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Difference Between a Full Wave Rectifier and Half Wave Rectifier

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
Voltage Regulation Good  Better
Rectification Efficiency 40% 80%
Ripple Factor 1.21 0.482
Transformer Utilization Factor 0.286 0.692
Fundamental Frequency of Ripple Equal to Supply Frequency Double of Supply Frequency
Form Factor 1.57 1.11
Peak Factor 2 1.414
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 board transistor that requires highly efficient conversion of AC to DC then a full wave rectifier should be used.

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