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U329

Sensibly equivalent to:
PY81 U251
See also:
Valves and their Habits - Valves at the 1953 Show
    
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The U329 is a television efficiency diode. Considerable energy is fed to the line deflection coils and this has to dissipate during flyback. The efficiency diode channels this energy back to the supply rail smoothing capacitors for use on the next line scan.
The rectifier is specified as having a peak inverse voltage rating of 7,500 volts, and a peak current rating of 450 mA. No voltage drop is quoted so the dissipation can not be given.
From the first picture the ceramic insulators and substantial cathode tube diameter can be seen. The second picture shows the valve from the side.
The thin glass tube envelope is 19 mm in diameter and excluding the B9A base pins the length is 71 mm.
References: Datasheet & 1040

 

Pin Connections
B9A
1
2
3
4
5
6
7
8
9
tc
ic
ic
ic
h
h
ic
ic
ic
a
k

 

Absolute Maximum Operating Conditions
Rectifier
Vh
Ah
Vg
mAa
17
0.3
-1
150
Thanks to Frank Philipse for supplying the above PDF datasheet.
Updated December08, 2015.
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