RE: comment in UL file
Brian - I reread your post and see I may have misunderstood your question. The statement you cited was in a UL report or in a Recognition Card? If in a report, it is utterly useless and is an example of poor report writing. Not quite useless if it was in a Recognition Card, since it would serve at least as a flag to look into the reason for the note. Regards, Peter L. Tarver, PE ptar...@ieee.org CONFIDENTIALITY This e-mail message and any attachments thereto, is intended only for use by the addressee(s) named herein and may contain legally privileged and/or confidential information. If you are not the intended recipient of this e-mail message, you are hereby notified that any dissemination, distribution or copying of this e-mail message, and any attachments thereto, is strictly prohibited. If you have received this e-mail message in error, please immediately notify the sender and permanently delete the original and any copies of this email and any prints thereof. ABSENT AN EXPRESS STATEMENT TO THE CONTRARY HEREINABOVE, THIS E-MAIL IS NOT INTENDED AS A SUBSTITUTE FOR A WRITING. Notwithstanding the Uniform Electronic Transactions Act or the applicability of any other law of similar substance and effect, absent an express statement to the contrary hereinabove, this e-mail message its contents, and any attachments hereto are not intended to represent an offer or acceptance to enter into a contract and are not otherwise intended to bind the sender, Sanmina-SCI Corporation (or any of its subsidiaries), or any other person or entity. _ Scanned by Sanmina-SCI eShield ___ _ - 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 __ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email __
RE: comment in UL file
From: Brian O'Connell Sent: Tuesday, March 13, 2007 12:48 PM In an OBMW2 (UL) file, this comment is attached to one of the wire types: Additional consideration is needed before its use in System's thermal aging. Brian - Looks like it's a catch-all flag. It doesn't appear to be specific to any construction method or ANSI type. I did a search on OBMW2, modified by the keywords Additional considerations. I found a mixture of information and noninformation. For some, the thermal index is better than 200°C, was specifically cited, while others with 155 C ratings had the more generic statement, and still others that had 130 C, 155 C and 200 C wire types where the statement only applied top the 130 C and 155 C wire. Still another stated, ... because results of the evaluation of this magnet wire indicate a higher temperature classification than required for this ANSI type. I expect that the shortest route to finding out what the statement means in your specific case, is to have to talk to the manufacturer to get a copy of their Conditions of Acceptability for that magnet wire. If you wait for UL to say anything, it's a good bet that it'll be protected as proprietary and UL won't be able to say anything. Regards, Peter L. Tarver, PE ptar...@ieee.org CONFIDENTIALITY This e-mail message and any attachments thereto, is intended only for use by the addressee(s) named herein and may contain legally privileged and/or confidential information. If you are not the intended recipient of this e-mail message, you are hereby notified that any dissemination, distribution or copying of this e-mail message, and any attachments thereto, is strictly prohibited. If you have received this e-mail message in error, please immediately notify the sender and permanently delete the original and any copies of this email and any prints thereof. ABSENT AN EXPRESS STATEMENT TO THE CONTRARY HEREINABOVE, THIS E-MAIL IS NOT INTENDED AS A SUBSTITUTE FOR A WRITING. Notwithstanding the Uniform Electronic Transactions Act or the applicability of any other law of similar substance and effect, absent an express statement to the contrary hereinabove, this e-mail message its contents, and any attachments hereto are not intended to represent an offer or acceptance to enter into a contract and are not otherwise intended to bind the sender, Sanmina-SCI Corporation (or any of its subsidiaries), or any other person or entity. _ Scanned by Sanmina-SCI eShield ___ _ - 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 __ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email __
ITE Product Certification South, Central America and the Caribbean
Good day Does anyone know where I can find Regulatory Information for marketing and importing, Disk Storage Arrays into Central and South American Countries, plus the Caribbean nations? Regards Roger Anderson EqualLogic, Inc. 9 Townsend West Nashua, NH 03063 U.S.A. Phone 1-603-249-7781 __ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email __ - 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
