Changes

How then is the electric current generated ?

How then is the electric current generated ?

[[File:PV cell with photon.png|left|thumb|314x314px]]

[[File:PV cell with photon.png|left|thumb|314x314px]]

[[File:PV cell with photon inside.png|thumb|352x352px|alt=]]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]]

[[File:PV cell with photon inside.png|thumb|352x352px|alt=]]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]]

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.

.

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.

.

          [[File:PV cell in circuit.png|left|thumb|350x350px]]

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.  

Negative charges flow out of the electrode on the n-type side, through a load (such as a light bulb}, and perform useful work on that load (such as heating the light bulb's filament to incandescence}. The electrons then flow into the p-type side, where they recombine with holes near the electrode.[[File:PV cell in circuit.png|left|thumb|350x350px]] 

Negative charges flow out of the electrode on the n-type side, through a load (such as a light bulb}, and perform useful work on that load (such as heating the light bulb's filament to incandescence}. The electrons then flow into the p-type side, where they recombine with holes near the electrode.

[[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.  

The incident light continually creates more electron-hole pairs and, thereby, more charge imbalance; the charge imbalance is relieved by the current, which gives up energy in performing work. The amount of light incident on the cell creates a near proportional amount of current.  

The incident light continually creates more electron-hole pairs and, thereby, more charge imbalance; the charge imbalance is relieved by the current, which gives up energy in performing work. The amount of light incident on the cell creates a near proportional amount of current.