RE: Breakdown voltage between pcb layers
Hi David, We have some experience with this at my company, although not involving TNV circuits. My company produces high voltage, high frequency power conversion equipment mainly for the semiconductor manufacturing industry. We are constantly challenging the voltage withstand capabilities of materials, and pcb's are no exception. We use FR-4 pcb material, and for years we have used a voltage withstand guideline of 1000 V/mil for the base material and 500 V/mil for the pre-preg. As another responder has already noted, you should be able to get numbers for your specific material from your supplier. Once you have these numbers, you get to make some easy calculations. The way we do it is to take the required transient withstand voltage (based on the operating voltage and the installation category) and divide it by the voltage withstand guideline for the material in question. This will give you two numbers: one for base material and one for pre-preg. Since you are dividing V by V/mil, the results will be in mils. Now you know how thick the base and pre-preg layers must be. If you have just a two-layer board, the pre-preg number doesn't matter and you can stop reading here. If you have a multi-layer board, read on. . . . You must account for the copper on inner layers, since this subtracts from your insulating material in the z axis (vertical dimension). The guideline we use is 1.4 mils per ounce of copper. So if you're using 2 oz. copper, your trace will be about 2.8 mils high. This gets subtracted from the thickness of the pcb layer. If you calculated that you needed an 18 mil thick pre-preg layer, and you're using 2 oz. copper, you actually need a 21 mil thick pre-preg layer because of the copper thickness. Something to consider: To what tolerance can your pcb manufacturer hold layer thicknesses, especially pre-preg layers? Obviously this affects voltage withstand capability and should be taken into account when making your calculations. If you have through-hole parts or vias in the area of an inner layer ground plane, of course you need to think about inner layer x,y plane (lateral) creepage requirements. Generally speaking, inner layer creepage distances must be the same as outer layers -- but, there is a way around this that allows for reduced inner layer spacings. The trick is to classify the inner layer x,y plane dimensions as through-thickness insulation, owing to epoxy bonding. Then you can reduce the dimension to 0.4 mm in accordance with UL 1950. You may choose not to reduce to this level; we don't. We use 1 mm minimum. The gotcha is that your agency might insist that your pcb manufacturer be certified to UL 796 in order to allow this. (Ours did.) We have used these methods for several years now with great success and acceptance from various agencies. Jeff Jenkins Regulatory Compliance Advanced Energy Industries, Inc. Fort Collins, CO USA -Original Message- From: David Gelfand [mailto:gelf...@memotec.com] Sent: Tuesday, May 23, 2000 9:33 AM To: 'EMC-PSTC Internet Forum' Subject: Breakdown voltage between pcb layers Hello group, We have an emissions problem on a board and I would like to suggest a ground plane in the area of an RJ-45 jack (TNV-1). But we have always asked our PCB designers to leave TNV traces free of ground and power planes to avoid arcing during surge and dialectric strength tests. Does anyone know where to find specs on breakdown voltages between PCB layers? Has anyone successfully used ground planes above or below TNV traces? We are testing to UL1950 and Part 68. Any input would be much appreciated. Thank you, David. David Gelfand Regulatory Approvals Group Leader Memotec Communications Inc. Montreal Canada --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
RE: Fwd:RTTE directive
Hi Jim, Try the following link. http://www.tsacc.ic.gc.ca/MRA/BlueGuide.pdf My 2 Cents and not that of my current employer. Regards, Kaz Gawrzyjal, P. Eng. Product Safety Engineer -- Nortel Networks-Wireless Solutions Wireless Development Centre 2924 11 Street NE Calgary, Alberta Canada, T2E 7L7 tel:403-232-4805 (ESN 765) fax:403-232-4813 (ESN 765) e-mail: k...@nortelnetworks.com -Original Message- From: Allan, James [mailto:james_al...@milgo.com] Sent: Tuesday, May 23, 2000 1:01 PM To: emc-p...@majordomo.ieee.org Subject: RE: Fwd:RTTE directive Does anyone have a link to a copy of the Blue Guide mentioned by Tony below? Jim Allan Senior Compliance Engineer Milgo Solutions Inc. E-mail james_al...@milgo.com -Original Message- From: Tony Reynolds [SMTP:reyno...@pb.com] Sent: Tuesday, May 23, 2000 10:56 AM To: k...@i-data.com; emc-p...@majordomo.ieee.org; jim_bac...@mail.monarch.com Subject: Re: Fwd:RTTE directive Kim, According to the information I have on the RTTE Directive (99/5/EC) the following applies to the Declaration of Conformity. 