comment in UL file
In an OBMW2 (UL) file, this comment is attached to one of the wire types: Additional consideration is needed before its use in System's thermal aging. While I am waiting for the usual 5 to 20 day reply time from an agency engineer, could someone please advise if this means anything speacil to its use in an UL-recognized Electrical Insulation System ? Thanks much. luck, Brian - 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 __ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email __
RE: OT: standard component values
From: John Woodgate [mailto:j...@jmwa.demon.co.uk] Sent: Tuesday, March 13, 2007 9:20 AM To: emc-p...@ieee.org Subject: Re: OT: standard component values In message be3336be85968d49be01e66d6e365b1e01b59...@sjc1amfpew01.am.sanm.corp, dated Tue, 13 Mar 2007, Tarver, Peter peter.tar...@sanmina-sci.com writes: Or maybe there's a mathematical reason that hasn't occurred to me, like some arithmetic progression, or even simple phobias or prejudices. Ah, you youngsters! (Strokes long, white beard.) It's based on geometric progression and it's about selling all the parts you make, Yes, there is mathematical beauty and logic behind it all, and I'm sure I figured out those odd value progressions by about 8th grade (when I was first confronted with storing and organizing all those resistors and capacitors I had recovered out of scrapped consumer electronic gadgets). Yeah, it made sense, even if it made the electrical design math a bit harder (pre-calculator days, stroking short white beard). Yet I never understood the real beauty until I started making paper and plastic film capacitors. I remember one day watching capacitors go through an automated sort, the bins filling with 1% 5% 10% 20%. I was struck by the realization that this test could have NO FAILURES, or practically, I could sell ever darn one of those things! And then it hit me that 1% parts aren't inherently better, they're just better known. And just because of that, I could charge lot's more for the parts that fell into the 1% bin. Sweet! I was truly standing on the shoulders of giants! Thanks for the system, guys! Ed Price mailto:ed.pr...@cubic.com ed.pr...@cubic.com NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (FAX) Military Avionics EMC Is Our Specialty __ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email __ - 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: Creepage on PCB acc to 60950-1
Determine installation environment, measure Working V, add I.T. safety standard, stir well. For a SMPS, only the MINIMUM creepage is determined by the rated input V; otherwise is determined by empirical measurements of the WV across a particular dim. 60950:1999 is obsolete. R/S, Brian -Original Message- From: emc-p...@ieee.org [mailto:emc-p...@ieee.org]On Behalf Of Amund Westin Sent: Tuesday, March 13, 2007 9:13 AM To: emc-p...@ieee.org Subject: Creepage on PCB acc to 60950-1 Trying to find out the different required creepage distances on a PCB (it's an AC/DC PSU) where the primary voltage is 230VAC avd secondary voltage is 24VDC. Interested in creepage distances 1) primary to secondary on the PBC 2) Primary to chassis 3) Secondary to chassis 4) Between primary leads on the PCB I have the 60950:1999 in front of me and a lot of creepage tables in chapter 2.10.4. Anyone out there who could give me a short guidance how to interpret the tables in my case? Thanks. #Amund - 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 __ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email __
RE: Creepage on PCB acc to 60950-1
From: Amund Westin Sent: Tuesday, March 13, 2007 10:13 AM Interested in creepage distances 1) primary to secondary on the PBC 2) Primary to chassis 3) Secondary to chassis 4) Between primary leads on the PCB I have the 60950:1999 in front of me and a lot of creepage tables in chapter 2.10.4. Anyone out there who could give me a short guidance how to interpret the tables in my case? Amund - There are too many things to take into consideration and your description doe not encompass all possibilities. I can only recommend to read all of §2.10 and Annex F. Regards, Peter L. Tarver, PE ptar...