The electricity supply to our homes is an alternating but a number of appliances need steady potential difference. The conversion of ac to dc is known as rectification. This may be achieved in a number of ways but the study of Semiconductors has led to a great achievement in the study of electronics. In addition, most signals in nature like, sound, temperature, pressure are continuously changing with time, and can be represented as combination of sinusoidal variations. In this unit you will be familiar with basic ac circuit components and with their corresponding working principles.