The EL81 was designed as a television line output stage valve. It is specified for a peak positive anode surge of 7,000 Volts. It probably dates from the late 1940s when EHT voltages were derived separately from the line output stage, usually via a mains transformer. See also PL81

The thin glass tube envelope is 20 mm in diameter and, excluding the B9A base pins, is 71 mm tall.

 
Pin Connections

B9A	1	2	3	4	5	6	7	8	9	tc
	ic	g1	k	h	h	ic	ic	g2	g3	a

 
Absolute Maximum Operating Conditions

Pentode	Vh	Ah	Va	Vs	Vg	mAa	mAs	Pdiss
	6.3	1.05	250	250	-1	32	2.4	8.0W

Thanks to Frank Philipse for supplying the above datasheet

This exhibit was last updated on 10 June 2007 {find valves by name}