@ieee.org CONFIDENTIALITY This e-mail message and any attachments thereto, is intended only for use by the addressee(s) named herein and may contain legally privileged and/or confidential information. If you are not the intended recipient of this e-mail message, you are hereby notified that any dissemination, distribution or copying of this e-mail message, and any attachments thereto, is strictly prohibited. If you have received this e-mail message in error, please immediately notify the sender and permanently delete the original and any copies of this email and any prints thereof. ABSENT AN EXPRESS STATEMENT TO THE CONTRARY HEREINABOVE, THIS E-MAIL IS NOT INTENDED AS A SUBSTITUTE FOR A WRITING. Notwithstanding the Uniform Electronic Transactions Act or the applicability of any other law of similar substance and effect, absent an express statement to the contrary hereinabove, this e-mail message its contents, and any attachments hereto are not intended to represent an offer or acceptance to enter into a contract and are not otherwise intended to bind the sender, Sanmina-SCI Corporation (or any of its subsidiaries), or any other person or entity. _ Scanned by Sanmina-SCI eShield ___ _ - 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 __ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email __
Creepage on PCB acc to 60950-1
Trying to find out the different required creepage distances on a PCB (it's an AC/DC PSU) where the primary voltage is 230VAC avd secondary voltage is 24VDC. Interested in creepage distances 1) primary to secondary on the PBC 2) Primary to chassis 3) Secondary to chassis 4) Between primary leads on the PCB I have the 60950:1999 in front of me and a lot of creepage tables in chapter 2.10.4. Anyone out there who could give me a short guidance how to interpret the tables in my case? Thanks. #Amund - 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 __ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email __
Re: standard component values
In message a7769e7222893043ae07d32e8d2254556b1...@bssexc06.aei.com, dated Tue, 13 Mar 2007, Powell, Doug doug.pow...@aei.com writes: Years ago, I even had a program for my HP-67 calculator that would take a desired value and show me the nearest standard value. There is a small app at: http://www.miscel.dk/MiscEl/miscel.html which does a lot more than that. I'm just a satisfied user. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk There are benefits from being irrational - just ask the square root of 2. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to 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 __ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email __
Re: OT: standard component values
In message be3336be85968d49be01e66d6e365b1e01b59...@sjc1amfpew01.am.sanm.corp, dated Tue, 13 Mar 2007, Tarver, Peter peter.tar...@sanmina-sci.com writes: Or maybe there's a mathematical reason that hasn't occurred to me, like some arithmetic progression, or even simple phobias or prejudices. Ah, you youngsters! (Strokes long, white beard.) It's based on geometric progression and it's about selling all the parts you make, with the fewest nominal values, even if the process results in a wide spread of values. It's simplest to explain if we go back to the agricultural tolerances on component values of 50 years and more ago. Then, the closest sensible tolerance available on carbon composition resistor values was +/-10%. +/- 5% parts were available, but values tended to drift with age more than that. OK, so a 1 k resistor could be as high as 1.1 k. If that is also the lowest limit for the next nominal value, that nominal value is 1.22 k, rounded to 1.2 k. And the next is 1.2 x 1.1/0.9 = 1.47 k, rounded to 1.5 k. The next is 1.8 k, and then 2.2 k, but if you carry on too far in that way, you find anomalies; a ratio of 1.2 gives values lower than the actual '10%' series, while 1.22 gives higher values. The reasons are often disputed, and I'm not going there, thank you. Another way of looking at it is that successive values are multiplied by the 12th root of 10, 1.211.., but that doesn't fit exactly, either. But you can now see the basic principle. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk There are benefits from being irrational - just ask the square root of 2. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to 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 __ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email __
RE: standard component values
