Item ST 28133 Electronic Valve - British Services (RAF), Diode. Type VU33. 1939-1942

Summary

The VU33, also designated as 10E/9829 and later as CV1033 was a diode designed for use as a signal detector or low power rectifier.
It has a 2.0 volt directly heated cathode.
The absence of the CV marking indicates that this valve was probably manufactured prior to 1942 when the CV system was introduced
Manufactured for British Services (Royal Air Force) by an unknown manufacturer.

Physical Description

Conical bulb with 4 European style base.