Re: [PSES] AW: [PSES] Friday Question - table of electrochemical potentials
Dürrer, The table in the Wikipedia article https://en.wikipedia.org/wiki/Galvanic_corrosion#Anodic_index has more entries, is more descriptive, and doesn't totally agree with Table 7-1 on page 156 of Gershon J. Wheeler's book, The Design of Electronic Equipment: A Manual for Production and Manufacturing: Table 7-1 Galvanic Series Metal Anodic Index (0.01 volt) - Gold, Platinum 0 Rhodium10 Silver 15 Nickel 30 Copper 35 Brass 40 Stainless Steel50 Chromium 60 Tin-Plate, Tin-Lead Solder 65 Iron 85 Aluminum Alloys90 Cadmium95 Zinc 125 Magnesium 175 Thanks! John Barnes KS4GL, PE, NCE, NCT, ESDC Eng, ESDC Tech, PSE, Master EMC Design Eng, SM IEEE (retired) 216 Hillsboro Ave Lexington, KY 40511-2105 (859)253-1178 phone jrbar...@iglou.com http://www.dbicorporation.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 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 Mike Cantwell For policy questions, send mail to: Jim Bacher: David Heald:
Re: [PSES] Electric Current Abroad
Douglas, Scott, John, A free .pdf file of the 1998 Edition of Electric Current Abroad, reprinted in 2002, is available at http://www.baldor.com/pdf/ElectricCurrentAbroad.pdf Thanks! John Barnes KS4GL, PE, NCE, NCT, ESDC Eng, ESDC Tech, PSE, Master EMC Design Eng, SM IEEE (retired) 216 Hillsboro Ave Lexington, KY 40511-2105 (859)253-1178 phone jrbar...@iglou.com http://www.dbicorporation.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 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 Mike Cantwell For policy questions, send mail to: Jim Bacher: David Heald:
Re: [PSES] classification of the output
Joe, I think that you are referring to the SawStop invented by Steve Glass. https://www.youtube.com/watch?v=dekzPA6nhC4 shows it in action. John Barnes KS4GL, PE, NCE, NCT, ESDC Eng, ESDC Tech, PSE, Master EMC Design Eng, SM IEEE (retired) 216 Hillsboro Ave Lexington, KY 40511-2105 (859)253-1178 phone jrbar...@iglou.com http://www.dbicorporation.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 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 Mike Cantwell For policy questions, send mail to: Jim Bacher: David Heald:
Re: [PSES] Thermal equilibrium - 10% rule
Ken, Most metals have a positive Temperature Coefficient of Resistance (TCR). As they get hotter, their resistivity-- and the resistance of a given conductor-- increases. If you have a current source (or a voltage source with a large series impedance) driving current through a small cross-section conductor with poor heat sinking for a long time, the conductor will go into thermal runaway-- and eventually melt in two-- when the current through it exceeds a certain critical value, depending on the ambient temperature. A. J. Rainal wrote two papers about this effect on printed circuit boards (PCB's) about 40 years ago: * Rainal, A. J., "Current-Carrying Capacity of Fine-Line Printed Conductors," The Bell System Technical Journal, vol. 60 no. 7, pp. 1375-1388, September 1981. * Rainal, A. J., "Temperature Rise at a Constriction in a Current-Carrying Printed Conductor," The Bell System Technical Journal, vol. 55 no. 2, pp. 233-269, February 1976. Non-resettable fuses use this principle, which is specified by the I^2t curves in their datasheets. You may also want to read up on Preece's Law (Fuse Equations) and Onderdonk's Fuse Equation. John Barnes KS4GL (retired) Lexington, Kentucky http://www.dbicorporation.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>
Re: [PSES] Unexplained High Fallout of Power Supplies
Brian, How is the furnace shut off? If you are using a contactor between the main line filter and the furnace, a phase line might open when it is carrying high current. The inductance of the line filter will try to keep this current flowing, generating a very-high kickback spike at the *output* of the line filter. Or, since the contacts in the contactor are unlikely to open/close at exactly the same time, a common-mode choke in the line filter can act as a transformer putting noise on the open phase(s) if only 1 or 2 phases are connected to the load. Some years ago, Bill Kimmel and Daryl Gerke wrote about a case where a 3-phase product had a contactor between a line filter and the load, which generated horrendous Conducted Emissions noise every time the contactor opened or closed, because of this transformer action. The solution was to replace the common-mode choke with 3 separate chokes, one for each phase line. John Barnes KS4GL, PE, NCE, NCT, ESDC Eng, ESDC Tech, PSE, Master EMC Design Eng, SM IEEE (retired) Lexington, KY http://www.dbicorporation.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>
Re: [PSES] RF Common Mode Immunity Test Question
John et al, I closed dBi Corporation in September 2013 and retired. So I haven't bothered keeping up with all of the niggling details of electromagnetic compatibility (EMC), electromagnetic interference (EMI), and electrostatic discharge (ESD) standards as they have evolved since then. But from early 2002 to late 2013 I personally did the official EMC/EMI/ESD approval tests of 389 products to a wide variety of US, Canadian, European Union, Australian, New Zealand, and Japanese standards (see my web site, http://www.dbicorporation.com/). As a working EMC Engineer, I observed that many countries/market areas had EMI and ESD requirements for military and medical products/ equipment-- because these could kill or severely injure people if they misbehaved due to EMI/ESD problems. But with the exception of the European Union-- and India for products with fax capability-- I don't recall any legal EMI/ESD standards or requirements for commercial products and equipment. I was told that governments regulate EMC because the product that fails is not the product/equipment that causes the problem-- thus the wrong party gets the blame, and the culprit gets off scot-free. But most governments consider EMI and ESD problems to be self-correcting: 1. If a company makes a product that is very susceptible to EMI or ESD, there will be many problems with it in the field. 2. If the manufacturer or seller can't/doesn't resolve these problems, unhappy customers will complain to anyone who will listen-- severely damaging the manufacturer's reputation. 3. Prospective buyers will look for alternatives, and be leery of buying/leasing *any* products made by the manufacturer. 4. Distributors and sellers will stop carrying the manufacturer's products. 5. The manufacturer will eventually go out of business-- solving the problem without government intervention/interference! Somewhere I heard/read that the European Union (EU) got into the regulating of EMI and ESD susceptibility because of the Treaty of Maastricht-- one of the major founding treaties of the European Union. This treaty allowed countries (states) in the EU to pass legislation to protect the "health and welfare" of their people-- and some countries, such as Germany, made a very-broad interpretation of "health and welfare". For example, Don Bush told me that in the 1970's, if you wanted to buy a television in Germany, that the PTT (Postal, Telegraph and Telephone) authority would send someone to your house to make signal-strength measurements-- and they would specify: * The type of television antenna you had to buy, * Where to mount the antenna, AND * In which direction to aim the antenna, to *guarantee* that you had an acceptable level of television reception! Therefore the EU started developing its market-wide EMI/ESD standards, to preempt these countries from making standards/requirements that could become barriers to free trade inside the EU. I worked at IBM and Lexmark from 1977 to early 2002, and both companies had internal standards for EMC/EMI/ESD that were frequently much tougher than the legally-mandated standards-- out of self-interest: * To keep our customers satisfied. * To maintain our reputation for building/supporting high-quality products. I don't know if it is still there, but there used to be a large map of the US posted in IBM/Lexmark's Conducted Emissions lab, with map pins showing all the places where EMC-Lab folks had gone to investigate field problems. John Barnes KS4GL, PE, NCE, NCT, ESDC Eng, ESDC Tech, PSE, Master EMC Design Eng, SM IEEE (retired) Lexington, KY http://www.dbicorporation.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>
Re: [PSES] FCC label - stick-on / permanently affixed ....
Amund, It has been over 13 years since I was last involved with product labels at Lexmark. But at that time the Canadian Standards Association (CSA) had the most stringent requirements for the LABELLING SYSTEM (as mentioned by John Allen) used for product-safety labels: * Label stock, * Ink or toner, AND * Pressure-sensitive adhesive (PSA), compatible with the housing material used on your product. As I recall, a CSA-Approved LABELLING SYSTEM had to meet a number of durability tests for the markings on the label, including adhesion and legibility tests after scrubbing labels *on the product housing* with water and kerosene. We found quite a few types of plastic labels available in various colors, shapes, and sizes, that could be run through a laser printer-- using specific toner cartridges-- that constituted CSA-approved LABELLING SYSTEMS. Some of these labels were available in tamperproof versions that would tear, or left a void message on the product, if someone tried to pull up the label. The major disadvantage of these LABELLING SYSTEMS was that we had to print an entire sheet of labels at one time. Our basic approach at Lexmark-- while I was in Product Development from 1990 to 2002-- was to have a fairly-large label that included: * The product model. * The unit's serial number. * FCC, CE, and other electromagnetic compatibility (EMC) markings and statements. * Product safety information, including all applicable safety marks. If there wasn't room on the back of the product for the label, we'd put it on the bottom in a large, flat area. Our labels were designed from the beginning with all of the EMC and product safety marks that we intended to get for the product. Then for early production-- while some EMC/product-safety certifications were still in progress-- we'd manually cover up those marks/markings on the label with a black Sharpie permanent marker. In production, we had a system (usually a personal computer running a special program) that would write the unit's serial number to its flash ROM, based on the serial number printed on the label. I think that we had some type of protection built into the firmware, that kept this information from being overwritten by any ordinary means. I remember the head of Product Safety grumbling to me once, that it seemed like half of the work of his department was dealing with the d**ned labels, and had nothing to do with the product itself Again, this information is 13+ years old. But it might give you some starting points for working with your developers, vendors, and production folks. Thanks! John Barnes KS4GL, PE, NCE, NCT, ESDC Eng, ESDC Tech, PSE, Master EMC Design Eng, SM IEEE Lexington, KY http://www.dbicorporation.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
Re: [PSES] Off Topic - Warranty Question
Scott, Correction-- in the second line of the second paragraph, I meant 2005. John Barnes - 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
Re: [PSES] Off Topic - Warranty Question
Scott, With the change-over to lead-free electronics-- forced by the European Union's RoHS Directive which took effect on July 1, 2006-- I saw the manufacturers' warranties for many electronic products plummet from several years down to 3 months to 1 year And I heard from some of my clients who bought computers and related equipment for their companies, that many of these new RoHS-Compatible electronics would start having massive failures after just 13 to 14 months of use. Personally, I cut way back (to about 20-25% of my previous level) on my electronics purchases right after the post-Christmas sales in 1995-- when I bought a laptop computer and other stuff that I *hoped* was built with good, tin-lead solder (and I'm still using some of these products today!) Now, if I'm buying something inexpensive like LED flashlights or Arduino boards, I'll usually buy at least 3 at a crack in the hope that at least one will still work when I need it. If I'm buying expensive electronics, like a computer monitor, I'll spend about 1 day doing research for every $100 that I expect to spend. And when I come down to the short-list of products that will meet my needs, a long manufacturer's warranty period will be THE major factor in what I buy. I also have about 60 to 70 pounds of tin-lead solder saved up, of various diameters and fluxes, to fix my old electronics when they break after 20+ years of service. Since late 2004 I've collected well over 22,500 documents on lead-free electronics-- see my bibliographies at: * http://www.dbicorporation.com/rohsbib.htm * http://www.dbicorporation.com/whiskbib.htm * http://www.dbicorporation.com/tinpest.htm and I *still* don't trust lead-free, RoHS-Compliant electronics for quality, reliability, or longevity. I recommend to my friends that if they buy new electronics of any significant cost, that they: 1. Buy them at a local store. 2. Have a clerk/tech at the store take the product out of the box, power it up, and *prove* that this specific unit comes up completely before they buy it. John Barnes Lexington, KY author of Robust Electronic Design Reference Book, Volumes I and II - 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
Re: [PSES] FCC and very low-power wireless devices
Dieter, Can I use any frequency if my transmission level is below the class B limit? No. You can find the current version of the United States' FCC 47 CFR Part 15 at http://www.ecfr.gov/cgi-bin/text-idx?c=ecfr; SID=c4968cff34d29b7b13d674c04d8392b8rgn=div5view=text node=47:1.0.1.1.16idno=47#47:1.0.1.1.16.3.234.2 Subpart C (currently 15.201 through 15.257) covers Intentional Radiators. 15.205(a) covers Restricted bands of operation, and says Except as shown in paragraph (d) of this section, only spurious emissions are permitted in any of the frequency bands listed below. 15.207(a) has the Conducted limits for Intentional Radiators. These are identical to the Class B Conducted limits for Unintentional Radiators in 15.107(a). 15.209(a) has the Radiated emission limits; general requirements for Intentional Radiators. These start at 9kHz. At 30MHz and higher they are identical to the Class B Radiated limits for Unintentional Radiators in 15.109(a). Canada has similar requirements. RSS-Gen Issue 3, dated December 2010 http://www.ic.gc.ca/eic/site/smt-gst.nsf/vwapj/rssgen-i3.pdf/$file/ rssgen-i3.pdf with NOTICE 2012-DRS0126 http://www.ic.gc.ca/eic/site/smt-gst.nsf/eng/sf10224.html covers Radio Apparatus. Table 3 on page 22 lists Restricted Frequency Bands. Table 4 on page 23 specifies the AC Power Line Conducted Emissions Limits, which are identical to FCC 47 CFR Pat 15 15.207(a). Tables 5 and 6 on page 24 specify the General Field Strength Limits for Transmitters, which are identical to FCC 47 CFR Part 15 15.209(a) for the electric field strength, but add magnetic field strength limits for 9 to 1,705kHz. John Barnes KS4GL, PE, NCE, NCT, ESDC Eng, ESDC Tech, PSE, Master EMC Design Eng, SM IEEE dBi Corporation http://www.dbicorporation.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://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 emcp...@radiusnorth.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
Re: [PSES] EN 61000-4-5
