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717A

Sensibly equivalent to:
CV3594 VT-269
    
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The delightful Type 717A is known as a 'little doorknob' (for the doorknob see 703A). Intended as a low-noise front-end amplifier in UHF radar receivers, the 717A achieves 4 ma/V despite its small size. Designed by Western Electric, the 717A was made in large numbers by several US manufacturers during WWII. It was a successful valve although it was soon superseded by improved (and cheaper) all-glass types.
In the John Lawrence collection are two of these valves, one is marked as a microwave triode and the other as a VHF triode.
See also VT-269 under close inspection it is clearly a pentode.
The balloon envelope is 34 mm in diameter and, excluding the IO base pins, is 37 mm tall.
References: Private Communication.

 

Pin Connections
IO
1
2
3
4
5
6
7
8
s
h
k
g1
k
g2
h
a

 

Absolute Maximum Operating Conditions
Pentode
Vh
Ah
Va
Vs
Vg
mAa
mAs
ra
gm
6.3
0.175
180
120
-2
7.5
2.5
0.25M
4.0
Thanks to Frank Philipse for supplying the above PDF datasheet.
Updated February 21, 2014.
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