SOLUTION

The rectifier is a device that converts alternating current into direct current. Rectifier circuits use semiconductor diodes as rectifying elements. Following are the different types of rectifier circuits:

1. Half-wave rectifier
2. Full-wave rectifier

The full-wave rectifier can be built in the following ways:

1. Full-wave rectifier using two diodes and a center-tapped transformer.
2. Full-wave bridge rectifier using four diodes and an ordinary transformer.

A step-down transformer is used to reduce the ac supply voltage to the required level. Center tapping in the secondary of the transformer is done to obtain two equal voltages but of opposite phase.

During the positive half-cycle of the ac supply, Diode D₁ conducts and D₂remains off. During the negative half-cycle of the ac supply, Diode D₂ conducts and D₁ remains off.

It is clear that each diode, together with the associated half of the transformer, acts as a half-wave rectifier. The outputs of the two half-wave rectifiers are combined to produce full-wave rectification in the load. As far as the transformer is concerned, the dc currents of the two halfwave rectifiers are equal and opposite, such that there is no dc current for creating a transformer core saturation problem. The voltage and current waveforms of the full-wave rectifier.