Full Wave Rectifier : For full wave rectifier we use two junction diodes. The circuit diagram for full wave rectifier using two junction diodes is shown in figure.
Suppose during first half cycle of input ac signal the terminal S1 is positive relative to and S2 is negative relative to , then diode I is forward biased and diode II is reverse biased. Therefore current flows in diode I and not in diode II. The direction of current i1 due to diode I in load resistance RL is directed from A to B. In next half cycle, the terminal S1 is negative relative to and S2 is positive relative to . Then diode I is reverse biased and diode II is forward biased. Therefore current flows in diode II and there is no current in diode I. The direction of current i2 due to diode II in load resistance is again from A to B. Thus for input a.c. signal the output current is a continuous series of unidirectional pulses. This output current may be converted in fairly steady current by the use of suitable filters.
