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    Capacitor selection for high current circuit?

    hi, generally i choose 100 to 1000uF capacitor as filter for micro controller based circuit for lower amps.

    on what basis the filter capacitance value should be chosen? how is it related with load current? presently designing a circuit for 100A. max operating voltage is 25.

    note: for similar product 0.1 farad capacitor was chosen.


    thanks

    •   Alt7th December 2017, 11:51

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    Re: capacitor selection for high current circuit?

    Load current isn't relevant for a filter capacitor, you have to look for ripple current (AC-current).



    •   Alt7th December 2017, 13:05

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    Re: capacitor selection for high current circuit?

    Hi,

    ..and ripple frequency

    100A output current... will cause a lot of ripple current.
    If you use an SMPS (high switching frequency) then I recommend ceramics capacitors.

    Hopefully it is not 100A at a bulk capacitor at mains frequency... Please clarify.

    Klaus
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    •   Alt7th December 2017, 13:25

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    Re: capacitor selection for high current circuit?

    Load current isn't relevant for a filter capacitor, you have to look for ripple current (AC-current).
    ..and ripple frequency. 100A output current... will cause a lot of ripple current.
    how to determine ripple current and ripple frequency, is it dependent/independent of load current? 100A is max rush current, generally load current around 20A will flow.

    the design has both DC and AC(SMPS). SMPS is for driver circuit biasing. the load current is from battery. the filter capacitor is for SMPS power supply only.


    thanks



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    Re: Capacitor selection for high current circuit?

    Hi,

    how to determine ripple current and ripple frequency,
    * there is a power source. It may be DC (like a battery), mains frequency, or an SMPS....
    * and there will be a load. Maybe with constant (DC) current, maybe a pulsed current...

    You need to consider both..only for the pathe where the capacitor is installed.

    I'm confused by your description, I can't find out what's your source and what's your load to the capacitor.

    If you need a more detailed answer you should give a drawing with your capacitor, it's source and it's load. Add the frequency and current informations...

    Klaus
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