Why, when you first connect a solar cell to a watt meter it first spikes and then continuously falls?
August 27th, 2008 | by Michael |
inak94 asked:
I did a science experiment that measures the output of solar cells and, based on the results, the wattages for each of the solar cells spike in the first 20 seconds and then began to level. Is there something real that is happening that I don 't know about, or is there just a problem with my measurements and / or voltmeter / currentmeter electric? Thanks in advance and don 't be afraid to explain the complicated answer!
MAX
I did a science experiment that measures the output of solar cells and, based on the results, the wattages for each of the solar cells spike in the first 20 seconds and then began to level. Is there something real that is happening that I don 't know about, or is there just a problem with my measurements and / or voltmeter / currentmeter electric? Thanks in advance and don 't be afraid to explain the complicated answer!
MAX
One Response to “Why, when you first connect a solar cell to a watt meter it first spikes and then continuously falls?”
By eyeonthescreen on Aug 30, 2008 | Reply
Solar cells operate under the so-called photo-electric effect. Here the momenta of photons strike bound electrons of photo electric material and that causes those electrons to become free electrons. Free electrons are the ones that create the current in your wattmeter.
Before you hook up the wattmeter, the solar panel is an open circuit; so those free electrons build up in the panels. When you hook on the meter, that closes the circuit and a current of free electrons starts to flow. Because of the buildup of free electrons while the circuit was open, the initial current surge is higher than the steady-state flow.
Once the excess electrons are siphoned off through the wattmeter, the remaining free electrons reach a steady state level because the sunlight is creating as many free electrons as the wattmeter is siphoning off.