'There is ONE Declaration of Conformity. It is held by the manufacturer with the technical file for the product. The standard EN45014 is an accepted model for the DoC, referred to in the Blue Guide*, therefore manufacturers would seem to have no good reason not to use this model. The DoC is signed by the manufacturer, and is expected to be in the language used by the manufacturer (and understood by the signatory). A COPY of the DoC (in its original language) must accompany every product.' *This is a guide to the implementation of Directives based on the New Approach and Global Approach (EC Doc Certif 98/1) also known as the 'Blue Guide'. This information was on a DTI FAQ paper recently distributed at a TAPC meeting. I hope this helps. Kind Regards Tony Reynolds Principal Compliance Engineer Pitney Bowes Ltd The Pinnacles Harlow Essex. CM19 5BD UK Tel +44 (0) 1279 449479 Fax +44 (0) 1279 449118 e-mail: reyno...@pb.com --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
RE: Fwd:RTTE directive
Hello Jim, Just visit the Safety Link www.safetylink.com, drop down to the Safety Articles, FAQs, MRAs, etc subsection and the third link there, titled, Guide to the Implementation of Directives Based On A New Approach and Global Approach will take you to a website with this document in a variety of formats. Or, to shorten the process, once at the Safety Link, just search on the term Implementation Note that the above document, issued in 1999, replaces Certif 98/1 Draft also known as the Blue Guide. Regards, Art Michael, Editor - Int'l Product Safety News * * * * * * * * * * * * * * * * * * * * * * * International Product Safety Bookshop * * Check out our current offerings! * * http://www.safetylink.com/bookshop.html * * * * Now offering BSI's Books Reports* * including, World Electricity Supplies * * * * Another service of the Safety Link* * www.safetylink.com * * * * * * * * * * * * * * * * * * * * * * * On Tue, 23 May 2000, Allan, James wrote: Does anyone have a link to a copy of the Blue Guide mentioned by Tony below? Jim Allan Senior Compliance Engineer Milgo Solutions Inc. E-mail james_al...@milgo.com -Original Message- From: Tony Reynolds [SMTP:reyno...@pb.com] Sent: Tuesday, May 23, 2000 10:56 AM To: k...@i-data.com; emc-p...@majordomo.ieee.org; jim_bac...@mail.monarch.com Subject:Re: Fwd:RTTE directive Kim, According to the information I have on the RTTE Directive (99/5/EC) the following applies to the Declaration of Conformity. 'There is ONE Declaration of Conformity. It is held by the manufacturer with the technical file for the product. The standard EN45014 is an accepted model for the DoC, referred to in the Blue Guide*, therefore manufacturers would seem to have no good reason not to use this model. The DoC is signed by the manufacturer, and is expected to be in the language used by the manufacturer (and understood by the signatory). A COPY of the DoC (in its original language) must accompany every product.' *This is a guide to the implementation of Directives based on the New Approach and Global Approach (EC Doc Certif 98/1) also known as the 'Blue Guide'. This information was on a DTI FAQ paper recently distributed at a TAPC meeting. I hope this helps. Kind Regards Tony Reynolds Principal Compliance Engineer Pitney Bowes Ltd The Pinnacles Harlow Essex. CM19 5BD UK Tel +44 (0) 1279 449479 Fax +44 (0) 1279 449118 e-mail: reyno...@pb.com --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
interference to Comm devices due to overhead catenaries
Could anyone provide any information relative to overhead catenary noise and its affects on locomotive roof top comm systems (e.g., GPS)? Susan Beard --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
[SI-LIST] : RE: Charge moving from decoupling capacitors
Barry, The current can flow from the cap, but it will get to the IC at the wrong time. Regards, George george_t...@dell.com -Original Message- From: Barry Ma [mailto:barry...@altavista.com] Sent: Tuesday, May 23, 2000 10:22 AM To: george_t...@exchange.dell.com Cc: si-l...@silab.eng.sun.com; emc-p...@ieee.org Subject: RE: Charge moving from decoupling capacitors George, I am impressed by your attitude to pursue the correctness, and glad to discuss with you further on “How does a decoupling capacitor support an IC?” Here is my two cents worth. The decap supplies necessary charge to the IC during Tr through a transmission line. As you mentioned before: “The current is an impulse function, although the voltage waveform is a step function.” This impulse function, actually a bell-like function on Tr, happens every time period T when the IC gate switches from low to high. The corresponding frequency spectrum contains lots of frequencies. There must be some frequencies making the transmission line a 1/4, 3/4, ... wavelength. It is hard for me to be convinced that currents of those frequencies cannot flow from the decap to the IC. ... Pleas correct me if misunderstood. Thanks. Regards, Barry Ma b...