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DiscoverCircuits.com -- Hobby Corner
Last Updated on:
Tuesday, November 29, 2011 08:14 PM
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Solar Cell Circuits
Tester Circuits |
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Solar Cell Test Fixture Circuit |
| If you are considering
building your own solar panel, you might try building the solar cell tester shown
below. When constructing a solar panel it is important to make sure that all the
solar cells used in the panel be closely matched for their short circuit current.
One weak cell will lower the efficiency of the whole panel. The system shown
allows individual solar cells to be tested for their short circuit current under a
constant light intensity condition. The system uses a low voltage 25 - 50 watt
halogen spot light to simulate the light from the sun. |
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A small PIN
photodiode is placed in the path of the light from the lamp and is connected to a
circuit, which converts the light intensity collected by the diode into a voltage.
Another circuit compares that voltage to a reference. The error signal is fed to a
pulse width modulation circuit, which controls the amount of power fed to the lamp.
The result is a uniform light source, whose intensity remains fixed. The system can be
calibrated to produce a light intensity equal to one sun. |
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The assembly could be made from piece of plywood
with cutout for the test area. A bracket of some kind could hold the lamp assembly
below the window. I’d recommend a piece of high temperature frosted glass as a
light diffuser to insure a more uniform light pattern. I think a glass window area
about 6 inches by 6 inches would be big enough for most solar cells. The current
generated by the solar cell under test is measured by any digital multimeter,
which can measure a few amps of current. I will add the complete control
circuit for this system later. |
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Click on Drawing Below to view PDF version of Schematic |
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eMail David A.
Johnson, P.E. about this circuit |