The DK92 is a miniature heptode frequency changer for use in dry battery powered radio receivers. Domestic long and medium wave receivers would have this as the mixer to produce a 455 kHz IF from the incoming signal. It can be used with a separate oscillator, but was probably designed as a self oscillating mixer, in the manner of other pentagrid converters.

The thin glass tube envelope is 17 mm in diameter and, excluding the B7G base pins, is 45 mm tall.

 
Pin Connections

B7G	1	2	3	4	5	6	7
	f+	a	g2	g1	g4	g3	f-,g5

 
Absolute Maximum Operating Conditions

Heptode	Vh	Ah	Va	Vs	Vg	mAa	mAs	ra	gm
	1.4	0.05	85	60	0	0.7	0.15	0.65M	0.39

Thanks to Frank Philipse for supplying the above datasheet

This exhibit was last updated on 06 July 2007 {find valves by name}