Rectification
Rectification (electricity), process of converting an alternating current (AC), which flows back and forth in a circuit, to direct current (DC), which flows only in one direction. A device known as a rectifier, which permits current to pass in only one direction, effectively blocking its flow in the other direction, is inserted into the circuit for the purpose. Rectification is carried out at all levels of electrical power, from a thousandth of a watt to detect an AM radio signal, to thousands of kilowatts to operate heavy electrical machinery. The first commercial rectifiers were used in the conversion of alternating to direct current in the operation of electrical motors; these early rectifiers were called mechanical commutators. Today, most rectification is carried out by electronic devices, such as combinations of vacuum-tube diodes, and mercury-arc rectifiers. Most mechanical rectifiers consist of a rotary switch that is synchronized with the current; the switch is arranged to con...