@anritsu.com On Mon, 22 May 2000, george_t...@dell.com wrote: Barry, I need to make a correction. I was rushing to lunch on Thursday, so I did not read over what I wrote. Here is the correction for the 2nd comment below: At 1/4 wavelength, the charges are 180 degrees out of phase, so they are working against the IC current draw. 1/8 wavelength (90 degrees out of phase) is what I consider to be acceptable. Regards, George Tang george_t...@dell.com ___ Why pay when you don't have to? Get AltaVista Free Internet Access now! http://jump.altavista.com/freeaccess4.go ___ --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org To unsubscribe from si-list or si-list-digest: send e-mail to majord...@silab.eng.sun.com. In the BODY of message put: UNSUBSCRIBE si-list or UNSUBSCRIBE si-list-digest, for more help, put HELP. si-list archives are accessible at http://www.qsl.net/wb6tpu
RE: Fwd:RTTE directive
Does anyone have a link to a copy of the Blue Guide mentioned by Tony below? Jim Allan Senior Compliance Engineer Milgo Solutions Inc. E-mail james_al...@milgo.com -Original Message- From: Tony Reynolds [SMTP:reyno...@pb.com] Sent: Tuesday, May 23, 2000 10:56 AM To: k...@i-data.com; emc-p...@majordomo.ieee.org; jim_bac...@mail.monarch.com Subject: Re: Fwd:RTTE directive Kim, According to the information I have on the RTTE Directive (99/5/EC) the following applies to the Declaration of Conformity. 'There is ONE Declaration of Conformity. It is held by the manufacturer with the technical file for the product. The standard EN45014 is an accepted model for the DoC, referred to in the Blue Guide*, therefore manufacturers would seem to have no good reason not to use this model. The DoC is signed by the manufacturer, and is expected to be in the language used by the manufacturer (and understood by the signatory). A COPY of the DoC (in its original language) must accompany every product.' *This is a guide to the implementation of Directives based on the New Approach and Global Approach (EC Doc Certif 98/1) also known as the 'Blue Guide'. This information was on a DTI FAQ paper recently distributed at a TAPC meeting. I hope this helps. Kind Regards Tony Reynolds Principal Compliance Engineer Pitney Bowes Ltd The Pinnacles Harlow Essex. CM19 5BD UK Tel +44 (0) 1279 449479 Fax +44 (0) 1279 449118 e-mail: reyno...@pb.com --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
FW: RTTE directive
--
From: Corinne SALINGRE [SMTP:corinne.salin...@cstelecom.com]
mailto:[SMTP:corinne.salin...@cstelecom.com]
Sent: Tuesday, May 23, 2000 1:25 PM
To: wo...@sensormatic.com mailto:wo...@sensormatic.com
Subject: Re: RTTE directive
This is a very 'touchy' discussion matter now in Brussels...
Main points :
* difference between 'a' declaration of conformity (writing indicating
that the product is in compliance with the essentail requirements of the
RTTE directive) and 'the' DoC (copy of the original) to be included in the
package : this makes a great difference ('a' DoC can be written in advance,
'the' DoC is often signed in the latest moment ...)
* 'a' DoC can be in the same language than the notice it is included
in, 'the' DoC will be in one (or 1+english) language (the language of the
manufacturer + eventually english). My boss will not signed a paper in 12
languages (and especially if he does not understand what he is signing !)
Even if a decision is made in Brussels, remember that only the local law is
applicable in one country. So some countries can require that 'a' or 'the'
DoC included in the package to be in their language.
Where is harmonization ?
Wait and see ...
Corinne Salingre
CS TELECOM, France
wo...@sensormatic.com mailto:wo...@sensormatic.com a écrit :
I don't recall reading anything in the directive that indicates
the DoC must
be in multiple languages. If you know otherwise, please specify
the section
number.
Richard Woods
--
From: jim_bac...@mail.monarch.com
mailto:jim_bac...@mail.monarch.com
[SMTP:jim_bac...@mail.monarch.com]
mailto:[SMTP:jim_bac...@mail.monarch.com]
Sent: Tuesday, May 23, 2000 8:04 AM
To: k...@i-data.com; mailto:k...@i-data.com;
emc-p...@majordomo.ieee.org mailto:emc-p...@majordomo.ieee.org
Subject: Fwd:RTTE directive
forwarded for Kim.
Reply Separator
Subject: RTTE directive
Author: k...@i-data.com mailto:k...@i-data.com
Date: 5/23/00 12:12 PM
Dear all
According to the new RTTE directive we will have to
supply our
Declaration
of Conformity in all EU languages.
Is RTTE accepted as a reference in all languages or do I
need to
translate
it ?
If I need to translate do anyone know an easy way to do
this ?
Best regards,
Kim Boll Jensen
i-data international
Denmark
P.S. The danish translation is: Rådets direktiv om Radio
og
Teleterminaludstyr 1999/5/EF
---
This message is from the IEEE EMC Society Product Safety
Technical Committee emc-pstc discussion list.
