Dear all
If a regular Diode is exposed to sunlight, generates voltage (like PV cell)? Why the circuit model of PV cell is a current source in parallel with a reverse diode?
its an equivalent circuit of PV cell and which has to exhibit the Current (I)-Voltage(V), Power (W) - Voltage (V) characteristics similar to the PV cell. The current source indicates the power generation and PV cell and diode to exhibit the characteristics.
If the diode is not connected in reverse then it will a short circuit path across the current source.
Hope this answer may be of use..
I don't think most commercial diodes would do this because the junction won't be exposed to ambient light. However in theory of course it would work because it's just a silicon solar cell designed to be a diode!
Dear Ahmad,
Well, Solar Cell it self actually p-n junction semiconductor (one kind of diode type) with anode being exposed to the sunlight. So it can be modeled as diode. You can check the attached link of youtube video for clearer explanation of the model.
https://www.youtube.com/watch?v=4imVOP_i_LI
actually the PV cell is a current source as a results of the photo-generated current.
notice that in the dark the current source symbol is removed and the remaining is only the diode.
why the diode in reverse? because part of the photo generated current is lost as a diode current (depends on the reverse saturation current, temperature, idealty factor and the terminal voltage)
Your question "Why the circuit model of PV cell is a current source in parallel with a reverse diode?" makes clear that there is a misunderstanding on your side: For regular operation, the diode in the standard equivalent model of a solar cell is always under forward bias; this you can see from the I--V curve under illumination. [Only in a partially shaded module some cells experience reverse biasing, and then (pre-)breakdown may occur.]
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