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Question
Explain briefly with the help of necessary diagrams, the forward biasing of a p-n junction diode. Also draw characteristic curves.
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Solution
p-n junction diode under forward bias
p-side is connected to positive terminal and n-side to the negative terminal.
Applied voltage drops across the depletion region.
Direction of applied voltage (V) is opposite to the build in potential (V0).
As the depletion layer width decreases, the barrier height is reduced.
Effective barrier height under forward bias is (V0 − V).
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Electron in n-region moves towards the p-n junction and holes in p-region move towards the junction. The width of the depletion layer decreases and hence, it offers less resistance.
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Diffusion of majority carriers takes place across the junction.
This leads to forward current.
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