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ID = 16731
Great Britain (UK)
Brand: Marconi-Osram - (Valves/Tubes); GB
Developer: Marconi-Osram - (Valves/Tubes); GB 
Tube type:  Thyratron   Text 
  Ca. 1925 up to 1945 rare.
Identical to GT1C = 10E/15 = CV1128 = VGT128 = VT189_GPO
Similar Tubes
Normally replaceable-slightly different:
Other base and other heater:
Successor Tubes NGT2   GT3  

Base Europe 5-Pin , B5 (Eu O, F, O5A) 1928 (Codex=F)
Was used by Radio/TV-reception etc.
Filament Vf 4 Volts / If 1.3 Ampere / Indirect / Specified voltage AC/DC

This tube was developed for use in television timebases when the UK London service opened. They were also used in the temperature control system of the British Post Office Quartz Clocks. They were apparently the least reliable component of the clocks and would fail unpredictably causing frequency variations. This was fixed by running two tubes in parallel and provided monitoring for failure. 

Va<500 peak. Ia<300mA mean, 1A peak. (Osram data 1938). The impedance of the anode circuit must ensure that the current can never exceed 1.0 amp. Special attention must be given to this point in circuits where the GT1C discharges a condenser.

Cathode preheat time of >30 seconds is essential to prevent premature ageing.


Dimensions (WHD)
incl. pins / tip
45 x 120 x mm / 1.77 x 4.72 x inch
Weight 56 g / 1.98 oz
Information source Taschenbuch zum Röhren-Codex 1948/49   
- - Manufacturers Literature   Osram data 1938, GEC Nov 1949
Babani, International Radio Tube Encyclopaedia

gt1c_sock.png GT1C: Tabu Röhren-Codex, 1948
Anonymous 15 Collector

Just Qvigstad
GT1C: own collection
Peter den Boer

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