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DK91

Sensibly equivalent to:
1C1 1H33 1R5 CV782 X17
See also:
Pentagrid Converters
    
Extras ▼

 

The DK91 is a miniature B7G dry battery heptode, it was designed for frequency changer use in battery portable radio receivers for medium and long wave. The valve was designed for self oscillating service.
The top mica with the single strand oxide coated filament in the centre. The tensioning spring support is on the right and it is also the final suppressor grid support.
The thin glass tube envelope is 17 mm in diameter and, excluding the B7G base pins, is 45 mm tall.
References: Datasheet & 1040. Type DK91 was first introduced in 1946.

 

Pin Connections
B7G
1
2
3
4
5
6
7
f-
a
g4,g4
g1
f-
g3
f+

 

Absolute Maximum Operating Conditions
Heptode
Vh
Ah
Va
Vs
Vg
mAa
mAs
ra
gm
1.4
0.05
90
67.5
0
1.6
3.2
0.6M
0.3
Thanks to Frank Philipse for supplying the above PDF datasheet.
Updated September 25, 2019.
shape:thin.glass.tube construction:all.glass type:heptode age:1940.1950 base:b7g heater:1.4v pins:7 pin:1.f- pin:2.a pin:3.g4.g4 pin:4.g1 pin:5.f- pin:6.g3 pin:7.f+
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