RECTIFICATION
With the aid of a diode which only allows current to flow one way through it a AC supply can be rectified to a DC one.
There are two basic types of rectification:
SMOOTHING
In order to smooth the current that is decrease the variation of the voltage with time, a capacitor can be put across the output D.C. voltage from
above, this charges when the voltage is high and discharges when it is lower, causing the voltage decay curve after the first charge to slow and
not get to zero before the voltage has increased again.