PV Gap

Herbert Said:

How much current and voltage is produced on a solar cell of calculator 3cm*1cm size to a 200ohm resistor?

We Answered:

If it's a single cell, it will output about 0.5 volts in bright sunlight.

But there may be several connected in series for 1 or 1.5 volts.

Current is unknown, but not more than 1 mA

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Jennie Said:

how can i set up a simple circuit to find the current and voltage output of a solar cell?

We Answered:

get a high wattage resistor

wire it across the cell measure the voltage (V) across the resistor and the current (I) through the resistor

power output = VI

measured in Watts

this is the amount of energy per second ie Joules per second

Lloyd Said:

Will i get a constant voltage from a solar cell if i keep the light and intensity the same??

We Answered:

The full answer is a bit more complicated then the first respondents wrote.

In principle, if the solar cell is NOT connected to anything, then the voltage will be constant for ANY amount of light, as long as it is above some minimum amount. This is a photoelectric effect, and for a given material, the voltage is constant. However, you may need a very sensitive voltage meter to measure it, because the meter itself will draw a current, and this applies if there is NO current.

But as soon as you begin to draw a certain current, the voltage will drop, and this voltage drop will depend on the amount of the current, and the amount of light striking the solar cells.

You can think of it as if the solar cell were a water pump. If there is no place for the water to go - if the output is blocked - if there is no circuit - you will get the full pressure, the full voltage. But as soon as you allow much water to flow, the pressure will drop, the voltage will drop.

Having said all of that, it might now be more clear that for a given load (current, amperage, power requirement) the voltage will vary depending on how much light falls on the solar panel - depending on how strongly the pump is pumping - but will stay the same if the light's intensity remains the same.