Bridge is an arrangement of four diodes in a bridge circuit configuration that provides the same polarity for either polarity of input. The most common use for this application for conversion of an alternating current input into a direct current output known as a bridge rectifier. A rectifier provides full-wave rectification from a two-wire AC input, resulting in lower cost and weight as compared to a rectifier with a 3-wire input from a transformer with a center-tapped secondary winding. A rectifier in itself is simply an electrical device that converts alternating current (AC) to direct current (DC) in a process called rectification. AC can flow in reverse direction while DC only flows in one direction. Rectify can come in many forms, which include but are not limited to vacuum tube diodes, mercury-arc valves, copper and selenium oxide rectifiers, semiconductor diodes, silicon-controlled rectifiers, in addition to other silicon-based semiconductor switches.
The main uses of bridge rectifier are in DC power supplies and high-voltage direct current power transmission systems. Initially, vacuum tube thermionic diodes and copper oxide or selenium-based metal rectifier stacks were used before the introduction of silicon semiconductor rectifiers. Once silicon semiconductor rectifier were introduced, other types of rectifier immediately became obsolete, with the exception of enthusiasts for vacuum tube radio equipment. There have been many types of different rectification technologies, beginning with the electromechanical rectifier in 1905 and progressing to the synchronous rectifier, vibrating rectifier, motor-generator set, electrolytic rectifier, plasma type, and solid state, respectively. The various specifications to consider when analyzing current day Bridge Rectifiersare the peak reverse voltage, maximum reverse voltage, forward continuous current, max surge current, forward voltage drop, maximum reverse leakage current, power dissipation, and maximum operating temperature. It also comes in varying dimensions of length, width, height as well as mounting style and packaging.
The most common sizes for maximum average Bridge Rectifiers current are 1 A, 1.5 A, 4 A, 25 A, and 35 A but can also be found as high as 1000 A. Forward voltage for bridge rectifier is most commonly 1.1 V or 1 V, although it can range from 450 mV to 1.1 kV.