T
Is it a problem that this capacitor will only ever see 20% of its rated voltage?…don’t electrolytics need to experience their rated voltage for at least a few minutes every year or so?
Who told you this? Sounds more like some old wives's tale (or in this case old engineer's tale) probably someone, came up with that one because their XYZ design worked better when they periodically injected max rated voltage into a cap, not realizing or discovering it was something else that was causing the problem.thanks, I think leakage current increases if they are not taken up near their rated voltage at least once in a while.
Who told you this? Sounds more like some old wives's tale (or in this case old engineer's tale) probably someone, came up with that one because their XYZ design worked better when they periodically injected max rated voltage into a cap, not realizing or discovering it was something else that was causing the problem.
Whacking the cap with max rated voltage is more likely to breakdown the dielectric and increase the leakage.
This is even beyond my time, so I second the question, what are you doing with 40 yr old caps? Feeling nostalgic? :wink:Why are you playing with 40yr old caps?
FvM did you just suggest both treez & SunnySkyguy are pre-WW-II engineers, that still have boxes full of 75+ year old caps with datasheets! :thinker:I'm not talking about pre world war II capacitors.
I wouldn't mind betting that the market is awash with ancient electrolytic capacitors,
I am convinced that this is happening...........and its a disaster for your production run of 100,000 SMPS's that will be using them.................this is why all electronics companies need very rich underwriters.
I was thinking the same thing. I've almost never seen a bad electrolytic cap from a reputable distributor, but on the other hand I've seen issues with parts that came from the gray market re-sellers. I'm pretty sure some (perhaps a lot) of those parts are fakes, clones, bad/marginal die, removed from circuit boards and "freshened up", or possibly even stolen.SunnySkyguy said:you must have experience buying off Ebay or Brokers via far east sources. Any competent distributor would get in deep doo doo for knowing doing this.
Well I narrowly avoided getting some severe 1st/2nd degree burns from a tantalum, the factory installed backwards, that exploded <20 seconds after I started scope probing the back side of a board. Darn thing burnt a hole in the tile floor of the lab! :shock: I'm sure glad I had switched sides!SunnySkyguy said:my biggest booboo as a summer student doing assembly of 48 ch mixers designed in a recording studio and assuming all the plastic shelled Spanish Caps were non-polarized.
Not particularly, but some electrolytic capacitor characterization presented in the discussion sounds like beeing preserved from those days. I checked electrolytic capacitors laying in a drawer for thirty or fourty years (they are already modern types related to this discussion) some time ago, and they performed well from the start.FvM did you just suggest both treez & SunnySkyguy are pre-WW-II engineers, that still have boxes full of 75+ year old caps with datasheets!
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