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How a photocell works

  1. Aug 3, 2005 #1
    I was wondering if anyone is able to tell me how a photocell works and why results for voltage versus current change the way they do. In particular i am looking for why the current increases rapidly at the start as voltages slightly increase, and then a flattening out occurs, i.e. the current doesn't rise much, and finally why the current starts rising again once the voltage gets sufficiently high enough

    Thanks in advance :smile:

  2. jcsd
  3. Aug 4, 2005 #2


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    Hi, Ben;
    All that I can address is the first part. Photovoltaic cells work because if a proper material is exposed to light, the photons knock electrons out of orbit and a chain reaction of sorts takes place to set up an electron 'flow'. I've never heard of those other stages that you mentioned. Sorry for the limited response, but that's the best that I can do right now.
  4. Aug 4, 2005 #3
    Hello! I have no idea here, I've just finished A-Levels, so I don't know a great deal about Physics at the mo, but I think I did some work experience on photocells...

    Just quoting Danger, but when the photons knock electrons out of orbit and they make a current, isn't it just a case of, when you have more electrons flowing, therefore a larger current you have a higher temperature, so a higher resistance - meaning the resistance isn't constant, so the graph is curved as it isn't an ohmic conductor....? Just thinking out loud really!

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