rectifiers

Rectifiers are electrical devices that convert alternating current (AC) into direct current (DC). They achieve this by exploiting the nonlinear current–voltage behavior of semiconductor junctions or vacuum tubes, which conduct preferentially in one direction. The output is typically pulsating DC and is often smoothed before use.

A half-wave rectifier conducts during only one half of the AC cycle, producing a single-polarity output with substantial ripple. A full-wave rectifier uses either a center-tapped transformer with two diodes or a bridge of four diodes to produce pulsating DC that contains both halves of the input waveform.

Most modern rectifiers are solid-state devices based on diodes. Controlled rectifiers employ devices such as thyristors or silicon-controlled rectifiers (SCRs) to regulate the output voltage or current. Vacuum-tube rectifiers were widely used in early power supplies but have mostly been replaced by semiconductor devices.

Because the rectified output is not pure DC, filtering networks are used. Capacitors provide smoothing, while inductors and RC/LC networks reduce ripple. Regulation may be achieved with linear regulators or switching regulators, especially in high-efficiency power supplies.

Applications include AC-to-DC power supplies for consumer electronics, battery charging circuits, DC motors, radio and telecommunications equipment, and various industrial systems.

Key considerations for rectifiers include voltage and current ratings, peak inverse voltage, forward voltage drop, efficiency, ripple, and thermal management. The combination of rectifier topology, filtering, and regulation determines the overall performance of the DC supply.