The HL23 is a low power low impedance low gain, battery triode. The external metalising suggests a role in RF/IF amplification, but the literature is not specific.

The metalised classic envelope is 30 mm in diameter and, excluding the MO base pins, is 67 mm tall.

 
Pin Connections

MO	1	2	3	4	5	6	7	8
	f	-	a	-	g1	m	-	f

 
Absolute Maximum Operating Conditions

Triode	Vh	Ah	Va	Vg	mAa	ra	gm
	2.0	0.05	150	-2.4	1.5	27,000	1.2

Thanks to Frank Philipse for supplying the above datasheet

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