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EF22

Sensibly equivalent to:
7B7 CV303 W143
See also:
CV303 short entry
    
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The EF22 is an early example of an all glass construction amplifier pentode. The metal spigot holder is located on the glass base by a shaped pillar for one of the pins, and then held in place by a metal sleeve. The pins themselves are of short hardened type.
The pentode is described as of variable mu. That is that the characteristic curve is such that different amplifications are possible by varying the grid bias point. Mullard describe the EF22 as primarily intended for use in DC/AC mains operated equipment in the role of RF or IF amplifier.
The wide glass tube envelope is 28 mm in diameter and, excluding the B8B base pins, is 62 mm tall.
References: Datasheet & 1040.

 

Pin Connections
B8B
1
2
3
4
5
6
7
8
h
a
g2
g3,s
-
g1
k
h

 

Absolute Maximum Operating Conditions
Pentode
Vh
Ah
Va
Vs
Vg
mAa
mAs
ra
gm
6.3
0.2
250
100
-2.5
6
1.7
1.2M
2.0
Thanks to Frank Philipse for supplying the above PDF datasheet.
Updated April 05, 2015.
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