Metal rectifier

A metal rectifier is an early type of semiconductorrectifier in which the semiconductor is copper oxide, germanium or selenium. They were used in power applications to convert alternating current to direct current in devices such as radios and battery chargers. Westinghouse Electric was a major manufacturer of these rectifiers since the late 1920s, under the trade name Westector (now used as a trade name for an overcurrent trip device by Westinghouse Nuclear).

In some countries the term "metal rectifier" is applied to all such devices; in others the term "metal rectifier" normally refers to copper-oxide types, and "selenium rectifier" to selenium-iron types.