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  1. #1
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    polarized capacitor

    Would someone pls advise the difference (construction) between both capacitors?

    Besides, why do we need non-polarized capacitor in some application? Can we just replace the non-polarized one with polarity one?

    Thanks.

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    non polarized capacitor

    Polarized capacitors are the electrolytic type or tandalium type.
    There are two types of non polarized capacitors. The plastic foil that are nonpolarized by nature and electrolytic nonpolarized capacitors that are actually two capacitors in series (back to back) so that the result is nonpolarized with half the capacitance.
    Polarized capacitors have large leakage current if the voltage is inverted. Nonpolarized capacitors are needed at AC applications in series or in parallel with the signal (or power). Examples are speaker crossover filters and power factor correction networks. In both applications a large voltage AC signal is applied accross the capacitors. If polarized types were used the leakage current would distort the signal and overheat the capacitor and potentially destroy it.


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    •   Alt15th February 2006, 08:39

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  3. #3
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    polarized capacitors

    Quote Originally Posted by ptmsl
    Polarized capacitors are the electrolytic type or tandalium type.
    There are two types of non polarized capacitors. The plastic foil that are nonpolarized by nature and electrolytic nonpolarized capacitors that are actually two capacitors in series (back to back) so that the result is nonpolarized with half the capacitance.
    Polarized capacitors have large leakage current if the voltage is inverted. Nonpolarized capacitors are needed at AC applications in series or in parallel with the signal (or power). Examples are speaker crossover filters and power factor correction networks. In both applications a large voltage AC signal is applied accross the capacitors. If polarized types were used the leakage current would distort the signal and overheat the capacitor and potentially destroy it.
    Since non-polarized capacitor does not suffer large leakage current, why do we STILL need polarized capacitor? Is it mainly due to the higher charge storage capability of polarized capacitor? Thanks.



    •   Alt15th February 2006, 15:27

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    non polarized capacitors

    Polarised capacitors are cheaper than equivalent non-polarised capacitors.
    Polarised capacitors are sometimes physically smaller than non-polarised equivalents.



    •   Alt16th February 2006, 03:49

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    non-polarized capacitor

    polarized cap is meant for AC applications..if we reverse the polarity ie if it is wrongly connected,then it will burst away...



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    polarised capacitor

    Hi,

    The difference is big, some applications need polarized capacitances itself.

    Electrolytic capacitors have a polarity, unlike most capacitors. This is due to the fact that the aluminum oxide layer is held in place by the electric field, and when reverse-biased, it dissolves into the electrolyte. This allows a short circuit between the electrolyte and the aluminum !!!



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    polarised capacitors

    can you give me 5 examples of polarized capacitance and voltage rating of capacitor.. thanks



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    capacitor polarized

    An old trick used in budget cross-over's is to connect 2 polarized capacitors back to back (- to - or + to +).



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    non-polarized capacitors

    P-C has a small size with the large capacitance, is used only in DC circuits or circuits related to DC current.

    P-C has a large leakage current, low frequency response - only up to about tens of kHz at aluminum or 1MHz at tantalium caps.

    NP-C has a big size with the smaller capacitance, is used both in DC or AC circuits, low or high frequencies.

    NP-C has a very small leakage current, high frequency response - up to hundreds of GHz up to types.

    In general, they cannot replace for each other.

    Sometimes, in household appliance in frequency of 50/60Hz, they can use 2 P-C caps (with capacitance doubled of the NP-C) connected in series by opposite terminals (and diodes in parallel with each cap to protect it from reversed voltage) to replace 1 NP-C cap to save space, but this type of replacement is not strongly recommended.

    nguyennam


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    non polarity capacitor

    usually polarized capacitors are in microfarad units, ex. 0.1uF, 10uF.
    you can choose 16V, 25V or 50V

    regards,
    nanang



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