EF40 @ The Valve Museum

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EF40

Sensibly equivalent^¶ to:

CV3885

See also:

From Triodes to Transistors

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Mullard Valve Donation by Peter Bates (GM4BYF) Other EF40 exhibits

Mullard describe the EF40 as a voltage amplifying pentode, primarily intended for use in high gain RC coupled AF voltage amplifier stages.

The B8A EF40 was developed into the B9A EF86.

The interesting thing about this exhibit is the BBC valve section sticker. IT shows the valve being tested in February and October 1953.

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

References: Data-sheet & ¹⁰⁴⁰. Type EF40 was first introduced in 1948. See also 1948 adverts.

Pin Connections

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

Absolute Maximum Operating Conditions^¶

Pentode	Vh	Ah	Va	Vs	Vg	mAa	mAs	gm
	6.3	0.2	250	140	-2	3.0	0.6	1.8

Thanks to Frank Philipse for supplying the above PDF datasheet.

Updated January 03, 2019.

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