Derek, I ran into a similar problem about six years ago, where a 10-30VDC product for use on earth-moving equipment had its DC power protected by a Microsemi 1.5KE51CA-T bidirectional transient suppressor. Applying a single -1kV EN 61000-4-5 surge between power and ground would short out the transient suppressor with fancy fireworks and lots of smoke. In the first page of the datasheet for the 1.5KE51CA-T http://www.microsemi.com/en/sites/default/files/SA4-15.pdf under Applications/Benefits is the comment: Secondary lightning protection per IEC61000-4-5 with 2 Ohms source impedance: * Class 2: 1.5KE5.0A to 1.5KE24A or CA * Class 3: 1.5KE5.0 to 1.5KE12A or CA Our fix was to solder a second 1.5KE51CA-T in anti-parallel with the first one, which got us through the immunity requirements of EN 61326:1997 with no more problems. Apparently these transient protectors are bidirectional but not symmetrical-- their breakdown voltages and surge capabilities are different in the forward and backward directions. John Barnes KS4GL, PE, NCE, NCT, ESDC Eng, ESDC Tech, PSE, Master EMC Design Eng, SM IEEE dBi Corporation http://www.dbicorporation.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://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 emcp...@radiusnorth.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
Re: [PSES] Microwave book
Derek, ABEbooks shows a copy of Microwave Antenna Measurements, by J. S. Hollis, T. J. Lyon, and L. Clayton, available from France for $63.81 plus $14.25 shipping and handling-- which looks like your best deal. If they offer a faster shipping method for a little more money, you may want to choose that. When I buy books from Europe and choose the regular shipping, they usually take 3 to 4 weeks to arrive. http://www.abebooks.com/ Addall shows four copies available for $63.81 up to $129.06 plus shipping handling. The cheapest one is from AbebooksFR (see above). http://used.addall.com/ Alibris shows one copy for $74.95 plus shipping handling. http://www.alibris.com/booksearch?cm_sp=search-_-advSearch-_-na Amazon shows 4 copies for $74.95 to $100.00 plus shipping handling http://www.amazon.com/ Bookfinder shows two copies for $78.94 to $103.98 plus shipping and handling http://www.bookfinder.com/ Bookfinder4u shows 3 copies for $78.94 to $140.51 plus shipping and handling http://www.bookfinder4u.com/ Half Price Books shows a copy for $74.95 plus shipping and handling http://www.hpb.com/ Last week I updated my web pageInternet Sources for Electronics Books, Standards, Manuals, Journals, and Magazines at http://www.dbicorporation.com/sources.htm to cover: * 207+ orders for 790+ books that I have bought online from October 2000 through June 2012, along with the range of delivery times that I have seen from each source. * 71 orders for 153 EMC standards that I have bought online from May 2002 through June 2012, along with the range of delivery times that I have seen from each source. * Sources for equipment manuals. * Sources for back issues of magazines. Being a cheapskate through-and-through, I'll check a number of online sources for a book/standard/other item that I need or want, because I've frequently seen a 2:1 or greater ratio in the prices that different sources want for the same or equivalent items. My favorite online source now for technical books is BetterWorldBooks http://www.betterworldbooks.com/ who I ran across in May. I noticed that a bunch of my orders to half.com, ABEbooks, Alibris, Amazon, etc., were all coming from this same place. Curiously, I'll sometimes find a certain book listed on one of these other web sites, but not on their own web site (or vice versa)! John Barnes KS4GL, PE, NCE, NCT, ESDC Eng, ESDC Tech, PSE, Master EMC Design Eng, SM IEEE dBi Corporation http://www.dbicorporation.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://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 emcp...@radiusnorth.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
Re: [PSES] Spread-Spectrum Clock Question
as fast as you can, to keep the quasipeak detector from seeing your signal. You might try to increase the size of your steps, so that at a frequency that is causing you grief, no two adjacent steps of the clock frequency are within the 120kHz bandwidth of the quasipeak detector. John Barnes KS4GL, PE, NCE, NCT, ESDC Eng, ESDC Tech, PSE, Master EMC Design Eng, SM IEEE dBi Corporation http://www.dbicorporation.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://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 emcp...@radiusnorth.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
Re: IEEE PSES / Please Read
Jim, To join only the society (not be a member of the IEEE) you may join as an affiliate. The cost is approximately half of what a full member of the IEEE would cost. What are the requirements for a person to join the Product Safety Engineering Society (PSES) as an affiliate? Is this offer open only to members of certain societies, such as iNARTE, whose home page at http://www.narte.org/ shows PSES as an Affiliated Professional Organization? (Please list any qualifying societies.) If a person belongs to iNARTE, do they have to be an iNARTE-Certified Product Safety Engineer or Product Safety Technician, or is membership in iNARTE with any Certification(s) sufficient? The cost is approximately half of what a full member of the IEEE would cost. ... Affiliate part of the Dues are show below. Add on the society fee (to the amount show below) of $35 for full year (after August 16) or $17.25 for a half year. What would the total cost be for a person to join the PSES as an affiliate: * Before August 16, 2009 (half-year membership)? * After August 16, 2009 (full-year membership)? IEEE Region 7, GST 67.73 33.87 IEEE Region 7, HST 72.89 36.45 The IEEE Region map at http://www.ieee.org/web/geo_activities/home/world_reg.html shows Region 7 of the IEEE as Canada. The web page at http://www.cra-arc.gc.ca/E/pub/gp/rc4027/rc4027-09e.pdf talks about a harmonized sales tax (HST) for Nova Scotia, New Brunswick, Newfoundland, and Labrador, and a national goods and services tax (GST), separate from the provincial taxes, for the rest of Canada. Are these the GST and HST in your table? Thanks! John Barnes KS4GL, PE, NCE, NCT, ESDC Eng, ESDC Tech, PSE, SM IEEE dBi Corporation Lexington, KY http://www.dbicorporation.com/
Re: Seeking labs to test to EN55020
Charles, You can find test labs that are accredited by the American Association for Laboratory Accreditation (A2LA) to test to EN 55020 (or any other specific standard) by: 1. Going to the A2LA web site http://www.a2la.org/ 2. On the left-hand side, click on Search for Accredited Organizations. 3. On the Directory Search Page, http://www.a2la.org/dirsearchnew/newsearch.cfm enter EN 55020 (or whichever standard you are interested in) in the Search For: box. Set Commercial Status to search commercially available scopes only, because some labs accredited by the A2LA only do testing for their own company. You may also want to narrow down the list by state, country, and field of testing. EN 55020 falls under Electrical (testing), for example. 4. Click on the Submit Query button. 5. Click on the certificate number (left-most column) of any labs that look interesting. 6. Page down to their SCOPE OF ACCREDITATION TO ISO/IEC 17025, and search for 55020 (or whatever) to see if they are accredited for the types of tests/calibrations that you need. 7. Clicking on the lab's name instead, will take you to their web site. 8. Depending on your needs, you may also want to search for equivalent or nearly-equivalent standards. For example: * CISPR 20 for EN 55020. * IEC 61000-4-3 for EN 61000-4-3. * 47 CFR Part 15 for FCC Part 15. I took a quick look at the NVLAP web page http://www.nvlap.org/ But I don't find any place there, where you can easily search for labs that NVLAP has redited to certain standards. Thanks! John Barnes KS4GL, PE, NCE, NCT, ESDC Eng, ESDC Tech, PSE, SM IEEE dBi Corporation jrbar...@iglou.com http://www.dbicorporation.com/ - 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 emc-p...@ieee.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 emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: New Version of FCC Part 15, Dated July 10, 2008
EMC-PSTC'ers, I spent several hours reading through the July 10, 2008 version of FCC Part 15 (47 CFR Part 15) at http://www.fcc.gov/oet/info/rules/part15/PART15_07-10-08.pdf , comparing it against the September 20, 2007 version. The only difference that I could see was that the note at the beginning of Section 15.212, Modular transmitters, has been removed. What did I miss? John Barnes KS4GL, PE, NCE, NCT, ESDC Eng, ESDC Tech, PSE, SM IEEE dBi Corporation jrbar...@iglou.com http://www.dbicorporation.com/ - 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 emc-p...@ieee.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 emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
New Version of FCC Part 15, Dated July 10, 2008
EMC-PSTC'ers, The Federal Communications Commission (FCC) posted a new version of FCC Part 15 = 47 CFR Part 15, dated July 10, 2008, at http://www.fcc.gov/oet/info/rules/part15/PART15_07-10-08.pdf Enjoy! John Barnes KS4GL, PE, NCE, NCT, ESDC Eng, ESDC Tech, PSE, SM IEEE dBi Corporation jrbar...@iglou.com http://www.dbicorporation.com/ - 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 emc-p...@ieee.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 emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: FCC Immunity Requirements
Ken, For those of you who live in California, or who have ever traveled there, just how many health hazards are ?known to the State of California? ? And what is the rate-of-increase of such postings? One would come to the conclusion that either the state of California is much smarter than the rest of the forty-nine states, or that CA is a very unhealthy place to live. The most recent listing that I can find of Chemicals Known to the State to Cause Cancer or Reproductive Toxicity, under California Proposition 65, is dated March 28, 2008, and is at http://www.oehha.ca.gov/prop65/prop65_list/files/032108list.pdf This list is 18 pages long I have read that one of the criteria for being put on the list is that the chemical could shorten the life of one person in 100,000 by one year. I feel that their runaway, toxic legislation is a major contributor to CA is a very unhealthy place to live. I frequently refer to California as EU West when discussing lead-free electronics with people. If you can find it, I suggest reading H. L. Bill Richardson's book What Makes You Think We Read the Bills?. Ottawa, IL: Caroline House Books, 1978. He was a California legislator. I am in the process of printing out well over 100 Ph. D. and Master's theses that I recently found on lead-free electronics in the Proquest database. My bibliography on lead-free electronics, the RoHS and WEEE Directives, and the like is now 800 pages long, at http://www.dbicorporation.com/rohsbib.htm http://www.dbicorporation.com/rohswant.htm lists my major sources of material, and has the references that I haven't had time to double-check and put into rohsbib.htm yet. Since December 2004 I have collected 235 books, 100+ Ph. D. and Master's theses, and 11,800+ reports/papers/magazine articles/web pages on these subjects. Thanks! John Barnes KS4GL, PE, NCE, NCT, ESDC Eng, ESDC Tech, PSE, SM IEEE author of Robust Electronic Design Reference Book, Volumes I and II dBi Corporation http://www.dbicorporation.com/ - 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 emc-p...@ieee.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 emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: EN55024 A2 2003
Don, The Official Journal of the European Union, volume 46 number C172, pages 2 to 15, has the most recent listing of harmonized standards under the EMC Directive. It shows that A2:2003 to EN 55024:1998 is the same as A2:2002 to CISPR 24:1997. If an EN standard, or an amendment thereto, differs from the IEC or CISPR standard, the listing will say (modified). John Barnes KS4GL, PE, NCE, ESDC Eng, SM IEEE dBi Corporation http://www.dbicorporation.com/ 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: PC noise and a standards question
Derek, A hi-pot tester should fall under EN 61326, Electrical equipment for measurement, control and laboratory use-- EMC requirements. The foreward in my copy of IEC 61326 edition 1.0 2002-02 says that it replaces IEC 61326-1:1997+A1:1998+A2:2000. This is a little confusing, ^^ because the July 22, 2003 listing of harmonized standards under the EMC Directive (http://europa.eu.int/eur-lex/en/dat/2003/c_172/ c_17220030722en00020015.pdf ) says that: * EN 61326:1997 is the same as IEC 61326:1997. * EN 61326:1997 Amendment A1:1998 is the same as IEC 61326:1997 Amendment A1:1998. * EN 61326:1997 Amendment A2:2001 is the same as IEC 61326:1997 Amendment A2:2000. John Barnes KS4GL, PE, NCE, ESDC Eng, SM IEEE dBi Corporation http://www.dbicorporation.com/ 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: X and Y caps
Dave, If an X capacitor shorts (line-to-line or line-to-neutral), it does not cause a safety hazard. If a Y capacitor shorts (line-to-ground or neutral-to-ground), it does cause a safety hazard. Please refer to IEC 950 sections: * 1.5.6, Capacitors in primary circuits. * 1.5.7.1, Bridging capacitors. Here is an excerpt taken from chapter 8, Capacitors, of Robust Electronic Design Reference, which I am writing for Kluwer: Capacitors that connect straight to primary power, such as ones used in AC-line filters, may be subjected to high-voltage spikes and surges, and thus require a surge-voltage rating. These capacitors are considered safety-critical parts by safety agencies, and usually must be certified to EN 60384-14, EN 132400, UL 1414, and CSA C22.2 No. 1. An X-capacitor goes line-to-ground or line-to-line, and can not cause an electric shock if it fails. A Y capacitor goes line-to-ground or neutral-to-ground, and can cause an electric shock if it fails. These capacitors have several subcategories, with surge-test voltages of: · 4,000V peak for X1 capacitors, connected line-to-line across a 3-phase line. · 2,500V peak for X2 capacitors, connected line-to-neutral, for voltages up to 250VAC from ordinary wall outlets. · 8,000V peak for Y1 capacitors, connected line-to-ground or neutral-to-ground, for voltages up to 250VAC, with one capacitor bridging double or reinforced insulation. · 5,000V peak for Y2 capacitors, connected line-to-ground or neutral-to-ground, for voltages up to 250VAC, with one capacitor bridging basic or supplemental insulation, but two capacitors in series bridging double or reinforced insulation. (We sometimes use a Y-connection, with three Y2 capacitors wired together, and having their other leads going to line, neutral, and ground.) John Barnes KS4GL, PE, NCE, ESDC Eng, SM IEEE dBi Corporation http://www.dbicorporation.com/ drcuthb...@micron.com wrote: Here is a new question/comment that is sure to stir up some responses. It seems that many use the term Y to refer to caps from line-to-line and the term X to refer to caps from line-to-ground (or is it the other way 'round). While researching caps I found that X basically designates a cap which is designed to never fail shorted. This would be the one to use for line-to-ground applications. And that Y refers to a cap which can fail shorted. This would be acceptable for line-to-line. Thanks to all for the input on my hipot question. That cleared things up for me. Dave Cuthbert Micron Technology --- 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: EN55022
Joshua, EN 55022:1998 and its amendment A1:2000 have been delayed to August 1, 2005 in the latest listing of Harmonized Standards for the EMC Directive--Official Journal of the European Communities (OJ), C172 Volume 46, pages 2-15, which came out July 22, 2003. The new listing can be downloaded from http://europa.eu.int/eur-lex/en/dat/2003/c_172/c_17220030722en00020015.pdf) Alan E Hutley posted the URL on this mailing list last Tuesday, right after the OJ came out. John Barnes KS4GL, PE, NCE, ESDC Eng, SM IEEE dBi Corporation http://www.dbicorporation.com/ 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: cable maximization - do you or don't you??
