(N/A) full-wave rectifier consists of a center-tapped transformer,two junction diodes $D_{1}$ and $D_{2}$,and a load resistance $R_{L}$.
The primary coil of the transformer is connected to the a.c. supply. The $p$-sides of the two diodes are connected to the ends of the secondary coil of the transformer,and the $n$-sides are connected together to one end of the load resistance $R_{L}$. The other end of the load resistance is connected to the center tap of the secondary coil.
During the first half-cycle of the a.c. input,if the potential at $A$ is positive with respect to the center tap,diode $D_{1}$ is forward-biased and conducts,while diode $D_{2}$ is reverse-biased and does not conduct. Current flows through $R_{L}$ from $X$ to $Y$.
During the second half-cycle,the potential at $B$ becomes positive with respect to the center tap. Now,diode $D_{2}$ is forward-biased and conducts,while diode $D_{1}$ is reverse-biased. Current again flows through $R_{L}$ from $X$ to $Y$.
Since the current through the load resistance $R_{L}$ flows in the same direction during both half-cycles,a unidirectional (rectified) output is obtained across $R_{L}$.