I read in !emc-pstc that Robert Wilson <robert_wil...@tirsys.com> wrote (in <3FF57405336C9B4C976A1819F860A2560F696F@xng_tirsys.TIRSYS.COM>) about 'Decoupling - capacitor values', on Wed, 17 Apr 2002: >The main >reason is that the ESR of the larger cap begins to rise to unacceptable >levels as frequency rises (chiefly due to its self inductance).
ESR is something quite separate from self-inductance. The effect of the inductance is to *reduce* the total impedance of the capacitor to just the ESR at the self-resonance frequency and to *increase* it above that frequency. The ESR may itself be frequency-dependent because it includes dielectric losses (in the simple CRL series model of the capacitor). -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Interested in professional sound reinforcement and distribution? Then go to http://www.isce.org.uk PLEASE do NOT copy news posts to me by E-MAIL! ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list"
