The 410PT from Cossor is a battery output pentode. The design dates from 1931 and this valve design was obsolete by 1933. The audio output was 0.9 Watt.

Seen from the top and side of the envelope the wire grids are clearly visible. The inner grids pass flat across the filament and are therefore parallel with the anode walls. The outer suppressor grid is an open spiral close to the anode.

The balloon envelope is 45 mm in diameter, and excluding the B5 base pins is 89 mm tall.

 
Absolute Maximum Operating Conditions

Pentode	Vh	Ah	Va	Vs	Vg	mAa	mAs	gm
	4.0	0.1	150	150	-7.5	17	-	2.0

This exhibit was last updated on 02 December 2007