I do. Output power FETs may have parasitic oscillations on the edges .... The one and only analog (analogue) high end power amp I tested did it at 66 MHz
Gert -----Oorspronkelijk bericht----- Van: [email protected] [mailto:[email protected]] Namens John Woodgate Verzonden: woensdag 31 oktober 2012 20:49 Aan: [email protected] Onderwerp: Re: [PSES] Possible Counterfeit EMC Components? In message <[email protected]>, dated Wed, 31 Oct 2012, "ce-test, qualified testing bv - Gert Gremmen" <[email protected]> writes: >Had a 200 Watt power supply last week that simply shut-off (fold back) >at 10V/m . It was applied in a laboratory equipment for creating >expensive bio-cultures for vaccination ... These cultures may cost up >to a million dollar. This was not a cheap unknown manufacturer, but one >With a quality system implemented. Design update without re-test ? Maybe it had an obscure fault. One of the interesting cases I had some years ago was an all-analogue hi-fi preamplifier which was radiating at 17 MHz. One section of a quad op-amp, used for producing a stable DC level, was faulty. If it had been in the signal chain, the fault would have been discovered. But you don't test analogue audio preamps for high-frequency emissions! -- OOO - Own Opinions Only. See www.jmwa.demon.co.uk The longer it takes to make a point, the more obtuse it proves to be. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ 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]> - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ 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]>