To cancel your subscription, send mail to:
majord...@ieee.org mailto:majord...@ieee.org
with the single line:
unsubscribe emc-pstc
For help, send mail to the list administrators:
Jim Bacher: jim_bac...@mail.monarch.com
mailto:jim_bac...@mail.monarch.com
Michael Garretson:pstc_ad...@garretson.org
mailto:pstc_ad...@garretson.org
For policy questions, send mail to:
Richard Nute: ri...@ieee.org
mailto:ri...@ieee.org
---
This message is from the IEEE EMC Society Product Safety
Technical Committee emc-pstc discussion list.
To cancel your subscription, send mail to:
majord...@ieee.org mailto:majord...@ieee.org
with the single line:
unsubscribe emc-pstc
For help, send mail to the list administrators:
Jim Bacher: jim_bac...@mail.monarch.com
mailto:jim_bac...@mail.monarch.com
Michael Garretson:pstc_ad...@garretson.org
mailto:pstc_ad...@garretson.org
For policy questions, send mail to:
Richard Nute: ri...@ieee.org
mailto:ri...@ieee.org
---
This message is from the IEEE EMC Society Product Safety
Technical Committee emc-pstc discussion list.
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:
Jim Bacher: jim_bac...@mail.monarch.com
Michael Garretson:
RE: Charge moving from decoupling capacitors
George, I am impressed by your attitude to pursue the correctness, and glad to discuss with you further on How does a decoupling capacitor support an IC? Here is my two cents worth. The decap supplies necessary charge to the IC during Tr through a transmission line. As you mentioned before: The current is an impulse function, although the voltage waveform is a step function. This impulse function, actually a bell-like function on Tr, happens every time period T when the IC gate switches from low to high. The corresponding frequency spectrum contains lots of frequencies. There must be some frequencies making the transmission line a 1/4, 3/4, ... wavelength. It is hard for me to be convinced that currents of those frequencies cannot flow from the decap to the IC. ... Pleas correct me if misunderstood. Thanks. Regards, Barry Ma b...@anritsu.com On Mon, 22 May 2000, george_t...@dell.com wrote: Barry, I need to make a correction. I was rushing to lunch on Thursday, so I did not read over what I wrote. Here is the correction for the 2nd comment below: At 1/4 wavelength, the charges are 180 degrees out of phase, so they are working against the IC current draw. 1/8 wavelength (90 degrees out of phase) is what I consider to be acceptable. Regards, George Tang george_t...@dell.com ___ Why pay when you don't have to? Get AltaVista Free Internet Access now! http://jump.altavista.com/freeaccess4.go ___ --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
RE: Hazardous Infrared radiation ?
IEC60825-1 contains requirements for noncoherent infrared radiation. Likewise does EN60825-1, with Amendment A11. Regards, Peter L. Tarver, PE ptar...@nortelnetworks.com From: Israel Yeshurun [mailto:israel_yeshu...@creoscitex.com] Can some comment on this ? Can Infrared radiation (not Laser) be hazardous ? Obviously, high enough IR intensity should be hazardous. As the eye may not blink under exposure to IR (as the eye can not see it) the natural eye protection mechanism may not function. Any standards, guidelines available for permissible exposure limits to Infra red radiation ? Many thanks to every contribution ! with Best Regards, Israel Yeshurun. CreoScitex. Israel
RE: Breakdown voltage between pcb layers
David - You should be able to get a ballpark figure from your PCB manufacturer (need to consider the properties of the materials you may be using in the PCB). You could also scan the various safety standards for values, but these are upper limits, and therefore conservative. Regards, Mark Gill, P.E. EMC/Safety/NEBS Design Nortel Networks - RTP, NC, USA -Original Message- From: David Gelfand [SMTP:gelf...@memotec.com] Sent: Tuesday, May 23, 2000 11:33 AM To: 'EMC-PSTC Internet Forum' Subject: Breakdown voltage between pcb layers Hello group, We have an emissions problem on a board and I would like to suggest a ground plane in the area of an RJ-45 jack (TNV-1). But we have always asked our PCB designers to leave TNV traces free of ground and power planes to avoid arcing during surge and dialectric strength tests. Does anyone know where to find specs on breakdown voltages between PCB layers? Has anyone successfully used ground planes above or below TNV traces? We are testing to UL1950 and Part 68. Any input would be much appreciated. Thank you, David. David Gelfand Regulatory Approvals Group Leader Memotec Communications Inc. Montreal Canada --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Hazardous Infrared radiation - THANKS
Richard Woods, John Juhasz, Geoff Lister Thank you for your responses ! Best Regards, Israel Yeshurun. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Breakdown voltage between pcb layers
Hello group, We have an emissions problem on a board and I would like to suggest a ground plane in the area of an RJ-45 jack (TNV-1). But we have always asked our PCB designers to leave TNV traces free of ground and power planes to avoid arcing during surge and dialectric strength tests. Does anyone know where to find specs on breakdown voltages between PCB layers? Has anyone successfully used ground planes above or below TNV traces? We are testing to UL1950 and Part 68. Any input would be much appreciated. Thank you, David. David Gelfand Regulatory Approvals Group Leader Memotec Communications Inc. Montreal Canada --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
