The Cossor 220PA is an interesting triode valve. A look at the envelope reveals two triode sections in parallel within the glass envelope. The filaments appear to be oxide coated and each section contains a single inverted V. Above the top mica are bright coil springs with hooks that hang from the top of the coil down through the middle and provide a tension force for the filament.

The 220PA battery triode was a popular type and had many equivalent types. The 220PA is an audio output valve and it produced 0.18 Watts.

Power was a wet accumulator for the filament and a dry battery for the anode supply.

The classic envelope is 43 mm in diameter and excluding the B4 base pins it is 93 mm high.

 
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	0.2	150	-4.5	10.0	4000	4.0

Thanks to Frank Philipse for supplying the above datasheet

This exhibit was last updated on 09 June 2007 {find valves by name}