The PM254 triode design dates from 1929 and is an audio output valve for battery wireless receivers. The μ was 4.2 and rated output was 380 mW into a 4,500 Ohm load. High impedance headphones are of the order of 4,000 Ohms. The envelope has etched into it a BBC logo, as well as the 254. The Bakelite base has a location groove filled with white paint.

The balloon envelope is 43 mm in diameter and, excluding the B4 base pins, is 93 mm tall.

 
Absolute Maximum Operating Conditions

Triode	Vh	Ah	Va	mAa	Vg	ra	gm
	4.0	0.25	150	14.0	-22.5	3,500	2.1

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This exhibit was last updated on 02 December 2007