Center-Tapped Full-Wave Rectifier

Although half-wave rectifiers have some applications, full-wave rectifiers are the most commonly used type of dc power supplies. A full-wave rectifier allows a unidirectional flow of current to the load during the entire input cycle, while the half-wave rectifier allows this only during one half-cycle of the input. There are two main types of full-wave rectifiers:center-tapped and bridge. Simplified animations will show you the way they work.

Center-tapped full-wave Rectifier:

This type of rectifier circuit uses two diodes connected to the secondary of a center-tapped transformer. The input signal is coupled through the transformer to the center-tapped secondary. Half of the total secondary voltage appears between the center tap and each one of the secondary windings.

The center-tapped full-wave rectifier works as follows:

During the positive half-cycle: The upper diode D1 is forward-biased and the lower diode D2 is reverse biased. The current path is through D1 and the load resistor RL.

During the negative half-cycle: The upper diode D1 is reverse-biased, while D2 is forward biased. The current path is through D2 and the load resistor RL.


Output voltage of the center-tapped full-wave rectifier:

Since the number of positive alternations that make up the full-wave rectified voltage is twice that of the half-wave voltage, the average value of a full-wave rectified sine wave voltage is twice that of the half-wave, as expressed in the following relationship:


The output peak voltage, taking the diode drop voltage into account is: , where V2 refers to the secondary's transformer voltage.


Peak inverse voltage of the center-tapped full-wave rectifier:

Each diode in this type of circuit is alternately forward biased and then reverse-biased. The maximum reverse voltage each diode must withstand is the peak secondary voltage. In terms of the output voltage, it is: 


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