The CV1091 is the service version of the EF50. UK government procurement specification valves normally do not identify their manufacturer. This exhibit is in a brand new condition.

The valve is a high impedance pentode and was a workhorse of receivers for both radio and especially radar.

The wide glass tube envelope is 32 mm in diameter and, excluding the B9G base pins, is 58 mm tall.

References: Datasheet & ¹⁰⁴⁰.

 
Pin Connections

B9G	1	2	3	4	5	6	7	8	9
	h	g2	a	g3	s	k	g1	s	h

 
Absolute Maximum Operating Conditions^¶

Pentode	Vh	Ah	Va	Vs	Vg	mAa	mAs	ra	gm
	6.3	0.3	250	250	-2	10	3	1M	6.5

Thanks to Frank Philipse for supplying the above PDF datasheet

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