help with a capacitor!!!!!!!

[bogdanfirst]

i know this is a stupid question
i got this old 1500uF/40 V cap and i dont know its polarity....
here's how it looks: its cilindrical, about 5 cm long, 3-3,5cm in diameter
it is metal on the outside and one pin(wire) is conected to the metal case, the other one is comes from the inside....and its insulated from the case.my guess is its th positive, but i'm not sure
please help...

 

[kinjalgp]

You may find your answer at this page:
http://www.illcap.com/FAQ.asp

I think your capacitor is a non-polarised electrolytic as the FAQ states.

 

[bogdanfirst]

there's something strange.......about it
i tried to charge it from a batt, then i tried it with a led, it lit it,
i reversed polarity, worked to.... :lol:
i conected it to my circuit , it wotked, and i minded my business....
but :twisted: :twisted: after a few mins, i hear some whiseling and all kind of strange noises, it haeted up and i looked like a baloon.....
i reversed it and it workes.....
! :arrow: topic closed!

 

[kinjalgp]

You are safe this time. But in future never try to connect the capacitor in reverese. Many a times capaciotrs explode when connected in reverse spilling hot electrolyte in the vicinity.

 

[bogdanfirst]

i'm so glad i was in the room, when i heared it making noise, if it would have blown up, judging by its size i am sure i would have alectrolyte all over my walls......it took a litle while to cool down, after 30 mins it was still hot...
anyway, thanks for the answer.....
i remember how they blow up, i had a small cap, a 470u/10V and i powered the circuit at about 15 v, but i couldn save this one...so i had a nasty boooooooooommm.....

 

[mechie]

Capacitor explosion

Did you get a fantastic snow-storm as well ???
I held a 100uF electrolytic cap in a blowtorch flame for a minute or so and it went [BOOM], confetti everywhere.
-- brilliant --
never found half of the case !!!

>>>good job it never hit anyone !<<<

 

[herbymcduff]

i'll tell you a good one. I was messing around one day, and I wonder what a 100 mic 10v cap would think of 120VAC. So I got a plug and stripped one end and soldered alligator clips the each end. Clamped the cap in, held it away, and plugged it in. Big Boom. Sounded like a double barrel sawed of shotgun. Insane. It left a big black mark on the wall. You all should give that a try. Completly safe as long as no one is near, or it's not around yourself. Have fun.

 

[bogdanfirst]

well it looks like all have some exoerience of blowing capacitors.....
how do u think a 4700u/16V would do at 220Vac?
well i might try that on the newyear eve, maybe i'll have the biggest boom around.....
:lol: 8)

 

[kinjalgp]

LOL :lol: The new year ELECTRONIC BOOM :!:

 

[bogdanfirst]

ya, the electrolythic fire works :!: