From: "Frank Bemelman"
Subject: Re: Bypass capacitor position
Date: Fri, 25 Oct 2002 22:03:56 +0200
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Organization: EuroNet Internet
NNTP-Posting-Date: 25 Oct 2002 20:05:27 GMT
"Dave VanHorn" schreef in bericht
> > A fun experiment is to take a working uP board, and start
> > cutting away bypass caps. Do that experiment and be amazed.
> > Then forget it, and stick to the guidelines as found in the
> > textbooks.
> > --
> > Thanks,
> > Frank Bemelman
> > (remove 'x' & .invalid when sending email)
> But what are you observing during this?
You answered the question yourself.
> I would expect that most systems would survive most, or maybe all of their
> bypasses removed, but if you're watching their EMI emissions, you might
> think of applying for an international broadcasting license.
> The purpose of the bypasses is to provide pulse current locally to the
> rather than having those pulse currents travel all over the board.
> the bypasses, the current travels through a larger loop, and that makes a
> more effective antenna to radiate the noise.
Right - but bypass caps serve other purposes too. They have been placed
for ages, even in times when nobody cared about EMI.
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