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Smoothing AC half wave

  1. Jul 26, 2009 #1
    Hi!
    As what I have studied, to smoothen the half wave voltage produced by AC passing through a diode is placing a capacitor parallel to the resistor.If I want to add an inductor inside my circuit to smooth the half wave, where should the inductor place?
    Does inductor help in smoothing the half wave?How is the working concept of the inductor in the circuit?
    Any idea?Thanks!
     
  2. jcsd
  3. Jul 26, 2009 #2

    vk6kro

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    Science Advisor

    A simple power supply has this arrangement:

    AC supply .......... diode or diode bridge..........capacitor ........ground. The load goes across the capacitor.

    If you wanted to add an Inductor, it should go after the capacitor in line with the load and there should be another capacitor after it to ground. The load goes across the second capacitor.


    The inductor ideally has no effect on DC current but it will help to limit the AC component on the DC.

    The input capactor is important as the inductor can cause voltage spikes which might destroy the diodes if the capacitor wasn't there.
    Also, the inductor should be a special one with an air gap in the iron core so that it does not saturate easily with DC passing through it.

    An inductor is not normally used because voltage regulator ICs are used and these give almost perfect smoothing.
     
  4. Jul 27, 2009 #3
    The topology vk mentions is correct, but in real life, you would need a very large (and therefore expensive) inductor to make a significant difference to the ripple, compared to just adding more capacitance.
     
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