phono- 
graphs. Outline  8B,  OUTLINES  SECTION.  Tube  requires  miniature  nine-contact 
socket  and  may  be  mounted  in  any  position.  For  typical  operation  as  a  resistance- 
coupled  amplifier,  refer  to  RESISTANCE-COUPLED  AMPLIFIER  SECTION. 


Heater  Voltage  (ac/dc)  ,   6.3  volts 

Heater  Current   0.3  ampere 

Direct  Interelectrode  Capacitances  (Each  Unit,  Approx.): 

Grid  to  Plate   1.5  pf 

Grid  to  Cathode  and  Heater   1.6  pf 

Plate  to  Cathode  and  Heater   0.2  pf 


257 


RCA  Receiving  Tube  Manual 


Equivalent  Noise  And  Hum  Voltage  (Referenced  to  Grid,  Each  Unit) : 

Average  Value*  

*  Measured  in  "true  rms"  units  under  the  following  conditions:  Heater  volts 
heater  transformer  grounded;  plate  supply  volts,  250;  plate  load  resistor,  100000 
2700  ohms;  cathode  bypass  capacitor,  100  jttf;  grid  resistor,  0  ohms;  amplifier 
10000  cps. 

CLASS  Ai  AMPLIFIER  {Each  Unit) 
Maximum  Ratings,  (Design-M aximum Values): 

Plate  Voltage  

Grid  Voltage: 

Negative-bias  value  

Positive-bias  value  

Plate  Dissipation  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  

The  dc  component  must  not  exceed  100  volts. 

Characteristics: 

Plate  Voltage  

Grid  Voltage  

Amplification  Factor  , 

Plate  Resistance  (Approx.)  

Transconductance  

Plate  Current  


1 . 8  microvolts  rms 
(ac),  6.3;  center-tap  of 
ohms;  cathode  resistor, 
frequency  range,  25  to 


330  max 

-55  max 
0  max 
1 , 2  max 

200  max 
200" wax 


volts 

volts 
volts 
watts 

volts 
volts 


100 

250 

volts 

-1 

-2 

volts 

100 

100 

80000 

62500 

ohms 

1250 

1600 

/Limhos 

0.5 

1.2 

ma 

AVERAGE  PLATE  CHARACTERISTICS 

EACH  UNIT 


0  100  200  300  400  500 

PLATE  VOLTS 

92CM-I0470T 

MEDIUM-MU  TRIODE- 
SHARP-CUTOFF  PENTODE  "hiJlr^^ 

ACI  I Q  Miniature  type  used  as  combined pj  ^^-n^^^^^a^gip 

OEU  O  triode  oscillator  and  pentode  mixer  in  ^^^M^ 
Related  type:        television  receivers. Outline  8B,  OUT-    (2i([|^  '^W?) 

5EU8  LINES  SECTION.  Tube  requires  min-  ^TW^^^i7V.JKp,G3p,ts 

iature  nine-contact  socket  and  may  be       fiJ^  ts) 
operated  in  any  position.  Heater  volts  ** 
(ac/dc),  6.3;  amperes,  0.45;  warm-up  time  (average),  11  seconds. 

CLASS  Ai  AMPLIFIER 

Triode  Pentode 

hKaxlmum  RaWngs,  (Design-Center  Values) :  Unit  Unit 

Plate  Voltage   330  max  330  max  volts 

Grid-No.2  (screen-grid)  Supply  Voltage   —  330  max  volts 

Grid-No.2  Voltage   See  curve  page  70 

Grid-No.1  (control-grid)  Voltage,  Positive-bias  value   0  max  0  max  volts 

Plate  Dissipation   3  max  3.1  max  watts 

258 


Grid-No.2  Input: 

For  grid-No.2  voltages  up  to  165  volts  

For  grid-No.2  voltages  between  165  and  330  volts . 
Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  


Characteristics: 

Plate  Supply  Voltage  

Grid-No.2  Supply  Voltage  

Grid-No.  1  Voltage  

Cathode-Bias  Resistor  

Amplification  Factor  

Plate  Resistance  (Approx.)  

Transconductance  

Grid-No.l  Voltage  (Approx.)  for  plate  current  of  10  /na. 

Plate  Current  

Grid-No.2  Current  

Cathode  Warm-up  Time"  


0 . 55  max 

watt 

See  curve  page  70 

200  max 

200  max 

volts 

200°maa; 

200°max 

volts 

150 

125 

125 

volts 

— 

-1 

volt 

56 

ohms 

40 

5000 

80000 

ohms 

8500 

6400 

/tmhos 

-12 

-9 

volts 

18 

12 

ma 

4 

ma 

35 

seconds 

0.1  max 

0.1  max 

megohm 

Maximum  Circuit  Values: 

Grid-No.  1-Circuit  Resistance  

°  The  dc  component  must  not  exceed  100  volts. 

■  The  cathode  warm-up  time  is  defined  as  the  time  required  for  the  transconductance  to  reach  6500 
Atmhos  when  the  tube  is  operated  from  a  cold  start  with  dc  plate  volts =100,  grid  volts =0,  and 
heater  volts=5. 5. 

SHARP-CUTOFF  TETRODE 


Miniature  type  used  as  rf  ampli- 
fier in  vhf  tuners  of  television  receivers. 
Outline  7B,  OUTLINES  SECTION. 
Tube  requires  miniature  seven-contact 
socket  and  may  be  operated  in  any 
position.  Heater  volts  (ac/dc),  6.3; 
amperes,  0.2. 

CLASS  Ai  AMPLIFIER 


6EV5 


Maximum  Ratings,  (Design-Maximum  Values): 

Plate  Voltage  

Grid-No  2  (screen-grid)  Supply  Voltage  

Grid-No.2  Voltage  

Grid-No.  1  (control-grid)  Voltage,  Positive-bias  value. 

Cathode  Current  

Grid-No.2  Input: 

For  grid-No.2  voltages  up  to  90  volts  

For  grid-No.2  voltages  between  90  and  180  volts .... 

Plate  Dissipation  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  


Characteristics: 


275  max  volts 
180  max  volts 

See  curve  page  70 
0  max  volts 

20  max  ma 

0 . 2  max  watt 
See  curve  page  70 
3.25  max  watts 


100  max 
100°wax 


volts 
volts 


250 
80 
-1 
0.15 
8800 
11.5 
0.9 
-4.5 


volts 
volts 
volt 
megohm 
/xmhos 
ma 
ma 
volts 


0 . 5  max  megohm 


Plate  Voltage  

Grid-No.2  Voltage  

Grid-No.l  Voltage  

Plate  Resistance  (Approx.)  

Transconductance  

Plate  Current  

Grid-No  2  Current  

Grid-No.l  Voltage  (Approx.)  for  transconductance  of  100  /*mhos  

Maximum  Circuit  Value: 

Grid-No.l-Circuit  Resistance  

®  The  dc  component  must  not  exceed  50  volts. 

^PT.  HIGH-MU  TWIN  TRIODE 

Miniature  type  used  as  a  relay- 
control  tube  in  remote-control  tuning 
units  of  television  receivers.  It  is  proc- 
essed  specifically  for  operation  under 
pt2^  "^nc  standby  conditions.  Outline  8D,  OUT- 
LINES SECTION.  Tube  requires  miniature  nine-contact  socket  and  may  be 
mounted  in  any  position. 

259 


6EV7 


RCA  Receiving  Tube  Manual 


Heater  Voltage  (ac/dc)   6.3  volts 

Heater  Current   0.6  ampere 

Direct  Interelectrode  Capacitances  (Approx.) :  Unit  No.l    Unit  No. 2 

Grid  to  Plate                                                                         3.4  3.4  pf 

Grid  to  Cathode  and  Heater                                                     3  3  pf 

Plate  to  Cathode  and  Heater                                                0.33  0.23  pf 

Characteristics:  CLASS  Ai  AMPLIFIER  {Each  Unit) 

Plate  Voltage   250 

Grid  Voltage     -2 

Amplification  Factor   60 

Plate  Resistance  (Approx.)   11500 

Transconductance   5200 

Plate  Current   9.2 

Grid  Voltage  (Approx.)  for  plate  current  of  100  h2l   -9 

RELAY-CONTROL  SERVICE  {Each  Unit) 
Maximum  Ratings,  {Design-Maximum Values): 

Plate  Voltage   300  max 

Grid  Voltage,  Positive-bias  value   0  max 

Cathode  Current   20  max 

Plate  Dissipation: 

When  "on"  time  exceeds  30  seconds  in  any  2-minute  interval   2.5  max 

When  "on"  time  does  not  exceed  30  seconds  in  any  2-minute  interval.  ,  4.5  max 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  max 

Heater  positive  with  respect  to  cathode   200*max 

■  The  dc  component  must  not  exceed  100  volts. 

Typical  Operation  with  2500-Ohm-Relay  Load:                    30  seconds  More  than 
With  **on"  time  in  any  2-minute  interval:                                or  less        30  seconds 

Plate  Supply  Voltage                                                                  250  150 

Zero-bias  Plate  Current                                                              18.5  10 

Grid  Voltage  (Approx.)  for  plate  current  of  100  /xa                            -9  -5 

Maximum  Circuit  Value: 

Grid-Circuit  Resistance   3.9  max  megohms 


volts 
volts 

ohms 
/imhos 
ma 
volts 


volts 
volts 
ma 

watts 
watts 

volts 
volts 


volts 
ma 
volts 


6EW6 

Related  types: 
4EW6,  5EW6 


SHARP-CUTOFF  PENTODE 

Miniature  type  used  in  the  gain- 
controlled  picture-if  stages  of  vhf  tel- 
evision receivers  operating  at  an  inter- 
mediate frequency  in  the  order  of  40 
megacycles  per  second.  This  tube  fea- 


tures controlled  plate-current  cutoff  and  high  transconductance  (14000  /xmhos) 
260 


combined  with  low  interelectrode  capacitance  values.  The  6EW6  is  provided  with 
separate  base  pins  for  grid  No.3  and  cathode  to  permit  the  use  of  an  unbypassed 
cathode  resistor  to  minimize  changes  in  input  conductance  and  input  capacitance 
with  bias,  without  causing  oscillation.  Outline  7B,  OUTLINES  SECTION.  Tube 
requires  miniature  seven-contact  socket  and  may  be  mounted  in  any  position. 


