Question

Explain the principle of operation of a photodiode.

Answer 1

Definition:

A special type of PN junction device that generates current when exposed to light is known as photodiode. It is also known as photodetector or photosensor. It operates in reverse biased mode and converts light energy into electrical energy. The figure below shows the symbolic representation of a photodiode.

Principle of Photodiode:

It works on the principle of the photoelectric effect. The operating principle of the photodiode is such that when the junction of this two terminal semiconductor device is illuminated then the electric current starts flowing through it. Only majority current flows through the device when the certain reverse potential is applied to it.