The H42 is a double diode triode designed for service as detection and first AF amplifier in superhet receivers. It was cost saving to make all three devices in a single envelope with a common cathode. This style became the normal configuration.

The paper label is for the M-OV brand name of Marconiphone. The electrode assembly is obscured.

The classic envelope is 41 mm in diameter and, excluding the B7 base pins, is 101 mm tall.

 
Pin Connections

B7	1	2	3	4	5	6	7	tc
	a(d2)	m	a(d1)	h	h	k	a	g1

 
Absolute Maximum Operating Conditions

Triode	Vh	Ah	Va	Vg	mAa	ra	gm
	4.0	0.6	250	-2	1.0	60,000	1.5

Thanks to Frank Philipse for supplying the above PDF datasheet

 

This exhibit was last updated on 17 March 2010