Heater  Voltage  (ac/dc)   6.3  volts 

Heater  Current   0.4  ampere 

Without  With 

External  External 

Direct  Interelectrode  Capacitances:                                Shield  Shield* 

Grid  No.l  to  Plate                                                           0 . 04  max  0 . 03  max  pf 

Grid  No.l  to  Cathode,  Heater,  Grid  No.2,  Grid  No.3  and 

Internal  Shield                                                                10  10  pf 

Plate  to  Cathode,  Heater,  Grid  No.2,  Grid  No.3,  and 

Internal  Shield                                                               2.4  3.4  pf 

CLASS  Ai  AMPLIFIER 
Maximum  Ratings,  (Design-Maximum  Values): 

Plate  Voltage   330  max  volts 

Grid  No.3  (suppressor-grid)  Voltage,  Positive  value   0  max  volts 

Grid-No.2  (screen-grid)  Supply  Voltage   330  wax  volts 

Grid-No.2  Voltage   See  curve  page  70 

Grid-No.1  (control-grid)  Voltage,  Positive-bias  value   0  max  volts 

Plate  Dissipation   3.1  max  watts 

Grid-No.2  Input: 

For  grid-No.2  voltages  up  to  165  volts.   0.65  max  watt 

For  grid-No.2  voltages  between  165  and  330  volts   See  curve  page  70 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  max  volts 

Heater  positive  with  respect  to  cathode   200 "max  volts 

Characteristics: 

Plate  Supply  Voltage   125  volts 

Grid  No.3   Connected  to  cathode  at  socket 

Grid-No.2  Supply  Voltage   125  volts 

Cathode-Bias  Resistor   56  ohms 

Plate  Resistance  (Approx.)   0.2  megohm 

Transconductance   14000  /xmhos 

Grid-No.l  Voltage  (Approx.)  for  plate  current  of  20  /ua   -3.5  volts 

Plate  Current   11  ma 

Grid-No.2  Current   3.2  ma 

*  With  external  shield  connected  to  cathode. 
■  The  dc  component  must  not  exceed  100  volts. 


RCA  Receiving  Tube  Manual 


DUAL  TRIODE 

.      A  f  ^  Neonoval  type  used  as  combined 

O  E  Vv  /        vertical-deflection  oscillator  and  verti- 
cal-deflection amplifier  in  television 
receivers.  Outline  IIB,  OUTLINES 
SECTION.  Tube  requires  neonoval 
nine -contact  socket  and  may  be  operated  in  any  position.  For  curve  of  average 
plate  characteristics,  Unit  No.l,  refer  to  type  6DE7  (Unit  No.l). 

Heater  Voltage  (ac/dc)  

Heater  Current  


Direct  Interelectrode  Capacitances  (Approx.) : 

Grid  to  Plate  

Grid  to  Cathode  and  Heater  

Plate  to  Cathode  and  Heater  


,  ...  CLASS  Ai  AMPLIFIER 

Characteristics: 

Plate  Voltage  

Grid  Voltage  

Amplification  Factor  

Plate  Resistance  (Approx.)  

Transconductance  

Grid  Voltage  (Approx.)  for  plate  current  of  10  |ta  

Grid  Voltage  (Approx.)  for  plate  current  of  100  /xa  

Plate  Current  

Plate  Current  for  plate  voltage  of  60  volts  and  zero  grid  voltage 
Plate  Current  for  grid  voltage  of  -25  volts  


Maximum  Ratings,  (Design-Maximum  Values): 

DC  Plate  Voltage  

Peak  Positive-Pulse  Plate  Voltage"  , 

Peak  Negative-Pulse  Grid  Voltage  

Peak  Cathode  Current  

Average  Cathode  Current  

Plate  Dissipation  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode. . . 

Heater  positive  with  respect  to  cathode. . . 


6.3 

volts 

0.9 

ampere 

Unit  No. 1 

UnitNo.2 

4.2 

9 

pf 

2.2 

7 

0.4 

1.2 

pf 

Unit  No.l 

Unit  No.2 

250 

150 

volts 

-11 

-17.5 

volts 

17.5 

6 

8750 

800 

ohms 

2000 

7500 

/Limhos 

-20 

volts 

-40 

volts 

5.5 

45 

ma 

95 

ma 

8 

ma 

AMPLIFIER 

stem 

Unit  No.l 

Unit  No.2 

Oscillator 

Amplifier 

330  max 

330  max 

volts 

1500  max 

volts 

-400  max 

-250  max 

volts 

77  max 

175  max 

ma 

22  max 

50  max 

ma 

1 . 6  max 

10  max 

watts 

200  max 

200  max 

volts 

200*max 

200*max 

volts 

2.2  max 

2 . 2  max 

megohms 

2.2  max 

2 . 2  max  megohms 

Maximum  Circuit  Values: 

Grid-Circuit  Resistance: 

For  cathode-bias  operation  

For  grid-resistor-bias  operation  

■  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  vertical  scanning  cycle.  In  a 
525-line,  30-frame  system,  15  per  cent  of  one  vertical  scanning  cycle  is  2 . 5  milliseconds. 
*  The  dc  component  must  not  exceed  100  volts. 

AVERAGE  CHARACTERISTICS 


50        100       150       200      250      300      350  400 
PLATE  VOLTS 


262 


BEAM  POWER  TUBE 

4 Glass  octal  type  used  as  horizontal  deflection 
amplifier  in  television  receivers.  Outline  25A, 
OUTLINES  SECTION.  Tube  requires  octal 
socket  and  should  be  operated  vertically  (base  ^  W\F 

down  or  up)  or  horizontally  with  pins  2  and  7  in  wt#VO 
a  vertical  plane.  Heater  volts  (ac/dc)  6,3;  am-  p  i  #  *i  •« 

"      peres,  2.25.  Characteristics  as  class  Ai  ampli-  Reiatedtype: 
fier:  plate  and  grid-No.2  volts,  175;  grid-No.l  21EX6 
G2  volts,  -30;  triode  amplification  factor,  4.2; 

plate  resistance  (approx.),  8500  ohms;  transconductance,  7700  /umbos;  plate  ma.,  67;  grid-No.2  ma., 
3.3.  Maximum  ratings  as  horizontal-deflection  amplifier:  dc  plate  volts,  770  max;  peak  positive-pulse 
plate  volts,  7000  max;  peak  negative-pulse  plate  volts,  -1500  max;  dc  grid-No.2  volts,  195  max;  peak 
negative-pulse  grid-No.l  volts,  -220  max;  cathode  ma.,  770  max  (peak),  220  max  (average) ;  plate  dissi- 
pation, 22  max  watts;  grid-No.2  input,  3.5  max  watts;  peak  heater-cathode  volts,  200  max  (the  dc  com- 
ponent must  not  exceed  100  volts).  This  type  is  used  principally  for  renewal  purposes. 

^^h^  BEAM  POWER  TUBE 

'*®^[r?z  \\  Glass  octal  type  used  as  vertical 

(         P  I  deflection  amplifier  in  television  re-  -  ■-%#^ 

H(l>5^-/^^  ceivers.  Outline  14E,  OUTLINES  OC  TO 

^^^^.^-K  SECTION.  Tube  requires  octal  socket  Related  type: 

^  and  may  be  operated  in  any  position.  7EY6 
Heater  volts  (ac/dc),  6.3 ;  amperes,  0.68. 

CLASS  Ai  AMPLIFIER 

Characteristics: 

Plate  Voltage   50  250  volts 

Grid-No.2  Voltage   250  250  volts 

Grid-No.l  Voltage   0  -17.5  volts 

Plate  Resistance  (Approx.)   —  60000  ohms 

Transconductance   —  4400  /xmhos 

Grid-No.l  Voltage  (Approx.)  for  plate  current  of  100    —  —48  volts 

Plate  Current   153*  44  ma 

Grid-No.2  Current   21  •  3  ma 

VERTICAL  DEFLECTION  AMPLIFIER 

For  operation  in  a  525-line,  30-frame  system 
Maximum  Ratings,  (Design-Maximum  Values): 

DC  Plate  Voltage   350  max  volts 

Peak  Positive-Pulse  Plate  Voltage®   2500  max  volts 

Grid-No.2  (screen-grid)  Voltage   300  max  volts 

Peak  Negative-Pulse  Grid-No.1  (control-grid)  Voltage   -250  max  volts 

Peak  Cathode  Current   180  max  ma 

Average  Cathode  Current  '   60  mox  ma 

Plate  Dissipation   11  max  watts 

Grid-No.2  Input   2.75  max  watts 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  max  volts 

Heater  positive  with  respect  to  cathode   200"max  volts 

Bulb  Temperature  (At  hottest  point)   200  max  °C 

Maximum  Circuit  Values: 

Grid-No.l-Circuit  Resistance: 

For  fixed-bias  operation   1  max  megohm 

For  cathode-bias  operation   2.2  max  megohms 

•  This  value  can  be  measured  by  a  method  involving  a  recurrent  waveform  such  that  the  maximum 

ratings  of  the  tube  will  not  be  exceeded. 

°  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  vertical  scanning  cycle.  In  a 
525-line,  30-frame  system,  15  per  cent  of  one  vertical  scanning  cycle  is  2 . 5  milliseconds. 
■  The  dc  component  must  not  exceed  100  volts. 


BEAM  POWER  TUBE 

Glass  octal  type  used  as  vertical 
deflection  amplifier  in  television  re- 
ceivers. Outline  14E,  OUTLINES 
SECTION.  Tube  requires  octal  socket 
and  may  be  operated  in  any  position. 
Heater  volts  (ac/ dc),  6.3 ;  amperes,  0.8. 


6EZ5 


263 


RCA  Receiving  Tube  Manual 


CLASS  Ai  AMPLIFIER 

Characteristics: 

Plate  Voltage                                                                                 60  250  volts 

Grid-No.2  Voltage                                                                        250  250  volts 

Grid-No.  1  Voltage                                                                         0^  -20  volts 

Plate  Resistance  (Approx.)                                                             —  50000  ohms 

Transconductance                                                                        —  4100  /iinhos 

Grid-No.l  Voltage  (Approx.)  for  plate  current  of  100  n&                     —  —50  volts 

Plate  Current                                                                            180*  43  ma 

Grid-No.2  Current                                                                       26*  3.5  ma 

VERTICAL  DEFLECTION  AMPLIFIER 

For  operation  in  a  525-line,  SO-frame  system 
Maximum  Ratings,  (Design-Maximum  Values): 

DC  Plate  Voltage   350  max  volts 

Peak  Positive-Pulse  Plate  Voltage®   2500  max  volts 

Grid-No.2  (screen-grid)  Voltage     300  max  volts 

Peak  Negative-Pulse  Grid-No.  1  (control-grid)  Voltage   -250  max  volts 

Peak  Cathode  Current   260  max  ma 

Average  Cathode  Current   75  max  ma 

Plate  Dissipation   12  max  watts 

Grid-No.2  Input   2.75  max  watts 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  max  volts 

Heater  positive  with  respect  to  cathode   200"max  volts 

Bulb  Temperature  (At  hottest  point)   200  max  °C 

Maximum  Circuit  Values: 

Grid-No.l-Circuit  Resistance: 

For  fixed-bias  operation   1  max  megohm 

For  cathode-bias  operation   2.2  max  megohms 

•  This  value  can  be  measured  by  a  method  involving  a  recurrent  waveform  such  that  the  maximum 

ratings  of  the  tube  will  not  be  exceeded. 