Charles, I maximize the cables anytime I run radiated emissions or conducted emissions tests. John Barnes KS4GL, PE, NCE, ESDC Eng, SM IEEE dBi Corporation http://www.dbicorporation.com/ 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: PCB marked for UL 94V-0
Doug, In researching the book that I am writing for Kluwer, Robust Electronic Design Reference, I ran across the following booklet: Lund, Preben, How to Design Printed Circuit Boards for UL Recognition. Westlake Village, CA: Bishop Graphics, 1983. In my manuscript, I discuss UL Recognition of PCB's on pages G-15 and G-16. Basically, a UL Recognition Card (Yellow Card) issued by UL to a printed circuit board (PCB) vendor covers: * The laminate, conductor, soldermask, surface finish, and legend materials to be used, and acceptable alternatives. * The vendor's manufacturing process. * The design rules to be followed, including: - Minimum trace width for Midboard Conductors. - Minimum trace width for Edge Conductors. - Minimum annular ring on vias and plated-through holes. - Maximum Unpierced Area. - Maximum operating temperature. - Minimum thicknesses for base laminate, C-stage laminates, B-stage laminates, and finished PCB's. - Conductor thickness. If you would like a deeper understanding of what a 94V-0 rating represents, I suggest you read Grand, Arthur F., and Wilkie, Charles A., Fire Retardancy of Polymeric Materials. New York: Marcel Dekker, 2000. John Barnes KS4GL, PE, NCE, ESDC Eng, SM IEEE dBi Corporation http://www.dbicorporation.com/ 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Amend A1 to EN 55011
Mike, Amendment A1:1999 to EN 55011:1998 mainly: * Changes the Measured on a test site, Group 1, Class A column of Table 3 to be measured at 10m instead of 30m; all the limits increase 10dB. * Changes the On a test site column of Table 5 to be measured at 10m instead of 30m; all the limits increase 10dB. * Adds Tables 8 to 10 with emission limits for ISM equipment operating at frequencies above 400MHz. * Spells out the testing of microwave cooking apparatus in more detail. John Barnes KS4GL, PE, NCE, ESDC Eng, SM IEEE dBi Corporation http://www.dbicorporation.com/ 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: ENV 50204
Joe, ENV denotes a European Pre-Standard. ENV 50204 was called out by: * EN 50082-1:1997, Electromagnetic compatibility - Generic immunity standard Part 1: Residential, commercial and light industry (expires July 1, 2004). * EN 50082-2:1995, Electromagnetic compatibility - Generic immunity standard - Part 2: Industrial environment (expired April 1, 2002). EN 50082-1:1997 is being replaced by EN 61000-6-1:2001, Electromagnetic compatibility (EMC) - Part 6-1: Generic standards - Immunity for residential, commercial and light-industrial environments. EN 50082-2:1995 has been replaced by EN 61000-6-2:1999 and EN 61000-6-2:2001, Electromagnetic compatibility (EMC) - Part 6-2: Generic standards - Immunity for industrial environments John Barnes KS4GL, PE, NCE, ESDC Eng, SM IEEE dBi Corporation http://www.dbicorporation.com/ 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 Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: ESD failure
Ravinder, I'd say that you are in pretty good shape now. EN 55024 (information technology equipment), EN 61000-6-1 (generic devices in residential, commercial, and light industrial environments), and EN 61000-6-2 (generic devices in industrial environments) all specify performance criterion B for: * +/-4kV contact discharges (including zaps to the horizontal and vertical coupling planes). * +/-8kV air discharges. I like to test up to +/-8kV contact discharge and +/-15kV air discharge. The effort we are willing to invest in trying to raise the ESD-immunity level depends on: * Where we are in the project. * How much margin we have already. * How much of a schedule crunch we are in. * The expected pain level for the next round of ESD fixes. * Whether my boss/client is starting to complain about the time I've already spent in ESD testing, versus everything else he/she needs me to do... If we are ESD testing an engineering unit, with another board spin planned-- and we have the time and opportunity-- I'll try to push the ESD-immunity level as high as I can so that we can include the fixes in the next layout pass. If we are testing a Design Verification Test unit, with no more board spins planned, I will shoot for at least 25% margin (meet performance criterion B for +/-5kV contact and +/-10kV air discharges), with no permanent damage for +/-8kV contact discharge and +/-15kV air discharge. If we are running the final approval tests on my own or a client's product, I grudgingly accept meeting performance criterion B for up to +/-4kV contact and +/-8kV air discharges. But I'll want to get the unit back into the ESD lab as soon as possible to see what happened to our margins! As always in engineering, we have to trade-off the time/effort to perfect a piece of a design versus getting the entire job done. I personally give ESD testing high priority, because it can help me find and fix so many weaknesses in designs quickly. But the person paying the bills has the final say, as long as we meet the legal and regulatory requirements. John Barnes KS4GL, PE, NCE, ESDC Eng, SM IEEE dBi Corporation http://www.dbicorporation.com/ 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 Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: AC outlet max current
Kenneth, NEC 2002 Section 210.20(A) says Where a branch circuit supplies continuous loads or any combination of continuous and noncontinuous loads, the rating of the overcurrent device shall not be less than the noncontinuous load plus 125 percent of the continuous load. overcurrent rating/125% = 80% of rating This has an Exception: Where the assembly, including the overcurrent devices protecting the branch circuit(s), is listed for operation at 100 percent of its rating, the ampere rating of the overcurrent device shall be permitted to be not less than the sum of the continuous load plus the noncontinuous load. John Barnes KS4GL, PE, NCE, ESDC Eng, SM IEEE dBi Corporation http://www.dbicorporation.com/ 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 Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: ESD failure
Ravinder, Try putting small (around 22pF) capacitors to ground on resets, interrupts, and other asynchronous inputs to the ASIC, very close to the ASIC. I would be especially suspicious of any signals that run close to the card edge or have significant loop areas between the signal and return. Do you see a significant difference in the ESD immunity if you zap the horizontal coupling plane (HCP) near different edges of the card? If so, the edge with the lowest ESD immunity probably has the sensitive signal(s). You can try narrowing down your search area by turning down the voltage on your ESD gun and zapping very close to the board, which will shrink the circle where dI/dt (on the order of 10^11 V/s for the initial spike) exceeds your board's ESD immunity. Put a piece of copper tape on top of the insulator on your HCP, with one end connected to the HCP. Insulate everything but the other end of the copper tape with some Kapton tape or packing tape. Put your board over the copper tape, and zap the uninsulated end of the copper tape with your ESD gun. Instead of a circle of high transient magnetic fields this gives you a line of high magnetic fields a little wider than the copper tape. Move the board around, and keep reducing the ESD voltage until the board barely fails-- it keeps working if you move/turn the board or decrease the ESD voltage any further. The sensitive signal/loop should now be right over the copper tape for a significant distance. My article Designing Electronic Systems for ESD Immunity, that was published in the February 2003 Conformity magazine may give you some more ideas. You can download it from their web site at http://www.conformity.com/0302designing.pdf John Barnes KS4GL, PE, NCE, ESDC Eng, SM IEEE dBi Corporation http://www.dbicorporation.com/ 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 Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: EN55022:1998 + Amendment A1:2000
John, Amendment A1:2000 to EN55022:1998 changes subclause 10.4, Equipment set-up, for tabletop units. Their linecords are now to come straight down from the tabletop, then go through ferrite clamps or ferrite tubes before they plug into the AC power outlet. According to the latest listing of harmonized standards for the EMC Directive, in the March 26, 2003 Official Journal of the European Union (C74 Volume 46 pages 1-18, which you can download from http://europa.eu.int/eur-lex/en/dat/2003/c_074/ c_07420030326en00010017.pdf) EN 55022:1998+A1:2000 is still scheduled to take effect August 1. We've had some extended discussions on the EMC-PSTC mailing list in the last few months about: * These clamps. * Whether you can make your own versus buying them. * The reasons for this amendment. I have been recommending to our clients for the last six months that if they have older products with internal AC power supplies, or that use brick external power supplies, that: * We need to run (rerun) the Radiated Emissions test to A1:2000 if they want to import the products into Europe after August 1. OR * They need to obsolete, or get any remaining units imported into Europe, before August 1. John Barnes Ks4GL, PE, NCE, ESDC Eng, SM IEEE dBi Corporation http://www.dbicorporation.com/ 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 Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Q. on responsible party for FCC CLass B
Charles, The FCC requires the responsible party for compliance to be located in the US. Thus the responsible party will be: * Responsible for every unit that is marketed. * The manufacturer, if they are located in the US. * An importer who brings the units into the US. * An assembler in the US who assembles units from component parts. * Anybody who modifies the units from their original configuration, who is not under the authority of one of the above. * A retailer or original equipment manufacturer (OEM) who agrees to take over this responsibility from the manufacturer/importer. The responsible party must maintain all records concerning compliance, and must provide test samples or test data to the FCC upon request. See * http://www.necmitsubishi.com/css/Techlibrary/FCC.htm * http://www.hallikainen.com/cgi-bin/section.pl?section=68.3 * http://www.fcc.gov/oet/info/filing/ead/doc.html John Barnes KS4GL, PE, NCE, ESDC Eng, SM IEEE dBi Corporation http://www.dbicorporation.com/ 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 Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: [SI-LIST] Re: Trace width and current capacity
Harry, A related subject to the ampacity (safe current-carrying capacity) of printed circuit board traces is the ampacity of wires. I've been studying both topics seriously since June 1999. I will be including the results of these studies in the book I am writing for Kluwer (Robust Electronic Design Reference, to be published late this year) in: * Appendix F: Important Properties of Wires and Cables. * Appendix G: Important Properties of PCB Traces, Flat Cables, and Busbars. I've come up with a simple way to estimate the ampacity of wires with about +/-34% accuracy (+/-2 standard deviations, should cover 95% of real data). I would like some SI-LIST'ers and EMC-PSTC'ers to try my method, see how it compares to data they have seen/gathered/used, and give me feedback. From various sources I found over 1300 datapoints of wire ampacity versus: * Type of conductor (Kcond, from Table F-6). * Environment (Kenv, from Table F-7). * Number of wires in bundle/cable (N). * Wire cross-sectional area (CSA, in mm^2 = 10^-6 m^2). * Wire temperature (Twire, in degrees C). AND * Ambient temperature (Tamb, in degrees C) (or temperature rise, in degrees C). For American Wire Gage (AWG), solid wire diameter = 0.0082515 * 0.89053^AWG meters CSA = (pi/4) * diameter^2 I had to use two equations, because plotting and regression analyses of the data showed a sharp bend at about 0.5-0.7 mm^2 CSA. For large wires changing the CSA has a strong effect on the wire resistance, and thus the heat produced in the wire by current (P = I^2 * R), but a relatively small effect on the surface area of the wire. For small wires changing the CSA seems to have a much greater relative effect on surface area, and thus the wire's ability to conduct/convect/radiate heat away. I decided to make the break-point between the equations at 0.5 mm^2, because this is the smallest size wire permitted for linecords. So the first equation covers linecords and other power wiring, while the second equation basically covers signal wiring. Here is my proposed method for estimating the ampacity of wires. For CSA = 0.5 mm^2 (20AWG and larger) I = Kcond * Kenv * N^-0.2 * CSA^0.642 * sqrt(Twire - Tamb) amperes For CSA = 0.5 mm^2 (21 AWG and smaller) I = Kcond * Kenv * N^-0.2 * 1.122 * CSA^0.808 * sqrt(Twire - Tamb) amperes Table F-6: Ampacity Factor for Base Conductor Material * Copper has Kcond = 1.00. * Aluminum has Kcond = 0.80. * Nickel has Kcond = 0.56. Table F-7: Ampacity Factor for Environment * Free air hasKenv = 2.60. * Cables have Kenv = 2.24. * Equipment has Kenv = 2.06. * Wire in conduit has Kenv = 1.77. Many standards specify the wire size to be used for a given current in a specified environment. So Appendix F also (already) includes 23 tables summarizing these requirements from: * IEC 950. * SAE AS50881. * MIL-W-5088. * HS-1738. * NFPA 79. * UL 486. * UL 817. * CAN/CSA C22.2 No.21-95. * IEC 60799. * National Electrical Code (NFPA 70). * Canadian Electrical Code. My list of references for Appendix F is 5 pages long, so I won't include it with this post. But I can post it later if there is interest. So, if you are working on something that requires you to choose a wire size/temperature rating based on the current through the wire, how about giving my proposed method a try? Please see how it compares to your present method(s), and let me know the results. I would like to specifically acknowledge Doug Brooks' article Temperature Rise in PCB Traces ( http://www.ultracad.com/pcbtemp.pdf ) as the inspiration for the method I used to come up with these equations. Thanks! John Barnes KS4GL, PE, NCE, ESDC Eng., SM IEEE dBi Corporation http://www.dbicorporation.com/ (859)253-1178 phone (859)252-6128 fax jrbar...@iglou.com 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 Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: surge Z?
