Electronics > Beginners
What happens when you put an electrolytic capacitor the wrong way?
<< < (3/6) > >>
c4757p:
The classic voltage doubler circuit that is (or used to be) commonly seen can reverse bias the capacitor at startup. However, unless I have my capacitor chemistry wrong, biasing it correctly can actually repair the small damage caused by a very short reverse bias condition.
david77:
I once saw a mate testing a power supply he'd just built up. Then there was an almighty BANG, smoke, fluff and my friend screaming and holding his bloody face.

After he'd calmed down we assessed what had happened. He put the big smoothing cap in the wrong way across a DC rail of about 40V and several amps. I can't remember but I'd say it was a 2200uF/50V cap, pretty substantial piece of kit. We were teenagers then and the thing probably came out of some old piece of junk - that makes it very likely it was unvented - this happened nearly 20 years ago so that puts the piece of junk we ripped it out of in the middle of the 70ies. 2200uf caps used to be a lot bigger than today, kids!

The aluminium cap had hit him on the upper lip right under his nose from a distance of about 30-40cm. His lip was swollen and he had a nose bleed. He said it was like somebody punched him on the nose.
Today we can laugh about it. Could very well have hit an eye...

If you want to try it use something small, like 1µf or so...and think about what you're doing!
I just let a cap pop when I saw this thread, it's still fun  8).
ablacon64:
Funny video! kkkkkkk... Try it with a little bigger capacitor.   :-DD  :-DD  :-DD
Nerull:
If they're properly vented, bigger caps are actually less spectacular.

Unvented ones, though...

JoeyP:
I saw a 2" hole in a drop ceiling once because someone exceeded rated voltage for a while on a good sized can. So, it's not just reverse bias that will do it.

I exploded one when I was a kid, and aside from the mess, the smell was the worst part. Absolutely disgusting smell that lingers for days.
Navigation
Message Index
Next page
Previous page
There was an error while thanking
Thanking...

Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod