Modern Physics > Quantum Effects > Photons

DCS# 7A10.40

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EFFECT OF SHADOW ON SOLAR CELL ARRAY

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APPARATUS

solar cell array mounted to a board	101-09-E6
overhead projector	200
two multimeters	214-01-B
fan or clock	202-19-E2 or D
wood block	101-09-E6

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DESCRIPTION

This demonstrates what happens to a photovoltaic array wired in series when a shadow falls across a single module.  When fully illuminated by the projector, the eleven solar cells in series can supply about 30 mA at 5 V to the fan.  Covering one of the cells with the wood block reduces the current through the array and it can no longer supply enough power to run the fan.

The modified clock (driven by a DC motor from a DVD drive) is more visible than the fan.