°  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  vertical  scanning  cycle.  In  a 
525-line,  30-frame  system,  15  per  cent  of  one  vertical  scanning  cycle  is  2. 5  milliseconds. 
■  The  dc  component  must  not  exceed  100  volts. 


HIGH-MU  TRIPLE  TRIODE       kt^.kt,  " 
Miniature  type  used  in  oscillator-      "  Q^-^^^ 
^  ^-v^  ^^ixer  and  afc  service  in  FM  receivers.  ^"^^(2)/^^ '^^^^{j)^^^ 

6EZ8  Outline  8B,  OUTLINES  SECTION.  Zlf'rl^^t^M^ 

Tube  requires  miniature  nine-contact  Gt3®\>^a^^A^ 

socket  and  may  be  operated  in  any   

position.  Heater  volts  (ac/dc),  6.3 ;  am-       KT3  gti 
peres,  0.45. 

CLASS  Ai  AMPLIFIER  (Each  Unit  Unless  Otherwise  Specified) 
Maximum  Ratings,  (Design-Maximum  Values) : 

Plate  Voltage   330  max  volts 

Grid  Voltage: 

Negative-bias  value   -50  max  volts 

Positive-bias  value   0  max  volts 

Plate  Dissipation   2  max  watts 

Total  Plate  Dissipation  (All  plates)   5  max  watts 

Heater-Cathode  Voltage  (Unit  No.3) : 

Heater  negative  with  respect  to  cathode   100  max  volts 

Heater  positive  with  respect  to  cathode   100  wax  volts 

Characteristics: 

Plate  Voltage   125  volts 

Grid  Voltage   1  volt 

Amplification  Factor   57 

Plate  Resistance  (Approx.) .  .  .   13600  ohms 

Transconductance   4200  /umhos 

Grid  Voltage  (Approx.)  for  plate  current  of  20    —  4  volts 

Plate  Current   4,2  ma 


264 


Technical  Data 


HIGH-MU  TRIODE 

Metal  type  6F5  and  glass  octal  type  6F5- 
GT  used  in  resistance-coupled  amplifier  cir- 
cuits. Outlines  3  and  15A,  respectively,  OUT- 
LINES SECTION.  Tubes  require  octal  socket 
and  may  be  mounted  in  any  position.  Type 
6F5-GT  may  be  supplied  with  pin  No. 1  omitted, 
w.  Heater  volts  (ac/dc),  6.3;  amperes,  0.3. Typical 

operation  as  class  Ai  amplifier:  plate  volts,  250  (300  max);  grid  volts,  -2;  amplification  factor,  100; 
plate  resistance  (approx.),  66000  ohms;  transconductance,  1500  /ihmos;  plate  ma.,  0.9.  Peak  heater- 
cathode  volts,  90  max.  Type  6F5-GT  is  a  DISCONTINUED  type  listed  for  reference  only.  Type  6F5 
is  used  principally  for  renewal  purposes. 


6F5 

6F5GT 

Related  type: 
12F56T 


POWER  PENTODE 


6F6 
6F6G 
6F6GT 


Metal  type  6F6  and  glass  octal 
types  6F6-G  and  6F6-GT  used  in  the 
audio  output  stage  of  ac  receivers. 
Tubes  are  capable  of  large  power  out- 
put with  relatively  small  input  voltage. 
Outlines  5,  26,  and  14E,  respectively,  OUTLINES  SECTION.  Type  6F6-GT  may 
be  supplied  with  pin  No.l  omitted.  Tubes  require  octal  socket  and  may  be  mounted 
in  any  position.  It  is  especially  important  that  these  tubes,  like  other  power- 
handling  tubes,  be  adequately  ventilated.  Types  6F6-G  and  6F6-GT  are  used 
principally  for  renewal  purposes.  Heater  volts  (ac/dc),  6.3;  amperes,  0.7. 


CLASS  Ai  AMPLIFIER 


Maximum  Ratings,  {Design-Center  Values): 

Plate  Voltage  

Grid-No.2  (screen-grid)  Voltage  

Plate  Dissipation  

Grid-No.2  Input  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode . 

Heater  positive  with  respect  to  cathode .  . 

Typical  Operation: 

Plate  Voltage  

Grid-No.2  Voltage  

Grid-No.l  (Control-Grid)  Voltage  

Peak  AF  Grid-No.l  Voltage  

Zero-Signal  Plate  Current  

Maximum-Signal  Plate  Current  

Zero-Signal  Grid-No.2  Current  

Maximum-Signal  Grid-No.2  Current  

Amplification  Factor  

Plate  Resistance  (Approx.)  

Transconductance  

Load  Resistance  

Total  Harmonic  Distortion  

Maximum-Signal  Power  Output  


Pentode 
Connection 
375  max 
285  max 
11  max 
3.75  max 


Triode 
Connection^ 
350  max 

10  max 


volts 
volts 
watts 
watts 


90  max 

90  max 

volts 

90  max 

90  max 

volts 

Pentode 

Triode 

Connection 

Connection^ 

250 

285 

250 

volts 

250 

285 

volts 

-16.5 

-20 

-20 

volts 

16.5 

20 

20 

volts 

34 

38 

31 

ma 

36 

40 

34 

ma 

6.5 

7 

ma 

10.5 

13 

ma 

6.8 

80000 

78000 

2600 

ohms 

2500 

2550 

2600 

jumhos 

7000 

7000 

4000 

ohms 

8 

9 

6.5 

per  cent 

3.2 

4.8 

0.85 

watts 

PUSH-PULL  CLASS  A^  AMPLIFIER 
Maximum  Ratings:  (Same  as  for  class  Ai  amplifier) 
Typical  Operation  {Values  are  for  two  tubes): 


Plate  Voltage   315  volts 

Grid-No.2  Voltage   285  volts 

Grid-No.l  (Control-Grid)  Voltage   -24  volts 

Peak  AF  Grid-No.l-to-Grid-No.l  Voltage   48  volts 

Zero-Signal  Plate  Current   62  ma 

Maximum-Signal  Plate  Current   80  ma 

Zero-Signal  Grid-No.2  Current   12  ma 

Maximum-Signal  Grid-No.2  Current   19.5  ma 

Effective  Load  Resistance  (Plate-to-plate)   10000  ohms 

Total  Harmonic  Distortion   4  percent 

Maximum-Signal  Power  Output   11  watts 


265 


RCA  Receiving  Tube  Manual 


0 . 1  max 
0 . 5  max 


megohm 
megohm 


G3p 


6F8G 


Maximum  Circuit  Values: 

Grid-No.  1  Circuit  Resistance: 

For  fixed-bias  operation  

For  cathode-bias  operation .  .  f  

*  Grid  No.2  connected  to  plate. 

LOW-MU  TRIODE- 
REMOTE-CUTOFF  PENTODE 

Glass  type  adaptable  to  circuit  design  in 
APT'  several  ways.  Outline  24B,  OUTLINES  SEC- 

wl  #  TION.  Heater  volts  (ac/dc),  6.3;  amperes,  0.3. 

Typical  operation  as  class  Ai  amplifier:  pentode 
unit — plate  volts,  250  max-,  grid-No.2  volts,  100; 
grid-No.  1  volts,  -3;  plate  resistance,  0.85  meg- 
ohm; transconductance,  1100  Mmhos;  plate  ma., 
6.5;  grid-No.2  ma.,  1.5;  triode  unit — plate  volts, 
100  max\  grid  volts,  -3;  amplification  factor,  8;  plate  resistance,  0.016  megohm;  transconductance,  500 
Mmhos;  plate  ma.,  3.5.  This  type  is  used  principally  for  renewal  purposes. 

MEDIUM-MU  TWIN  TRIODE 

Glass  octal  type  used  as  voltage  amplifier 
or  phase  inverter  in  radio  equipment.  Outline  23, 
OUTLINES  SECTION.  Tube  requires  octal 
socket.  Except  for  the  heater  rating  of  6.3  volts 
(ac/dc)  and  0.6  ampere  and  interelectrode  ca- 
pacitances, each  triode  unit  is  identical  elec- 
trically with  type  6J5.  Type  6F8-G  is  used  prin- 
cipally for  renewal  purposes. 

DIODE-SHARP-CUTOFF, 
TWIN-PLATE  TETRODE 

Miniature  type  used  in  frequency- 
divider  and  complex-wave  generator 
circuits  of  electronic  musical  instru- 
ments. Outline  8D,  OUTLINES  SEC- 
TION. Tube  requires  miniature  nine- 
contact  socket  and  may  be  operated 
in  any  position. 

Heater  Voltage  (ac/dc)  

Heater  Current.  

Direct  Interelectrode  Capacitances: 
Tetrode  Unit: 

Grid  No.l  to  Plate  A  

Grid  No.  1  to  Plate  B  

Grid  No.l  to  Cathode,  Heater,  Grid  No.2,  and  Internal  Shield  

Plate  A  to  Cathode,  Heater,  Grid  No.  2  

Plate  B  to  Cathode,  Heater,  Grid  No.2,  and  Internal  Shield  

Tetrode  Grid  No.l  to  Diode  Plate  

Tetrode  Plate  A  to  Diode  Plate  

Tetrode  Plate  B  to  Diode  Plate  


6FA7 


pbtr 


patr 


6.3 
0.3 


0.040 

0 . 030  max 

5.5 

1.8 

1.8 
0.022 
0 . 020  max 
0.055 


volts 
ampere 

Pf 
Pf 
pf 
pf 
pf 
pf 
pf 
pf 


CLASS  Ai  AMPLIFIER 

Characteristics,  {Tetrode  Unit): 

Plate  A  and  Plate  B  connected  together 

Plate  Voltage  

Grid-No.2  Voltage  

Grid-No.  1  Supply  Voltage  

Grid-No.  1  Resistor  (Bypassed)  

Plate  Resistance  (Approx.)  

