What is a half wave rectifier?

A half wave rectifier is a type of circuit that is used to convert alternating current (AC) power into direct current (DC) power. It gets its name from the fact that only half the sine wave of the AC current passes through it and is converted to DC.

A half wave rectifier uses a single diode which effectively cuts off the sine wave at anything below 0 Volts, resulting in a single direction flow of the circuit in a stuttering pattern that omits the negative flow. Half wave rectifiers are sometimes used for AM radio transmission, but are not considered ideal for conversion purposes since half the power output is in effect wasted.