RE: RTTE directive
I don't recall reading anything in the directive that indicates the DoC must be in multiple languages. If you know otherwise, please specify the section number. Richard Woods -- From: jim_bac...@mail.monarch.com [SMTP:jim_bac...@mail.monarch.com] Sent: Tuesday, May 23, 2000 8:04 AM To: k...@i-data.com; emc-p...@majordomo.ieee.org Subject: Fwd:RTTE directive forwarded for Kim. Reply Separator Subject:RTTE directive Author: k...@i-data.com Date: 5/23/00 12:12 PM Dear all According to the new RTTE directive we will have to supply our Declaration of Conformity in all EU languages. Is RTTE accepted as a reference in all languages or do I need to translate it ? If I need to translate do anyone know an easy way to do this ? Best regards, Kim Boll Jensen i-data international Denmark P.S. The danish translation is: Rådets direktiv om Radio og Teleterminaludstyr 1999/5/EF --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
RE: Evaluation Boards
I had forwarded this to Vic upon receiving his request last week, but viewing some on the responses that I have seen, I feel it would be appropriate to put it out for general viewing. Look at 47 CFR § 2.803 Marketing of radio frequency devices prior to equipment authorization. (a) Except as provided elsewhere in this section, no person shall sell or lease, or offer for sale or lease (including advertising for sale or lease), or import, ship, or distribute for the purpose of selling or leasing or offering for sale or lease, any radio frequency device unless: (1) In the case of a device subject to certification, such device has been authorized by the Commission in accordance with the rules in this chapter and is properly identified and labeled as required by § 2.925 and other relevant sections in this chapter; or (2) In the case of a device that is not required to have a grant of equipment authorization issued by the Commission, but which must comply with the specified technical standards prior to use, such device also complies with all applicable administrative (including verification of the equipment or authorization under a Declaration of Conformity, where required), technical, labeling and identification requirements specified in this chapter. (b) The provisions of paragraph (a) of this section do not prohibit conditional sales contracts between manufacturers and wholesalers or retailers where de-livery is contingent upon compliance with the applicable equipment authorization and technical requirements, nor do they prohibit agreements between such parties to produce new products, manufactured in accordance with designated specifications. (c) Notwithstanding the provisions of paragraphs (a), (b), (d) and (f) of this section, a radio frequency device may be advertised or displayed, e.g., at a trade show or exhibition, prior to equipment authorization or, for devices not subject to the equipment authorization requirements, prior to a determination of compliance with the applicable technical requirements provided that the advertising contains, and the display is accompanied by, a conspicuous notice worded as follows: This device has not been authorized as required by the rules of the Federal Communications Commission. This device is not, and may not be, offered for sale or lease, or sold or leased, until authorization is obtained. (1) If the product being displayed is a prototype of a product that has been properly authorized and the prototype, itself, is not authorized due to differences between the prototype and the authorized product, the following disclaimer notice may be used in lieu of the notice stated in paragraph (c) introductory text of this section: Prototype. Not for sale. (2) Except as provided elsewhere in this chapter, devices displayed under the provisions of paragraphs (c) introductory text, and (c)(1) of this section may not be activated or operated. (d) Notwithstanding the provisions of paragraph (a) of this section, the offer for sale solely to business, commercial, industrial, scientific or medical users (but not an offer for sale to other par-ties or to end users located in a residential environment) of a radio frequency device that is in the conceptual, developmental, design or pre-production stage is permitted prior to equipment authorization or, for devices not subject to the equipment authorization requirements, prior to a determination of compliance with the applicable technical requirements provided that the prospective buyer is advised in writing at the time of the offer for sale that the equipment is subject to the FCC rules and that the equipment will comply with the appropriate rules be-fore delivery to the buyer or to centers of distribution. If a product is marketed in compliance with the provisions of this paragraph, the product does not need to be labeled with the statement in paragraph (c) of this section. (e)(1) Notwithstanding the provisions of paragraph (a) of this section, prior to equipment authorization or determination of compliance with the applicable technical requirements any radio frequency device may be