Dave, Section 6.1 of EN 61000-4-5:1995 says the generator has an effective output impedance of 2 ohms. John Barnes KS4GL, PE, NCE, ESDC Eng., SM IEEE dBi Corporation http://www.dbicorporation.com/ 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 Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Fire Retardants
Richard, A book that may help you is Fire Retardancy of Polymeric Materials, by Arthur F. Grand and Charles A. Wilkie (New York: Marcel Dekker, 2000). Chapter titles are: 1. The Changing Nature of Fire Retardancy in Polymers. 2. Chemical Aspects of Thermal Decomposition. 3. Fire Test Methods for Evaluation of Fire-Retardant Efficacy. 4. Synergists, Adjuvants, and Antagonists in Fire-Retardant Systems. 5. Phosphorus-Containing Flame Retardants. 6. Char Formation. 7. Intumescence. 8. Halogen-Containing Fire-Retardant Compounds. 9. Inorganic Hydroxides and Hydrocarbonates: Their Function and Use as Flame-Retardant Additives. 10. Silicon-Based Flame Retardants. 11. Solid-State Thermochemistry of Flaming Combustion. 12. The Performance of Fire Retardants in Relation to Toxicity. 13. Molecular-Level Design of Fire Retardants and Suppressants. 14. Fire-Hazard and Fire-Risk Assessment of Fire-Retardant Polymers. I borrowed the book from a local technical library just this afternoon, and have only had time to skim through it. But the impression that I got was It all depends., just like John Woodgate said in his post. You may also find pertinent information under Comparative Tracking Index or CTI. John Barnes KS4GL, PE, NCE, ESDC Eng, SM IEEE dBi Corporation http://www.dbicorporation.com/ 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 Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: VDE 0100 Part 253, VDE 0298 Part 4
John, Thank you for the tip on BS 7671. Techstreet wants $215 for BS 7671:2001, which is a bit too much for my budget when the ampacity tables are all that I am looking for. (I've already ordered over $1017 in engineering books and standards this week-- my mailman is going to hate me, having to deliver 27 heavy books if all the orders go through.) But I found a used copy of P. Cook's Commentary on BS 7671:1992 Requirements for Electrical Installations on Amazon.com for $30 plus shipping, so I ordered it. Do you know if there are any changes in the ampacity tables of BS 7671 between the 1992 and the 2001 editions? Thanks! John Barnes KS4GL, PE, NCE, ESDC Eng, SM IEEE dBi Corporation http://www.dbicorporation.com/ Woodgate wrote: I read in !emc-pstc that John Barnes jrbar...@iglou.com wrote (in 3e64d54d.7...@iglou.com) about 'VDE 0100 Part 253, VDE 0298 Part 4' on Tue, 4 Mar 2003: I am researching the ampacity (current-carrying capacity, Leitung in German) of wires for Appendix F of my book, Robust Electronic Design Reference. BS 7671 (the UK version of IEC 60364) has a lot of information on this subject. I suspect it's also in IEC 606364, but I haven't looked. -- 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 Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc 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 Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
VDE 0100 Part 253, VDE 0298 Part 4
EMC/PSTC'ers, I am researching the ampacity (current-carrying capacity, Leitung in German) of wires for Appendix F of my book, Robust Electronic Design Reference. A WECO catalog pointed me to VDE 0100 Part 253, and searching the Internet I also ran across a number of references to VDE 0298 Part 4 for the ampacity of wires and cables under various installation conditions. Some of the web pages that I found seem to mix values from these two standards, which is very confusing because they seem to differ by 10% for the same wire size, temperature rating for the insulation, ambient temperature, and installation condition (in conduit, in equipment, in cable, in free air). I am willing to buy the standards to resolve this question (even though they seem to be available only in German, as paper copies) if I can find out which ones to buy. I think that I am looking for VDE 0100 part 523.6-81 (VDE 0100 Teil 523.6-81) with tables for Gruppe 1, Gruppe 2, and Gruppe 3 and Tables 3 and 4. Techstreet ( http://www.techstreet.com/ ) lists: * VDE 0100dated 01-May-1973. === this one? * VDE 0100 Beiblatt 1 dated 01-Nov-1982.(Supplement 1) * VDE 0100 Beiblatt 2 dated 01-Mar-1983.(Supplement 2) * VDE 0100 Beiblatt 5 dated 01-Nov-1995.(Supplement 5) If VDE standards are like a lot of the EMC standards, supplements only give the information that has changed, so buying the wrong supplement would just be a waste of my time and money. Similarly, I think that I am looking for VDE 0298 part 4: * VDE 0298-100 dated 01-Dec-1992. * VDE 0298-3 dated 01-Aug-1983. * VDE 0298-300 dated 01-Feb-1997. * VDE 0298-4 dated 01-Aug-1995. === this one? I have E-mailed VDE directly, but don't know if/when I will get a reply from them. Thanks! John Barnes KS4GL, PE, NCE, ESDC Eng, SM IEEE dBi Corporation http://www.dbicorporation.com/ (859)253-1178 phone (859)252-6128 fax 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 Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Conformity Article
EMC-PSTC'ers, My article Designing Electronic Systems for ESD Immunity just came out in the February 2003 Conformity magazine, pages 18-27. If you don't receive the magazine you can download the article from their web site at http://www.conformity.com/ Enjoy! John Barnes KS4GL, PE, NCE, ESDC Eng, SM IEEE dBi Corporation http://www.dbicorporation.com/ 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 Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Looking for Tables of Metric Wire Sizes
EMC-PSTC'ers, Where can I find a table(s) or list(s) of the preferred wire sizes (electrical and otherwise) used in Europe, Japan, and other countries on the metric system? I'm looking for: * Names/numbers of standards. * URL's for wire-manufacturer's websites. * URL's for distributors' catalogs. * URL's for web pages on the subject. * URL's for linecord manufacturer's web pages. OR * Anything of the sort that may lead me to this information. Or can you tell me from your own experience which of the following (or other?) gages are currently used outside the US? I've gone through manufacturer's catalogs, searched the Internet, and looked through some 15 bookcases of electronics and metal-working books in my personal collection without finding a definitive answer as to which metric wire gages are currently used worldwide. I am working on the ampacity (current-carrying capacity) appendix to my new book, Robust Electronic Design Reference, which I am writing for Kluwer. I also plan to put the wire gage information on dBi's web site, to make it readily available so that I can get comments and corrections via the Internet. In the US we use American Wire Gage (AWG, also called Brown Sharp Gage, BS) and even gages for the most part, which correspond to a roughly 20% reduction in diameter for each step. So far I have found tables that specify metric cross-sectional area in: * Hitachi Electronic Wires and Cables catalog, 1991-- page 278 lists JIS sizes for 0.035, 0.05, 0.1, 0.14, 0.18. 0.2, 0.3, 0.5, 0.75, 1.25, 2, 3.5, 5.5, 8, 14, 22, 38, 60, and 100 mm^2. * Oleflex Cable Advanced Cable Technology catalog, 1984/1985-- page 54 lists European Cable Stranding for 0.14, 0.25, 0.34, 0.38, 0.5, 0.75, 1.0, 1.5, 2.5, 4, 6, 10, 16, 25, 35, 50, 70, 95, 120, 150, 185, 240, 300, 400, and 500 mm^2. * IEC 950, 1996-- Table 11 lists sizes of conductors for power supply cords of 0.75, 1.00, 1.25, 1.5, 2.5, 4, 6, 10, 16, 25, 35, and 50 mm^2. I have found tables that specify metric diameters for solid wires: * Querschnitt und Gewicht von Runddrahten aus Kupfer, date unknown-- page unknown lists Durchmesser (diameters) of 0.04, 0.05, 0.56, 0.06, 0.063, 0.07, 0.08, 0.09, 0.1, 0.112, 0.118, 0.125, 0.132, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.2, 0.224, 0.236, 0.25, 0.265, 0.28, 0.3, 0.315, 0.335, 0.355, 0.38, 0.4, 0.425, 0.45, 0.475, 0.5, 0.53, 0.56, 0.6, 0.63, 0.65, 0.71, 0.75, 0.8, 0.85, 0.9, 0.95, 1, 1.06, 1.12, 1.18, 1.25, 1.32, 1.4, 1.5, 1.6, 1.8, 2, 2.5, 2.65, and 3 mm. * Metric wire gage-- gages 0.5 to 100 corresponding to diameters of 0.050mm to 10.0mm. * German Wire Gage (GWG)-- gages 1 through 25 corresponding to diameters of 5.5mm to 0.438mm. I've also found tables based on diameters in inches: * British Standard Wire Gage (SWG), also called New British Standard (NBS), English Legal Standard, and Imperial Wire Gage. * Birmingham Wire Gage (BWG), also called Stub's Iron Wire Gage. * London Gage, also called the Old English Wire Gage. * Twist Drill Gage. * Stubs Steel Wire Gage. * Steel Wire Gage (Stl.W.G.), also called Washburn Moen (WM), Roebling steel wire gage, or American Steel Wire Co.'s gage. * Steel music wire gage. * Music wire gage. But some of my sources go back to the 1940's, so I don't know how far I can trust them... Thanks! John Barnes KS4GL, PE, NCE, ESDC Eng, SM IEEE dBi Corporation http://www.dbicorporation.com/ (859)253-1178 phone (859)252-6128 fax 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 Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
[Fwd: Feb 11 / Pettion for Formation of a Product Safety Society within IEEE]
This is a multi-part message in MIME format. Don, Elwood, Art, et al, If you are an IEEE member, please look at this petition to create a Product Safety Society within the IEEE. I attended the TC-8 meeting at the IEEE EMC Symposium last August, where this was discussed. I thought that having such a group as an official part of the IEEE would really add a lot of value to my IEEE membership. I would be very interested in helping form a local chapter of such a Product Safety Society in Lexington, Kentucky. But I can't invest much time in such a project until after August 1, 2003, when I am supposed to have the camera-ready manuscript for my second book, Robust Electronic Design Reference, submitted to Kluwer. Chapter 34, EMC and Safety, and Appendix J, International Safety Requirements, will be specifically devoted to product safety. Thanks! John Barnes KS4GL, PE, NCE, ESDC Eng, SM IEEE dBi Corporation http://www.dbicorporation.com/ ---BeginMessage--- Next week, several key players in the field of product safety will be attending the IEEE board series meeting. At this meeting, the President of the IEEE, the Board of Directors, and every department and organization within IEEE will be present. The unit identified as the Technical Activities Board (TAB) is responsible for the oversight of 50 Societies and Councils. Our representatives will attend the TAB caucus along with other operational units as we finalize the creation of the new IEEE Product Safety Society. If all goes well, the society should be voted into existence no later than June of this year. There is some administrative work left uncompleted. One item is to present a petition from IEEE members, to TAB, indicating an interest in seeing a society created. A petition campaign was started two years ago. We are asking every subscriber to emc-pstc that is an IEEE member, to sign this petition whether you did so a long time ago or not. We currently have the required number of petitions but desire more to show that support is out in industry for this new Society. Due to the urgency of this request, a response must occur before Feb. 11, 2003, only a few days away. Signing of this petition does not commit you to membership in this new Society. It only provides statistical information regarding the level of interest in this society worldwide. Petition to IEEE TAB For many years, discussion on creating a Product Safety Society within IEEE has been discussed, both through the Internet and the IEEE EMC Society's TC-8 (Electromagnetic Product Safety Technical Committee) and its working group, the Product Safety Technical Committee (PSTC). Due to administrative reasons, benefits as a committee within EMCS is limited in scope. Many in our ranks hold joint membership in both the IEEE and PSTC. Safety is a worldwide concern to both manufacturers and consumers. A shift in the safety paradigm has occurred from adding safety at the back end to incorporating safety in the earliest phases of product concept, design and specification. Therefore, the time is right to establish a Product Safety Society within IEEE. If we successfully complete the formal IEEE Society application process, we can enjoy the following benefits, and more: 1. Operating funds to improve our programs and services. 2. Professional publications (Transactions, newsletters, etc); opportunity to publish papers in a technical forum. 3. The hosting of an international conference or symposium every year. 4. Ability to attract a wider range and variety of speakers from local, national and international IEEE chapters through a distinguished lecturer program. 5. Creation of local product safety chapter that are autonomous. 5. Improved networking opportunities for professional growth. 7. The opportunity to participate in the formation of IEEE and International standards as a recognized committee member, which is a major benefit because we live within these regulations. The first phase of the application process is to collect signatures in support of our petition to create a Product Safety Society. If you are an IEEE member and approve of this action, please download the form off of our website at: http://www.ewh.ieee.org:80/soc/emcs/pstc/ print the page, sign it where indicated, and either mail it to Daniece Carpenter, 9709 Quilberry Drive, Austin, TX 78729, or fax it to 512-728-5278, or email a signed copy to daniece_carpen...@dell.com, as soon as possible, but no later than Feb. 11, 2003. Please add your areas of interest, comments and suggestions if desired. Many thanks for your support! Note: You may also go to https://www.ieeecommunities.org/emc-pstc?go=l137008 and fill in your information. Thanks. TC-8 and the IEEE Product Safety Society Steering Committee. This message is from the IEEE EMC Society Product Safety Technical Committee emc
Re: EN60950 protective conductor test (was Re: Circuit Breaker Tripping Dring Fault Tests)
Chris, Douglas Brooks wrote an article about Preese's and Onderdonk's equations for fusing currents of wires, which was published in Printed Circuit Magazine. It can be downloaded from UltraCAD's web site at http://www.ultracad.com/fusing.pdf Appendix F of the book that I am writing for Kluwer, Robust Electronic Design Reference, will cover the ampacity (current-carrying capacity) of wires, printed circuit board traces, busbars, etc. The manuscript is due August 1st, so I had better get back to my writing... John Barnes KS4GL, PE, NCE, ESDC Eng, SM IEEE dBi Corporation http://www.dbicorporation.com/ 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 Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
230V Transition for EU?
