Capacitors

[Lakota 5,000+ posts]

I just wanted to say that I spoke with my professor that has a PhD and is also a PE in electrical engineering about external capacitors for car audio systems. He's not really familiar with the world of car audio, but he's intelligent enough to understand how it all works. Anyways I told him about how people often times use a cap in the place of where a battery could go and his response was, "why would you do that?":laugh: In summary, he was basically stating that in this application they're really only useful for filtering noise, etc., but not useful for your charging system. That is all.

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[Minto Took 10+ year member]

While the cap will act as a big-*** low pass filter, it will also smooth any imposed voltage ripple caused by the amp(s) pulling too much voltage from the battery.

If you look at any discrete voltage regulator in an AC -> DC power supply, the cap is there to give you the DC signal.

BTW, whats your prof's specialty?

 

[helotaxi 5,000+ posts]

Most caps aren't big enough to deal with spikes, and the alt ripple is more than adequately handled by the battery.

The cap is in the ac/dc power supply to remove the ripple. It can't turn AC into DC. That's what the rectifier is for.

 

[Minto Took 10+ year member]

It can't turn AC into DC. That's what the rectifier is for.

Yes. I forgot about the rectifier.

 

[Lakota 5,000+ posts]

BTW, whats your prof's specialty?

http://www.ece.louisville.edu/fac_cleaver.html

He's also the professor for Capstone Design, where students have to design something in order to get their B.S. So, I figure that he usually deals with smaller integrated circuits.