1)   They are based on principle of photovoltaic action i.e. conversion of light energy into (D.C.) electric energy.

 2)  It consist of P-type & N-type semiconductor material forming P-N junction.

3)  When P-N junction is illuminated electron-hole pairs are generated causing an electric field near the P-N junction by the positive and negative ions. Many of electrons are pulled across the junction due to electric field. This cause the current to flow in cell & through the external resistive load. Each cell provides about 0.5V to 150mA.

4)  Solar cells act as like a battery when connected in series-parallel connection into give more power.