One very easy way to understand Solar Cell key function

I have found a very good way to understand the basic key function (or phenomenon) of a Solar Cell. I have read some documents on the function (or phenomenon) of a Solar Cell in some books and some websites (some are good, some are not good or even wrong at least confusing). But I did not encounter my method so far.

To check Diode Voltage by a multimeter (my digital multimeter has this function) with the opposite direction of the +/- shown on the back side of the panel at not very bright place. My multimeter shows "----", which means more than the max checkable (about 2VDC). Then gradually give more light to the panel. The multimeter shows "2.1- 1.9V", which shows . And then further increase the light. It shows less and less values 1.8V -- 1.5V -- 1.2V -- and finally 0.00. This indicates the increasing light creates an increasing voltage at the PN junction opposite to the original PN junction voltage (under a little light condition). This is it. Very easy and you can easily guess what light does to the panel (Solar Cell). After I found this fact it was much easier for me to understand what the text books say like "the current in Solar cell is the reverse current." or "Internal Voltage Difference Creation", etc.


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