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EF8

Sensibly equivalent to:
CV1123 VR123
See also:
Mullard EF8, ECH2, EBC3, EF9, EB4, EL3 & AZ3 Advert
    
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The EF8 valve is a variable μ amplifier pentode with a fourth grid.
The variable μ amplifier pentode would be used in the AGC controlled stages of superhet receivers.
Our exhibit has the distinctive red of Mullard and is labelled Philips, the parent company. The dimensions are identical to the Mullard version and the Ct8 base was much more popular on the continent than in the UK and so it is probably that both were made on the same Dutch production line.
See EF8 for more details.
The classic envelope is 29 mm in diameter, and excluding the Ct8 base pins, is 84 mm tall.
References: Datasheet, 1040 & 1043. Type EF8 was first introduced in 1938.

 

Pin Connections
Ct8
1
2
3
4
5
6
7
8
tc
m
h
h
k
g4
g2
g3
a
g1

 

Absolute Maximum Operating Conditions
Pentode
Vh
Ah
Va
Vs
Vg
mAa
mAs
ra
gm
6.3
0.2
250
250
-2.5
8
0.25
2.0M
1.8
Thanks to Frank Philipse for supplying the above PDF datasheet.
Updated January 31, 2013.
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