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717A

Sensibly equivalent to:
CV3594 VT-269
    
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The Type 717A is known as the '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 It was a successful valve although it was soon superseded by improved (and cheaper) all-glass types.
The US Government procurement code was VT-269 and this also appears on the metal base shell.
The Tung-Sol name.
The dome on this exhibit is fully silvered by the internal gettering.
The balloon envelope is 34 mm in diameter and, excluding the IO base pins, is 35 mm tall.
References: Datasheet & 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 December19, 2018.
shape:balloon construction:glass.foot type:pentode age:1940.1950 base:io heater:6.3v pins:8 pin:1.s pin:2.h pin:3.k pin:4.g1 pin:5.k pin:6.g2 pin:7.h pin:8.a
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