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Ripples in the pulsating D.C.

  1. Apr 14, 2014 #1
    Which value of capacitor should i use in rectification so as to remove the ripples from the pulsating d.c? Having 50 hz 12 volts ..any formula related with ripples and capacitance?
    Last edited: Apr 14, 2014
  2. jcsd
  3. Apr 14, 2014 #2
    You can use this equation

    C = Q/V = ( I * t )/V

    I - load current
    t - discharge time 1/50Hz (20ms) for half wave rectifier and 1/100Hz (10ms) for full wave rectifier or 1/60Hz and 1/120Hz for countries with 60Hz mains.
    V - capacitor ripple voltage
  4. Apr 14, 2014 #3
    Oh thanks i'll use this formula lets c...
  5. Apr 14, 2014 #4
    And what's the value of t for bridge rectifier? Same as full wave ?
  6. Apr 14, 2014 #5
    Yes, the same as for full wave.
    t = 10ms
  7. Apr 14, 2014 #6


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    Staff: Mentor

  8. Apr 14, 2014 #7
    Thanks and m one more ques please why we mostly use capacitor filter and inductor not ??? Inductor also blocks high frequency waves...its only because capacitor is easy to fabricate in the circuits?
  9. Apr 15, 2014 #8


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    Staff: Mentor

    Inductors are comparatively heavy and expensive. They can hum audibly. Also, the capacitor input filter is a peak detector, whereas the inductor is an averaging filter so delivers a lower output voltage for the same transformer voltage input.

    You'll still need a filter capacitor to accommdate load variations (to realize a low-impedance), because the inductor has a steady-current characteristic (a high impedance characteristic).
    Last edited: Apr 15, 2014
  10. Apr 16, 2014 #9
    Ok thanks :)
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