Power rectifiers are electrical devices that convert alternating current (AC) to direct current (DC). They are an integral part of telecom rectifiers for the telecommunications industry, and in battery chargers, DC power systems, and other power system devices. Power rectifiers include one or more diodes, electronic components that conduct current in only one direction. Single-diode power rectifiers omit the negative portion of the AC waveform. By contrast, multi-diode power rectifiers reverse the negative portion of the AC waveform, allowing it to merge with the positive part to produce an entirely positive current. Typically, single-phase power rectifiers use four diodes. If the AC is center-tapped, then the diodes are arranged anode-to-anode or cathode-to-cathode to form a full-wave rectifier. If the AC is not center-tapped, then the four diodes are arranged in a bridge. With three-phase AC power, six diodes are used. Each of the three pairs is arranged in series. Many diodes have four terminals so that they can be used in a single-phase split supply, a half-bridge, or for three-phase use.

