The PM3 was introduced in 1926 as a general purpose triode with a μ of 14. The filament current, initially 0.1 Amp was later reduced to 0.075 Amps and the label on this specimen specifies 0.075 A filament current.

The identification details are printed on the dome of the envelope. looking from the base up under the silvering on the glass reveals a horizontal box anode.

This is supported from the pinch by stout wires that form a wide U. The anode is stippled.

The Balloon envelope is 43 mm in diameter and, excluding the B4 base pins, is 87 mm tall.

 
Absolute Maximum Operating Conditions

Triode	Vh	Ah	Va	ra	gm
	4.0	0.075	125	16,000	0.85

This exhibit was last updated on 02 December 2007