EMC-PSTC'ers, Some of my references on international primary power say that the European Union was to transition to 230V power in two phases: * On 1 JAN 1995 the United Kindon and other countries using 240VAC were supposed to declare that their power was now 230VAC +10% -6%, while the countries using 220VAC would declare that their power was now 230VAC +6% -10%. * On 1 JAN 2003 all the countries in the European Union would declare that their power was now 230VAC +10% -10%. Did that actually happen? Can you point me to any official documents to that effect, maybe in the Official Journal of the European Communities (OJ)? Thanks! John Barnes KS4GL, PE, NCE, ESDC Eng, SM IEEE dBi Corporation http://www.dbicorporation.com/ 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 Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Three Phase Power in Japan?
Rick, The bookletWorld Electricity Supplies, 5th Edition published by BSi in April 1989 says: * Japan (East): - 50+/-0.2Hz - Household voltages 200/100(K), 100(L) - Commercial voltages 200/100(H)(K) - Industrial voltages 6.6kV, 200/100(H), 200(G)(J) - Voltage tolerance +/-10% * Japan (West): - 60+/-0.1Hz - Household voltages 210/105(K), 200/100(K), 100(L) - Commercial voltages 210/105(H)(K), 200/100(K), 100(L) - Industrial voltages 22kV, 6.6kV, 210/105(H), 200/100(H) - Voltage tolerance +/-10% (G) is three-phase delta; four-wire; earthed mid point of phase (H) is three-phase open delta; four-wire; earthed mid point of phase (J) is three-phase open delta; three-wire; earthed junction of phases (K) is single-phase; three-wire; earthed mid point (same as we use in the United States) (L) is single-phase; two-wire; earthed end of phase This booklet is one of the very few sources that discusses the topology of various countries' electrical power distribution systems. It costs 65 English pounds, and you can order it from BSi at http://www.bsi-global.com/Technical+Information/Publications/ _Publications/tig38.xalter This is one of the 60 sources that Oscar Overton and I used to compile our web pages: * INTERNATIONAL POWER, PLUGS, AND LANGUAGES, at http://www.dbicorporation.com/internat/intpower.htm (summary covering 240 countries, 60KB, 9 pages printed out) * INTERNATIONAL PRIMARY POWER, PLUGS, LANGUAGES, APPROVAL MARKS, AND APPROVAL AGENCIES, at http://www.dbicorporation.com/internat/internat.htm (full database covering 300 countries, 360KB, 50+ pages printed out). I am incorporatingINTERNATIONAL POWER, PLUGS, AND LANGUAGES into the book that I am writing for Kluwer,Robust Electronic Design Reference , to be published late this year. If you spot any errors or major omissions in it, please let me know so that I can fix them. Thanks! John Barnes KS4GL, PE, NCE, ESDC Eng, SM IEEE dBi Corporation http://www.dbicorporation.com/ 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
EN 55022:1998 +Amendment A1:2000
To the Group, Amendment A1:2000 to EN 55022:1998 becomes mandatory (has a DOCOPOCOSS of) August 1, 2003-- see http://europa.eu.int/eur-lex/en/dat/2002/c_304/ c_30420021207en00020015.pdf For testing tabletop equipment, note 6 of Figure 10 says Mains cables, telephone lines or other connections to auxiliary equipment located outside the test area are to be fitted with ferrite clamps or ferrite tubes placed on the floor at the point where the cable reaches the floor. This note also says that No extension cords shall be used to mains receptacle. If we are testing a product with an AC line cord or a brick power supply, it is clear that we need to run the Radiated Emissions test with a ferrite clamp/tube on the line cord. But if we are testing a product that uses a wall wart direct plug-in power supply, do we need to bother with the ferrite clamps/tubes? My interpretation is that we don't, because the AC/DC cord from the wall wart is not a mains cable, nor a connection to auxiliary equipment located outside the test area. How do the rest of you interpret this requirement? Thanks! John Barnes KS4GL, PE, NCE, ESDC Eng, SM IEEE dBi Corporation http://www.dbicorporation.com/ 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
Re: EN55024 - Burst / fast transient test
Amund, EN55024:1998 Table 2 2.3 for the EN16000-4-4 Electrical Fast Transient/Burst (EFTB) test refers to note 3, which says Applicable only to cables which according to the manufacturer's specification supports communication cable lengths greater than 3 m. Please note that EN55024:1998 replaces this table as one of the COMMON MODIFICATIONS to IEC CISPR 24:1997. John Barnes KS4GL, PE, NCE, ESDC Eng, SM IEEE dBi Corporation http://www.dbicorporation.com/ 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
Re: DOCOPOCOSS?
Ian, Dates in the Official Journal of the European Communities (OJ) are in the form dd.mm.. John Barnes KS4GL, PE, NCE, ESDC Eng, SM IEEE dBi Corporation http://www.dbicorporation.com/ 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
Re: EN 60601-1-2/ EN 55022: 1998
David, EN 55022:1998 + Amendment A1:2000 was listed in the Official Journal of the European Community on 26 JUL 2001, in C208 Volume 44. So you have had the *option* of using it since then. It is still included in the latest listing of harmonized standards for the EMC directive, which came out 7 DEC 2002, in C304 Volume 45. The date of cessation of presumption on conformity of the superseded standard (DOPOCOSS) is 1 AUG 2003. So EN 55022:1994 and its amendments are valid for only another seven months. This worries a number of EMC and design engineers that I know, because EN 55022:1998 has Conducted Common Mode Voltage/Current Limits for Telecommunication Ports that aren't in EN 55022:1994. And to date, local area network (LAN) ports like Ethernet have had a very hard time meeting these limits. If you would like a lot more information about EN 55022, please read our web page about emission standards for ITE at: http://www.dbicorporation.com/emission.htm John Barnes KS4GL, PE, NCE, ESDC Eng, SM IEEE dBi Corporation http://www.dbicorporation.com/ 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
Re: strange symbols (to me anyway)-- Japanese Jate Mark
Dan, http://www.bay-labels.com/agency_marks.htmnumber 44 is identified as the Japanese Jate Mark, from the Japan Approvals Institute for Telecommunications Equipment. It is a Telecommunications Terminal Equipment Conformity mark-- see http://www.jate.or.jp/english/equipment/pdf/process.pdf John Barnes dBi Corporation 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
Re: strange symbols (to me anyway)
Dan, If you go tohttp://www.cellotape.com/contents.pdfpage 9, is symbol 139 the one that is on your wireless unit? They don't tell what the symbols mean in this design guide, but maybe someone can recognize it now... John Barnes KS4GL, PE, NCE, ESDC Eng, SM IEEE dBi Corporation http://www.dbicorporation.com/ 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
Re: strange symbols (to me anyway)
Dan, Gary, http://www.ksqlab.com/overseas/ove_bsmi.htm briefly discusses the Chinese National Standards and the CNS Mark, and shows two marks. Neither one of them looks like a C with a lightning bolt to me, however... http://www.ofco.com.tw/company.asp shows the same two marks. Some other web pages show the right hand mark, which I personally would interpret as the CNS Mark. http://www.weishin.com/a04.html shows the left hand mark on a Quality Assurance certificate. John Barnes KS4GL, PE, NCE, ESDC Eng, SM IEEE dBi Corporation http://www.dbicorporation.com/ 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
Re: strange symbols (to me anyway)
Gary, The house symbol means indoor use only. John Barnes KS4GL, NCE, ESDC Eng, SM IEEE dBi Corporation http://www.dbicorporation.com/ 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
Re: ESD Testing Method
Alex, Amendment 2:2001 to EN 61000-4-2:1995 (same as Amendment A2:2000 to IEC 61000-4-2:1995) calls for discharging ungrounded equipment, or ungrounded part(s) of equipment between ESD zaps. You use a bleeder cable with 470k resistors at both ends, connected to the horizontal coupling plane for tabletop equipment. You may leave the bleeder cable attached if it doesn't bother the equipment under test (EUT). But the definitive method is to briefly touch the bleeder cable to the EUT, zap the EUT, briefly touch the bleeder cable to the EUT, etc. This amendment also permits: * Long delays between ESD zaps. * Using a carbon-fiber brush with bleeder resistors. * Using an air ionizer (must be turned off for the air-discharge zaps). John Barnes KS4GL, SM IEEE dBi Corporation http://www.dbicorporation.com/ --- 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
Re: electronic copies of EN
Jim, You can buy electronic copies of some EN standards from the ANSI Online Store, at: http://webstore.ansi.org/ansidocstore/default.asp John Barnes KS4GL, SM IEEE dBi Corporation http://www.dbicorporation.com/ --- 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
Re: Ground potential differences
Jeff, I used to develop network interfaces for printers at IBM and Lexmark. As I recall, the Ethernet 10BASE2, 10BASE-T, and 100BASE-Tx standards required 1500V isolation between the network cabling and the product. This was no problem for 10BASE-T and 100BASE-Tx, because the transformers easily gave us this much isolation. But we had to put TransGuards on several 10BASE2 products because the circuitry required both a capacitive and a weak resistive connection between shield ground and chassis ground to work. As part of our product qualification tests, we would hit 10BASE-T and 100BASE-Tx ports with +/-400V surges, and 10BASE2 ports with +/-800V surges. These could be rather noisy when the 40 joules of available energy blasted weak components right off a prototype card... (This was not a test to run if you were tired or careless-- it could kill you with one zap.) I've never seen a document that mentioned/specified the maximum AC or DC voltage that you could expect between the network cabling and the product under normal conditions. But I don't think that it is very high, because the BNC connectors and BNC T's used for 10BASE2 have exposed bare metal connected to the shield of the cable. So when you are connecting/disconnecting a 10BASE2 cable from a product, you can have one hand on network voltage and the other hand on chassis ground, with any leakage current going through your heart. IEC 950 specifies a maximum of 30 Vrms for alternating current, or 42.4 Vdc (60 Vdc for a telecom port), for exposed metal in Safety Extra-Low Voltage (SELV) circuits. So I expect that normal network-to-product voltage are well under these limits. John Barnes KS4GL SM dBi Corporation http://www.dbicorporation.com/ --- 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
Re: Can a Haefely EM-101 Coupling Clamp Serve as an Absorbing Clamp?
John, You are correct-- The EN 61000-4-6 coupling clamp (EN 61000-4-6 Annex A, and Figure A.3) is a whole different beast than an EN 55014-1 absorbing clamp (CISPR 16-1:1993 Annex K, Figure 38, and Figure 39). I'll look around some more. The *goal* of the EN 55014-1 30-300MHz disturbance-power test is to protect against excessive radiated emissions. Would it be valid to do a CISPR Class B Radiated Emissions test at 10m instead, to meet the spirit of the standard? Thanks! John Barnes KS4GL dBi Corporation http://www.dbicorporation.com/ --- 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
Can a Haefely EM-101 Coupling Clamp Serve as an Absorbing Clamp?
