PRINCIPLE :-

In photoelectric effect when radiation is incident on a metal surface electron are ejected. In photovoltaic effect, certain materials being exposed to radiation generates electron hole pairs available for conduction. As a result a voltage is developed across the material. The radiation energy $E= hϑ$ is required to be greater then the band gap energy $E_g$ of the material. This is a phenomenon in which light energy is converted into electrical energy.

ADVANTAGES :-

• Environmentally friendly.
• No noise, no moving parts.
• No emission.
• Minimum maintenance required.
• Long lifetime, up to 30 years.
• PV operator even in cloudy weather condition.

Disadvantages:-

• PV cannot operate without light .
• High initial costs that overshadow the low maintenance costs and lack of fuel costs.
• Large area needed for large scale applications.
• PV generates direct current special DC appliances or an inverter are needed.