Transconductance  

Plate  Current  

Grid-No.2  Current  

Grid-No.l  Voltage  (Approx.)  for  plate  current  of  20  /xa  


Using  either  Plate  A  or  B,  with  unused  plate  grounded 

Plate  Voltage  

Grid-No.2  Voltage    

Grid-No.l  Supply  Voltage  

Grid-No.l  Resistor  (Bypassed)    

Plate  Resistance  (Approx.)  

Transconductance.  

Plate  Current  

Grid-No.2  Current  

266 


100 
100 
0 

2  2 
90000 
3200 
3.8 
1.7 
-4 

100 
100 
0 

2  2 
130000 
1900 
2.2 
3 


volts 
volts 
volts 
megohms 
ohms 
/umhos 
ma 
ma 
volts 

volts 
volts 
volts 
megohms 
ohms 
/imhos 
ma 
ma 


FREQUENCY  DIVIDER  &  COMPLEX-WAVE  GENERATOR 

Tetrode  Unit 
Maximum  Ratings,  (Design-Maximum  Values): 

Plate- A  Voltage  

Plate-B  Voltage  

Grid-No.2  (screen-grid)  Supply  Voltage  

Grid-No.2  Voltage  

Grid-No.  1  (control-grid)  Voltage: 

Negative-bias  value  

Positive-bias  value  

Plate- A  Dissipation  

Plate-B  Dissipation  

Grid-No.2  Input: 

For  grid-No.2  voltages  up  to  165  volts  

For  grid-No.2  voltages  between  165  and  330  volts  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  

Maximum  Circuit  Values: 

Grid-No.  1  Circuit  Resistance: 

For  grid-No.  1  resistor-bias  operation  

Diode  Unit 

Maximum  Ratings,  (Design-Maximum  Values): 

Plate  Current  

Characteristics,  Instantaneous  Value: 

Tube  Voltage  Drop  for  plate  current  of  2  ma  

■  The  dc  component  must  not  exceed  100  volts. 


330  max  volts 
330  max  volts 
330  max  volts 
See  curve  page  70 


-50  max 
0  max 
1 . 5  max 
1 . 5  max 


volts 
volts 
watts 
watts 


0 . 65  max  watt 
See  curve  page  70 


200  max 
200"mox 


volts 
volts 


2.2  max  megohms 


1  max 


10 


volts 


AVERAGE  CHARACTERISTICS 


1         I         1         1  1 
TYPE  6FA7 
E,  '6.3  VOLTS 
GRID-No  2  VOLTS  :IOO 

PLAT 

E  A  CO 

NfJECTE 

D  TO  P 

.ATE  B 

)-No.\  V 

/OLTS 

Ecr-0. 

—  GB»C 

'  o 

7 

-0.5 

I 

-1.5 

-0,5  • 

•  Icro 

Z 

-2,5 

0  100  200  300  400  500 

PLATE  VOLTS  92Cm-i069JI 

'  DUAL  TRIODE 

Glass  type  containing  high-mu  -  rr\T 

pTOp  ^""^--Jt)           low-mu  triode  units  used  as  com-  OFD/ 

Gt^^^^^^^_/^»^T|  bined  vertical-deflection  oscillator  and  Related  type: 

— vertical-deflection  amplifier  in  televi-  13FD7 
sion  receivers.  Maximum  dimensions: 
over-all  length,  2.9  inches;  seated  height,  2.62  inches;  diameter,  1.188  inches.  Tube 
requires  miniature  nine-contact  socket  and  may  be  mounted  in  any  position. 
Heater  volts  (ac/dc),  6.3;  amperes,  0.925. 

CLASS  Ai  AMPLIFIER 

Characteristics:                                                                Unit  No.  1  Unit  No.  2 

Plate  Voltage                                                                             250  60     150  volts 

Grid  Voltage                                                                                -3  0-17.5  volts 

Amplification  Factor                                                                     64  -  6 

Plate  Resistance  (Approx.)                                                        40000  -     800  ohms 

Transconductance                                                                     1600  -    7500  Aimhos 


267 


RCA  Receiving  Tube  Manual 


Plate  Current  

Grid  Voltage  (Approx.) : 

For  plate  current  of  10  /xa  

For  plate  current  of  100  /xa  

Transconductance,  for  plate  current  of  1  ma . 
Plate  Current,  for  grid  voltage  of  -25  volts .  . 


-5.5 


95°  40 


-40 
500 


volts 
volts 
/imhos 
ma 


VERTICAL-DEFLECTION  OSCILLATOR  AND  AMPLIFIER 

For  operation  in  a  525-line,  30-frame  system 


Maximum  Ratings,  {Design-Maximum  Values) : 

DC  Plate  Voltage  

Peak  Positive-Pulse  Plate  Voltage"  

Peak  Negative-Pulse  Grid  Voltage  

Peak  Cathode  Current.  

Average  Cathode  Current  

Plate  Dissipation  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode. . 

Heater  positive  with  respect  to  cathode .  . 


Unit  No.  1 

Unit  No.  2 

Oscillator 

Amplifier 

330  max 

330  max 

volts 

1500  max 

volts 

-400 

-250  max 

volts 

70  max 

175  max 

ma 

20  max 

50  max 

ma 

1 . 5  max 

10  max 

watts 

200  max 

200  max 

volts 

200*max 

200 'wax 

volts 

2.2  max 

2.2  max 

megohms 

Maximum  Circuit  Values: 

Grid-Circuit  Resistance: 

For  grid-resistor-bias  or  cathode-bias  operation  

°  This  value  can  be  measured  by  a  method  involving  a  recurrent  waveform  such  that  the  maximum 
ratings  of  the  tube  will  not  be  exceeded. 

■  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  vertical  scanning  cycle.  In  a 
525-line,  30-frame  system,  15  per  cent  of  one  vertical  scanning  cycle  is  2.5  milliseconds. 
•  The  dc  component  must  not  exceed  100  volts. 


6FE5 

Related  type: 
50FE5 


K.O3 


BEAM  POWER  TUBE 

Glass  octal  type  used  in  the  audio 
output  stages  of  compact  stereophonic 
phonographs  and  in  radio  and  televi- 
sion receivers.  Tube  has  high  sensi- 
tivity at  very  low  plate  and  screen- 
grid  voltages;  it  can  deliver  relatively  high  power  output  at  low  values  of  plate 
load  resistance.  Outline  14F,  OUTLINES  SECTION.  Tube  requires  octal  socket 
and  may  be  mounted  in  any  position. 

Heater  Voltage  (ac/dc)  

Heater  Current  

Direct  Interelectrode  Capacitances  (Approx.): 

Grid  No.l  to  Plate  

Grid  No.l  to  Cathode,  Heater,  Grid  No.2,  and  Grid  No.3  

Plate  to  Cathode,  Heater,  Grid  No.2,  and  Grid  No.3  


CLASS  Ai  AMPLIFIER 
Maximum  Ratings,  {Design-Maximum  Values): 

Plate  Voltage  

Grid-No.2  (screen-grid)  Voltage  

Grid-No.2  Input  

Plate  Dissipation   

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  

Typical  Operation: 

Plate  Supply  Voltage  

Grid-No.2  Supply  Voltage  

Grid-No.l  (Control-Grid)  Voltage  

Cathode-Bias  Resistor  

Peak  AF  Grid-No.l  Voltage  

Zero-Signal  Plate  Current  

Maximum-Signal  Plate  Current   

Zero-Signal  Grid-No.2  Current   

Maximum-Signal  Grid-No.2  Current  

Plate  Resistance  (Approx.)  

268 


6.3 

volts 

1.2 

amperes 

0.44 

Pf 

15 

Pf 

9 

pf 

175 

max 

volts 

175 

max 

volts 

2.4 

max 

watts 

14.5 

max 

watts 

300 

max 

volts 

200 

'max 

volts 

Fixed  Bias 

Cathode  Bias 

130 

145 

130 

145 

volts 

130 

145 

130 

145 

volts 

-12.5 

-16 

volts 

120 

150 

ohms 

12.5 

15 

11.9 

15.4 

volts 

82 

80 

88 

86 

ma 

94 

100 

90 

86 

ma 

4 

4 

5 

4.2 

ma 

15 

18 

9 

17 

ma 

8000 

ohms 

AVERAGE  PLATE  CHARACTERISTICS 


92CM-I0405T 


Transconductance  

Load  Resistance  

Total  Harmonic  Distortion  

Maximum-Signal  Power  Output. 


1000 
12 
4.2 


1000 
15 
5.6 


PUSH-PULL  CLASS  Ai  AMPLIFIER 


Maximum  Ratings:  (Same  as  for  class  Aj  amplifier) 

Typical  Operation  {Values  are  for  two  tubes): 

Plate  Supply  Voltage  

Grid-No.2  Supply  Voltage  

Cathode-Bias  Resistor  

Peak  AF  Grid-No.l-to-Grid-No.l  Voltage  

Zero-Signal  Plate  Current  

Maximum-Signal  Plate  Current  

Zero-Signal  Grid-No.2  Current  

Maximum-Signal  Grid-No.2  Current  

Effective  Load  Resistance  (Plate-to-plate)  

Total  Harmonic  Distortion  

Maximum-Signal  Power  Output  


130 
130 
75 
25.8 
150 
154 
7.2 
17 
1600 
6 
7 


9500 

1000  1000 

10  13 

3.5  4.3 


145 
145 
75 
28.8 
160 
172 
8 
20 
1600 
6 

8.5 


Maximum  Circuit  Values: 

Grid-No.l-Circuit  Resistance: 

For  fixed-bias  operation  

For  cathode-bias  operation  

■  The  dc  component  must  not  exceed  100  volts. 


AVERAGE  CHARACTERISTICS 


0 . 1  max 
0 . 5  max 


ftmhos 
ohms 
per  cent 
watts 


volts 
volts 
ohms 
volts 
ma 
ma 
ma 
ma 
ohms 
per  cent 
watts 


megohm 
megohm 


269 


RCA  Receiving  Tube  Manual 


6FG6 


6FG7 

Related  type: 
5FG7 


Refer  to  type  EM84/6FGS 

MEDIUM-MU  TRIODE- 
SHARP-CUTOFF  PENTODE 

Miniature  type  used  as  combined 
oscillator  and  mixer  tube  in  vhf  tele- 
vision receivers  employing  series-con- 
nected heater  strings.  Outline  8B,  OUT- 
LINES SECTION.  Tube  requires  min- 
iature nine-contact  socket  and  may  be  mounted  in  any  position.  Heater  volts 
(ac/dc),  6.3;  amperes,  0.45;  warm-up  time  (average),  11  seconds. 