EMC-PSTC'ers, We would like to test a product to EN 55014-1 and EN 55014-2. EN 55014-1 Section 6 calls for disturbance power to be measured from 30MHz to 300MHz using an absorbing clamp that meets CISPR 16-1 Clause 13 requirements. Long before I became associated with the EMC Lab, they used to test to VDE (0871? 0876?) using an absorbing clamp. But I've looked around the labs and storage areas and can't find it. We have a Haefely EM-101 coupling clamp that we use for EN 61000-4-6 conducted immunity testing. This coupling clamp is specified for operation from 150kHz to 1GHz. Can we calibrate the EM-101, following CISPR 16-1 Annex H, and use it for disturbance power measurements? Thanks! John Barnes KS4GL dBi Corporation http://www.dbicorporation.com/ --- 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
Re: RADIATED IMMUNITY TESTING ABOVE 1GHz
Chris, It sounds like you are referring to ENV 50204:1995, which simulates a digital radio telephone transmitting close to the equipment under test (EUT). This test is performed at a single frequency between 895MHz and 905MHz, keyed on and off at 200Hz with a 50% duty cycle. The only standards that I have seen that call for ENV 50204 are: * EN 50082-1:1997, for generic residential/commercial/light industrial apparatus, calls for ENV 50204 to be performed at 3V/m under the enclosure port tests in Table 1. * EN 50082-2:1995, for generic industrial apparatus, calls for ENV 50204 to be performed at 10V/m under the enclosure port tests in Table 1. EN 50082-1:1997 may be used until July 1, 2004, when EN 61000-6-1:2001 takes over as the generic immunity standard for residential/commercial/ light industrial apparatus. EN 50082-2:1995 was replaced by EN 61000-6-2:1999 on April 1, 2002 as the generic immunity standard for industrial apparatus. John Barnes KS4GL dBi Corporation http://www.dbicorporation.com/ --- 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
Re: EMC immunity requirements in Canada?
Amund, Like the US, Canada has just radiated and conducted emissions requirements. The pertinent standard for Digital Apparatus is Industry Canada's ICES-003 Issue 3, dated November 22, 1997. This standard may be downloaded from: http://strategis.ic.gc.ca/SSG/1/sf00020e.html and the implementation/interpretation guide from: http://strategis.ic.gc.ca/SSG/1/sf01006e.html You may want to refer to three web pages on our company's web site about international electromagnetic compatibility (EMC), electromagnetic interference (EMC), and electrostatic discharge (ESD) requirements: * http://www.dbicorporation.com/ite.htm for information technology equipment (ITE). * http://www.dbicorporation.com/generic.htm for generic devices used in residential, commercial, and light industrial areas. * http://www.dbicorporation.com/industry.htm for generic devices used in industry. John Barnes KS4GL dBi Corporation http://www.dbicorporation.com/ --- 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
Re: FCC Testing of Intentional Radiators
EMC-PSTC'ers, I just ran across the following article on measuring low-frequency radiated emissions to meet FCC regulations: Straus, Isidor, Loops and Whips, Oh My! On Low Frequency Measurements Issues, Conformity, pp. 22-28, August 2002. After reading your posts (especially the one from Michael Peters on 6 Sep 2002) and more studying of FCC Part 15, I believe the best procedure for FCC testing of intentional radiators is: 1. Measure radiated and conducted emissions just as we would do for any unintentional radiator. 2. Measure radiated and conducted emissions from the lowest radio frequency generated in the device on up to the specified highest frequency, to meet clause 15.33(a). I had followed this procedure to FCC test two 418MHz telemetry transmitters for a client. In this particular case I was comfortable, because Don Bush had tested previous products for this client this way, and they had all been licensed by the FCC without any problems. But I wanted more justification for not testing intentional radiations to FCC Part 15 clause 15.209(a) below the fundamental frequency, than just because we've always done it that way. Thanks all! John Barnes KS4GL dBi Corporation http://www.dbicorporation.com/ --- 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
Re: SMPS EMC Emissions
Alex, When I was developing power supplies at my previous employer, I'd include a statement like this in our Request For Quotation (RFQ): The power supply must meet the following limits with 6dB margin when supplying power to an 10-ohm resistive load: * FCC Class B (USA). * CISPR 22-B (Europe). * VCCI-B (Japan). The power supply must meet the following requirements: * EN 61000-3-2 Class A. * EN 61000-3-3. * EN 61000-4-2 level 4. * EN 61000-4-3 level 2. * EN 61000-4-4 level 3. * EN 61000-4-5 level 3. * EN 61000-4-6 level 2. * EN 61000-4-8 level 1. * EN 61000-4-11. I've updated the statement to meet the current international standards for information technology equipment (ITE), but it is based on an RFQ for a power supply that we used on at least three products. The resistive loads were chosen to set each output to its maximum rated continuous load at its nominal output voltage. My previous employer also specified higher levels for EN 61000-4-2 and EN 61000-4-4 than required for the CE Mark, as a matter of company policy. The southwest United States, for example, tends to be much drier than Europe, so a higher electrostatic discharge immunity requirement reduces field problems there. John Barnes KS4GL dBi Corporation http://www.dbicorporation.com/ --- 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
EMC/EMI/ESD Requirements for Medical Electronics in US?
EMC-PSTC'ers, Does the United States have any electromagnetic compatibility (EMC), electromagnetic interference (EMI), or electrostatic discharge (ESD) standards for medical electronics? If so, where can I find them? A prospective client has asked about EMC/EMI/ESD testing for a wearable medical-monitor. It looks like the applicable standards for Europe are: * EN 55011:1998 +Amendment A1:1999. * EN 60601-1-2:2001. I found some references on the Internet to: * The Food and Drug Administration using UL 2601-1 for medical devices. * UL 2601-1 having the same immunity requirements as EN 60601-1-2. Having been bitten by supposedly-identical standards being just a little different in areas critical to products I've designed, we bought UL2601-1 ($155 with shipping and handling), and received it yesterday. The cover letter is dated June 16,2000, and describes it as Second Edition, Dated October 24, 1997. Section 39.2 has a couple of paragraphs about Prevention of electrostatic charges. Appendix A1, section A1.5.2, says The sensitivity of EQUIPMENT to external interference (electromagnetic field, perturbations of the supply voltage) is under consideration. Appendix L refers to IEC 601-1-2:1993. Is there a newer amendment to UL 2601-1 that has EMC/EMI/ESD requirements, or just what *do* people use to verify/certify medical electronics? Thanks! John Barnes dBi Corporation http://www.dbicorporation.com/ --- 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
Re: HALT and HAAS
Andrew, David, A method that I read about in the 1980's, in the Hewlett-Packard Journal, was a method called STRIFE Testing. In this method you tested prototypes to the design limits, then you progressively increased the stresses until your prototype(s) broke. You analyzed the failures, hardened your prototypes against this failure mode, and resumed testing. At some point you would see several different failure modes within a fairly narrow band of (hopefully outside the design window) stresses. This told you that you had pushed your basic design scheme about as far as it would go. You now knew: 1. How to squeeze the most out of your design. 2. How much margin you had. If you wanted more design margin in this area, you would have to look at other design schemes. A. D. Moore's book Electrostatics talks about this kind of progressive hardening of a design on pages 78 to 83. I still haven't managed to find that original HP Journal article, but Meeker, William Q., and Hamada, Michael. Statistical Tools for the Rapid Development Evaluation of High-Reliability Products, Sept. 20, 1999 (download from http://www.stat.iastate.edu/preprint/articles/1995-07.pdf) talks about STRIFE testing on page 21. John Barnes dBi Corporation http://www.dbicorporation.com/ Andrew Carson wrote: I would agree with Brian in that the name HALT is misleading. There is no way to relate HALT data to a failure rate or MTBF figure within a field population. Saying that though, HALT testing does very quickly reveal mechanical weakness within a design and is incredibly useful. I always take the approach that HALT testing pushes your product to the limit and finds the weak points. Then from this data you set up a HASS regime to screen all your outgoing goods. Non military parts do carry MTBF figures, and I have been finding in recent months, more and more customers requiring calculated and proven reliability data before they place an order for goods. Andrew Carson - Senior Compliance Engineer, Xyratex, UK Phone: +44 (0)23 9249 6855 Fax: +44 (0)23 9249 6014 -Original Message- From: David Sproul [mailto:david.spr...@alexanderlynn.co.uk] Sent: 01 August 2002 11:22 To: Brian O'Connell Cc: EMC-PSTC Subject: RE: HALT and HAAS Hello group, I would actually disagree that HALT is misnamed, as Brian suggests. I have seen clients find mechanical and electronic weakness in their designs within days of testing that may otherwise have taken many weeks of conventional temperature and vibration testing, or even years in the field, before they were discovered. By fixing these problems these companies were able to strengthen their product still further and greatly reduce, and in some cases eradicate, repairs or returns from customers. I may be wrong, but is it not the case that components destined for non military use do not come with MTBF figures, thus making it impossible to calculate accurate MTBF figures for products they are used in? I must stress that I this is more supposition that known fact. If it is so, then perhaps HALT could be seen as a commercial alternative to MTBF. I think HAAS may actually be HASS, which stands for highly accelerated stress screening. This I'm afraid I've had very little experience of, but It seems to take the product lessons learned from your HALT testing and apply them, in a less destructive manner, to the manufacturing process. HALT and HASS are very expensive and must be weighed against perceived potential savings from reduced field repairs or replacements. I know it is not for all companies. I used to work for a large British manufacturer of military electronics who made as much money (if not more) from spares and repairs, as they did from the original product sales. I hope this has helped. Best regards, David Sproul. -Original Message- From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of Brian O'Connell Sent: 31 July 2002 14:12 To: emc-p...@ieee.org Subject: RE: HALT and HAAS Geez, just jump to Google. HALT- misnamed: Highly Accelerated Life Testing. Actually has noting to do with Life-time or MTBF-type longevity analysis. Look at the Calmer web site; they were one of the pioneers of HALT. Also, GM has published an engineering standard, GMW8287, that provides a decent overview of HALT and HASS/HASA processes. There may be minimal ROI for simple digital stuff, but mixed-signal and/or more complex mechanical constructions should be subject to HALT, and perhaps HASS follow-up. If your manufacturing and design engineers take the time to actually READ your HALT report and take corrective action, you will probably find that RMA problems are greatly reduced. In any case, playing
Re: GR 1089
Sam, The key phrase is free-space wave impedance. At the source, the wave impedance matches the impedance of the driving circuit. The electric fields and magnetic fields interact (near-field conditions), working toward the free-space wave impedance of about 377 ohms. The impedance actually overshoots 377 ohms a little bit (see Figure H-1 in my book, Electronic System Design: Interference and Noise Control Techniques), but past about lambda/(2*pi) has stabilized at a nominal 377 ohms (far-field conditions). Since the wave impedance also affects the antenna factor, and thus the V/m or A/m that the antenna thinks it sees, you have to measure both ways. John Barnes dBi Corporation http://www.dbicorporation.com/ --- 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
Re: Tantalum Capacitor Reliability
Chris, You may want to look at some of the polymer aluminum electrolytic capacitors from: * Cornell Dubilier. * Elna. * Jaro Components. * Kemet. * Matsushita. * NIC Components Corporation. * Nichicon. * Panasonic. * Samchung. * SDK. * etc. I've used them on the last two controller cards that I designed for my previous employer, for the DC-DC converters and general bypassing, with very good results: * Equivalent series resistance (ESR) down to 0.015 ohms. * No worry about the capacitors catching fire in low-impedance circuits. * Priced about 1/3 of equivalent tantalums. * Readily available in quantity- no worry about being on allocation. They do tend to be a little taller than equivalent tantalums, if you are height-limited. But you don't have to derate them nearly as much as tantalums to be safe. I used the 105C-rated capacitors to ensure a longer lifetime than the more commonly available 85C capacitors. The pin-through-hole (PTH) radial versions had about 2/3 the ESR of the surface mount technology (SMT) versions when I did my last design. So we laid out my cards to use either style, with the SMT bulk capacitors turned 90 degrees from the PTH bulk capacitors, and their footprints overlaying one another for compactness. If you want to stick with tantalums, we have a bibliography for Power Distribution on Printed Circuit Boards at http://www.dbicorporation.com/pwr-bib.htm I just added Ken Javor's report to the bibliography, [215a], so out of the 380+ references, the following ones apply directly to the proper use of tantalum capacitors: [91] Precautions and guidelines for users (Tantalum), Nippon Chemi-con. (download from http://www.chemi-con.co.jp/english/support/tantal_note_e.html) [92] Precautions in Using Tantalum Capacitors. (download from http://www.bostonaic.com/tantalum/precautions4.html) [107] Tantalum Capacitors With Solid Electrolyte (Chip Type), Mectron. (download from http://www.mectron.co.kr/components/tan-2.html) [145] Cain, Jeffrey, Comparison of Multilayer Ceramic and Tantalum Capacitors. (download from http://www.avxcorp.com/docs/techinfo/mlc-tant.pdf) [180] Franklin, R. W., Equivalent Series Resistance of Tantalum Capacitors. (download from http://www.avxcorp.com/docs/techinfo/eqtantcp.pdf) [181] Franklin, R. W., Ripple Rating of Tantalum Chip Capacitors. (download from http://www.avxcorp.com/docs/techinfo/rpleinfo.pdf) [190] Gill, John, Surge in Solid Tantalum Capacitors. (download from http://www.avxcorp.com/docs/techinfo/solid_ti.pdf) [215a] Javor, K., Investigation Into the Effects of Microsecond Power Line Transients on Line-Connected Capacitors, NASA/CR-2000-209906, NASA Marshall Space Flight Center, AL 35812, February 2000. (download from http://mtrs.msfc.nasa.gov/mtrs/2000/cr209906.pdf) [271] Loh, Eugene, Physical Interpretation of the Tantalum Chip Capacitor Life-Test Results, IEEE Transactions on Components, Hybrids, and Manufacturing Technology, vol. CHMT-3 no. 4, pp. 647-654, Dec. 1980. [280] Mattingly, David, Increasing Reliability of SMD Tantalum Capacitors in Low Impedance Applications. (download from http://www.avxcorp.com/docs/techinfo/rel_ti.pdf) [283] Mogilevsky, Boris and Shirn, George A., Surge Current Failure in Solid Electrolyte Tantalum Capacitors, IEEE Transactions on Components, Hybrids, and Manufacturing Technology, vol. CHMT-9 no. 4, pp. 475-479, Dec. 1986. I wrote design guidelines for, and gave a couple of informal seminars on this subject, at my former employer in 2000. My boss there has given me permission to publish the design guidelines on dBi's web site after I remove the proprietary information (about 10% of the document) and get his approval. So far I haven't had time to work on that task, but it is in my queue. John Barnes dBi Corporation http://www.dbicorporation.com/ --- 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
