In message <feb0755e258881479c47feae8ba66bf106a24...@amusmsg11.viasystems.pri>, dated Wed, 16 Apr 2008, "Denomme, Paul S." <[email protected]> writes:
>Can anyone provide me with the difference between a bypass and >decoupling capacitor? I think there is a difference between US English and British English. Fundamentally, there is no difference; the idea is that the capacitor keeps the voltage across it constant, by diverting alternating currents to where they do no harm, usually earth/ground. In UK, they were all 'decoupling', although it's true that some people drew a distinction between capacitors intended to divert signals, such as a capacitor across an emitter resistor in a BJT amplifier, and those intended to divert other things such as power supply ripple. I think 'bypass' was/is a term more common in US. But whatever you call them, they are there to present a low impedance to the currents you don't want. I don't see any need for two different terms. In the days of valves/tubes, people also had palpitations about such convenient phrases as 'decouple g2 to cathode with a 0.1 uF capacitor'. It's very clear what it means; the capacitor prevents any signal voltage difference between g2 and cathode, and language should serve us; we should not be required to use awkward wording just for pedantry. -- 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
