Caps used to be used in series in audio amps to block dc from being amplified. Caps are used in series in ac-coupled o'scopes. In that sense, a cap can be a high impedance decoupler. Ken Javor
Phone: (256) 650-5261 > From: John Woodgate <[email protected]> > Date: Wed, 16 Apr 2008 18:18:38 +0100 > To: Brian O'Connell <[email protected]> > 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 - 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
