Electronics

A rectifier is a device that converts alternating current (AC) to direct current (DC) by allowing current to flow in one direction. 
Half-Wave Rectifier: Uses a single diode to pass only one half of the AC cycle. 
Diagram: 

Working: 
During positive half-cycle, diode is forward-biased, allowing current through the load. During negative half-cycle, diode is reverse-biased, blocking current. Output is pulsating DC with only positive halves. 
Answer: Rectifier converts AC to DC; half-wave rectifier uses diode to pass one AC half-cycle.