electrolitic capacitor life, best brands

Discussion in 'General Electronics Chat' started by electronis whiz, Sep 4, 2011.

  1. electronis whiz

    Thread Starter Well-Known Member

    Jul 29, 2010
    519
    27
    i have colected all kinds of electroletic capacitors, most are less than 10 yrs old. i have some that i pulled from a old junk reel to reel tape player, made by nipon cimi con. i'm afraid thay might blow up due to there age.
    i have all difrint brands of caps. a few other nipons cimicons, rubycon, nipicon, elena. are any of these brands any good? are there any brands i should avoid.
    i had one small 100 uf cap pop on a radio shack kit i had. it stunk, and left a gob of stuff on the board where the cap was, and the can flew acros the room.
    I don't want to have the same thing happen with a big cap so i would like to know if age and brand can be somthing tho avoid to prevent this.
    i have seen things online using boost caps welding and melting stuff. but won't this type stuff make a cap blow. also is it true that pollarity can cause electrlitics to pop.
     
  2. steveb

    Senior Member

    Jul 3, 2008
    2,433
    469
    I don't know which brands are best, but I'd stick with well known brands. Hopefully someone can provide better information on that question.

    However, a general rule of thumb with electrolytic capacitors is to use them at half of their rated voltage to significantly increase their life. Obviously watch the polarity because a reverse bias will blow them fast.

    You can also do burn in testing. Test any capacitor you want to use at 90% of the rated voltage, but do it in plexiglass cage of other strong box for protection. A capacitor that survives a day like this is likely to last a long time when run at 50 % of the rated voltage.

    You may even want to consider running at 33% of rated voltage as an extra safety margin.

    Another issue is how they were stored. If they were stored at room temperature in a water tight bag or container, that's much better than being loose in a garage or basement.

    Oh, and try an measure the capacitance by some method. Clearly a capacitor value way out of spec is a sign of a bad device.
     
    Last edited: Sep 4, 2011
  3. JDT

    Well-Known Member

    Feb 12, 2009
    658
    85
    The lifetime of electrolytic capacitors is greatly shortened if they run hot. So don't re-use capacitors that have come from equipment that often runs hot (like power supplies).
     
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