Objective: To study the I-V characteristics of a p-n junction diode

 

Equipment & components required: Power Supply (0-30V), Voltmeter (0-30V), Ammeter (µA & mA range), resistors, p-n junction diode.

Theory :

When an external voltage is applied across a p-n junction, a current flows in the circuit (Fig 1.1). If the p and n side of the diode are connected to the positive and negative terminal of the power supply respectively ( forward bias ), the holes in p side and electrons in n side are accelerated and move towards the junction, a large current is observed in the ammeter. However, when the polarity of the power supply is reversed (ie p side is connected to the negative terminal of the power supply and the n-side is connected to the positive terminal, reverse bias ), very small current corresponding to the minority charge carriers (holes in n side and electrons in p side) move towards the junction and very small current flows. The current in the circuit varies with voltage as