The EAF42 is a single diode variable μ pentode with a common cathode. Mullard describe this valve in 1949 as: A single diode RF pentode for use in AC mains-operated equipment. The pentode section is suitable for automatic volume control.

In this exhibit the locating into the valve base is by the pip on the skirt only. The spigot on the original EAF42 has been discarded as redundant. In the final production form the metal skirt is itself replaced by a wider section of glass envelope with a locating pip moulded in.

The thin glass tube envelope is 20 mm in diameter and, excluding the B8A base pins, is 52 mm tall.

 
Pin Connections

B8A	1	2	3	4	5	6	7	8
	h	a	a(d)	g3	g2	g1	k,s	h

 
Absolute Maximum Operating Conditions

Pentode	Vh	Ah	Va	Vs	Vg	mAa	mAs	ra	gm
	6.3	0.2	250	85	-2.0	5.0	1.5	1.4M	2.0

Diode	Va	mAa
	200	0.8

Thanks to Frank Philipse for supplying the above datasheet

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