Rectification

The essntial item in the Rectification process is the diode.
The word 'diode' is made up from di (=two) + electrode, and it is therefore a device which has two electrodes or terminals. These terminals are called anode and cathode respectively. Identification of the cathode is by means of marking the appropriate end the body of the component, usually with a band.
The diode is a one-way device, that is, it will conduct, or allow current to flow, in one direction only, when its anode is positive with respect to cathode. The direction in which this current flows is called the forward direction.
When the anode is negative with respect to the cathode, no current should flow.
This is called the reverse direction.
The diode can regarded as a switch, current able to flow only when the switch is on. Click Here!