Rectification `:` The process of converting on alternating currentinto a direct current is called rectification.
The device used for this purpose is called rectifier.
(i) A full wave rectifier can be constructed with the help of two diodes `D_(1)` and `D_(2)`.
(ii) The secondary transformer is centre tapped at C and its ends are connected to the p regions oftwo diods `D_(1)` & `D_(2)`.
(iii) The output voltage is measured across the load resistance `R_(L)`.
(iv) During positive half cycles of ac, the diode `D_(1)` is forward biased and current flows through the load resistance `R_(L)`. At this time `D_(2)` will be reverse biasedand will be in switch off position.
(v) During negative half cyclesof ac, the diode `D_(2)` is forward biased and the current flows through `R_(L)`.At this time `D_(1)` will be reverse biased and will be in switch off position.
(vi) Hence positive output is obtained for all the input ac signals.
(viii)The efficiency of a rectifier is defined as the ratio between the output dc power to the input ac power.
`eta = ( P_(dc))/(P_(ac))= ( 0.812R_(L))/( r_(f) + R_(L))`
The maximum efficiency of a full wave rectifier is `81.2%`
