Photocell ID?

Discussion in 'General Electronics Chat' started by IowanChef, May 14, 2010.

  1. IowanChef

    Thread Starter Active Member

    Mar 6, 2010
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    My engineering neighbor who is responsible for sparking (wakka) this new interest in electronics, brought home a discarded jumbo television in the back of his truck and we spent an afternoon gutting it for the wonderful parts inside. Among the innards was an array of photocells that I've never seen before. I am fairly certain they were around the perimeter of the screen and used as ambient light detectors of some sort for the auto-brightness adjusting feature. They're glass, they're polarized, and they're incredibly sensitive. I've only used one to control a simple light-theremin-type breadboard experiment, but I'd like to know more about these in case there's a better use for them...

    Sorry the picture is so big.. But for detail, it's probably not the worst thing I could do..

    Thanks for the help, as always..


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  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Is it a cell that generates an output with light falling on it. or a light dependent resistor? If you don't get an indication on a voltage setting, then an ohmmeter should see a change in resistance with illumination.
     
  3. IowanChef

    Thread Starter Active Member

    Mar 6, 2010
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    Actually, it does produce voltage. Seems to top out at about .7v. So that would essentially make this one very tiny solar cell used as a photodiode? It's reading .9v on the diode setting of my meter..
     
  4. BMorse

    Senior Member

    Sep 26, 2009
    2,675
    234
    If they produce voltage then they have to be some sort of photovoltaic cells (photocell), and yes, they do use solar cells as light detectors, since they do not consume power only produce it, this makes it ideal for "Low Energy" devices..

    Did you ever see this thread where I designed a laser detector based on a 1/8"x1/8" solar cell (Photocell) >>http://forum.allaboutcircuits.com/showthread.php?t=33549 ?

    B. Morse
     
  5. IowanChef

    Thread Starter Active Member

    Mar 6, 2010
    34
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    You know, I actually DID see that entire thread some time ago. I'd gotten there by some other means I guess.. Thanks for the input guys. I'll stash these with the rest of the precious oddities..

    Cheers
     
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