The 2X2A is an EHT half wave rectifier. The values given are for the 2X2 and we believe the 'A' variant to be the same.

The 2.5 volt heater indicates that it would be powered by a special heater winding of high insulation. Such a valve would have found application in oscilloscopes or in multiplier chains for higher voltages.

The classic envelope is 36 mm in diameter and, excluding the UX4 base pins, is 97 mm tall.

 
Pin Connections

UX4	1	2	3	4	tc
	h	-	-	h,k	a

 
Absolute Maximum Operating Conditions

Rectifier	Vh	Ah	Va	mAa
	2.5	1.75	4,500	7.5

Thanks to Frank Philipse for supplying the above datasheet

This exhibit was last updated on 09 June 2007 {find valves by name}