operated, but not marketed, for the following purposes and under the following conditions: (i) Compliance testing; (ii) Demonstrations at a trade show provided the notice contained in paragraph (c) of this section is displayed in a conspicuous location on, or immediately adjacent to, the device; (iii) Demonstrations at an exhibition conducted at a business, commercial, industrial, scientific, or medical location, but excluding locations in a residential environment, provided the notice contained in paragraphs (c) or (d) Furthermore it would be wise to include an engineering data gathering request to be returned to you upon completion. Best regards, JOHN E. STUCKEY EMC Engineer Micron Technology, Inc. Integrated Products Group Micron Architectures Lab 8455 West Emerald St. Boise, Idaho 83704 PH: (208) 363-5313 FX: (208) 363-5596
Re: Fwd:RTTE directive
Kim, According to the information I have on the RTTE Directive (99/5/EC) the following applies to the Declaration of Conformity. 'There is ONE Declaration of Conformity. It is held by the manufacturer with the technical file for the product. The standard EN45014 is an accepted model for the DoC, referred to in the Blue Guide*, therefore manufacturers would seem to have no good reason not to use this model. The DoC is signed by the manufacturer, and is expected to be in the language used by the manufacturer (and understood by the signatory). A COPY of the DoC (in its original language) must accompany every product.' *This is a guide to the implementation of Directives based on the New Approach and Global Approach (EC Doc Certif 98/1) also known as the 'Blue Guide'. This information was on a DTI FAQ paper recently distributed at a TAPC meeting. I hope this helps. Kind Regards Tony Reynolds Principal Compliance Engineer Pitney Bowes Ltd The Pinnacles Harlow Essex. CM19 5BD UK Tel +44 (0) 1279 449479 Fax +44 (0) 1279 449118 e-mail: reyno...@pb.com __ Reply Separator _ Subject: Fwd:RTTE directive Author: jim_bac...@mail.monarch.com at SMTPGWY List-Post: emc-pstc@listserv.ieee.org Date:23/05/00 13:04 forwarded for Kim. Reply Separator Subject:RTTE directive Author: k...@i-data.com List-Post: emc-pstc@listserv.ieee.org Date: 5/23/00 12:12 PM Dear all According to the new RTTE directive we will have to supply our Declaration of Conformity in all EU languages. Is RTTE accepted as a reference in all languages or do I need to translate it ? If I need to translate do anyone know an easy way to do this ? Best regards, Kim Boll Jensen i-data international Denmark P.S. The danish translation is: RÕdets direktiv om Radio og Teleterminaludstyr 1999/5/EF --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
RE: Charge moving from decoupling capacitors
George, can you pls explain your correction ? I supposed your first statement (At 1/4 wavelength, the charges are 90 degrees out of phase) was the correct one ! Paolo Roncone Compuprint s.p.a. Reply Separator Subject:RE: Charge moving from decoupling capacitors Author: george_t...@dell.com List-Post: emc-pstc@listserv.ieee.org Date: 5/22/00 9:14 PM Barry, I need to make a correction. I was rushing to lunch on Thursday, so I did not read over what I wrote. Here is the correction for the 2nd comment below: At 1/4 wavelength, the charges are 180 degrees out of phase, so they are working against the IC current draw. 1/8 wavelength (90 degrees out of phase) is what I consider to be acceptable. Regards, George Tang george_t...@dell.com -Original Message- From: Tang, George Sent: Thursday, May 18, 2000 12:31 PM To: 'Barry Ma'; Tang, George Cc: si-l...@silab.eng.sun.com; emc-p...@ieee.org Subject: RE: Charge moving from decoupling capacitors Barry, Thanks for the comments. Here are my comments: Ok, you put caps at a certain distance away from the IC because you only want them to work at 100 MHz. But that distance turns out to be the 1/4 wave distance at 400 MHz, and you placed enough caps at the 1/4 wave distance to cause board resonance. Now what? Do you tell the caps not to work at 400 MHz because it's not their frequency? For your 2nd comment: I used the words loosely define for that reason. If you are interested in high frequency decoupling and instantaneous current, you really want to have all your charges moving in phase. At 1/4 wavelength, the charges are 90 degrees out of phase, so they will not do much for your instantaneous current. 1/8 wavelength is what I consider to be acceptable. You can certainly pick a different number. Regards, George Tang george_t...@dell.com --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Fwd:RE: Charge moving from decoupling capacitors
