The VGT121 is an early thyratron. Comparison with the T41 from Mazda that it is equivalent to suggests that this valve is also of Mazda manufacture. The fact that it has a MO base completes the picture.

The thyratron is a special gas filled valve that at a given grid voltage rapidly moves into full conduction, when the gas ionises, thus acting as a switch. Under the correct circuit conditions this action can be made to generate ramps or pulses.

These valves were used in early radar and television as ramp generators, and in the first computers as pulse generators.

The classic envelope is 30 mm diameter and 78 mm tall. The base is Mazda Octal (MO).

 
Pin Connections

MO	1	2	3	4	5	6	7	8
	h	k	a	nc	g	m	nc	h

 
Absolute Maximum Operating Conditions

Thyratron	Vh	Ah	Va	mAa	f.max
	4.0	1.5	400	500	0.02

This exhibit was last updated on 13 August 2005