Aim:

To draw the static current-voltage (I-V) characteristics of a junction diode.

Apparatus:

Diode, resistor, variable DC power supply, milliammeter, voltmeter, Rheostat and wire.

Theory:

A diode, in electronics, is a two terminal electronic component with an asymmetric transfer characteristics, with low resistance to current flow in one direction and high resistance to current flow in the other direction. A semi-conductor diode is the most common type diode, which is a piece of semi-conductor material with a p-n junction connected to two terminals.

A diode allow electric current to pass in forward direction and block current in reverse direction. The behaviour of a diode in a circuit is given by its I-V characteristics. The shape of the curve is determined by the transport of charge carriers through the depletion layer that exist at the p-n junction. When a p-n junction is first cretaed, diffusion of holes and electrons take place through the junction. As recombination proceeds, more ions are created at the junction and a built-in potential is developed at the depletion zone.

If a voltage of same polarity as that of built-in potential is applied across the junction, depletion zone acts as an insulator, preventing significant current flow through the junction. This is the reverse bias phenomenon.