The PM2HL battery triode was designed as a small signal amplifier. The valve is of medium impedance.

This example has a clear envelope thus revealing the electrodes.

The box anode has a W shaped filament allowing for four emitting surfaces. Filament tension is maintained by coil springs attached to the top mica. The fact that the envelope is clear and a top mica is used indicates a late production with an spray coated oxide filament rather than the earlier Azide process filament.

The balloon envelope is 41 mm in diameter and, excluding the B4 base pins, is 86 mm tall.

 
Pin Connections

B4	1	2	3	4
	a	g	f	f

 
Absolute Maximum Operating Conditions

Triode	Vh	Ah	Va	Vg	mAa	ra	gm
	2.0	0.1	135	-1.5	2.2	21,500	1.4

More

This exhibit was last updated on 10 February 2008