Changes

== The Sun ==

== The Sun ==

The [[wikipedia:Sun|sun]] is the star at the center of the solar system, it has been shinning for more than 4-billion years. It is a nearly perfect sphere of hot plasma with internal convective motion that generates a magnetic field via a [[wikipedia:Solar_dynamo|dynamo]] process.  

{{#seo:|title=Photovoltaic Effect - Wikisolar|description=WikiSolar explain the Photovoltaic Effect|keywords=PV, photovoltaic, how does solar panels work,}}The [[wikipedia:Sun|sun]] is the star at the center of the solar system, it has been shinning for more than 4-billion years. It is a nearly perfect sphere of hot plasma with internal convective motion that generates a magnetic field via a [[wikipedia:Solar_dynamo|dynamo]] process.  

Some stars are enormous sources of X-rays; others mostly generate radio signals. The sun, while producing these and other energies, releases 95% of its output energy as light, some of which cannot be seen by the human eye.  

Some stars are enormous sources of X-rays; others mostly generate radio signals. The sun, while producing these and other energies, releases 95% of its output energy as light, some of which cannot be seen by the human eye.  

When sunlight or energy from the light (Photons, that has enough energy to free an electron from a bond in the silicon crystal) strikes the PV cell, and is absorbed by the semiconductor in the depletion zone.[[File:PV cell with photon and electron holes.png|left|thumb|316x316px]]

When sunlight or energy from the light (Photons, that has enough energy to free an electron from a bond in the silicon crystal) strikes the PV cell, and is absorbed by the semiconductor in the depletion zone.[[File:PV cell with photon and electron holes.png|left|thumb|316x316px]]

[[File:PV cell with photon and electron holes 2.png|thumb|alt=|342x342px]]An electron hole pair is created, i.e a free electron and a free hole.  Because of the existing electric field at the depletion Zone, this freed electron is attracted to the n-type side, being repelled by the barrier. Likewise, the holes encounter is attracted to the p-type side.

[[File:PV cell with photon and electron holes 2.png|thumb|alt=|342x342px]]An electron hole pair is created, i.e a free electron and a free hole.  Because of the existing electric field at the depletion Zone, this freed electron is attracted to the n-type side, being repelled by the barrier. Likewise, the holes encounter is attracted to the p-type side.

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Now what? The electrons and holes are free and excited with nowhere to go. The continual incident rays of the photons continue to generate electron hole pairs and charge separation causes the presence of uncombined excess negative charges on the n-type side and excess holes on the p-type side, a charge imbalance exists in the cell.

If we then connect the n-type side to the p-type side of the cell by means of an external electric circuit, current flows through the circuit (which responds just as if powered by a battery} because this reduces the light induced charge imbalance in the cell.

If we then connect the n-type side to the p-type side of the cell by means of an external electric circuit, current flows through the circuit (which responds just as if powered by a battery} because this reduces the light induced charge imbalance in the cell.

[[File:PV cell in circuit 3.png|thumb|350x350px|alt=]][[File:PV cell in circuit 2.png|thumb|351x351px|alt=|center]]   

[[File:PV cell in circuit 3.png|thumb|350x350px|alt=]][[File:PV cell in circuit 2.png|thumb|351x351px|alt=|center]]   

The light energy originally absorbed by the electrons is used up while the electrons power the external circuit. Thus, an equilibrium is maintained.  

The light energy originally absorbed by the electrons is used up while the electrons power the external circuit. Thus, an equilibrium is maintained.