Re: EN61000-3-2:2000 Harmonic current emissions
Neil, If the power supplies are intended for audio equipment, where the peak power required for some types of music can be 10 times the average power, I could buy the manufacturer's explanation. Otherwise their explanation of how they pass EN 61000-3-2:2000 sounds bogus to me. An EN 61000-3-2:2000 harmonics test will usually take between 2.5 minutes and 25 minutes (Section 6.2.4, Test observation period). Beginning 10 seconds after the EUT is turned on (Section 6.2.3.2, Starting and stopping), the harmonic current drawn by the equipment under test (EUT) is measured and analyzed in 1.5-second time chunks (Section 6.2.2, Measurement Procedure). Section 6.2.3.3, Application of limits, specifies that for an individual harmonic current (one frequency), the average over the entire test observation period must be under the specified limit. But the average over a 1.5 second time chunk may exceed the specified limit by up to 50%. This makes more sense when we read Annex C, detailing the test conditions for various types of equipment. Audio amplifiers stand out because of the wide normal variations in output-power, and thus current draw. Similarly, washing machines stand out because certain modes may require stopping and re-starting the motor, and starting an induction motor can draw five to seven times its full-load running current. A brief, infrequent burst of input current is not going to cause overheating of neutral wires or power transformers, which is the major concern of EN 61000-3-2. Do an Internet search for triplen if you would like to read more about this subject. John Barnes dBi Corporation http://www.dbicorporation.com/ --- 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
Changes to FCC Conducted Limits for Part 15 18
EMC-PSTC'ers, There has been talk for several months about the FCC changing the conducted emission limits for Part 15 and Part 18 devices. Well, it is official. FCC docket 98-80 was published in the Federal Register on July 10, 2002- volume 67, number 132, pages 45666-45671, see (all one URL): http://frwebgate1.access.gpo.gov/ cgi-bin/waisgate.cgi?WAISdocID=38880224794+0+0+0WAISaction=retrieve FCC Part 15, incorporating the new Section 15.107, may be downloaded from http://www.fcc.gov/oet/info/rules/part15/part15_5_30_02.pdf This will not be printed in the Code of Federal Regulations (CFR), downloadable from the National Archives and Records Administration (NARA) at: http://www.access.gpo.gov/nara/cfr/cfr-table-search.html until spring 2003. This change probably will not affect products that have been marketed in Taiwan and Japan, because they have already had to meet the CISPR limits for those markets. But products that are sold only in the US/Canada may be affected, because conducted emissions are now to be tested clear down to 150kHz, versus the former 450kHz lower limit. The new conducted emission limits are: * Mains port on Class B devices: - 66dB(uV) quasi-peak and 56dB(uV) average at 0.15MHz, to 56dB(uV) quasi-peak and 46dB(uV) average at 0.50MHz, decreasing linearly with the logarithm of the frequency. - 56dB(uV) quasi-peak and 46dB(uV) average from 0.50MHz to 5MHz. - 60dB(uV) quasi-peak and 50dB(uV) average from 5MHz to 30MHz. * Mains port on Class A devices: - 79dB(uV) quasi-peak and 66dB(uV) average from 0.15MHz to 0.50MHz. - 73dB(uV) quasi-peak and 60dB(uV) average from 0.50MHz to 30MHz. Paragraph 15 of FCC Docket 98-80, Transition Provisions, says that FCC part 15/18 products may be authorized using the old or the new FCC limits for two years (until July 10, 2004). After July 10, 2004, FCC part 15/18 products must be authorized using the new FCC limits. Furthermore, the new limits will apply to all FCC part 15/18 products that are manufactured or imported after three years (after July 10, 2005). So for the next two or three years you have a third option for meeting FCC Part 15/18 requirements: 1. Meet the old FCC conducted-emission and radiated-emission limits. 2. Meet CISPR conducted-emission and radiated-emission limits. 3. Meet CISPR conducted-emission limits and the old FCC radiated- emission limits. John Barnes dBi Corporation http://www.dbicorporation.com/ --- 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
Bibliographies
EMC-PSTC'ers and SI-LIST'ers, We've had some interesting discussions recently about: * Designing power distribution systems for printed circuit boards (PCB's). * The current-carrying capability of traces and vias. In 1999-2000 I researched and developed design guidelines on these topics for my previous employer, a major printer manufacturer. We tested many of these guidelines on my X820e controller card, which won a 3rd place in Mentor Graphics' 2002 PCB Technology Leadership Awards (http://www.mentor.com/press_releases/mar02/pcb_awards_pr.html ) I've continued to research these and various other aspects of robust electronic design, and would like to share two up-to-date bibliographies with you: * POWER DISTRIBUTION ON PRINTED CIRCUIT BOARDS- Bibliography, at http://www.dbicorporation.com/pwr-bib.htm * AMPACITY (CURRENT-CARRYING CAPACITY) OF PRINTED CIRCUIT BOARDS (PCB's)- Bibliography, at http://www.dbicorporation.com/amp-bib.htm Quite a few of these documents can be downloaded from the Internet, in which case I've included their universal resource locators (URL's) in the citations. If you know of a pertinent document that I've missed, please E-mail me, and I will add it to the list. Thanks! John Barnes dBi Corporation http://www.dbicorporation.com/ jrbar...@iglou.com --- 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
Sources for EMC/EMI/ESD Standards?
We have bought/downloaded EMC/EMI/ESD standards from 14 companies and organizations so far this year. I've put links to them, along with other promising sources that we've looked at, on our web page http://www.dbicorporation.com/emcbibli.htm Are there some other sources, for either downloadable or paper copies of EMC/EMI/ESD standards, that we should be aware of? Thanks! John Barnes dBi Corporation http://www.dbicorporation.com/ --- 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
Re: Telecomm Safety clearance
Alex, What I have done in your situation is to treat the inner copper layers of the card as Polution Degree 1 (sealed so as to exclude dust and moisture), and calculate creepages and clearance from there. This protects you just in case you have a small air pocket in the inner layers. Some precautions are: 1. Don't use too-thick copper in the inner layers (helps prevent air pockets). 2. Make sure that the vias and component mounting holes near the PSTN wiring have pads in all layers (keeps you from drilling into and plating an air pocket). 3. If you don't do #2, make sure that your spacing accomodates the drill-location tolerance plus the maximum outside diameter (inside diameter plus twice the plated copper thickness) of vias and component-mounting holes. John Barnes dBi Corporation http://www.dbicorporation.com McNeil wrote: Hi Group, My products use an external double insulated power supply which supplies SELV to the product. For an analogue modem there has to be a creepage and clearance between the PSTN side and the other product electronic circuitry. I normally allow for 2.5mm and I apply this rule to all 4 layers of my PCB. I am now designing a 6 layer PCB and I intend to route some tracking in the inner layers. This has created a few questions. I would very much appreciate the forums input. Q1. Is 2.5mm OK (Norway and Sweden are to be included) and what is the minimum? Q2. Does this creepage and clearance need to apply to all 6 layers (and 4 layers)? As usual, I am very grateful for the forums help! Kind Regards ALEX --- 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 --- 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
Re: Class 2 Power Unit
Brian, The short answer is that a Class 2 Power Unit is what we would normally call a wall wart or a brick power supply. Clause 1.1 of UL 1310 (August 21, 1992) says: These requirements cover (1) direct plug-in Class 2 power units intended for connection to a 15-ampere nominal 120- or 240-volt ac branch circuit, and (2) cord-connected Class 2 power units intended for connection to a 15- or 20-ampere ac branch circuit with a potential of 150 volts or less to ground. These products utilize an isolating transformer and may incorporate rectifiers and other components to provide a source of alternating- or direct-current supply. These products provide Class 2 power levels in accordance with the National Electrical Code, and are intended primarily to provide power to low voltage, electrically operated devices. Other clauses in the Scope say that UL 1310 does not cover: * Products whose input power could exceed 660W. * Battery chargers for charging engine-starting batteries. * Power supplies for toys. * Products with other than Class 2 outputs. * Battery chargers to charge batteries for wheelchairs and other mobility aids. * Class 2 transformers intended for field connection (i.e. bell transformers). Section 725 of the National Electrical Code (NEC) covers Class 1, Class 2, and Class 3 Remote-Control, Signalling, and Power-Limited Circuits. The Scope in 725-1 says that (these) are not an integral part of a device or appliance. The Definition in 725-2 says Due to its power limitations, a Class 2 circuit considers safety from a fire initiation standpoint and provides acceptable protection from electric shock. Chapter 9, Tables 11(a) and 11(b) of the NEC show: * Class 2 ac source is limited to: - For 0 to 20V output, 8A output under any load conditions, with a nameplate rating 5*Vmax volt-amps and 5.0 Amps. - For 20 to 30V output, 8A output under any load conditions, with a nameplate rating 100 volt-amps and 100/Vmax Amps. - For 30 to 150V output, 0.005A output under any load conditions, with a nameplate rating 0.005*Vmax volt-amps and 0.005 Amps. * Class 2 dc source is limited to: - For 0 to 20V output, 8A output under any load conditions, with a nameplate rating 5*Vmax volt-amps and 5.0 Amps. - For 20 to 30V output, 8A output under any load conditions, with a nameplate rating 100 volt-amps and 100/Vmax Amps. - For 30 to 60V output, 150/Vmax output under any load conditions, with a nameplate rating 100 volt-amps and 100/Vmax Amps. John Barnes dBi Corporation --- 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
Effective Dates Record Retention for ITE EMC/EMI/ESD Standards
We're trying to clarify the effective dates of the major worldwide emissions and immunity standards for information technology equipment (ITE). We're also trying to find out how long a manufacturer/ distributer must retain the EMC/EMI/ESD test reports. This is for the family tree of EMC/EMI/ESD standards that we've put together at http://www.dbicorporation.com/standard.htm with ITE-specific standards at http://www.dbicorporation.com/ite.htm and generic standards at http://www.dbicorporation.com/ Our goal is to be able to spell out for a client, that to market their product in a certain area we could test and create a Declaration of Conformity (DOC) to option #1, or option #2, etc. That if we go with option #1 we need to test to such-and-such a list of standards, must meet a certain set of requirements, and that the DOC would then give coverage to a given date without retesting. (Assuming that the product doesn't change in a way that affects EMC/EMI/ESD, of course.) Similarly for option #2, option #3, etc. The client can then choose the option that best meets their business needs. Furthermore, if we fail a test or are marginal, the client can choose to: 1. Fix the problem. 2. Choose a different DOC option that lets them put the product on the market for at least a limited time, while engineering continues to work on the problem. We would appreciate any corrections or additions you may have, and where these items are spelled out in official documents. Thanks! John Barnes dBi Corporation This is what we've complied so far in information technology equipment: EMC/EMI/ESD TESTS for ITE Australia/New Zealand basic rules: * Two year transition period from the date of publication for AS/NZS, CISPR, and IEC standards. * Transition period as published in the Official Journal of the European Communities for EN standards. * Must keep records for 5 years after ceasing to supply a product to Australia/New Zealand. Or must keep records for 10 years after the last product has been manufactured? AS/NZS CISPR 22:2002 Ratified/printed: 21 JAN 2002 Published in Official Journal: 21 JAN 2002 Must use starting: 21 JAN 2004 Must use until: Withdrawn: AS/NZS 3548-1995 +Amendment 1:1997 Ratified/printed: Published in Official Journal: 5 JAN 1997 Must use starting: 5 JAN 1999 Must use until: 21 JAN 2002 Withdrawn: 21 JAN 2004 AS/NZS 3548-1995 Ratified/printed: Published in Official Journal: 5 DEC 1995 Must use starting: 5 DEC 1997 Must use until: 5 JAN 1997 Withdrawn: 5 JAN 1999 Sources: * http://www.aca.gov.au/publications/industry/manuals/emcbook.pdf * http://www.aca.gov.au/consumer/faq/emc.htm --- Canada basic rules: * Standard takes effect at the dates given in section 1 of the standard. * Must keep records for 5 years. ICES-003 Issue 3 Ratified/printed: 22 NOV 1997 Published in Official Journal: 22 NOV 1997 Must use starting: 31 MAY 1998 Must use until: Withdrawn: Sources: * http://strategis.ic.gc.ca/pics/sf/ices003.pdf --- China basic rules: * Standards take effect when? * Must keep records for how long? GB9254-1998 Ratified/printed: Published in Official Journal: Must use starting: Must use until: Withdrawn: --- Europe basic rules: * Product or product family specific standards take precedence over generic standards. * You may start using a standard/amendment once it has been published in the Official Journal of the European Communities (OJ). * You must use the standard beginning with the Date of cessation of presumption of conformity of the superceded standard. * You must use the standard until a standard/amendment that supercedes it, or has a tighter scope, is published in the OJ. * You may use the standard until it reaches its Date of cessation of presumption of conformity. * Must keep records for 10 years after the last product has been manufactured? EN 55022:1998 +Amendment A1:2000 (for emissions) Ratified/printed: Published in Official Journal: 26 JUL 2001 C208 Volume 44 Must use starting: 1 AUG 2003 Must use until: Withdrawn: EN 55022:1998 (for emissions) Ratified/printed: SEP 1998 Published in Official Journal: 27 FEB 1999 C57 Volume 42 Must use starting: 1 AUG 2003 (pushed back from 1 AUG 2001 on 26 JUL 2001 C208 Volume 44) Must use until: 26 JUL 2001 Withdrawn: 1 AUG 2003 EN 55022:1994 +Amendment A1:1995 +Amendment A2:1997 (for emissions) Ratified/printed: Published in Official Journal: 3 APR 1998 C101 Volume 41 Must use starting: 31 DEC 1998 Must use until: 27 FEB 1999 Withdrawn: 1 AUG 2003 (pushed back from 1 AUG 2001 on 26 JUL 2001 C208 Volume 44) EN 55024:1998
