Draw circuit arrangement for studying V-I characteristics of a p-n junction diode. Show the shape of the characteristics of a diode.

Question

(a) Draw circuit arrangement for studying V-I characteristics of a p-n junction diode.

(b) Show the shape of the characteristics of a diode.

(c) Mention two information that you can get from these characteristics.

Answer 1

(a) A circuit diagram is needed with a diode, ammeter, voltmeter and a variable power source in forward and reverse bias.

• The forward bias shows an exponential increase in current after a threshold (–0.7 V for Si, ~0.3 V for Ge).

• The reverse bias shows negligible current until breakdown.

(c) Information obtained:

1. Threshold voltage – The minimum voltage required to conduct in forward bias.

2. Breakdown voltage – The voltage where reverse current suddenly increases.