Friday, July 11, 2014

Half Wave and Full Wave Rectifier Circuit and Simulation

In the last post, a circuit was drawn in orcad capture that consisted of a AC signal source and a transformer and the circuit was stimulated to see the waveform at the primary side and secondary side. In this post, to continue the analysis of full and half wave rectification by simulation, the half wave rectifier is designed and stimulated.

See 1st part- Transfomer circuit and simulation
3rd part -  Capacitor Input Filter

Now we add a diode 1N4001 to the secondary circuit to see what it does. Shown below is the schematic.

The output waveform is shown below-

In the above picture, the amplitude of downconverted ac signal remains zero during the negative half cycle part. This is what a half wave rectifier does.

 Now to can make a full wave rectifier by adding few components to the schematic above. First we need a center tapped transfomer and another diode at the lower arm.

This is shown below-

The center tapped transformer is formed by adding another inductor, dividing the two inductor by a ground wire to the ground, making the value of the two inductor value equal to 0.865mH, that is half of the earlier value of 1.73mH.

Simulating this design gives a waveform as shown below-

Notice that the frequency now has changed due to full wave rectification. The frequency spectrum of the above graph is shown below-

The peak of the green spectrum gives the frequency of the output signal after the rectification. Zooming in we find that the frequency is 125Hz.

While the half wave rectifier does not change the frequency the full wave rectifier does as illustrated by simulation above.

In the next post, a filter will be added to the end of the rectifier to smooth the noisy signal.
See Capacitor Input Filter.

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