The V-I characteristic of a silicon diode is shown in the figure . Calculate the resistance of the diode at (a) `I_(D) = 15 mA` and (b) `V_(D) = -10 V `

Explanation

Considering the diode characteristics as a straight line between I = 10 mA to I = 20 mA passing through the origin, we can calculate the resistance using Ohm’s law.
(a) From the curve, at I = 20mA, V= 0.8 V, I= 10mA, V= 0.7 V
`r_(fb) = DeltaV//DeltaI = 0.1V //10 mA = 10 Omega`
(b) From the curve at `V = -10 V, I=-1 muA`,