Question

The forward characteristic curve of a junction diode is shown in Figure.
Calculate the resistance of the diode at:
(1) $V=0.5$V
(2) I$=60$mA.

Answer 1

Reciprocal of the slope of I-V graph gives the resistance of diode.
Resistance of the diode is given by $R=\frac{\Delta V}{\Delta I}$
(1) : Given, $V=0.5$ volts
Resistance $R=\frac{0.5-0.4}{(40-20)\times {10}^{-3}}=5\Omega$
(2) : Given, $I=60$ mA
Resistance $R=\frac{0.6-0.4}{(60-20)\times {10}^{-3}}=5\Omega$