CLASS  A,  AMPLIFIER 

Maximum  Ratings,  {Design-M aximum  Values) : 
Plate  Voltage  

GRID-NO.2  (SCR3BN-GRID)  SUPPLY  VOLTAGE  

Grid-No.2  Voltage  

Grid-No.1  (control-grid)  Voltage,  Positive-bias  value  

Grid-No.2  Input: 

For  grid-No.2  voltages  up  to  165  volts  

For  grid-No.2  voltages  between  165  and  330  volts  

Plate  Dissipation  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  

Characteristics: 

Plate  Voltage  

Grid-No.2  Voltage  

Grid-No.  1  Voltage  

Amplification  Factor  

Plate  Resistance  (Approx.)  

Transconductance  

Plate  Current  

Grid-No.2  Current  

Grid-No.l  Voltage  (Approx.)  for  plate  current  of  30  /la  

°  The  dc  component  must  not  exceed  100  volts. 


Triode 

Pentode 

Unit 

Unit 

330  max 

330  max 

volts 

330  max 

volts 

See  curve  page  70 

0  max 

0  max 

volts 

0.55  max 

watt 

See  curve  page  70 

2 . 5  max 

3  max 

watts 

200  max 

200  max 

volts 

200  max° 

200  max° 

volts 

125 

100  125 

volts 

100  125 

volts 

-1 

0  -1 

volts 

43 

5700 

-180000 

ohms 

7500 

7400  6000 

^mhos 

13 

11 

ma 

4 

ma 

6.5 

-  -7.5 

volts 

6FH5 

Related  types 
2FH5,  3FH5 


HIGH-MU  TRIODE 

Miniature  type  used  as  an  rf  am- 
plifier in  vhf  tuners  of  television  re- 
ceivers. Outline  7B,  OUTLINES 
SECTION.  Tube  requires  seven-con- 
tact socket  and  may  be  mounted  in 
any  position. 


Heater  Voltage  (ac/dc)  . 
Heater  Current  


Direct  Interelectrode  Capacitances  (Approx,): 

Grid  to  Plate  

Grid  to  Cathode,  Heater,  and  Internal  Shield  

Plate  to  Cathode,  Heater,  and  Internal  Shield  

e  With  external  shield  connected  to  cathode. 

CLASS  Ai  AMPLIFIER 
Maximum  Ratings,  (Design- Maximum  Values): 

Plate  Voltage  

Grid  Voltage,  Positive-bias  value  

Cathode  Current  

Plate  Dissipation  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   . 

Heater  positive  with  respect  to  cathode  


150  max 
0  max 
22  max 
2 . 2  max 

100  max 
100  max 


volts 
volts 
ma 
watts 

volts 
volts 


270 


Technical  Data 


Characteristics: 

Plate  Voltage   135  volts 

Grid  Voltage   -1  volt 

Plate  Resistance  (Approx.)   5600  ohms 

Transconductance   9000  fimhos 

Plate  Current   11  ma 

Grid  Voltage  (Approx.)  for  plate  current  of  100  ha   -5.5  volts 

Maximum  Circuit  Values: 

Grid-Circuit  Resistance: 

For  cathode-bias  operation   1  max  megohm 

AVERAGE  PLATE  CHARACTERISTICS 


120       140  IbO 
PLATE  VOLTS 


240  2b0 

■jaCM-IOJSSTt 


P2tR 


MEDIUM-MU  TRIODE— 

THREE-PLATE  TETRODE 

Miniature  type  used  in  complex- 
^2tr  wave  generator  applications.  Sharp- 
cutoff  tetrode  unit  has  pair  of  additional 
P,;,^^  plates.  Outline  8B,  OUTLINES  SEC- 
TION. Tube  requires  nine-contact 
socket  and  may  be  mounted  in  any 
position. 


Heater  Voltage  (ac/dc)  

Heater  Current  

Direct  Interelectrode  Capacitances:® 
Triode  Unit: 

Grid  to  Plate  

Grid  to  Cathode  and  Heater  

Plate  to  Cathode  and  Heater  

Tetrode  Unit: 

Grid  No.l  to  Plate  No.2  

Grid  No.l  to  Cathode,  Heater,  Grid  No.2,  Plate  No.l  A,  and  Plate  No.lB 
Plate  No.2  to  Cathode,  Heater,  Grid  No.2,  Plate  No.l  A,  and  Plate  No.lB 

Tetrode  Grid  No.l  to  Triode  Plate  

Tetrode  Plate  No.2  to  Triode  Plate  

^With  external  shield  connected  to  cathode. 


6FH8 


6.3 
0.45 


1.4 
2.6 
1 

0 . 06  max 

4.5 

1.4 
0.35  max 
0 . 008  max 


volts 
ampere 

Pf 
Pf 

Pf 
pf 
pf 
pf 
pf 


CLASS  A,  AMPLIFIER 
Characteristics:  Triode  Unit 

Plate  Voltage                                                                                            100  volts 

Grid  Voltage                                                                                                 -1  volt 

Amplification  Factor   40 

Plate  Resistance  (Approx.)                                                                               7400  ohms 

Transconductance                                                                                       5400  /imhos 

Plate  Current                                                                                               7.9  ma 

Grid  Voltage  (Approx.)  for  plate  current  of  100  fia.                                               -7  volts 

Tetrode  Unit  with  Plates  No.  lA  and  No.  IB  Connected  to  Cathode  at  Socket 

Plate-No.2  Voltage                                                                                        250  volts 

Grid-No.2  Voltage    250  volts 

271 


RCA  Receiving  Tube  Manual 


Grid-No.l  Voltage  

Plate-No.2  Resistance  (Approx.)  

Transconductance,  Grid  No.l  to  Plate  No.2  

Plate-No.2  Current  

Grid-No.2  Current  

Grid-No.l  Voltage  (Approx.)  for  plate-No.2  current  of  100   

COMPLEX- WAVE  GENERATOR 

Maximum  Ratings,  {Design-Maximum  Values):  Triode  Unit 

Plate  Voltage   275  max 

Plate-No.1  A  Voltage  

Plate-No.IB  Voltage  

Plate-No.2  Voltage  

Grid-No.2  (screen-grid)  Supply  Voltage  

Grid-No.2  Voltage  

Grid-No.1  (control-grid)  Voltage: 

Negative-bias  value     -40  max 

Positive-bias  value   0  max 

Plate  Dissipation   1.7  max 

Plate-No.  1 A  Dissipation  

Plate-No.IB  Dissipation  

Plate-No.2  Dissipation  

Grid-No.2  Input: 

For  grid-No.2  voltages  up  to  137.5  volts   - 

For  grid-No.2  voltages  between  137.5  and  275  volts  

Typical  Operation  With  Separate  Plate  Operation  {Tetrode  Unit): 

Plates-No.lA,  No.lB,  and  No.2  Voltage  

Grid-No.2  Voltage  

Grid-No.l  Voltage  

Plate-No.  1 A  Current  

Plate-No.IB  Current  

Plate-No.2  Current  

Grid-Mo.2  Current  

Transconductance  (Approx.) : 

Grid  No.l  to  Plate  No.l  A  

Grid  No.l  to  Plate  No.lB  

Grid  No.l  to  Plate  No.2  

Maximum  Circuit  Values: 

Grid-No. 1-Circuit  Resistance: 

For  fixed-bias  operation  


-2 
0.75 
4400 
7.3 
1.4 
-7 


volts 
megohm 
/xmhos 
ma 
ma 
volts 


Tetrode  Unit 

200  max 
200  max 
275  max 
275  max 


volts 
volts 
volts 
volts 
volts 
See  curve  page  70 


-40  max 
0  max 

0 . 3  max 
0 . 3  max 
2 . 3  max 


volts 
volts 

watts 
watt 
watt 

watts 


0.45  max  watt 
See  curve  page  70 


100 
50 
-1 
0.04 
0.C4 
1.6 
0.3 

70 
70 
2500 


volts 
volts 
volt 
ma 
ma 
ma 
ma 

jiimhos 
iimhoa 
/imhos 


Triode  Unit    Tetrode  Unit 
0 . 5  max        0 .  5  max  megohm 


MEDIUM-MU  DUAL  TRIODE  ^^^^^^^kt, 
i'^  Duodecar  type  used  as  combined      ^^^/l— .  — 

OrJ#  vertical-deflection-oscillator  and  ver-  GieSv^ — 

tical-deflection-amplifier  tube  in  tele-  (hs/^_\/& 
vision  receivers.  Outline  12B,  OUT-  ©  '^tj 

LINES  SECTION.  Tube  requires  duo-  h  h 

decar  twelve-contact  socket  and  may  be  mounted  in  any  position.  Heater  volts 
(ac/dc),  6.3;  amperes,  0.9. 

CLASS  Ai  AMPLIFIER 

Characteristics:  Unit  No.l   Unit  No.2 

Plate  Voltage   250     150     250  volts 

Grid  Voltage   -8         0    -9  .5  volts 

Amplification  Factor   22.5        -  15.4 

Plate  Resistance  (Approx.)   9000        -    2000  ohms 

Transconductance   2500        -    7700  ^mhos 

Plate  Current   8       68"     41  ma 

Grid  Voltage  (Approx.)  for  plate  current  of  10    -18         -         -  volts 

Grid  Voltage  (Approx.)  for  plate  current  of  50  /xa   -        -     -23  volts 

VERTICAL-DEFLECTION  OSCILLATOR  AND  AMPLIFIER 

For  operation  in  a  525-line,  20-frame  system 

Unit  No.l  Unit  No.2 

fAaximvm  Katmgs,  {Design-Maximum  Values):                             Oscillator  Amplifier 

DC  Plate  Voltage                                                                 350  maa:  550  wax  volts 

Peak  Positive-Pulse  Plate  Voltage*                                        -  2500  max  volts 

Peak  Negative-Puise  Grid  Voltage                                       -400  max  -250  max  volts 

Peak  Cathode  Current                                                           -  150  waa:  ma 

Average  Cathode  Current                                                      -  50  max  ma 

Plate  Dissipation                                                                     1  max  10  max  watts 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode                                  200  max  200  max  volts 

Heater  positive  with  respect  to  cathode                                     200  °max  200  °max  volts 

272 


Maximum  Circuit  Values: 

Grid-Circuit  Resistance: 

For  fixed-bias  operation   2.2  max        2 . 2  max  megohms 

For  cathode-bias  operation   2.2  max         -  megohms 

■  This  value  can  be  measured  by  a  method  involving  a  recurrent  waveform  such  that  the  maximum 
ratings  of  the  tube  will  not  be  exceeded. 

