The conversion from AC to DC involves several key stages: Diodes are used in a bridge rectifier circuit to convert AC into pulsating DC. Capacitors and inductors smooth out voltage fluctuations, reducing ripple. This chapter discusses fundamental topics including the idea of a power supply, characteristics and functions of AC and DC power supplies, and the construction and operation of AC/DC power sources. A power supply is a device or circuit that translates electricity from the mains or different sources. Keep reading to learn the basic principles of electricity and the difference between DC & AC power supply. AC (Alternating Current): The current changes direction periodically. AC-to-DC power supplies are vital components of virtually every piece of electronic equipment.