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12SF7

Sensibly equivalent to:
CV921
    
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The 12SF7 is a diode pentode for RF and IF amplification. The valve has a variable-μ characteristic and the diode is intended for use as an AGC detector.
Command radios of WWII like the R-23 and R-23A used the 12SF7 as second IF stages with their own local AGC.
The RCA logo.
The thin metal tube envelope is 25 mm in diameter, and excluding the IO base pins is 52 mm tall.
Reference: Data-sheet & tuberadio Type 12SF7 was first introduced in 1940. See also 1940 adverts.

 

Pin Connections
IO
1
2
3
4
5
6
7
8
m
g1
k,g3,s
g2
a(d)
a
h
h

 

Absolute Maximum Operating Conditions
Pentode
Vh
Ah
Va
Vs
Vg
mAa
mAs
ra
gm
12.6
0.15
250
100
-1
12.4
3.3
0.7M
2.0
Thanks to Frank Philipse for supplying the above PDF datasheet.
Updated January 11, 2017.
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