•  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  vertical  scanning  cycle.  In  a 
525-line,  30-frame  system,  15  per  cent  of  one  vertical  scanning  cycle  is  2.5  milliseconds. 

°  The  dc  component  must  not  exceed  100  volts. 
IC 

^^^^>^T,  DUAL  TRIODE 

Duodecar  type  used  as  combined  M^r^AT 
q(J)^ — I  r— J^)      vertical-deflection  oscillator  and  verti-  OFlVl/ 
cal-deflection  amplifier  in  television  re- 
(iJ  —  vi)  ceivers.  The  high-mu  triode  unit  No.l 

H  M  is  used  as  an  oscillator,  and  the  low- 

mu  triode  unit  No.2  is  used  as  an  amplifier.  Outline  12B,  OUTLINES  SECTION. 
Tube  requires  duodecar  twelve-contact  socket  and  may  be  mounted  in  any  posi- 
tion. Heater  volts  (ac/dc),  6.3;  amperes,  1.05. 

CLASS  Ai  AMPLIFIER 

Characteristics:  Unit  No.  1    Unit  No.  2 

Plate  Voltage   250  175  volts 

Grid  Voltage   -3  -25  volts 

Amplification  Factor   66  5.5 

Plate  Resistance  (Approx.)   30000  920  ohms 

Transconductance   2200  6000  /xmhos 

Grid  Voltage  (Approx.)  for  plate  current  of  20  /xa   -5.3  -  volts 

Grid  Voltage  (Approx.)  for  plate  current  of  200  n&   -  -45  volts 

Plate  Current   2  40  ma 

VERTICAL-DEFLECTION  OSCILLATOR  AND  AMPLIFIER 

For  operation  in  a  525-line,  30-frame  system 

Maximum  Ratings,  (Design-Maximum  Values):                            Oscillator  Amplifier 

DC  Plate  Voltage                                                                 350  max  550  wax  volts 

Peak  Positive-Pulse  Plate  Volt AGE#                                         -  1500  wax  volts 

Peak  Negative-Pulse  Plate  Voltage                                    -400  wax  -250  wax  volts 

Peak  Cathode  Current                                                           -  175  wax  ma 

Average  Cathode  Current                                                        -  50  wox  ma 

Plate  Dissipation!                                                                 1  wax  10  wax  watts 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode                                  200  wax  200  wax  volts 

Heater  positive  with  respect  to  cathode                                   200"wax  200"wax  volts 

Maximum  Circuit  Values: 

Grid-Circuit  Resistance: 

For  fixed-bias  operation   1  wax  1  wax  megohm 

For  cathode-bias  operation   2.2  wax       2 . 2  wax  megohms 

#  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  vertical  scanning  cycle.  In  a 
525-line,  30-frame  system,  15  per  cent  of  one  vertical  scanning  cycle  is  2.5  milliseconds. 

t  An  adequate  bias  resistor  or  other  means  is  required  to  protect  the  tube  in  the  absence  of  excitation. 

■  The  dc  component  must  not  exceed  100  volts. 

H  TWIN  DIODE-HIGH-MU  TRIODE 

*(4^^£lrS)^^  Miniature  type  used  as  combined 

KDirV^-£^^\^'^T  detector  and  af  voltage  amplifier  Mr^m^ 

<lfJJ      -Op  in  FM  receivers.  Outline  8B,  OUT-  OrlVlO 

pp  (FxV^^  LINES  SECTION.  Tube  requires  min- 
iature  nine-contact  socket  and  may  be 

*^D2  pt  operated  in  any  position.  Heater  volts 

^  (ac/dc),  6.3;  amperes,  0.45. 

TRIODE  UNIT  AS  CLASS  Ai  AMPLIFIER 
Maximum  Ratings,  (Design-Maximum  Values): 

Plate  Voltage   330  wax  volts 

Grid  Voltage,  Positive-bias  value   0  max  volts 

273 


RCA  Receiving  Tube  Manual 


Plate  Dissipation   \.lmax  watts 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  max  volts 

Heater  positive  with  respect  to  cathode   200°max  volts 

Characteristics: 

Plate  Voltage   250  volts 

Grid  Voltage   —  3  volts 

Amplification  Factor   70 

Plate  Resistance  ( Approx.)   58000  ohms 

Transconductance   1200  Mmhos 

Plate  Current   1  ma 

DIODE  UNITS  (Each  Unit) 
Maximum  Ratings,  {Design-Maximum  Values): 

Plate  Current   5  max  ma 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  max  volts 

Heater  positive  with  respect  to  cathode   200° wax  volts 

Characteristics,  Instantaneous  Value: 

Tube  Voltage  Drop  for  plate  current  of  20  ma   5  volts 

°  The  dc  component  must  not  exceed  100  volts. 

H  p 

HIGH-MU  TRIODE  ^ 

^         f  m  Miniature  type  with  frame  grid  \  «  \^ 

OPCifdA        used  as  rf-amplifier  tube  in  vhf  tuners  r4M^/"""''""-~Tr> 

of  television  receivers.  Outline  7B,  gCHAM4^  yvl^K 


OUTLINES  SECTION.  Tube  re- 
quires  miniature  seven-contact  socket  ^ 
and  may  be  mounted  in  any  position.  Heater  volts  (ac/dc),  6.3;  amperes,  0.18. 

CLASS  A,  AMPLIFIER 


Maximum  Ratings,  (Design-Maximum  Values): 

Plate  Voltage   200  max  volts 

Grid  Voltage,  Negative-bias  value   -50  wox  volts 

Average  C/^thodb  Current   22  max  ma 

Plate  Dissipation   2.5  max  watts 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   100  max  volts 

Heater  positive  with  respect  to  cathode   100  max  volts 

Characteristics: 

Plate  Voltage   135  volts 

Grid  Voltage   -1.2  volts 

Amplification  Factor   74 

Plate  Resistance  (Approx.)   6300  ohms 

Transconductance   12000  /xmhos 

Plate  Current   8.9  ma 

Grid  Voltage  (Approx.)  for  plate  current  of  100  na.   -4.5  volts 

Maximum  Circuit  Values: 

Grid-Circuit  Resistance: 

For  cathode-bias  operation   1  max  megohm 

H 

MEDIUM-MU  TV/IN  TRIODE  "^5^^::^'*^' 

,  — ^^.y  Miniature  type  used  as  combined 

OPCal /  vertical-  and  horizontal-deflection  os-      /-Wj^  '""uIZ 

Related  type:  cillator  in  television  receivers.  Outline  gt2®>\ 

8FQ7  8D,  OUTLINES  SECTION.  Tube  re-  ^yi:^^ 

quires  miniature  nine-contact  socket       ^'^^  nc 
and  may  be  operated  in  any  position.  Except  for  direct  interelectrode  capacitances, 
this  type  is  identical  with  miniature  type  6CG7.  For  typical  operation  as  a  resistance- 
coupled  amplifier,  refer  to  RESISTANCE-COUPLED  AMPLIFIER  SECTION. 

Heater  Voltage  (ac/dc)   6 . 3  volts 

Heater  Current.   0.6  ampere 

Heater  Warm-up  Time  (average)   11  seconds 


274 


Direct  Intbrelectrode  Capacitances  ( Approx.) :  Unit  No.  1       Unit  No.  2 

Grid  to  Plate   3.6  3.8  pf 

Grid  to  Cathode  and  Heater   2.4  2.4  pf 

Plate  to  Cathode  and  Heater   0 . 34  0 . 26  pf 

Plate  of  Unit  No.l  to  Plate  of  Unit  No.2   1  pf 


H  P 

^i^^  BEAM  HEXODE 

^^Jfyr:::-^^            Miniature  type  used  as  rf-ampli-  ^CCC 

^   (y  |£^I__L  ^    fier  tube  in  vhf  television  receivers.  In  OP^O 

62®SAI^N>OvDg2    this  tube,  grid  No.l  is  the  control  grid,  Related  type: 

®*                      ^    grid  No.2  is  a  focusing  grid,  grid  No.3  2FS5 

6i  is  the  screen  grid,  and  grid  No.4  is  the 

suppressor  grid.  Grid  No.2  is  internally  connected  to  the  cathode  and  grid  No.4, 
and  aligned  with  grid  No.3.  Outline  7B,  OUTLINES  SECTION.  Tube  requires 

miniature  seven-contact  socket  and  may  be  mounted  in  any  position.  Heater 
volts  (ac/de),  6.3;  amperes,  0.2. 

CLASS  Ai  AMPLIFIER 
Maximum  Ratings,  {Design-Maximum  Values)-. 

Plate  Voltage   300  max  volts 

Grid-No.3  (screen-grid)  Voltage   150  max  volts 

Grid-No.1  (control-grid)  Voltage: 

Negative-bias  value   -50  max  volts 

Positive-bias  value   0  max  volts 

Cathode  Current   20  max  ma 

Grid-No.3  Input   0.15  max  watt 

Plate  Dissipation   3 . 25  max  watts 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  max  volts 

Heater  positive  with  respect  to  cathode   200  °max  volts 

Characteristics: 

Plate  Voltage   275  volts 

Grid-No.3  Voltage   135  volts 

Grid-No.  1  Voltage   -0.2  volt 

Plate  Resistance  (Approx.)   0.24  megohm 

Transconductance   10000  /xmhos 

Plate  Current   9  ma 

Grid-No.3  Current   0.17  ma 

Grid-No.l  Voltage  (Approx.)  for  transconductance  of  100  /xmhos   -5  volts 

Maximum  Circuit  Values: 

Grid-No.  1-Circuit  Resistance,  for  fixed-bias  operation   0.5  max  megohm 

°  The  dc  component  must  not  exceed  100  volts. 


C5)  SHARP-CUTOFF  TETRODE 

Miniature  type  used  as  rf  ampli- 
fier  in  vhf  tuners  of  television  receivers.  OP  V  W 

,sC£\VVJ7^K      Outline  7B,  OUTLINES  SECTION. 

Tube  requires  seven-contact  socket 
G-  and  may  be  mounted  in  any  position. 

Heater  Voltage  (ac/dc)   6.3  volts 

Heater  Current   0.2  ampere 

Direct  Intbrelectrode  Capacitances :° 

Grid  No.l  to  Plate   0 . 03  max  pf 

Grid  No.l  to  Cathode,  Heater,  Grid  No.2,  and  Internal  Shield   4.5  pf 

Plate  to  Cathode,  Heater,  Grid  No.2,  and  Internal  Shield   3  pf 

Cathode  to  Heater   2 . 7  •  pf 

°  With  external  shield  connected  to  cathode  except  as  noted. 

