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Transmitting tubes - old system: AAnn/nn or AAnn-nn (e.g. QC05/15, KS9-20)

1st letter - tube classification

B Backward wave tube
D Rectifying tube (including grid-controlled tubes)
J Magnetron
K Klystron
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 Inert gas filled
S Reflex klystron
T Multiple resonator (klystrons)
V Indirectly heated oxide 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 Approx 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



This file was last modified 11:49:20, Thursday April 14, 2022