This exhibit is in wonderful condition. The top cap style shows this to be an early version possibly from the introduction year of 1935. This battery RF pentode was produced in two versions, one on a B7 base and another on a B4 base.

We have no specific application details but RF amplification in broadcast radio receivers seems the most likely.

The picture above shows in detail the construction of the wire grids.

The further magnification demonstrates the way the grids were wound. The grid wire can be seen to be fitted into the support rod. In production the support rods were first notched by one cutting disc, the grid wire then was then wound into the notch and finally a blunt peening wheel would be used to close the metal over the grid wire and thus hold it in place.

The classic envelope is 36 mm in diameter and, excluding the B7 base pins, is 104 mm tall.

 
Pin Connections

B7	1	2	3	4	5	6	7	tc
	m	g1	g3	f	f	-	g2	a

 
Absolute Maximum Operating Conditions

Pentode	Vh	Ah	Va	Vs	Vg	mAa	mAs	ra	gm
	2.0	0.1	150	60	-0	2.95	0.75	0.6M	1.3

Thanks to Frank Philipse for supplying the above datasheet

This exhibit was last updated on 02 December 2007 {find valves by name}