Question

Explain the working to obtain $V-I$ characteristic curve in forward biasing of P-N junction diode. Draw a circuit diagram of experimental arrangement.

Answer 1

The attached diagram shows the circuit of p-n junction under forward bias.

In forward-bias, p- side is supplied with a positive potential and n-side is supplied with a negative potential. Hence, electric field generated is opposite that of the electric field generated by barrier potential. This leads to the generation of extra carriers on both sides and hence, reduction of depletion width and barrier potential.

Hence, resistance of the diode becomes very small and it can be approximated to a short circuit after application of forward cutoff voltage.

Corresponding $V-I$ characteristics are shown in the attached figure.