Take E12 series - 12 values based on 10^1/12 = 1.212 - you calculate the next value by multiplying the last by this number 1.212 and rounding thus: 1.0 1.0 x 1.212 = 1.2 1.212 x 1.212 = 1.47 = 1.5 1.47 x 1.212 = 1.78 = 1.8 Regards, Chris From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Barker, Neil Sent: 13 March 2007 15:34 To: 'Tarver, Peter'; PSTC 1 Subject: RE: standard component values Peter, My understanding is that each series, E12, E24, etc increments approximately according to the corresponding tolerance such that adjacent values approximately meet at the upper tolerance of one value and the lower tolerance of the next greater value. This is rounded off to the nearest integer value, hence 10, 12, 15, 18, 22, etc for a tolerance of ±10%; i.e. E12 series for ±10%, E24 series for ±5%, and so on. Best regards Neil R. Barker CEng MIET FSEE MIEEE Manager Quality Engineering e2v technologies (uk) ltd 106 Waterhouse Lane Chelmsford Essex CM1 2QU UK Tel: (+44) 1245 453616 Fax: (+44) 1245 453571 Mob: (+44) 7801 723735 P Please consider the environment before printing this email. From: Tarver, Peter [mailto:peter.tar...@sanmina-sci.com] Sent: 13 March 2007 15:24 To: PSTC 1 Subject: OT: standard component values An off-topic question that hopefully someone can shed a little light upon. I have wondered for as long as I've been involved in things electrical, why standard component values are what they are. Text books are of no use and I've done more than a few internet searches on this in the last ten years (or so; maybe I've used the wrong search terms, but I haven't found an answer). I'm interested to hear what others might know or think about this arcane topic. It's probably lost to history now, but it may well be based on some limitations of physical characteristics of early devices or one manufacturer dominating the early production of components and they had some idea that they could sell more components if they were in strange increments. Or maybe there's a mathematical reason that hasn't occurred to me, like some arithmetic progression, or even simple phobias or prejudices. Maybe someone gave it the deepest thought and surmised that particular values would yield the minimum of mixing of components in series/parallel combinations. Maybe they're still laughing from the grave. Regards, Peter L. Tarver ptar...@ieee.org CONFIDENTIALITY This e-mail message and any attachments thereto, is intended only for use by the addressee(s) named herein and may contain legally privileged and/or confidential information. If you are not the intended recipient of this e-mail message, you are hereby notified that any dissemination, distribution or copying of this e-mail message, and any attachments thereto, is strictly prohibited. If you have received this e-mail message in error, please immediately notify the sender and permanently delete the original and any copies of this email and any prints thereof. ABSENT AN EXPRESS STATEMENT TO THE CONTRARY HEREINABOVE, THIS E-MAIL IS NOT INTENDED AS A SUBSTITUTE FOR A WRITING. Notwithstanding the Uniform Electronic Transactions Act or the applicability of any other law of similar substance and effect, absent an express statement to the contrary hereinabove, this e-mail message its contents, and any attachments hereto are not intended to represent an offer or acceptance to enter into a contract and are not otherwise intended to bind the sender, Sanmina-SCI Corporation (or any of its subsidiaries), or any other person or entity. _ Scanned by Sanmina-SCI eShield _ - 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 Sent by E2V TECHNOLOGIES PLC or a member of the E2V group of companies. A company registered in England and Wales. Company number: 04439718. Registered address: 106 Waterhouse Lane, Chelmsford, Essex, CM1 2QU, UK. - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules:
RE: standard component values
Peter, My understanding is that each series, E12, E24, etc increments approximately according to the corresponding tolerance such that adjacent values approximately meet at the upper tolerance of one value and the lower tolerance of the next greater value. This is rounded off to the nearest integer value, hence 10, 12, 15, 18, 22, etc for a tolerance of ±10%; i.e. E12 series for ±10%, E24 series for ±5%, and so on. Best regards Neil R. Barker CEng MIET FSEE MIEEE Manager Quality Engineering e2v technologies (uk) ltd 106 Waterhouse Lane Chelmsford Essex CM1 2QU UK Tel: (+44) 1245 453616 Fax: (+44) 1245 453571 Mob: (+44) 7801 723735 P Please consider the environment before printing this email. From: Tarver, Peter [mailto:peter.tar...