for George Reply Separator Subject:RE: Charge moving from decoupling capacitors Author: george_t...@dell.com List-Post: emc-pstc@listserv.ieee.org Date: 5/22/00 9:14 PM Barry, I need to make a correction. I was rushing to lunch on Thursday, so I did not read over what I wrote. Here is the correction for the 2nd comment below: At 1/4 wavelength, the charges are 180 degrees out of phase, so they are working against the IC current draw. 1/8 wavelength (90 degrees out of phase) is what I consider to be acceptable. Regards, George Tang george_t...@dell.com -Original Message- From: Tang, George Sent: Thursday, May 18, 2000 12:31 PM To: 'Barry Ma'; Tang, George Cc: si-l...@silab.eng.sun.com; emc-p...@ieee.org Subject: RE: Charge moving from decoupling capacitors Barry, Thanks for the comments. Here are my comments: Ok, you put caps at a certain distance away from the IC because you only want them to work at 100 MHz. But that distance turns out to be the 1/4 wave distance at 400 MHz, and you placed enough caps at the 1/4 wave distance to cause board resonance. Now what? Do you tell the caps not to work at 400 MHz because it's not their frequency? For your 2nd comment: I used the words loosely define for that reason. If you are interested in high frequency decoupling and instantaneous current, you really want to have all your charges moving in phase. At 1/4 wavelength, the charges are 90 degrees out of phase, so they will not do much for your instantaneous current. 1/8 wavelength is what I consider to be acceptable. You can certainly pick a different number. Regards, George Tang george_t...@dell.com -Original Message- From: Barry Ma [mailto:barry...@altavista.com] Sent: Thursday, May 18, 2000 10:50 AM To: george_t...@exchange.dell.com Cc: si-l...@silab.eng.sun.com; emc-p...@ieee.org Subject: RE: Charge moving from decoupling capacitors George, Thanks for your long input. I'd like to make some comments below. - On Wed, 17 May 2000, george_t...@dell.com wrote: Large parallel plates behave as transmission lines. A quarter wavelength transmission line with a short at the end has infinite impedance, so capacitors placed 1/4 wavelength away are bad. That's why decaps work on low frequency portion. Let's set 100 MHz and below for decaps to cover. The wavelength at 100 MHz is 3 meters. A quarter of it is 75 cm. It's long enough to ordinary PCB size. (The cap is directly connected to pwr/gnd planes.) This means that we can loosely define the largest usable board area capacitance as 1/8 wavelength radius of copper surrounding the IC power pin. Charges stored on the planes further than 1/8 wavelength away are not very usable due to the time delay. At 500MHz in FR4, 1/8 wavelength is 1.5 inches. Is such a board capacitor good enough for your IC? George, I beg for differentials. How did you jump from capacitors placed 1/4 wavelength away are bad to the largest usable board area capacitance as 1/8 wavelength radius? Can I use the same token to infer from caps placed one wavelength away are good to the largest usable board area capacitance is within 1/2 wavelength radius? And so, and so on. Regards, Barry Ma b...@anritsu.com ___ Why pay when you don't have to? Get AltaVista Free Internet Access now! http://jump.altavista.com/freeaccess4.go ___ --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Fwd:RTTE directive
forwarded for Kim. Reply Separator Subject:RTTE directive Author: k...@i-data.com List-Post: emc-pstc@listserv.ieee.org Date: 5/23/00 12:12 PM Dear all According to the new RTTE directive we will have to supply our Declaration of Conformity in all EU languages. Is RTTE accepted as a reference in all languages or do I need to translate it ? If I need to translate do anyone know an easy way to do this ? Best regards, Kim Boll Jensen i-data international Denmark P.S. The danish translation is: Rådets direktiv om Radio og Teleterminaludstyr 1999/5/EF --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
RE: Evaluation Boards
Vic, There is no US legal obligation for EMC/safety on development boards so long as they are offered for sale. If a system containing the board is offered for sale, then the system must pass EMI requirements any market-imposed safety requirements (e.g. UL1950). If the customer usually incorporates the development board circuitry into a larger PWBA, app. notes will prevent frantic calls at the end of the development cycle about not passing EMC and safety. EMC If the development board fails applicable requirements, you should provide an app. note explaining how to meet the requirements. SAFETY Any special markings, warnings, telco restrictions, etc. should be explained in an app. note. David __ Reply Separator _ Subject: Evaluation Boards Author: Vic Gibling SMTP:v...@virata.com at ADEMCONET List-Post: emc-pstc@listserv.ieee.org Date:5/22/2000 11:34 AM Hi All As a chip manufacturer we provide Evaluation Boards to licencees for product development. I would appreciate any advice, guidance or comments regarding safety and emc issues with regard to these boards. Thank you. Vic Gibling v...@virata.com --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
RE: Safety: Hi-Pot Suppression for TNV lines
Chris, Have you considered spray-on conformal coating in the telco area? Tech Spray SR is one option that is also UL Recognized. Best Regards, Jody Leber jle...@ustech-lab.com http://www.ustech-lab.com U. S. Technologies 3505 Francis Circle Alpharetta, GA 30004 770.740.0717 Fax: 770.740.1508 -Original Message- From: Maxwell, Chris [SMTP:chr...