• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

What kind of tube is this

I found two of these tubes some time ago. I cant find any information on it so I have no idea what it is good for.
Does anyone know how to use this tube and what it does?



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by the looks of the structure, I'd say it is a <i forget the name>

it is sensitive to light, sort of like a photo-diode, but in tube format..
there is no heater, and the plate has some sort of mildy radioactive substance on it (like cesium? i forget)

for use of transmitting a signal via visible light, like the audio track on a old film.

I think I've got a similar tube from tim..


2003-07-08 12:47 pm
I'ts a photodiode

I worked at a factory that made silicon photodiodes vacuum multipliers and CRT's amongst other things like neutron detectors and Boron isotopes.

I cant' help with specs but remember seeing one of these in the lab for calbration purpose.

Its a photo-cell!

Used to use these in old cinema projectors!--Machines like Kalee with B.A.F Soundheads and Westar machines.

Biassed at around 90v, the film audio track was projected through a slit and optics to the selenium coated cathode which then emitted electrons depending on light intensity

Used to go noisy, microphonic and all sorts, Just an ornament these days!