PN Junction Diode working in Tamil

PN JUNCTION DIODE WORKING PRINCIPLE OF OPERATION:
To explain the properties of a pn junction, p-type and n-type semiconductor are suitably joined.
Keep in mind that n-type material has a high concentration of free electrons while p-type material has a high concentration of holes.
Therefore, at the junction, there is a tendency for the free electrons to diffuse over to the p-side and holes to the n-side.This process is called diffusion.

The combination of these holes and electrons create a new region between the two layers. This region is called “depletion layer”.
Only inside this, there is positive charge on ‘n’ side and negative charge on ‘p’ side. Because of this a potential is produced in this layer which is called “barrier potential”. The barrier potential in directly related to depletion layer. The barrier potential opposes the flow of majority carriers through the junction and it aids the flow of minority carriers.
For both of these opposite effects, no charge carriers will flow through the junction at normal condition. The potential difference across a pn junction can be applied in two ways namely, forward biasing and reverse biasing.

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