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From: John Robertson <jrr@flippers.com>
Newsgroups: sci.electronics.design
Subject: Re: Survivor!
Date: Wed, 20 Mar 2024 08:19:52 -0700
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On 2024/03/20 2:45 a.m., Liz Tuddenham wrote:
> Cursitor Doom <cd@notformail.com> wrote:
> 
>> Hi all,
>>
>> Just a quick one. But first, I'd just like to reiterate that I'm
>> noting your comments on the ripple thread and will deal with them in
>> due course when i have a couple of hours to spare next Sunday.
>> Yesterday I had 2 minutes to waste so I blew up another electrolytic
>> capacitor - or rather I *tried* to. A 10uF 10V cap across the output
>> of a variac with Vo set to 240VAC. There was a considerable *pop* but
>> no bang and it turned out the T3.15 Amp fuse in the variac had blown
>> spectacularly - but the cap had survived unscathed! Tested fine for
>> capacitance and ESR! I never would have believed it. Just wondering
>> how the hell it didn't get destroyed...
> 
> It's only doing it to annoy you.  Make sure it is run well within its
> ratings and put it on a board that has to be buried several layers deep
> in some complicated equipment and is rivetted in place.   It will fail
> in no time at all and probably take several other valuable components
> with it.
> 
> 

Lots of parts can be forced way past their rated maximums and suffer 
internal damage that won't then show for a period of time in normal use.

That's why we have fuses, TSVs, MOVs, etc to help protect against spikes 
and their aftereffects.

The only way to find what happened to the cap is to take the capacitor 
apart and study the elements under a microscope for punctures and do a 
chemical analysis on the electrolyte.

This is just A-Waste-Of-Time experiment and I can't believe I am 
commenting on it...

John :-#(#
-- 
(Please post followups or tech inquiries to the USENET newsgroup)
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