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..
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..
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!
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!
Yup what Colt said, the word is phototube. The cathode is coated with cesium which has a lot "work potential", basically electrons are more prone to being bumped out by light rays. Add 300V and you get a few micro to miliamperes plate current depending on intensity. I think response drops off around 10-20kHz typically.
Tim
Tim
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