Table of Contents

**Static and Dynamic resistance of Diode **

In a junction diode, applied voltage (V) is not proportional to the diode current and hence it does obey **Ohm’s law**. So junction diode is the example of** non-ohmic conductor**. The resistance of a is the function of the operating current.

Diode has two possible resistances i.e.

- d.c. or
**static resistance of diode**. - a.c. or
**dynamic resistance of diode**.

## Static resistance of diode

**D.C.** or **Static resistance of the diode** is defined as the ratio of the d.c. voltage across the diode direct current flowing through it.

**Static resistance formula**

**Dynamic resistance of diode**

**A.C.** or **Dynamic resistance of the diode** is defined as the ratio of the small change in voltage to corresponding small change in current in the diode.

**Dynamic resistance formula**

For a p-n junction diode at room temperature,

But from eqn. 1, we get

For a forward biases p-n junction, I>>I_{s}.

Therefore,

In case of Ge semiconductor, n=1

For a reverse biased p-n junction, R_{ac}is very large.