Many electrical devices run on DC or direct currents, but the signal coming out the wall is AC or alternating current. Rectifier circuits are used to convert AC currents to DC currents. There are many types, but two common ones are full-wave and bridge.

Rectifier circuits are constructed with the use of diodes as a basis. This is because diodes have the ability to change AC to DC.

Rectifiers make it possible for electronic devices, such as portable 12-volt DC power drills, to use the 120-volt AC that is supplied from wall outlets. Other important roles include surge protection and battery charging.

Full-wave rectifiers use two diodes where one conducts on the positive half cycle of the AC wave, and the other conducts on the negative half cycle. The current that is rectified thus continues to flow throughout the entire cycle of the input.

Bridge rectifiers, sometimes referred to as full-wave bridges, are similar to full-waves in that they produce currents that flow throughout an entire circuit. They use four diodes, where two conduct on the positive half cycle, and the other two conduct on the negative half cycle.

Both full-wave and bridge rectifiers may be constructed from circuit diagrams. They are used in high or voltage situations. Bridge rectifiers are available as modules, where small ones may have current ratings of 1 amp, and giant ones may be as small as 25 amps.