Question

Dynamic resistance of a diode is given by

• A. $r_{d}=\frac{\Delta V}{\Delta I}$
• B. $r_{d}=-\frac{\Delta V}{\Delta I}$
• C. $r_{d}=\frac{\text { Threshold voltage }}{\text { Current }}$
• D. $r_{d}=\frac{\text { Breakdown voltage }}{\text { Current }}$

Answer 1

Answer: (A)

A $p-n$ junction diode primarily allows the flow of current only in one direction (forward bias). The forward bias resistance is low as compared to the reverse bias resistance. For diodes, we define a quantity called dynamic resistance as the ratio of small change in voltage $\Delta V$ to a small change in current $\Delta I$,
$r_{d}=\frac{\Delta V}{\Delta I}$