3 ms·
Is it possible those old caps used something else? He said the electrolyte was hygroscopic.
by galangalalgol 5y ago
Is it possible those old caps used something else? He said the electrolyte was hygroscopic.
- formerly_proven 5y agoYes. Capacitors before around ~1990 used organic solvents and were, generally speaking, very reliable. Capacitors since then switched to water-based electrolytes, which are 1) much more aggressive which 2) leads to circuit board damage if they leak and 3) if done improperly has very bad longevity. Capacitor plague is basically all of these downsides combined in one sweet package: capacitors that fail quickly, and do so while leaking acid all over your circuit boards, acid which is strong enough to eat through solder resist, copper, fiberglass and even goes into IC packages, damaging them invisibly. Old-timey capacitors with organic electrolytes are still available for applications that need reliability more than the best ESR or highest density, but they're kinda rare and expensive.
- dfox 5y agoI would not be surprised if this trick was meant for early encapsulated foil capacitors. These were encapsulated in various semi-natural resins of not exactly known or repeatable properties (usually the intention was that the resin is hygroscopic, but often it was also porous and prone to cracking with aging). Edit: then there is “RIFA plague”, which shows that you can get same issue even with better engineered encapsulation material.