@sanmina-sci.com] Sent: 13 March 2007 15:24 To: PSTC 1 Subject: OT: standard component values An off-topic question that hopefully someone can shed a little light upon. I have wondered for as long as I've been involved in things electrical, why standard component values are what they are. Text books are of no use and I've done more than a few internet searches on this in the last ten years (or so; maybe I've used the wrong search terms, but I haven't found an answer). I'm interested to hear what others might know or think about this arcane topic. It's probably lost to history now, but it may well be based on some limitations of physical characteristics of early devices or one manufacturer dominating the early production of components and they had some idea that they could sell more components if they were in strange increments. Or maybe there's a mathematical reason that hasn't occurred to me, like some arithmetic progression, or even simple phobias or prejudices. Maybe someone gave it the deepest thought and surmised that particular values would yield the minimum of mixing of components in series/parallel combinations. Maybe they're still laughing from the grave. Regards, Peter L. Tarver ptar...@ieee.org CONFIDENTIALITY This e-mail message and any attachments thereto, is intended only for use by the addressee(s) named herein and may contain legally privileged and/or confidential information. If you are not the intended recipient of this e-mail message, you are hereby notified that any dissemination, distribution or copying of this e-mail message, and any attachments thereto, is strictly prohibited. If you have received this e-mail message in error, please immediately notify the sender and permanently delete the original and any copies of this email and any prints thereof. ABSENT AN EXPRESS STATEMENT TO THE CONTRARY HEREINABOVE, THIS E-MAIL IS NOT INTENDED AS A SUBSTITUTE FOR A WRITING. Notwithstanding the Uniform Electronic Transactions Act or the applicability of any other law of similar substance and effect, absent an express statement to the contrary hereinabove, this e-mail message its contents, and any attachments hereto are not intended to represent an offer or acceptance to enter into a contract and are not otherwise intended to bind the sender, Sanmina-SCI Corporation (or any of its subsidiaries), or any other person or entity. _ Scanned by Sanmina-SCI eShield _ - 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 Sent by E2V TECHNOLOGIES PLC or a member of the E2V group of companies. A company registered in England and Wales. Company number: 04439718. Registered address: 106 Waterhouse Lane, Chelmsford, Essex, CM1 2QU, UK. - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to 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: OT: standard component values
The standard resistor values are selected to ensure that any resistor manufactured can be marked as a valid part and sold. For 5% resistors, each value is approximately 10% larger than the previous value. Anything between 9.5 and 10.5 could be called 10 within 5%. Likewise, the 1% resistor values are 2% apart. Common capacitor values are more widely spaced because the tolerance on cheap ceramic capacitors is poor. For these, each value is 50% larger than the last. If you buy capacitors with a 5% tolerance, the values will be 10% apart. The scales for 5% tolerance components start at 1 and go up 10% at a time. There is some rounding at the low end, for example where you go from 1.6 to 1.8. Ted Eckert American Power Conversion/MGE http://www.apc-mge.com/ The items contained in this e-mail reflect the personal opinions of the writer and are only provided for the assistance of the reader. The writer is not speaking in an official capacity for APC, MGE or Schneider Electric. The speaker does not represent APC's, MGE's or Schneider Electric's official position on any matter. Tarver, Peter peter.tarver@san mina-sci.com To Sent by: PSTC 1 emc-p...@ieee.org emc-p...@ieee.org cc Subject 03/13/2007 10:24 OT: standard component values AM An off-topic question that hopefully someone can shed a little light upon. I have wondered for as long as I've been involved in things electrical, why standard component values are what they are. Text books are of no use and I've done more than a few internet searches on this in the last ten years (or so; maybe I've used the wrong search terms, but I haven't found an answer). I'm interested to hear what others might know or think about this arcane topic. It's probably lost to history now, but it may well be based on some limitations of physical characteristics of early devices or one manufacturer dominating the early production of components and they had some idea that they could sell more components if they were in strange increments. Or maybe there's a mathematical reason that hasn't occurred to me, like some arithmetic progression, or even simple phobias or prejudices. Maybe someone gave it the deepest thought and surmised that particular values would yield the minimum of mixing of components in series/parallel combinations. Maybe they're still laughing from the grave. Regards, Peter L. Tarver ptar...