reason for using a capacitor?

hi all, whats the reason for using a capacitor and what is it meant to do? thanks

I second zhalverson. They are for the most part useless, and nobody ever uses them how they are meant to be used. If you really want one, at least get one that looks good, that's all it will be good for.

There's been a lot of talk about the uselessness of caps, from my experience they do what they're supposed to.  In my camry when i added a cap, the headlights quit dimming and the bass overall seemed a little stronger.  In my xB, same thing; I add a cap and the headlights quit dimming, bass seems a little stronger.  They don't make bad systems good, they don't make weak systems strong but, from my experience, they do what they're supposed to do which is help out a little bit.

Do a search on capacitors this has been beaten to death. There a ton of very well written posts on what a "cap" is for and what is not. And remember some our quick to give advice with little or no experience other than my car did this and my buddies did that, just keep that in mind.

The purpose of a capacitor in a power supply is to help sustain input side voltage during transient demand peaks on the output side.  They do this function extremely well.  This is not the reason most people buy them for car audio, however.  Most people in car audio think that they will supply power to their amps for extended periods (like more than a half second) and think they will cure ills like dimming headlights.  They are mostly useless for this.Support the12volt.com

sqsq wrote: There's been a lot of talk about the uselessness of caps, from my experience they do what they're supposed to. In my camry when i added a cap, the headlights quit dimming and the bass overall seemed a little stronger. In my xB, same thing; I add a cap and the headlights quit dimming, bass seems a little stronger. They don't make bad systems good, they don't make weak systems strong but, from my experience, they do what they're supposed to do which is help out a little bit.

bass seems stronger??? most amps these days have regulated power supplies so unless you have an amp that has an unregulated power supply than you will notice zero difference in bass

haha yeah my friend told me that his subs hit harder (audiobahns btw) after he installed his cap... he wouldnt believe me when i told him it wouldnt do that

Actually yes, in a system where the intermittent demands from an amplifier is pushing the vehicle electrical system just over the edge of what it can sustain, causing transient voltage dips, a perfect sized cap might be able to help and the bass might indeed 'hit" better.  This is not impossible.  In fact, it is probably an ideal application of a power stiffening cap, although it would be a rare case indeed where one actually helped by actually being sized properly for the application.  I still say the real solution in this case is to upgrade the alternator, as the weak alt being overloaded and assisted by the cap may soon burn out.Support the12volt.com

atleast upgrade your big three