Rectifierer

Rectifierer are electrical devices that convert alternating current (AC) into direct current (DC). They are essential in power electronics and are used wherever DC is required from an AC source, such as in mains adapters, battery chargers, and DC distribution systems. The basic principle relies on semiconductor junctions that conduct in only one direction or on controlled devices that can be turned on at chosen times to shape the output.

Most rectifiers use diodes to pass current only during the appropriate half-cycles of the AC input, producing a pulsating DC. Half-wave rectification uses a single diode, while full-wave rectification uses either two diodes with a center-tapped transformer or a bridge configuration of four diodes. Bridge rectifiers are common because they can produce DC without a center-tapped transformer. To achieve smoother DC, rectified output is often filtered with capacitors and sometimes inductors, reducing ripple and improving regulation.

Rectifiers can be passive or active. Controlled rectifiers employ thyristors or silicon-controlled rectifiers (SCRs) to regulate output voltage by delaying the triggering angle. Modern rectifiers often use power transistors such as MOSFETs or IGBTs to realize active rectification with better control and efficiency.

Key performance figures include output voltage, ripple, efficiency, peak inverse voltage, and current rating. Diode drops (about 0.7 V for silicon, lower for Schottky types) influence overall efficiency, especially at high current. Applications span AC adapters, power supplies, battery charging, welding equipment, and high-voltage direct current (HVDC) transmission.