@ieee.org CONFIDENTIALITY This e-mail message and any attachments thereto, is intended only for use by the addressee(s) named herein and may contain legally privileged and/or confidential information. If you are not the intended recipient of this e-mail message, you are hereby notified that any dissemination, distribution or copying of this e-mail message, and any attachments thereto, is strictly prohibited. If you have received this e-mail message in error, please immediately notify the sender and permanently delete the original and any copies of this email and any prints thereof. ABSENT AN EXPRESS STATEMENT TO THE CONTRARY HEREINABOVE, THIS E-MAIL IS NOT INTENDED AS A SUBSTITUTE FOR A WRITING. Notwithstanding the Uniform Electronic Transactions Act or the applicability of any other law of similar substance and effect, absent an express statement to the contrary hereinabove, this e-mail message its contents, and any attachments hereto are not intended to represent an offer or acceptance to enter into a contract and are not otherwise intended to bind the sender, Sanmina-SCI Corporation (or any of its subsidiaries), or any other person or entity. _ Scanned by Sanmina-SCI eShield _ - 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
RE: standard component values
Quote: These values were supposed to have been derived from the mathematical series of equally spacing values logarithmically for each decade. http://www.eng-tips.com/viewthread.cfm?qid=71035page=5 Dave Cuthbert Linear Technology From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Tarver, Peter Sent: Tuesday, March 13, 2007 9:24 AM To: PSTC 1 Subject: OT: standard component values An off-topic question that hopefully someone can shed a little light upon. I have wondered for as long as I've been involved in things electrical, why standard component values are what they are. Text books are of no use and I've done more than a few internet searches on this in the last ten years (or so; maybe I've used the wrong search terms, but I haven't found an answer). I'm interested to hear what others might know or think about this arcane topic. It's probably lost to history now, but it may well be based on some limitations of physical characteristics of early devices or one manufacturer dominating the early production of components and they had some idea that they could sell more components if they were in strange increments. Or maybe there's a mathematical reason that hasn't occurred to me, like some arithmetic progression, or even simple phobias or prejudices. Maybe someone gave it the deepest thought and surmised that particular values would yield the minimum of mixing of components in series/parallel combinations. Maybe they're still laughing from the grave. Regards, Peter L. Tarver ptar...@ieee.org CONFIDENTIALITY This e-mail message and any attachments thereto, is intended only for use by the addressee(s) named herein and may contain legally privileged and/or confidential information. If you are not the intended recipient of this e-mail message, you are hereby notified that any dissemination, distribution or copying of this e-mail message, and any attachments thereto, is strictly prohibited. If you have received this e-mail message in error, please immediately notify the sender and permanently delete the original and any copies of this email and any prints thereof. ABSENT AN EXPRESS STATEMENT TO THE CONTRARY HEREINABOVE, THIS E-MAIL IS NOT INTENDED AS A SUBSTITUTE FOR A WRITING. Notwithstanding the Uniform Electronic Transactions Act or the applicability of any other law of similar substance and effect, absent an express statement to the contrary hereinabove, this e-mail message its contents, and any attachments hereto are not intended to represent an offer or acceptance to enter into a contract and are not otherwise intended to bind the sender, Sanmina-SCI Corporation (or any of its subsidiaries), or any other person or entity. _ Scanned by Sanmina-SCI eShield _ - 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 - 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 __ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email __
OT: standard component values
