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MH4105

Sensibly equivalent to:
15A2 41MPG CV3576 FC4 MX40 V04 VHT4
See also:
Pentagrid Converters
    
Extras ▼

 

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.
This unscreened version was made in England.
The construction is plain to see. The circular cathode has a close wound control grid followed by two plain rods (g2) that act as the oscillator anode. g3 and g5 are strapped together at the top. The signal grid (g4) is connected to the top cap.
The classic envelope is 39 mm in diameter and, excluding the B7 base pins, is 96 mm tall.
References: 1040 & 1043. Type MH4105 was first introduced in 1934. See also 1934 adverts.

 

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
200
100
-3.0
5.0
1.2
0.6M
0.5

 

Absolute Maximum Operating Conditions
Triode
Va
mAa
100
1.2
Updated February 22, 2022.
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