Question

What do you mean by reverse biasing of P-N junction diodes? Draw circuit diagram for reverse biasing of P-N junction diode and explain its working process. Draw V-I characteristic curve for reverse biasing.

Accepted Answer

In a P-N junction diode, the P terminal is doped in such way that the majority charge carriers are holes, whereas the N terminal is doped in such a way that the majority charge carriers are electrons. When higher or positive potential is applied to N terminal of the diode and lower or negative potential is applied to P terminal of the diode, the P-N junction diode is said to be in reverse bias condition.

The circuit of P-N junction diode in reverse bias:

When no voltage is applied or $V = 0$ then potential develops across the junction i.e. of $0.3 V$ if it is $Si$ diode or $0.7 V$ if its $Ge$ diode. If the potential is increased then it will increase the electric field at the junction as a result the depletion region will also increase. The higher electric field in the depletion region decreases the probability that carriers can diffuse from one side of the junction to the other, hence the diffusion current decreases. A s we increase the reverse bias, the overall width of the depletion layer increases along with its barrier potential. This increment of the depletion layer’s width will continue till the barrier potential reaches to applied reverse biased voltage. When the applied voltage is increased, the minority charges will have increased kinetic energy which affects the majority charges. This is the stage when the diode breaks down. This may also destroy the diode.

What do you mean by reverse biasing of P-N junction diodes? Draw circuit diagram for reverse biasing of P-N junction diode and explain its working process. Draw V-I characteristic curve for reverse biasing.

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