PV Gap

Lester Said:

Can anyone tell me the uses of a solar cell?

We Answered:

I think what you are actually asking is that you have a few small solar cells, and want to "play around" with it....
If they are quite small, then there are not many "useful" things you can do with them.
Firstly, you need a simple Volt Meter, range 0 - 10 Volt DC.
Hook it up to one of the cells in broad daylight, and determine -
a) the polarity of the 2 wires coming out: If the needle of your volt meter goes "to the right", then remember: The "plus" of the cell is the plus (or +V) of your volt meter. If the needle tries to go left, reverse the wires and try again.
b) Read the number where the needle points to: This is the voltage of your cell.
Then find something which requires a small DC voltage, like a calculator and see whether the voltage matches. If not, you can daisy-chain some cells like so + to - of the next, that + to - of the next, and so on, until the accumulated voltage is what you need.
Then hook it up (watch the polarity!) to your calculator's external DC power plug, and take the batteries out. Should work.... you just saved yourself (and the world) 0.3 Watt, or 1/200th of a light bulb !

Lucy Said:

Questions about Solar Cells?

We Answered:

1. no, but you may need a diode between the solar cell and the battery to prevent the battery from discharging through the solar cell when there is no sunshine. The solar cell has to put out enough voltage to charge the battery. For example, a 12 volt lead acid battery requires 15 volts to charge.

2. no. It requires lots of special chemicals, and machinery. Start up costs for a solar cell factory is in the hundreds of millions of dollars.

3. You need a volt meter and a load resistor sized for the ratings of the solar cell.

For example if it is rated at 12 volts and 1 amp, you need a R = E/I = 12 ohm resistor, rated at 20 watts. If you connect this to the solar cell and you read 12 volts, they you are, by ohms law, getting 1 amp, and 12 watts.

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