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DIY Stompboxes => Building your own stompbox => Topic started by: merlyner on June 07, 2004, 10:45:34 PM

Title: cap problem
Post by: merlyner on June 07, 2004, 10:45:34 PM
on an  axial cap which side is negative: is it the side with the arrow pointing towards it? like so -------[    >  >  > ]-----------
Title: cap problem
Post by: sir_modulus on June 07, 2004, 11:04:33 PM
arrows, -'s, and a combination all point to the side with the negative (it's a electronic standard). The side on your right is negative.
Title: cap problem
Post by: merlyner on June 07, 2004, 11:06:28 PM
if i put them in wrong would that cause it not to work at all?
Title: cap problem
Post by: brett on June 07, 2004, 11:41:48 PM
Hi.  If you put it in the wrong way around, you won't get much capacitance (ie it won't work).  At high voltages (>20 ?), it will heat up and explode.

If there is doubt about the polarity, use a non-polar cap (usually marked NP).

have fun
Title: cap problem
Post by: Lonestarjohnny on June 07, 2004, 11:45:10 PM
Yes, and if it's high voltage, they can explode, but on 9 v. I would'nt worry, just turn them around, normally there will be a groove around the pos end of the cap, the other end will be smooth,on the one's marked with the arrow, it will be pointing at the Neg. end.
JD
Title: cap problem
Post by: erio fraga on June 08, 2004, 09:54:39 AM
The arrows should point the negative end, unless there is a ”+” mark inside the arrows ( that’s what used by some manufacturs so many years ago )
Anyway, if is an aluminium electrolyte cap, take a look on the cap side ends. Probably you will note that one of the terminals ( can be called “leads” ) is fixed directly to the body ( an aluminium case, you can mesure the resistence between the case and the terminal, it will very very close to zero ), this is the negative. On the other side, the lead probably is fixed on a rubber surface ( in some special types, there is an epoxi filling over the rubber surface ), this is the positive.
If you use the cap in the wrong position, with 9v the risk of explosion is, in a short time, very low. But you will have a considerable increase in energy consumption.

Erio