This tetrode thyratron is built on a glass disc base. The base is dished and the supports for the electrodes pass through beads of glass. The wires are then connected to the octal base pins. Close visual inspection suggests that the wires that pass through the base do not directly mate up with the base pins.

The control ratio is high at 350 and the voltage drop across the tube when conducting is 9 Volts.

The wide glass tube envelope is 28 mm in diameter and, excluding the IO base pins, is 70 mm tall.

Reference: Datasheet. Type 20A2 was first introduced^¶ in 1957.

 
Pin Connections

IO	1	2	3	4	5	6	7	8
	-	h	a	-	g1	g2	h	k

 
Absolute Maximum Operating Conditions^¶

Thyratron	Vh	Ah	Va	mAa
	6.3	1.0	600	1,250

Thanks to Frank Philipse for supplying the above PDF datasheet

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