PV Gap

Peter Said:

how does a solar cell work?and can it be made with samll investment?

We Answered:

A solar cell works on Einsteins photoelectric effect. Through this effect, Einstein determined that light has momentum and this momentum can be used to "expel" an electron from its nucleus. This free electron can thus be carried via a wire and produce a net current.

The way that they are made is through thin film deposition. Might be a little hard to make that in your basement.

Leonard Said:

i've got a problem with my science project regarding solar cells and a dc motor.10 pts for best answer.?

We Answered:

Solar cells will ALWAYS product a voltage or current that changes with the amount and angle of the sunlight. There is nothing you can do about that.

But the cell numbers you list should charge the battery fine. But if the motor draws more than about 0.6 amps, then the battery will not get charged and you need a larger array.

An AC-DC converter (power supply) won't help unless you want to use it in place of the solar cell. That will work.

What is missing is the battery info and the motor info. And missing is what your goal is and what the problem is.

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Maria Said:

Are solar cell really helpful?

We Answered:

Here's where science enters the picture. Two plates of pure silicon would not generate electricity in solar panels, because they have is no positive or negative charge. Solar panels are created by combining silicon with other elements that do have positive or negative charges.

Phosphorus, for example, has five electrons to offer to other atoms. If silicon and phosphorus are combined chemically, the result is a stable eight electrons with an additional free electron along for the ride. It can't leave, because it is bonded to the other phosphorus atoms, but it isn't needed by the silicon. Therefore, this new silicon/phosphorus plate is considered to be negatively charged.

In order for electricity to flow, a positive charge must also be created. This is achieved in solar panels by combining silicon with an element such as boron, which only has three electrons to offer. A silicon/boron plate still has one spot left for another electron. This means the plate has a positive charge. The two plates are sandwiched together in solar panels, with conductive wires running between them.

With the two plates in place, it's now time to bring in the 'solar' aspect of solar panels. Natural sunlight sends out many different particles of energy, but the one we're most interested in is called a photon. A photon essentially acts like a moving hammer. When the negative plates of solar cells are pointed at a proper angle to the sun, photons bombard the silicon/phosphorus atoms.

Eventually, the 9th electron, which wants to be free anyway, is knocked off the outer ring. This electron doesn't remain free for long, since the positive silicon/boron plate draws it into the open spot on its own outer band. As the sun's photons break off more electrons, electricity is generated. The electricity generated by one solar cell is not very impressive, but when all of the conductive wires draw the free electrons away from the plates, there is enough electricity to power low amperage motors or other electronics. Whatever electrons are not used or lost to the air are returned to the negative plate and the entire process begins again.

One of the main problems with using solar panels is the small amount of electricity they generate compared to their size. A calculator might only require a single solar cell, but a solar-powered car would require several thousand. If the angle of the solar panels is changed even slightly, the efficiency can drop 50 percent.

Some power from solar panels can be stored in chemical batteries, but there usually isn't much excess power in the first place. The same sunlight that provides photons also provides more destructive ultraviolet and infrared waves, which eventually cause the panels to degrade physically. The panels must also be exposed to destructive weather elements, which can also seriously affect efficiency.

Ricky Said:

how does the solar cell work?

We Answered:

it is made up of silicon & works on the principles of photolytic energy