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W31

Sensibly equivalent to:
CV3806 CV3807
See also:
VMP4G and W31 Advert
    
Extras ▼

 

The W31 is a variable-μ RF pentode on a B7 base and designed for use on a 300 mA series heater chain in universal (AC and DC) mains sets.
The W31 is pin compatible with the Catkin W30 but has a higher specification.
Looking under the extensive silver gettering the only clear detail is of the heater entering the round cathode tube, The cathode is fixed to a lower screen.
The classic envelope is 44 mm in diameter, and excluding the B7 base pins is 119 mm tall.
References: Data-sheet, 1040 & 1043. Type W31 was first introduced in 1935. See also 1935 adverts.

 

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

 

Absolute Maximum Operating Conditions
Pentode
Vh
Ah
Va
Vs
Vg
mAa
mAs
gm
13.0
0.3
200
100
-2.0
8.0
5.0
2.7
Thanks to Frank Philipse for supplying the above PDF datasheet.
Updated August 29, 2018.
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