Full wave bridge rectifier

In the bridge circuit four diodes are connected in the form of a Wheatstone bridge, two diametrically opposite junctions of the bridge are connected to the secondary of a transformer and the other two are connected to the load.When the upper end of the transformer second ary winding is positive, say during first half-cycles of the input supply, diodes D1 and D3 are forward biased and current flows through arm AB, enters the load at positive terminal, leaves the load at negative termi nal, and returns back flowing through arm DC.

 Dur ing this half of each input cycle, the diodes D2 and D4 are reverse biased and so the current is not allowed to flow in arms AD and BC. The flow of current is indicated by solid arrows in the figure. In the second half of the input cycle the lower end of ac supply becomes positive, diodes D,2 and D4 become forward biased and current flows through arm CB, enters the load at the positive terminal, leaves the load at nega tive terminal and returns back flowing through arm DA. Flow of current has been shown by dotted ar rows in the figure. Thus the direction of flow of cur rent through the load resistance RL remains the same during both half^eycles of the input supply voltage.