lytle@noao.edu (Dyer Lytle CCS) (07/14/90)
Does anyone here know much about selenium photo-electric cells of the
type found in *old* camera light meters? I have an old camera whose light
meter has lost much of its accuracy and I would like to repair it. I don't
think the parts are available anymore so I will have to substitute something.
Is the selenium cell photo-voltaic? Does it generate a voltage
proportional to the amount of light hitting it. Does it generate a
proportional current? The circuit has a 5600 ohm resistor and a meter
which I suspect is similar to a galvanometer. I can play with the resistor
in an attempt to calibrate the circuit I suppose.
Can I replace the selenium cell with a silicon solar cell such as those
I can buy at Radio Shack? I've fooled around with these and the current
verses light curve seems to have a different shape than the selenium cell
although I can't be sure since I don't have a milliammeter.
Otherwise, where can I get a selenium cell that I could cut to fit in
this camera? Any information would be helpful. Thanks.
-Dyer lytle@noao.edu
--
Dyer Lytle, National Optical Astronomy Observatories, Tucson, AZ, 602-323-4136
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