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Solar cell (recording the power)

  1. May 7, 2013 #1
    I tried today to calculate the power that the solar cell produced, connecting it to an ammeter(digital) and a voltmeter(digital) in series, my initial idea was to use the P=IV formula. However as i carried out the experiment the ammeter gave a showed 0.00 whilst the voltmeter showed 0.56 volts.Then i tired to place a resistor in series to increase the resistance of the circuit to see wether the ammeter showed any reading however there where still 0.00 .Is there any other way to calculate the power of the solar cell without having to find the current???
    If so could could someone explain how thanks in advance.
  2. jcsd
  3. May 7, 2013 #2
    Voltmeters go in parallel, not series. They have very, very high resistance (ideally, infinite resistance).

    You have a device that you are running with the solar cell right? Some kind of load? (besides the voltmeter)
  4. May 7, 2013 #3


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    Staff: Mentor

    As ModusPwnd points out, you need to get your instrumentation corrected, and you need to have a load connected to the cell.

    The ammeter has a small series resistance, but it is probably too small to be used for the load itself. Be aware that the power you can get out of a solar cell depends on the operating point (V,I) where it is biased. If you want to measure the efficiency, you should try it at several different operating points (more or less output load), to see where it seems to operate best.
  5. May 7, 2013 #4


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    Gold Member

    For measuring the power output of a single solar cell, follow these instructions for solar panels. The one difference is that you will not need “power” resistors...1/4 watt resistors will be adequate.

    “The method of measuring the power output of a solar panel is to connect resistors of various values to the panel and measure the voltage. The measurements can be used to calculate the power output. The same measurements can be used to plot the power output and create a performance graph for the panel.
    A digital multimeter for measuring DC voltage is required for this test. An assortment of power resistors is also needed. In practice, each power resistor is connected to the panel and the voltage is measured with the meter, as shown in the drawing.”

  6. May 7, 2013 #5
    Thank you, 100% agree (as if that matters to you :tongue:) Voltages of cells are known and given per type of cells. Typical cells are grouped into one of three classes with the known efficiency of each categorical expected.

    The load would depend on the amount of resistance in parallel or series.

    Here, read up on these:

    Monocrystalline, polycrystalline & amorphous sillicin.
  7. May 7, 2013 #6
    Just as a side note. Voltages are measured with a DMM by shorting to ground in parallel. Depending on the type of DMM you are using (digital multimeter) you must measure amps in series. This is terrible most of the time so it's easiest to use an amp clamp. Simply open the clamp and engulf the wire. Careful on your use of power in the electrical sense since power is understood as a measurement of energy typ in heat (or a watt.)
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