Video Transcript

The most commonly used renewable energy source is solar energy.

But how is solar energy used to generate electricity? A photovoltaic or PV system is used to convert the solar or light energy into electrical energy.

The basic component of the PV system is known as the solar cell. A single solar cell has the capacity of producing about 0.5 volts of electricity.

A solar or solar module is the combination of several solar cells connected in series to generate usable voltage.

The solar panel voltage can be increased by increasing the number of solar cells. For example, 30 solar cells connected in series will produce an output of 15v.

A combination of solar panels connected together is known as solar array and can be used to achieve required current and voltage.

How does the solar cell work?

The generation of electricity on exposure to sunlight is known as the photovoltaic effect. This principle is used by solar cells to produce electricity.

The solar cells are made up of semiconductors, mainly silicon and comprises three layers. The top layer, called the N type layer, is comparatively thin and contains high concentration of electrons.

The bottom layer, called the P type layer, contains high concentration of holes. When the P type and the N type semiconductor is joined, it forms APN junction.

On forming APN junction, the electrons of the N type material try to reach the P region creating a negatively charged layer.

Similarly, the holes of the P type material try to reach the N region creating a positively charged layer.

This region between the two layers, known as the depletion region of the semiconductor. Sunlight penetrates the top thin layer easily to reach the depletion region.

Due to the deficiency of charge in the depletion region, it contains neutral atoms. These neutral atoms are broken when the photons from the sunlight strike the depletion layer.

This knocks the electrons from the neutral atoms leaving behind the holes and producing free charge carriers.

Then the electrons move towards towards the N type layer and the holes move towards the P type layer.

Due to the electric field present in the depletion region. On connecting an electronic circuit, the electrons flow through it generating electricity to electrical devices like bulb fan etc.

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