Polymer cap ratings

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  • Lance Thornton
    Senior Member
    • Jan 2005
    • 84
    #1

    Polymer cap ratings

    Hi all,

    I hope this is not a double posting, but I would like to know the method of replacing an aqueous cap with a polymer one. Specifically, are there any formulas that would help me buy or size the right one if I'm replacing a 1000uf@6.3 volts, etc. I assume that the diameter must be equal or smaller, depending on spacing. I also wonder about the heat issues with polymer capacitors rather than electrolytic. My apologies if this question has already been posted.

    Thanks all,

    Lance
    Tags: None
    • ratdude747
      Black Sheep
      • Nov 2008
      • 17136
      • USA
      #2
      Re: Polymer cap ratings

      it can be hit and miss.

      the two values you need to keep in mind are the voltage and esr:

      voltage- lowest voltage that is in spec with the circuit (measure with a multimeter, 6.3v caps often get less than 4v going to them)

      capacitance- generally half the 'lytic value, but:

      esr- same or lower, which is generally half the capacitance.
      sigpic

      (Insert witty quote here)

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