capacitors

Discussion in 'Homework Help' started by amilton542, Jan 20, 2011.

  1. amilton542

    Thread Starter Active Member

    Nov 13, 2010
    494
    64
    lets say ive got three capacitors in series ( 4 , 8 and 12 micro farad) the total capacitance will be smaller than the smallest capacitor and the smallest capacitor will drop the biggest voltage to keep Q constant. i cant understand why you would waste two capacitors to a value smaller than the smallest capacitor, would it not be easier to just stick with one capacitor at a constant value. or is there a purpose beyond my scope to this???
     
  2. someonesdad

    Senior Member

    Jul 7, 2009
    1,585
    141
    One reason might be if the capacitors you have don't have the voltage rating you need, but in series they do.
     
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  3. Adjuster

    Well-Known Member

    Dec 26, 2010
    2,147
    300
    Capacitors can be connected in series to achieve a larger total voltage rating, but this is not easy to do safely. Usually capacitors of equal nominal value will be employed, but even so, steps need to be taken to ensure that the voltage distribution is as required, despite value tolerances and spreads in leakage currents.

    Some circuit configurations also result in capacitors operating in series. The effective tuning capacitance of some oscillators consists of capacitors in series, as does the output capacitance of certain voltage multiplying circuits.

    http://en.wikipedia.org/wiki/Colpitts_oscillator
     
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