•  With  external  shield  connected  to  ground. 

CLASS  Ai  AMPLIFIER 
Maximum  Ratings,  {Design-Maximum  Values): 

Plate  Voltage   275  max  volts 

Grid-No.2  (screen-grid)  Supply  Voltage   180  max  volts 

Grid-No.2  Voltage   See  curve  page  70 

Grid-No.1  (control-grid)  Voltage,  Positive-bias  value   0  m^x  volts 


275 


RCA  Receiving  Tube  Manual 


Cathode  Current   20  max  ma 

Grid-No.2  Input: 

For  grid-No.2  voltages  up  to  90  volts   0.5  max  watt 

For  grid-No.2  voltages  between  90  and  180  volts   See  curve  page  70 

Plate  Dissipation   2  max  watts 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  max  volts 

Heater  positive  with  respect  to  cathode   200*maa;  volts 

Characteristics: 

Plate  Voltage   125  volts 

Grid-No.2  Voltage   80  volts 

Grid-No.  1  Voltage   -1  volt 

Plate  Resistance  ( Approx.)   0.1  megohm 

Transconductance   8000  /imhos 

Plate  Current   10  ma 

Grid-No.2  Current   1.5  ma 

Grid-No.l  Voltage  (Approx.)  for  plate  current  of  20  Ma   -6  volts 

Maximum  Circuit  Value: 

Grid-No.  1-Circuit  Resistance   0.5  max  megohm 


*  The  dc  component  must  not  exceed  100  volts. 


MEDIUM-MU  TRIODE-  h 

6FV8              SHARP-CUTOFF  PENTODE  "'^yh^^^'* 
-  ^\m^  m               Miniature  type  used  in  television  ^^©/j^^ 

OF  vOA        receivers  as  combined  oscillator  and  J^JJ^ 
Related  type:          amplifier.  Triode  is  used  as  vertical 

5FV8              deflection  oscillator;  pentode  is  used  (f)^^ — ^t!^) 

as  if  or  general-purpose  amplifier.  Out-  ^'^ 
line  8B,  OUTLINES  SECTION.  Tube  requires  nine-contact  socket  and  may  be 
operated  in  any  position.  Heater  volts  (ac/dc),  6.3;  amperes,  0.45;  heater  warm- 
up  time  (average),  11  seconds. 

CLASS  Ai  AMPLIFIER 

Pentode  Unit 
Maximum  Ratings,  {Design-Maximum  Values): 

Plate  Voltage.   330  max  volts 

Grid-No.2  (sgrebn-grid)  Supply  Voltage   330  max  volts 

Grid-No.2  Voltage   See  curve  page  70 

Grid-No.1  (control-grid)  Voltage,  Positive-bias  value   0  max  volts 

Plate  Dissipation   2.3  wax  watts 

Grid-No.2  Input: 

For  grid-No.2  voltages  up  to  165  volts   0 . 55  max  watt 

For  grid-No.2  voltages  between  165  and  330  volts   See  curve  page  70 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  max  volts 

Heater  positive  with  respect  to  cathode   200° waa;  volts 

Maximum  Circuit  Values: 

G rid-No.  1-Circuit  Resistance: 

For  fixed-bias  operation   0 . 25  max  megohm 

For  cathode-bias  operation   1  max  megohm 

^,        .    .                                                                    Triode  Unit  Pentode 

Characteristics:                                                        ^py^     6FV8A  Unit 

Plate  Voltage                                                                  125          125  125  volts 

Grid-No.2  Voltage                                                           -            -  125  volts 

Grid-No.l  Voltage                                                            -1           -1  -1  volt 

Amplification  Factor                                                         40           45  - 

Plate  Resistance  (Approx.)                                              5000        5600  200000  ohms 

Transconductance                                                         8000        8000  6500  /xmhos 

Grid-No.l  Voltage  (Approx.)  for  plate  current  of  20  /xa        -9        -7.5  -9  volts 

Plate  Current                                                                 14           12  12  ma 

Grid-No.2  Current                                                           -            --  4  ma 


VERTICAL-DEFLECTION  OSCILLATOR— TRIODE  UNIT 

For  operation  in  a  525-line,  30-frame  system 
Maximum  Ratings,  {Design-Maximum  Values): 

DC  Plate  Voltage   330  max 

Peak  Negative-Pulse  Grid  Voltage   -250  max 

Peak  Cathode  Current   70  max 

Average  Cathode  Current   20  max 

276 


volts 
volts 
ma 
ma 


Plate  Dissipation  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode. . . . 

Heater  positive  with  respect  to  cathode .... 

Maximum  Circuit  Values: 

Grid-Circuit  Resistance: 

For  cathode-bias  operation  

■  The  dc  component  must  not  exceed  100  volts. 


2  max 


200  max 
200°max 


volts 
volts 


3  max  megohms 


BEAM  POWER  TUBE 

g3/^nX         \  Glass  octal  type  used  as  horizontal- 

deflection  amplifier  in  television  re-  ^  m  a  #  r" 

ceivers.  Outline  19A,  OUTLINES         OFW 5 
(  K-^yKJ»^         SECTION.  Tube  requires  octal  socket 
^    {s)  and  may  be  mounted  in  any  position. 

°2         Heater  volts  (ac/dc),  6.3;  amperes,  1.2. 

HORIZONTAL-DEFLECTION  AMPLIFIER 

For  operation  in  a  525-line,  30-frame  system 
Maximum  Ratings,  (Design-Maximum  Values): 

DC  Plate  Voltage   770  max  volts 

Peak  Positive-Pulse  Plate  Voltage  °   6500  max  volts 

DC  Grid-No.2  (screen-grid)  Voltage   220  max  volts 

Peak  Negative-Pulse  Grid-No.1  Voltage   -330  max  volts 

DC  Grid-No.  1  (control-grid)  Voltage   -55  max  volts 

Peak  Cathode  Current   610  max  ma 

Average  Cathode  Current   175  max  ma 

Grid-No.2  Input   3.6  max  watts 

Plate  Dissipation*   18  max  watts 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  max  volts 

Heater  positive  with  respect  to  cathode   200"max  volts 

Bulb  Temperature  (At  hottest  point)   220  max  °C 

Maximum  Circuit  Values: 

Grid-No.  1-Circuit  Resistance   1  max  megohm 

°  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  horizontal  scanning  cycle.  In  a 
525-line,  30-frame  system,  15  per  cent  of  one  horizontal  scanning  cycle  is  10  microseconds. 
■  The  dc  component  must  not  exceed  100  volts. 

•  An  adequate  bias  resistor  or  other  means  is  required  to  protect  the  tube  in  the  absence  of  excitation. 


6FW8 


MEDIUM-MU  TWIN  TRIODE 

Miniature  type  used  in  direct-coupled  cath- 
ode-drive rf-amplifier  circuits  of  vhf  television 
tuners.  In  such  circuits,  one  triode  unit  is  used 
as  the  direct-coupled  grounded-cathode  driver 
for  the  other  unit.  Outline  8B,  OUTLINES 
SECTION.  Tube  requires  nine-contact  socket. 
Heater  volts  (ac/dc),  6.3;  amperes,  0.4.  Char- 
acteristics as  class  Ai  amplifier  (each  unit): 
plate  volts,  100  (250  max);  grid  volts,  -1.2;  amplification  factor,  33;  plate  resistance  (approx.),  2500 
ohms;  transconductance,  13000  /tmhos;  plate  ma.,  15;  cathode  ma.,  22  max;  plate  dissipation,  2.2  max 
watts;  peak  heater-cathode  volts,  200  max  (the  dc  component  must  not  exceed  100  volts).  This  type  is 
used  principally  for  renewal  purposes. 


DUAL  TRIODE 

Duodecar  type  used  as  combined 
vertical-deflection  oscillator  and  verti- 
cal-deflection amplifier  in  television  re- 
ceivers. The  high-mu  triode  unit  No.l 
is  used  as  an  oscillator,  and  the  low- 


6FY7 

Related  type: 
15FY7 


mu  triode  unit  No.2  is  used  as  an  amplifier.  Outline  12D,  OUTLINES  SECTION. 


277 


RCA  Receiving  Tube  Manual 


Tube  requires  duodecar  twelve-contact  socket  and  may  be  mounted  in  any  position. 
Heater  volts  (ac/dc),  6.3;  amperes,  1.05. 

CLASS  Ai  AMPLIFIER 

Characteristics:  Unit  No.  1  Unit  No.  2 

Plate  Voltage   250  150  volts 

Grid  Voltage   -3  -17.5  volts 

Amplification  Factor,   65  6 

Plate  Resistance  (Approx.)   40500  800  ohms 

Transconductance   1600  7500  jumhos 

Grid  Voltage  (Approx.)  for  plate  current  of  30  /xa   -5.5  -  volts 

Grid  Voltage  (Approx.)  for  plate  current  of  50  /^a   -  -55  volts 

Plate  Current   1.4  45  ma 

Plate  Current  (Approx.)  for  grid  voltage  of  -25  volts   -  10  ma 

VERTICAL-DEFLECTION  OSCILLATOR  AND  AMPLIFIER 

For  operation  in  a  525-line,  30-frame  system 

Unit  No.  1  Unit  No.  2 

Maximum  Ratings,  (Design-Maximum  Values):                               Oscillator  Amplifier 

DC  Plate  Voltage                                                               330  max  275  max  volts 

Peak  Positive-Pulse  Plate  Voltage#                                        -  2000  max  volts 

Peak  Negative-Pulse  Plate  Voltage                                   -400  max  -250  max  volts 

Peak  Cathode  Current                                                          70  max  175  max  ma 

Average  Cathode  Current                                                   20  max  50  max  ma 

Plate  Dissipation                                                                 1  max  7tmax  watts 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode                                  200  max  200  max  volts 

Heater  positive  with  respect  to  cathode                                   200  max"  200"max  volts 

Maximum  Circuit  Values: 

Grid-Circuit  Resistance   2.2  max       2 . 2  max  megohms 

#  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  vertical  scanning  cycle.  In  a 
525-line,  30-frame  system,  15  per  cent  of  one  vertical  scanning  cycle  is  2.5  milliseconds, 
t  An  adequate  bias  resistor  or  other  means  is  required  to  protect  the  tube  in  the  absence  of  excitation. 
■  The  dc  component  must  not  exceed  100  volts. 


POWER  PENTODE 

Glass  octal  type  used  in  output  stage  of 
radio  receivers  where  moderate  power  output  is 

M^M^  required.  Outline  22,  OUTLINES  SECTION. 

