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VHT4

Sensibly equivalent to:
15A2 41MPG A80 A80A CV2955 CV3576 FC4 FC4 FCH MH4105 MX40 X42
See also:
Pentagrid Converters - Ferranti Advert, March 1935 - Some Important British Valves
    
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The VHT4 is a frequency changer of heptode construction dating from 1933s. The UK built heptodes followed the lead of the American manufacturers with their Pentagrid converters.
The oscillator voltage needs to be 15 Volts peak to peak for correct operation. The triode oscillator is formed between the cathode and grid2 with g1 as the control grid. The signal injection control grid for the mixer part of the single electron stream is to g4 on the top cap.
The classic envelope is 42 mm in diameter and, excluding the B7 base pins, is 106 mm tall.
References: 1040 & 1043. Type VHT4 was first introduced in 1933.

 

Pin Connections
B7
1
2
3
4
5
6
7
tc
g2
g1
g3,g5
h
h
m,k
a
g4

 

Absolute Maximum Operating Conditions
Heptode
Vh
Ah
Va
Vs
Vg
mAa
mAs
ra
gm
4.0
1.0
250
80
-3
2.6
5.1
0.5
0.7

 

Absolute Maximum Operating Conditions
Triode
Va
mAa
100
1.2
Updated December13, 2012.
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