Good point. So I wasted a senior design engineer's time with this one, and his verbage seems similar, but he also said that the two the two terms, while similar, should not be considered interchangeable because bypass indicates a series event and de-couple indicates a parallel event.
luck, Brian > -----Original Message----- > From: John Woodgate [mailto:[email protected]] > Sent: Wednesday, April 16, 2008 10:19 AM > To: Brian O'Connell > Cc: [email protected] > Subject: Re: Bypass and decoupling capacitor definitions. > > In message <[email protected]>, > dated Wed, > 16 Apr 2008, Brian O'Connell <[email protected]> writes: > >> welllll, I borrowed the Pressman book from one of the >> design engineers, >> and it seems to indicate that a decoupling action is, in >> fact, a hi-Z >> action. > > There is always the possibility that someone in the distant > past used > the term 'decoupling' incorrectly, and the error has persisted. > > Elementary thinking is 'voltage-mode' and so if you wanted > to 'decouple' > (reduce coupling) you would include a high series impedance (but the > term 'decouple' isn't, as far as I know, commonly used in > that context). > Shunt capacitors live in the 'current-mode' world, where you reduce > coupling by adding low impedance to earth/ground. > -- > OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk > Murphy's Law has now been officially re-named The Certainty Principle > John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK > > - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
