What is full wave rectifire?

The full wave rectifier is a means of converting alternating current (ac) into direct current (dc). It is done with either the use of 2 diodes coming off a center tapped transformer, or by using a bridge rectifier, which conists of 4 diodes ganged together in a certain configuration. As it's name implies, it converts both the positive going and the negative going parts of the sign wave into useable dc, and therefore is more efficient than a half wave rectifier, which only converts 1/2 of the complete sign wave into useable dc.