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Solar Cell Physics Coursework (Calculating Internal Resistance)

  1. Dec 1, 2009 #1
    Basically I want to Calculate the internal resistance of a solar cell.

    I set up a circuit with a voltmeter across the solar cell and an ammeter and variable resistor in series with the solar cell. The variable resistor is the load.

    Image at http://elyaschaudhary.schools.officelive.com/video.aspx [Broken]

    As i change the resistance the value of current changes which is GOOD
    However the Voltage stays the same BAD

    This results is a graph with a horizontal Line implying that internal resistance is 0. BAD

    I need the current and voltage to change i think to get a graph which will be able to give me the EMF and Internal resistance.

    Could some one please explain how this is done

    Thank you very much

    Elyas
     
    Last edited by a moderator: May 4, 2017
  2. jcsd
  3. Dec 1, 2009 #2

    Redbelly98

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    How low in resistance did you go? If you short out the solar cell, you will definitely get a lower voltage.
     
  4. Dec 1, 2009 #3

    Delphi51

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    If you replace the solar cell with a voltage source (V) and an internal resistance (r) in series, then calculate the measured voltage (V1), you will see that a constant V1 just means that the internal resistance r is small compared to R. You will need to do the experiment again with smaller values of R that do cause a change in V1 in order to calculate r.
     
  5. Dec 1, 2009 #4

    Redbelly98

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    Also, the v-i curve for a solar cell is not a straight line.
     
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