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    SMPS input capacitor calculation

    Hi All,

    In my Fly back smps circuit after the bridge rectifier there is a 22uF/400V capacitor. Instead of one 22uf/400V capacitor, what will happen If I use two number of 22uf/200V capacitor in series

    •   Alt11th January 2017, 14:40

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    Re: SMPS input capacitor calculation

    You could do one of the last two options to get the same filtering effect as with one 400V 22 uF capacitor. In the last two options, the capacitor voltage rating is 200 V each.
    The resistors over the caps just balance the voltage equally over each capacitor. The 1 k resistor is the simulated load.



    •   Alt11th January 2017, 19:01

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    Re: SMPS input capacitor calculation

    Hi,

    Two 22uF capacitors in series will result in 11uF capacitance.

    You need four capacitors of 22uF/200V to get 22uF/400V. 2S2P

    This complies with stored energy: W = 0.5 × C × U × U
    Double the voltage and get four times the energy.

    Klaus



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