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VT-203

Sensibly equivalent to:
9003
See also:
Acorn Antiques
    
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The VT-203 is the American procurement code for the commercial Type 9003 and both designations appear on this exhibit.
Electrically it is equivalent to 'acorn' type 956 but re-engineered to a B7G base. The valve is classed as a vari-mu UHF receiving pentode.
The design dates to 1943 but B7G based valves were not made in the UK until the late 1940's.
The 9003 repeated on the other side. The anode has two small plates either side of the central section and these are joined by the strap visible in the picture. The central dark metal structure is the screen but it is solid in the anode direction in the middle region, only allowing electrons to pass through the notches above and below the central zone - strange. Three grid support rods can be seen with close inspection of the valve.
The thin glass tube envelope is 18 mm in diameter and, excluding the B7G base pins, is 37 mm tall.
Reference: Datasheet. Type VT-203 was first introduced in 1943.

 

Pin Connections
B7G
1
2
3
4
5
6
7
g1
k
h
h
a
g2
k,g3,s

 

Absolute Maximum Operating Conditions
Pentode
Vh
Ah
Va
Vg
mAa
ra
gm
6.3
0.15
100
-3
2.7
700k
1.8
Thanks to Frank Philipse for supplying the above PDF datasheet.
Updated February 03, 2017.
shape:thin.glass.tube construction:all.glass type:pentode age:1940.1950 base:b7g heater:6.3v pins:7 pin:1.g1 pin:2.k pin:3.h pin:4.h pin:5.a pin:6.g2 pin:7.k.g3.s
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