Capacitor +ve & -ve

Discussion in 'General Electronics Chat' started by aamirali, Jul 14, 2012.

  1. aamirali

    Thread Starter Member

    Feb 2, 2012
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    1. What if +ve terminal of voltage is applied to negative plate of cap & -ve terminla is connected to +ve plate of cap. Cap is electrolytic.

    2. What is it which make separate +ve & -ve plate in electrrlytic capacitor while in ceramic plates can be interchanged
     
  2. Jony130

    AAC Fanatic!

    Feb 17, 2009
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  3. bretm

    Member

    Feb 6, 2012
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    The dialectric in an electrolytic capacitor is a thin layer of metal oxide formed on the plate surface by current-driven chemical reaction. With forward current it's somewhat self-repairing, but with reverse current the reaction is reversed and the oxide layer degrades, which allows current to leak through, which accelerates the reaction making it degrade faster, etc. Desctruction happens quickly.
     
  4. aamirali

    Thread Starter Member

    Feb 2, 2012
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    Cap will break even if reverse voltage is less than breakdown voltage.
    If yes, If I have a ac source & put a cap across it then will it break on -ve cycle of capacitor?????????
     
  5. WBahn

    Moderator

    Mar 31, 2012
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    The breakdown voltage for a polarized capacitor is the FORWARD breakdown voltage. Unless the specific device is spec'ed otherwise, you need to assume that there is NO reverse breakdown voltage (or, more to the point, that ANY reverse voltage will cause breakdown).
     
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