What is rectification? Explain the working of full wave rectifier ?

Rectification : The process of converting alternating current or voltage into direct current or voltage is called Rectification.
Full wave Rectifier :-
i) A Full wave rectifier can be constructed with two p-n junction diodes as shown. The input A.C signal to be rectified is applied across primary of transformer and rectified output D.C signal is taken across load resistance (RL) connected across the secondary of transformer.
Circuit Diagram :


ii) The secondary of transformer is centre tapped because with respect to centretap ‘C’ the inputs of the diodes A and B are out of phase.
iii) For all the positive half cycles of input A.C. signal the diode D₁ is in forward bias and it conducts current. Now the diode D₂ is in reverse bias and it does not conduct current.
iv) For all the negative half cycles of input A.C signal the diode D₂ is in forward bias and it conducts current. Now the diode D₁ is in reverse bias and does not conducts current.
v) Both positive and negative half cycles of input A.C signal are converted into rectified D.C output.
vi) The ratio of output D.C power to input A.C power is called efficiency of full wave rectifier
$\mathrm{\eta }=\frac{0.812{\mathrm{R}}_{\mathrm{L}}}{{\mathrm{r}}_{\mathrm{f}}+{\mathrm{R}}_{\mathrm{L}}}\mathrm{\eta }=\frac{\text{ output d.c power }}{\text{ input a.c power }}$
R_L-Load Resistance, r_f- Forward Resistance of diode. The maximum efficiency of full wave rectifier is 81.2%.