Re: Family Tree of EMC/EMI/ESD Standards
John, The dates that I give in the introduction to each web page are for the family of standards as a whole. So EN 61000-3-2 (16 SEP 1995 to ???) Europe is my shorthand for: * EN 61000-3-2:2000 +Amendment A1:2001, not published in the Official Journal of the European Community (OJ) yet; * EN 61000-3-2:2000, published in the 9 MAR 2002 OJ with no replacement named yet (hence the to ???); * EN 61000-3-2:1995 +Amendment A1:1998 +Amendment A2:1998 +Amendment A14:2000, published in the 14 DEC 2000 OJ, and good through 1 JAN 2004; * EN 61000-3-2:1995 +Amendment A1:1998 +Amendment A2:1998, published in the 27 FEB 1999 OJ and also good through 1 JAN 2004. * EN 61000-3-2:1995 +Amendment A1:1998, published in the 27 FEB 1999 OJ and withdrawn 1 JAN 2001. * EN 61000-3-2:1995 +Amendment A13:1997, published in the 3 APR 1999 OJ and withdrawn 1 JAN 2001. * EN 61000-3-2:1995, published in the 16 SEP 1995 OJ and withdrawn 1 JAN 2001 (hence the 16 SEP 1995 to). So the little blurb (16 SEP 1995 to ???) tells us that since 16 SEP 1995, and for the foreseeable future, we need to satisfy some version of the EN 61000-3-2 harmonics standard to sell most electronic equipment into Europe. Whereas an entry like EN 50082-2 (16 SEP 1995 to 1 APR 2002) Europe tells us that if: 1. We have a product that was verified/certified to EN 50082-2:1995, AND 2. Its Declaration of Conformity has not been updated since then, THAT we may be in trouble with European Customs if we try shipping any more units into Europe without taking some kind of action... Thank you for your comments! John Barnes dBi Corporation --- 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
Family Tree of EMC/EMI/ESD Standards
I've just put a family tree of EMC/EMI/ESD standards for information technology equipment (ITE) and related (generic) products on our company web site at http://www.dbicorporation.com/standard.htm This came out to 15 web pages, totalling about 200KB of HTML. Please look it over. I would appreciate any comments, corrections, additions, or suggestions for improvements that you may have. Thanks! John Barnes dBi Corporation jrbar...@iglou.com --- 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
Looking for Official Journal of the European Communities, C 44 dated 19.2.92
I am looking for a listing of electromagnetic compatibility standards that comply with Council Directive 89/336/EEC, that was supposedly published in issue C 44 Volume 37 of the Official Journal of the European Communities (OJ) on February 19, 1992 (19.2.92). Can anyone point me to a web page with this listing, or send it to me somehow? This is for a family tree of international EMC/EMI/ESD standards for Information Technology Equipment (ITE), to be posted on our company web site. So far this document is over 60 pages (130KB) long... For completeness, I am trying to find out when the following European standards were first listed in the OJ: * EN 55022:1987 * EN 60555-2:1987 * EN 60555-3:1987 Several references on the Internet say that these were first listed in issue C 44 Volume 35, dated 19.2.92. But the earliest listing for Council Directive 89/336/EEC that I have found is C 90 Volume 35, dated 10.4.92. And it only mentions EN 50081-1 and EN 50082-1. C 49 Volume 37, dated 17.2.94, mentions all three above standards and says that they were ratified in 1986. Thanks! John Barnes dBi Corporation http://www.dbicorporation.com/ --- 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
Re: Voltage Spikes on Power Lines etc
George, I discuss problems with powerline-spikes in chapter 8, Designing Power Supplies, of my bookElectronic System Design: Interference and Noise Control Techniques (Prentice-Hall, 1987, now out of print). For equipment that will be used indoors, you should try to design your equipment to be immune to 6kV spikes. That is approximately the voltage at which our wall outlets arc over. A quick and dirty test is to plug a vacuum cleaner into the same wall outlet as your product, and try to run your product with the vacuum cleaner running. Vacuum cleaners use universal motors, which have the rotor windings connected to the field winding through a commutator. The arcing at the commutator puts a tremendous amount of hash on the powerline, which will sneak through linear or switching power supplies if you aren't careful. One of my first business trips after I got out of college was going to Chemical Bank in New York City, because one of the Sycor 250 terminals (for which I had written the firmware) would lock up every night. The hardware designer and I installed some hardware and software monitors on this unit, and left for the evening. Next morning we returned, and discovered that it had died shortly after 11pm-- the very time that the cleaning people were making their rounds! We discovered that the cleaning people were plugging their industrial vacuum cleaners into the same wall outlet as our terminal because it was convenient. I think that the bank changed to a simplex wall outlet there, and that solved the problem. A very basic precaution is to put ceramic capacitors in parallel with the bulk electrolytic capacitors in your power supply, to short out the high-frequency components of the spikes. A common-mode choke on the input can also help a lot. To see if this would help, you can put a snap-on ferrite sleeve around the power cord next to the power supply. John Barnes dBi Corporation http://www.dbicorporation.com/ --- 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...@mediaone.net 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
Re: EMC Emissions Safety Margins
Russell, At IBM and Lexmark, our EMC department was comfortable if one unit showed at least a 3dB margin between the measured emissions and the specified test limits. If we were a little closer than that, and unable to improve the margin for whatever reason, they would have us test two more units. Then if all three units had over 1.5dB margin they would pass us, but might require us to retest production units quarterly or after every significant hardware/software-design change. They also asked us to be up-front with them, and to show them our pre-approval runs to prove that these measured emission peaks did not change much run-to-run. John Barnes dBi Corporation --- 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...@mediaone.net 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
Re: Using PCB traces as transient voltage suppressor
Gabi, Check out [912] Linholm, Loren W., and Plachy, Richard F., Electrostatic Gate Protection Using an Arc Gap Device, 11th Annual Proceedings Reliability Physics. Las Vegas, NV, Apr. 3-5, 1973, pp. 198-202. [1387] Wallash, Albert J. and Hughbanks, Timothy H., CapacitiveCoupling Effects in Spark Gap Devices, Electrical Overstress/ Electrostatic Discharge Symposium Proceedings/CITE, Las Vegas, NV, Sept. 27-29, 1994, pp. 273-278. These citations are from a nearly 1500-item bibliography of books, papers, articles, etc. on electrostatic discharge that I have on my webpage http://www.r-e-d-inc.com/esd-anno.htm Enjoy! John Barnes Consultant Robust Electronic Design, Inc. Lexington, KY Hoffknecht wrote: Hi all, I have seen PCB designs with two triangular shaped copper pads pointed towards each other at very close proximity, meant as an air gap discharge path for transients. Does anyone have information about such designs, whether they work and how well ? At a breakdown voltage for air of 1 Megavolt per meter, they should theoretically work: 10mil distance would have a breakdown voltage of only 254V. Such a PCB design basically comes for free, so I was thinking of adding it on top of my already existing series impedance - TVS network. Thanks in advance for your comments. Best regards, Gabi Hoffknecht --- 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...@mediaone.net 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 --- 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...@mediaone.net 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
Re: Resistors pulse loading capabilities
Massimo, All the tests that I've seen for evaluating the peak-pulse-power handling capabilities of resistors are based on charging a bank of capacitors to a high voltage, then applying this energy (E = 1/2 * c * V * V) to the part/equipment-under-test through a low-resistance low-inductance switch or relay. You need to be very careful running these tests, because there is enough energy involved to kill you! For the Keytek surge generator that I used to run IBM Lightning Surge Susceptibility tests on network adapter cards, this came to something like 4 joules at 800 volts, with the tester rated to deliver up to 200 amps maximum. That tester required you to toggle two widely-spaced switches to trigger a discharge, to make sure that you had both hands on the tester. I always triple-checked my test setup, then had another experienced engineer double-check me, before I even plugged in the surge tester. I blew up quite a few components, and fried a few circuit boards, while developing/helping develop some 35 IBM and Lexmark networking/digital-office products from 1990 through January 2002. NOTE: You also want to put a direct short across the capacitors when the tester is not in use. Dielectric absorbtion stores some energy in the dielectric of a capacitors as a physical displacement of the atoms. This can take seconds to hours to relax, and as it does it induces a corresponding charge on the capacitors' plates. Without a bleeder resistor of some type across the capacitors, up to 10% or so of the initial charging voltage can appear on the capacitors after they have supposedly been discharged. This could give you a nasty, if non-fatal shock, next time you want to use the tester. As for help choosing the resistors for your circuit, check out The Resistor Handbook by Cletus J. Kaiser (98 pages, 1994, CJ Publishing, Olathe, Kansas, ISBN 0-9628525-1-1). This is the best single source I've found for information on resistors. On page 3, under the subheading One Short Pulse it says: The theory of pulse handling depends on the pulse width. One short pulse of 100 milliseconds or less is assumed to never havetime enough to do more than heat the element. Therefore the calculation is based on the total mass of the element (wire) being heated to the maximum internal hot-spot temperature. As Bob Wilson said, this will depend on the overall type of resistor, and on the specific details of its construction (i.e. manufacturer/ series). You need to consider the bulk sections of the resistor, which have relatively-uniform construction, and the interfaces between them. So I would expect bulk-metal resistors, such as those made by Vishay, to have the highest peak-power/rated-power capability because they are essentially one piece of metal. From there I would look at: 1. Carbon-composition resistors. 2. Wirewound resistors. 3. Untrimmed metal-film resistors. 4. Untrimmed carbon-film resistors. 5. Untrimmed cermet resistors. 6. Trimmed metal-film resistors. 7. Trimmed carbon-film resistors. 8. Trimmed cermet resistors. The untrimmed film resistors have rather sloppy tolerances, on the order of +/-20% or so, but have much higher pulse-power handling capability than their trimmed brethren. (We got bitten by this, when purchasing had trouble getting the part we had specified for a Token-Ring card, and substituted a part that the salesman said was even better than the one we wanted.) If you must use a trimmed resistor, because of tolerances, abrasive trimming would probably be better than laser trimming, because it makes a smoother cut and leaves less debris. I found it very educational to look at resistors under a microscope (about 10-30x magnification sufficed), both before and after running the Lightning Surge Susceptibility test. The failed resistors looked like they had been machine-gunned, with a vertical line of pits across the surface of the resistor from the corner of the L (left by trimming) to the edge of the resistor. John Barnes dBi Corporation --- 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...@mediaone.net 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
Let-Go Current as a Function of Frequency
We had a discussion on this forum back a month or so ago on let-go current (the maximum current at which you can let go of an energized wire). I mentioned a magazine article that I found some years ago, which discussed some experiments that were run on young men to determine the let-go current as a function of frequency, but was unable to find the article again at that time. Well, I made a special trip to the University of Kentucky Engineering Library, and finally managed to find the article. It is: Dalziel, Charles F., and Lagen, John B., Muscular Paralysis Caused by Electric Currents, Electronics, vol. 14 no. 3, pp. 22-23, March 1941. Enjoy! John Barnes Chief Engineer dBi Corporation --- 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...@mediaone.net 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
