| 1st
letter - tube classification |
B |
Backward
wave tube |
| D
|
Rectifying
tube (including grid-controlled tubes) |
| J |
Magnetron |
| K |
Klystron |
| L |
TWT |
| M |
Triode
(AF amplifying tube or modulator) |
| P |
Pentode |
| Q |
Tetrode |
| R |
Rectifier |
| T |
Triode
(RF, AF or oscillator tube) |
| X |
Large
thyratron (>500mA mean Ia) |
| For
tubes having dual systems, this letter is doubled up, e.g. QQxxxx
is a double tetrode. |
| 2nd
letter (or 3rd for dual systems) |
A
|
Outputs
up to 1W (BWO/TWT); Tungsten filament (valves) |
| B |
Outputs
over 1W (BWO/TWT); Thoriated filament (valves) |
| C |
Directly
heated oxide-coated filament |
| D |
Disc-seal
construction |
| E |
Indirectly
heated oxide-coated cathode |
| G |
Mercury
vapour filled |
| H |
Hydrogen
filled |
| N |
External
magnet required (magnetrons) |
| P |
Packaged
construction (magnetrons) |
| R |
Inter
gas filled |
| S |
Reflex
klystron |
| T |
Multiple
resonator (klystrons) |
| V |
Indirectly
heated oxidSe coated cathode |
| X |
Directly
heated tungsten filament |
| Y |
Directly
heated thoriated tungsten filament |
| Z |
Directly
heated oxide coated filament (except mercury vapour rectifiers) |
| 3rd
letter (4th for dual systems) if present. If this letter is not
present the tube is radiation cooled. |
G
|
Mercury-vapour |
| H |
Helix
or other integral cooling |
| L |
Forced
air cooling |
| Q |
Tetrode
thyratron |
| S |
Silica
envelope |
| T |
Tunable
(microwave device) |
| W |
Water
cooling |
| X |
Xenon |
| 1st
group of figures: |
Rectifiers
|
Approx
DC output voltage in kV per tube in a three-phase half-wave rectifying
circuit |
| Thyratrons |
Approx
PIV in kV |
| Microwave
valves |
Aporx
frequency in GHz |
| Transmitting
valves |
Approx
max anode voltage in kV. Specified as peak voltage for pulse operation
valves. |
| 2nd
group of figures: |
Transmitting
valves |
Max
permissible anode dissipation in W, or in kW for larger valves. |
| Pulse
TX valves |
Prefixed
by P, the is the maximum peak current in Amps |
| BWO/TWT |
Output
power in mW (2nd letter=A) or W (2nd letter=B) |
| Magnetrons |
Pulse
output power in kW |
| Klystrons |
Output power in mW |
| Rectifiers |
Approx
rectifier output current in mA |
| Thyratrons |
Approx
max permissible mean anode current in mA. At least 3 digits. If the
1st is 0, the current rating is mA, otherwise A. E.g. 045=45mA, 6400=6.4A,
12=12A. |
| Additional
letters - tube base
Where this does not indicate
the base, a 'W' indicates water cooled and 'A' forced air cooled. |
B
|
Cables |
| E |
Medium
7-pin base |
| ED |
Edison
base |
| EG |
Goliath
base |
| G |
Medium
4-pin base |
| GB |
Jumbo
4-pin base |
| GS |
Super
jumbo 4-pin base |
| N |
Medium
5-pin base |
| P |
P-base |
