A rectifier is an electronic device that converts alternating current into a pulsating direct current. A halfwave rectifier is a rectifier that utilizes only one half of the AC cycle and converts it into a pulsating direct current. On the contrary, a full-wave rectifier converts the entire cycle of an alternating current into a pulsating DC. A halfwave rectifier is unidirectional while a full-wave rectifier is bidirectional.
Overview of Half Wave Rectifier
A half-wave rectifier uses only one diode for the transformation. A half-wave rectifier circuit consists of three main components, and they are:
- A diode
- A Transformer
- A resistive load
The halfwave rectifier waveform before and after rectification is shown below in the figure.
A half wave rectifier is widely used in rectification and signal peak applications.
Overview of Full Wave Rectifier
Full wave rectifiers transform the complete cycle of an AC waveform into a pulsating DC. The full wave rectifier circuit can be constructed in two ways. The first method uses a centre tapped transformer and two diodes. This arrangement is known as a centre tapped full wave rectifier. The second method uses a transformer with four diodes arranged as a bridge. This is known as a bridge rectifier.
Some Advantages of Full Wave Rectifier over Half Wave Rectifier
- -Halfwave rectifiers’ efficiency is 40.6%, while the rectification efficiency of full-wave rectifiers is 81.2%. We can see that the efficiency of the full-wave rectifier is double that of a half wave rectifier.
- A simple filter is required for a full wave rectifier as the ripple factor is low. The ripple factor in a full-wave rectifier is 0.482 while in a half-wave rectifier it is about 1.21.
- The output voltage obtained in full wave rectifiers is higher than that obtained using half wave rectifiers.
The only disadvantage of a full wave rectifier as compared to a half wave rectifier is that they are costlier compared to a half wave rectifier.
Here, let us compare half wave and full wave rectifier against important parameters and understand their differences.
|Parameters||Half Wave Rectifier||Full Wave Rectifier|
|Transformer Utilization Factor||0.286||0.692|
|Fundamental Frequency of Ripple||Equal to Supply Frequency||Double of Supply Frequency|
|Peak Inverse Voltage||Vs||2Vs|
|Number of Diodes||1||4|
|DC Output Voltage||Imax/π RL||2/π RL Imax|
If we need a low-cost device and are ready to compromise on the efficiency then using a half wave rectifier is suitable. But if we are working on a circuit that requires highly efficient conversion of AC to DC then a full wave rectifier should be used.