Sensibly equivalent¶ to:
The VGT121 is a thyratron. The T41 from Mazda is equivalent and only Mazda used the MO (Mazda Octal or British Octal) base.
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 reverse is plain zinc loaded screening paint.
The classic envelope is 32 mm in diameter, and excluding the MO base pins is 73 mm tall.
References: Data-sheet, 1040 & 1043. Type VGT121 was first introduced in 1940.
Absolute Maximum Operating Conditions¶
Updated April 10, 2019.