"Trust but verify.", wasn't that the same guy who tried to teach morals to a chimp in Bedtime for Bonzo? -Dave
From: Doug Smith [mailto:d...@emcesd.com] Sent: Sunday, December 14, 2014 6:49 PM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: [PSES] Brick power supplies and test errors (two topics) Hi All, A number of you have attended my web presentation on ESD/EFT internally generated in system power supplies. As little as 500 V of applied ESD or EFT is able to break down the supply in both polarities for only one applied polarity. I have posted on this before. Now, in addition, to the small wall plug power supplies tested, I have now confirmed that "brick" type supplies used in PCs can also exhibit these characteristics. Next to try on larger internal power supplies, likely to see the effect here too. We will see. When I was at Auspex Systems (1996-2001) we had 8 EMC radiated emissions tests performed on our equipment (three 1500 lb cabinets full of disk drives). Of these, 4 tests had significant test errors, two major and two minor errors, but all had a large impact to our company! The tests were done at three different labs over time, all made at least one error. "Trust but verify." In 2010-2011, I evaluated 8 ESD guns, all had current calibration stickers. 2 of the 8 did not produce the correct output, off by a lot. "Trust but verify." (Any of you know who said that quote? It is someone from a completely different field from us.) All the bad data I have ever seen, came from "calibrated" equipment. Here are some links on the above topics (if your computer puts a "[1]" in the link, remove it. Internet files do not end with "[1]": http://www.emcesd.com/tt2014/tt120214.htm (my latest Technical Tidbit) December 2010, Comparing "IEC 61000-4-2 Compliant" ESD Simulators<http://www.emcesd.com/tt2010/tt120210.htm> March 2011, Using High Frequency Measurement of ESD Current to Find Problems with an ESD Simulator<http://www.emcesd.com/tt2011/tt030211.htm> Also check out my YouTube channel tech videos, >100,000 view now. Look for "Doug Smith EMC" and that should bring up my channel. I am not one of the Doug Smiths who are musicians. Doug -- University of Oxford Tutor Department for Continuing Education Oxford, Oxfordshire, United Kingdom -------------------------------------------------------------- ___ _ Doug Smith \ / ) P.O. Box 60941 ========= Boulder City, NV 89006-0941 _ / \ / \ _ TEL/FAX: 702-570-6108/570-6013 / /\ \ ] / /\ \ Mobile: 408-858-4528 | q-----( ) | o | Email: d...@dsmith.org<mailto:d...@dsmith.org> \ _ / ] \ _ / Web: http://www.dsmith.org -------------------------------------------------------------- - ---------------------------------------------------------------- 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 <emc-p...@ieee.org<mailto:emc-p...@ieee.org>> 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://www.ieee-pses.org/list.html (including how to unsubscribe)<http://www.ieee-pses.org/list.html> List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <sdoug...@ieee.org<mailto:sdoug...@ieee.org>> Mike Cantwell <mcantw...@ieee.org<mailto:mcantw...@ieee.org>> For policy questions, send mail to: Jim Bacher <j.bac...@ieee.org<mailto:j.bac...@ieee.org>> David Heald <dhe...@gmail.com<mailto:dhe...@gmail.com>> - ---------------------------------------------------------------- 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 <emc-p...@ieee.org> 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://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <sdoug...@ieee.org> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com>
