Q. The $i$-$V$ characteristic of a $P$-$N$ junction diode is shown below. The approximate dynamic resistance of the $P$-$N$ junction when a forward bias of $2volt$ is applied\
A) $1\ \Omega$
B) $0.25\ \Omega$
C) $0.5\ \Omega$
D) $5\ \Omega$
Explanation
(b) The current at $2V$ is $400\ mA$ and at $2.1\ V$ it is $800\ mA$. The dynamic resistance in this region
$R = \frac{\mathrm{\Delta}V}{\mathrm{\Delta}i} = \frac{(2.1 - 2)}{(800 - 400) \times 10^{- 3}} = \frac{1}{4} = 0.25\Omega$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.