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GT1C

Sensibly equivalent to:
AN1 CV1128 NGT2 VGT128
See also:
The World's First Computer - GEC GT1C Box - Gas Clean-up in Xenon Thyratrons
    
Extras ▼

 

The GT1C thyratron is from the 1930s and was used in timebases for Radar. Thyratron was a trade name for a gas filled triode. In the case of the GT1C the low pressure gas was Argon.
At a defined grid voltage, the valve will rapidly switch to full conduction. The valve is turned off by reducing the anode voltage. Thyratrons are gas filled and can be considered as triggered gas discharges. The precision of construction gives the defined and reproducible operating characteristics. This valve not only has a high peak current but is designed for operation at up to 8,000 pulses per second.
The GT1 had similar ratings and had a mercury vapour filling.
The worlds first computer, Colossus, used these thyratrons as pulse generators. The operating speed of Colossus was 5,000 cycles per second.
The GEC brand label. M-OV used GEC for valves sold to the professional market and Marconi and Osram for consumer valves
Turning the envelope round reveals the CV1128 Type designation.
Within the corrugated card inside the original carton was this note.
The classic envelope is 44 mm in diameter and, excluding the B5 base pins, is 101 mm tall.
References: Data-sheet, 1040 & 1043. Type GT1C was first introduced in 1937.

 

Pin Connections
B5
1
2
3
4
5
a
g1
h
h
k

 

Absolute Maximum Operating Conditions
General Notes
Vh
Ah
Va
mAa
4.0
1.35
500
1000
Thanks to Frank Philipse for supplying the above PDF datasheet.
Updated May 22, 2021.
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