PHOTODIODE & SOLAR CELL
Photodiode A photodiode is a special type of junction diode used for detecting optical signals. It is a reverse biased p-n junction made from a photosensitive material.In photodiode,current carriers are generated by photons through photo excitation.Its symbol is Construction A photodiode is fabricated with a transparent cover to allow light to fall on the diode and operated under reverse bias. Working When the photodiode is illuminated with light (photons),with energy greater than the energy gap of the semiconductor,then electron-hole pairs are generated due to the absorption of photons. These charge carriers contribute to the reverse current. V-I Characteristics Its V-I characteristics are shown in figure.We observe from the figure that current in photodiode changes with the change in light intensity(I) when reverse bias is applied. Solar cell Solar cell is a p-n junction diode,which converts solar energy into electr