The i-V characteristic of a p-n junction diode is shown in figure.Find the approximate dynamic resistance of the p-n junction when (a) a forward bias of 1 volt is applied ,(b) a forward bias of 2 volt is applied is applied .

Explanation

The current at 1 volt is 10 mA and at 1.2 volt it is 15 mA. The dynamic resistance in this region is
`R=(DeltaV)/(Deltai)=(0.2 "volt")/(5mA)=40Omega`
(b). The current at 2 volt is 400 mA and at 2.1 volt it is 800 mA. The dynamic resistance in the region is
`R=(DeltaV)/(Deltai)=(0.1 "volt")/(400mA)=0.25Omega`.