The PM22A is a battery audio output valve for use in domestic broadcast receivers. It was made during the 1930s and features in the 1934-5 Mullard catalogue. The power output is low at 350 mW and so efficient loudspeakers were required to achieve an adequate listening volume. The output is lower than the PM22 but the filament power consumption was also less.

For correct operation the anode load should be 19,000 ohms.

The move away from the messy Azide process allowed makers to show clear glass to the world again. The painted envelope has almost gone just a painted envelope dome remains to carry the identification details.

The classic envelope is 38 mm in diameter and, excluding the B5 base pins, is 94 mm tall.

 
Pin Connections

B5	1	2	3	4	5
	a	g1	f(-)	f(+)	g2

 
Absolute Maximum Operating Conditions

Pentode	Vh	Ah	Va	Vs	Vg	mAa	ra	gm	Pout	D
	2.0	0.15	135	135	-4.5	5.6	0.15M	2.2	0.34W	10%

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This exhibit was last updated on 21 July 2005