The 14A7 is an early all glass construction pentode. The central spigot hides the evacuation seal.

This variable μ valve was designed for high gain signal amplification, probably at intermediate frequencies in receivers for radio or radar.

The wide glass tube envelope is 28 mm in diameter and, excluding the B8B base pins, is 56 mm tall.

 
Pin Connections

B8B	1	2	3	4	5	6	7	8
	h	a	g2	g3	s	g1	k	h

 
Absolute Maximum Operating Conditions

Pentode	Vh	Ah	Va	Vs	Vg	mAa	mAs	ra	gm
	12.6	0.15	250	100	-3	9.2	2.6	0.8M	2

Thanks to Frank Philipse for supplying the above datasheet

This exhibit was last updated on 12 June 2007 {find valves by name}