ATAR Notes: Forum
VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Physics => Topic started by: Shark 774 on May 19, 2011, 10:31:22 am
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The current through a reverse biased photodiode can be measured and then looking at the graph we can find the lux. However, could we find the potential difference across a FORWARD biased photodiode and from the graph also work out the lux??
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Diodes are non-ohmic, so the voltage across the diode is constant. It won't tell you anything other than the reverse bias voltage across the diode!
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Diodes are non-ohmic, so the voltage across the diode is constant. It won't tell you anything other than the reverse bias voltage across the diode!
If you look at the graph of the characteristics of a photodiode, the voltage actually increases as the lux increases. However I don't think that it's sensitive enough to the change in lux, where as the change in current when reversed biased is very sensitive to the lux.