You have a photocell. You can test it with a meter that uses a 22 1/2 or 30 volt battery for the high ohms scale. Connect the 923 across leads while on highest resistance range. Shine light on the tube. Meter deflection will increase.
http://frank.pocnet.net/sheets/049/9/923.pdf
Norm
:Can anyone steer me to a site where I can get the info on this tube. I think it is a sensor of some type as the "plate" is semicircular(not closed and the "cathjode" is centered in the semicircle. PL
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