The PM1HL is an amplifier triode and it has external bronze metalising and a 2.0 Volt filament.

The electrodes are obscured by the coating on the envelope. The PM1HL was designed as a detector and general purpose valve and dates from on or before 1934. It was intended to be used in domestic broadcast receivers.

The top of the envelope carries the identification, plus filament rating and maximum anode potential.

The balloon envelope is 39 mm in diameter, and excluding the B4 base pins, is 77 mm tall.

 
Pin Connections

B4	1	2	3	4
	a	g1	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

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This exhibit was last updated on 04 February 2008