An off-topic question that hopefully someone can shed a little light upon. I have wondered for as long as I've been involved in things electrical, why standard component values are what they are. Text books are of no use and I've done more than a few internet searches on this in the last ten years (or so; maybe I've used the wrong search terms, but I haven't found an answer). I'm interested to hear what others might know or think about this arcane topic. It's probably lost to history now, but it may well be based on some limitations of physical characteristics of early devices or one manufacturer dominating the early production of components and they had some idea that they could sell more components if they were in strange increments. Or maybe there's a mathematical reason that hasn't occurred to me, like some arithmetic progression, or even simple phobias or prejudices. Maybe someone gave it the deepest thought and surmised that particular values would yield the minimum of mixing of components in series/parallel combinations. Maybe they're still laughing from the grave. Regards, Peter L. Tarver ptar...@ieee.org CONFIDENTIALITY This e-mail message and any attachments thereto, is intended only for use by the addressee(s) named herein and may contain legally privileged and/or confidential information. If you are not the intended recipient of this e-mail message, you are hereby notified that any dissemination, distribution or copying of this e-mail message, and any attachments thereto, is strictly prohibited. If you have received this e-mail message in error, please immediately notify the sender and permanently delete the original and any copies of this email and any prints thereof. ABSENT AN EXPRESS STATEMENT TO THE CONTRARY HEREINABOVE, THIS E-MAIL IS NOT INTENDED AS A SUBSTITUTE FOR A WRITING. Notwithstanding the Uniform Electronic Transactions Act or the applicability of any other law of similar substance and effect, absent an express statement to the contrary hereinabove, this e-mail message its contents, and any attachments hereto are not intended to represent an offer or acceptance to enter into a contract and are not otherwise intended to bind the sender, Sanmina-SCI Corporation (or any of its subsidiaries), or any other person or entity. _ Scanned by Sanmina-SCI eShield ___ _ - 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 __ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email __
China CNCA 2007 Notice No. 8
To Those Who are Interested in: The following two standards took effect March 1, 2007. GB 7251.2-2006 ( IEC 60439-2:2000) 低压成套开关设备和控制设备 第2部分：对母线干线系统(母线槽)的特殊要求 Low-voltage switchgear and controlgear assemblies—Part 2:Particular requirements for busbar trunking systems (busways) GB 7251.3-2006 ( IEC 60439-3:2001) 低压成套开关设备和控制设备 第3部分:对非专业人员可进入� �地的低压成套开关设备和控制设备——配电板的特殊要求 Low-voltage switchgear and controlgear assemblies—Part 3:Particular requirements for low-voltage switchgear and controlgear assemblies intended to be installed in places where unskilled persons have access for their use—Distribution boards 1. Starting effective date, all designated certification organizations and test laboratories must adopt the new versions of the standards for certification and testing. 2. For certified products with complete test reports issued based on the old versions of the standards, the certificate holders should submit requests to the certification center to transfer the certificates before the next follow-up inspection, no later than May 31, 2008. The new added test items must be tested. 3. For those products obtaining CCC certification through CCEE, CCIB, and production permission, and without complete CCC test reports, they need to be tested based on the new versions of the standards. All missing data and information must be completed. The original text in Chinese can be located at http://www.cnca.gov.cn/cnca/zwxx/ggxx/13472.shtml. Regards, Grace Lin __ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email __
Re: Mercury in Flourescent Lamps
In message of317bf308.346aec2f-on8525729c.0069eb9a-8525729c.006aa...@hobartcorp.com , dated Mon, 12 Mar 2007, Richard Pittenger richard.pitten...@hobartcorp.com writes: I assume that some of you are involved with products such as back-lit LCD displays which use small fluorescent lamps for back-lighting. I'm working on a product that will be imported to the USA and it uses such a display. In this case the manufacturer won't reveal the amount of mercury in each lamp. I think that that refusal indicates that you should think about another source. Suppose you have a sample lamp analysed and get the result 5 mg. How do you know that the next batch doesn't have 20 mg? Bearing responsibility for a manufacturing process that is not only not under your control but about which you are specifically denied information is a recipe for trouble. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk There are benefits from being irrational - just ask the square root of 2. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to 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 __ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email __
