Rectifier is device which converts alternating current (AC) into direct current (DC). The component used to convert AC signal to DC signal we know it very well! Yes your guess is right, Diode.
HALF WAVE RECTIFIER
Diodes allow current to pass in one direction only so only the positive cycle we get at output. Check the circuit diagram and wave cycle to understand it better.
Here you can see the output is half of the input because diodes can pass only positive signals, that’s why this type of rectifiers are named as “Half wave rectifiers”.
So can we make a full wave rectifier circuit! Yes off course.
FULL WAVE RECTIFIER
As it is named this type of rectifiers gives full wave output. There are two types of full wave rectifiers one is center-tap and other is bridge. Bridge rectifiers are commonly used because of its electrical characteristics (Ripple, RMS, PIV values or factor). Output of both the circuits will be the same but there is a difference in circuit diagram. In the center tap we are using 2 diodes and in the bridge we are using 4 diodes. See diagrams
FULL WAVE BRIDGE RECTIFIER
We can use 4 diodes to make this or we can simply use bridge rectifier IC
RELAY AN ELECTROMECHANICAL SWITCH