^>CyQCy  Tube  requires  octal  socket.  Except  for  inter- 

electrode  capacitances  and  a  plate  resistance  of 
175000  ohms,  this  type  is  electrically  identical 
with  type  6AK6.  Heater  volts  (ac/dc),  6.3; 
amperes,  0.15.  Type  6G6-G  is  used  principally 
for  renewal  purposes. 


BEAM  POWER  TUBE— 
SHARP-CUTOFF  PENTODE 

M^^m  Duodecar  type  used  as  FM  detec- 

0(71 1  tor  and  audio-frequency  output  am-  ^ 

plifier  in  television  receivers.  Outline 
12B,  OUTLINES  SECTION.  Tube  re-  »<p 
quires  duodecar  twelve-contact  socket 
and  may  be  mounted  in  any* position.  Heater  volts  (ac/dc),  6.3 

BEAM  POWER  TUBE  UNIT  AS  CLASS  Ai  AMPLIFIER 

« 

Maximum  Ratings,  (Design-Maximum  Values): 

Plate  Voltage  

Grid-No.2  (screen-grid)  Voltage  

Average  Cathode  Current  

Plate  Dissipation  

Grid-No.2  Input    

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode.  

278 


amperes. 


150 

max 

volts 

135 

max 

volts 

65 

max 

ma 

6.5 

max 

watts 

1.8 

max 

watts 

200 

max 

volts 

200'max 

volts 

Technical  Data 


Typical  Operation: 

Plate  Voltage   120  volts 

Grid-No.2  Voltage   110  volts 

Grid-No.l  (Control-Grid)  Voltage   -8  volts 

Peak  AF  Grid-No.l  Voltage   8  volts 

Zero-Signal  Plate  Current   49  ma 

Maximum-Signal  Plate  Current   50  ma 

Zero-Signal  Grid-No.2  Current   4  ma 

Maximum-Signal  Grid-No.2  Current   8  .5  ma 

Plate  Resistance  (Approx.)   10000  ohms 

Transconductance   7500  ^mhos 

Load  Resistance   2500  ohms 

Total  Harmonic  Distortion   10  per  cent 

Maximum-Signal  Power  Output   2  .3  watts 

PENTODE  UNIT  AS  CLASS  Ai  AMPLIFIER 

Characteristics: 

Plate  Supply  Voltage   150  volts 

Grid-No.3  (Suppressor-Grid)  Voltage   0  volts 

Grid-No.2  (Screen-Grid)  Supply  Voltage   100  volts 

Cathode-Bias  Resistor   560  ohms 

Plate  Resistance  (Approx.)   0.15  megohm 

Transconductance,  Grid  No.  1  to  Plate   1000  ^mhos 

Transconductance,  Grid  No.3  to  Plate   400  /tmhos 

Plate  Current   1.3  ma 

Grid-No.2  Current   2  ma 

Grid-No.l  Voltage  (Approx.)  for  plate  current  of  10    -4.5  volts 

Grid-No.3  Voltage  (Approx.)  for  plate  current  of  10    -4  .5  volts 

PENTODE  UNIT  AS  FM  DETECTOR 
Maximum  Ratings,  (Design-Maximum  Values): 

Plate  Voltage   330  max  volts 

Grid-No.3  Voltage   28  max  volts 

Grid-No.2  Supply  Voltage   330  max  volts 

Grid-No.2  Voltage   See  curve  page  70 

Grid-N 0.1  (control-grid)  Voltage,  Positive-bias  value   0  max  volts 

Plate  Dissipation   1.7  max  watts 

Grid-No.2  Input: 

For  grid-No.2  voltages  up  to  165  volts   1.1  max  watts 

For  grid-No.2  voltages  between  165  and  330  volts   See  curve  page  70 

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode   200  max  volts 

Heater  positive  with  respect  to  cathode   200"max  volts 

■  The  dc  component  must  not  exceed  100  volts. 


BEAM  POWER  TUBE 

Neonoval  type  used  as  output  tube 
in  audio-amplifier  applications.  Out- 
line llC,OUTLINESSECTION.Tube 
requires  neonoval  nine-contact  socket 
and  may  be  mounted  in  any  position. 


Heater  Voltage  (ac  /dc)  

Heater  Current  

Direct  Interelectrode  Capacitances  (Approx.) : 

Grid  No.l  to  Plate  

Grid  No.l  to  Cathode,  Heater,  Grid  No.2,  and  Grid  No.3 . 

Plate  to  Cathode,  Heater,  Grid  No.2,  and  Grid  No.3  

CLASS  Ai  AMPLIFIER 
Maximum  Ratings,  (Design-Maximum  Values) : 

Plate  Voltage  

Grid-No.2  (screen-grid)  Voltage  

Grid-No.2  Input  

Plate  Dissipation  

Peak  Heater-Cathode  Voltage: 

Heater  negative  with  respect  to  cathode  

Heater  positive  with  respect  to  cathode  


6GC5 


6.3 
1.2 

0.9 
18 
7 


volts 
amperes 

Pf 
Pf 
pf 


220  max 
140  max 
1 . 4  m  ax 
12  max 

200  max 
200'max 


volts 
volts 
watts 
watts 

volts 
volts 

279 


RCA  Receiving  Tube  Manual 


AVERAGE  PLATE  CHARACTERISTICS 


TYPE  6GC5 
Ef  «6.3  VOLTS 
GRID- No.  1  VOLTS  «0 

6R 

ID-No.  2 

VOLTS 

EC2«I5( 

5 

00 

50 

PLATE  VOLTS 


92CM-lia24r 


Typical  Operation  and  Characteristics: 

Plate  Voltage  

Grid-No.2  Voltage  

Grid-No.  1  Voltage  

Cathode-Bias  Resistor  

Peak  AF  Grid-No.l  Voltage  

Zero-Signal  Plate  Current  

Maxinjium-Signal  Plate  Current  

Zero-Signal  Grid-No.2  Current  

Maximum-Signal  Grid-No.2  Current  

Plate  Resistance  (Approx.)  

Transconductance  

Load  Resistance  

Total  Harmonic  Distortion  

Maximum-Signal  Power  Output  

Maximum  Circuit  Values: 

Grid-No.  1-Circuit  Resistance: 

For  fixed-bias  operation  

For  cathode-bias  operation  

■  The  dc  component  must  not  exceed  100  volts. 


110 

200 

volts 

110 

125 

volts 

-7.5 

volts 

180 

ohms 

7.5 

8.5 

volts 

49 

46 

ma 

50 

47 

ma 

4 

2.2 

ma 

10 

8.5 

ma 

13000 

28000 

ohms 

8000 

8000 

Atmhos 

2000 

4000 

ohms 

10 

10 

per  cent 

2.1 

3.8 

watts 

0 . 1  max  megohm 
0 . 5  max  megohm 


AVERAGE  CHARACTERISTICS 


150 


s 


50 
25 


TYPE  6GC5 
E^  =  6.3  VOLTS 

 GR 

D-No.l\ 

OLTS  EC 

2  

-4 

o 

-6 

/o 

« — 

SI 

-8 

lAMPERI 

-10 

1 

5  i 

i 

0  o 

-16 

280 


====^^  Technical  Data  ===^^^===== 

ic  P 

^r^^^^^'c  POWER  TUBE 

^^^OSr''          ^          Duodecar  type  used  as  horizontal-  ^  ^  ^  _ 

CiOryTP^^             deflection-amplifier  tube  in  television  OGc5 

(i^^^^><^2^>^^\      receivers.   Outline  20,   OUTLINES  Related  types: 

(v     ^®          SECTION.  Tube  requires  duodecar  i2ge5,  izges 
"          twelve-contact  socket  and  may  be 
mounted  in  any  position.  Heater  volts  (ac/dc),  6.3;  amperes,  1.2. 

Characteristics:  CLASS  Ai  AMPLIFIER 

Plate  Voltage                                                                              60  250  volts 

Grid-No.2  (Screen-Grid)  Voltage                                                   150  150  volts 

Grid-No.l  (Control-Grid)  Voltage                                                    0  -22.5  volts 

Triode  Amplification  Factor*                                                          -  4.4 

Plate  Resistance  (Approx.)                                                              -  18000  ohms 

Transconductance                                                                         -  7300  M^hos 

Plate  Current                                                                            345»  65  ma 

Grid-No.2  Current                                                                     21*  1.8  ma 

Grid-No.l  Voltage  (Approx.)  for  plate  current  of  1  ma                        -  -42  volts 

*  Triode  connection  (grid  No.2  tied  to  plate);  plate  and  grid-No.2  volts  =150. 

•  This  value  can  be  measured  by  a  method  involving  a  recurrent  waveform  such  that  the  maximum 
ratings  of  the  tube  will  not  be  exceeded. 

HORIZONTAL-DEFLECTION  AMPLIFIER 

For  operation  in  a  525-line,  SO-frame  system 
Maximum  Ratings,  {Design-Maximum  Values): 

DC  Plate  Supply  Voltage   770  max  volts 

Peak  Positive-Pulse  Plate  Voltage#   6500  max  volts 

Peak  Negative-Pulse  Plate  Voltage   -1500  waa;  volts 

DC  Grid-No.2  Voltage   220  max  volts 

Peak  Negative-Pulse  Grid-No.1  Voltage   -330  max  volts 

DC  Grid-No.1  Voltage   -55  max  volts 

Peak  Cathode  Current   550  max  ma 

Average  Cathode  Current   175  maa;  ma 

Plate  Dissipation t   17.5  wax  watts 

Grid-No.2  Input     3.5  max  watts 

Peak  Heater-Cathode  Voltage: 

Heater  negative  withrespect  to  cathode   200  max  volts 

Heater  positive  with  respect  to  cathode   200  "wax  volts 

Bulb  Temperature  (At  hottest  point)   200  wax  "C 

Maximum  Circuit  Values: 

Grid-No.l-Circuit  Resistance   1  wax  megohm 

#  The  duration  of  the  voltage  pulse  must  not  exceed  15  per  cent  of  one  horizontal  scanning  cycle.  In  a 
525-line,  30-frame  system,  15  per  cent  of  one  horizontal  scanning  cycle  is  10  microseconds. 

t  An  adequate  bias  resistor  or  other  means  is  required  to  protect  the  tube  in  the  absence  of  excitation. 
■  The  dc  component  must  not  exceed  100  volts. 

IC  P 

K  '""(S^^T^  BEAM  POWER  TUBE 

^q^zzz     }ii           Duodecar  type  used  as  ho