@gnlp.com] Sent: Monday, May 22, 2000 10:34 AM To: 'EMC-PSTC Internet Forum' Subject:Safety: Hi-Pot Suppression for TNV lines Group, Is there an in-line adapter that we can install on a TNV line (in our case, a typical RJ12 phone line) to our product that will provide a second layer of hi-pot protection? The whole explanation follows for those who think they can help. Others can press delete right now and get on with their day. We produce a piece of fiber optic test equipment that is rack mounted and operates from 48VDC. Most of our typical equipment does not have TNV connections, however this does. We have designed a remote reset option. The remote reset consists of an RJ12 jack on the back of the unit. The user can plug a phone line into this jack. Once installed, the user can perform a 5 second power down on the unit by dialing the unit's phone number and letting the line ring 5 times. This has proved valuable to customers because the units are designed for remote installation. If the unit hangs up, they don't have to drive, fly, hike or swim out to where the unit is installed to perform a hard re-boot. This remote reset line only takes in the TIP and RING signals (the RJ12 only has pins 3 and 4 populated). Both TIP and RING have MOV's going to chassis ground. We have had the unit safety tested. During safety testing, the MOV's were cut (creating a single fault condition). When the MOV's were cut, the hipot test caused an arc to ground on a circuitboard within the unit. This arc was considered a failure. My guess is that the arc is caused by the fact that the tip and ring signals run close to a piece of the ground plane on the top layer of the board. My first stab at fixing this would be to clear out the ground plane so that it is furthur away from tip and ring. Now, even minor changes to circuitboards can cost thousands. It can also mean scrap. This unit is a very low volume product (hundreds annually). It may be more cost effective for us to add some sort of in-line suppressor external to the unit as opposed to revising the circuitboard. Given that the unit is rack mounted, I am assuming that there would be room in the rack to mount such a device, if it existed. Hence my question. Anybody have any ideas? Thank you for your time. Chris Maxwell, Design Engineer GN Nettest Optical Division 109 N. Genesee St. Utica, NY 13502 PH: 315-797-4449 FAX: 315-797-8024 EMAIL: chr...@gnlp.com --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
[SI-LIST] : RE: Charge moving from decoupling capacitors
Barry, I need to make a correction. I was rushing to lunch on Thursday, so I did not read over what I wrote. Here is the correction for the 2nd comment below: At 1/4 wavelength, the charges are 180 degrees out of phase, so they are working against the IC current draw. 1/8 wavelength (90 degrees out of phase) is what I consider to be acceptable. Regards, George Tang george_t...@dell.com -Original Message- From: Tang, George Sent: Thursday, May 18, 2000 12:31 PM To: 'Barry Ma'; Tang, George Cc: si-l...@silab.eng.sun.com; emc-p...@ieee.org Subject: RE: Charge moving from decoupling capacitors Barry, Thanks for the comments. Here are my comments: Ok, you put caps at a certain distance away from the IC because you only want them to work at 100 MHz. But that distance turns out to be the 1/4 wave distance at 400 MHz, and you placed enough caps at the 1/4 wave distance to cause board resonance. Now what? Do you tell the caps not to work at 400 MHz because it's not their frequency? For your 2nd comment: I used the words loosely define for that reason. If you are interested in high frequency decoupling and instantaneous current, you really want to have all your charges moving in phase. At 1/4 wavelength, the charges are 90 degrees out of phase, so they will not do much for your instantaneous current. 1/8 wavelength is what I consider to be acceptable. You can certainly pick a different number. Regards, George Tang george_t...@dell.com -Original Message- From: Barry Ma [mailto:barry...@altavista.com] Sent: Thursday, May 18, 2000 10:50 AM To: george_t...@exchange.dell.com Cc: si-l...@silab.eng.sun.com; emc-p...@ieee.org Subject: RE: Charge moving from decoupling capacitors George, Thanks for your long input. I'd like to make some comments below. - On Wed, 17 May 2000, george_t...@dell.com wrote: Large parallel plates behave as transmission lines. A quarter wavelength transmission line with a short at the end has infinite impedance, so capacitors placed 1/4 wavelength away are bad. That’s why decaps work on low frequency portion. Let’s set 100 MHz and below for decaps to cover. The wavelength at 100 MHz is 3 meters. A quarter of it is 75 cm. It’s long enough to ordinary PCB size. (The cap is directly connected to pwr/gnd planes.) This means that we can loosely define the largest usable board area capacitance as 1/8 wavelength radius of copper surrounding the IC power pin. Charges stored on the planes further than 1/8 wavelength away are not very usable due to the time delay. At 500MHz in FR4, 1/8 wavelength is 1.5 inches. Is such a board capacitor good enough for your IC? George, I beg for differentials. How did you jump from capacitors placed 1/4 wavelength away are bad to the largest usable board area capacitance as 1/8 wavelength radius? Can I use the same token to infer from caps placed one wavelength away are good to the largest usable board area capacitance is within 1/2 wavelength radius? And so, and so on. Regards, Barry Ma b...@anritsu.com ___ Why pay when you don't have to? Get AltaVista Free Internet Access now! http://jump.altavista.com/freeaccess4.go ___ To unsubscribe from si-list or si-list-digest: send e-mail to majord...@silab.eng.sun.com. In the BODY of message put: UNSUBSCRIBE si-list or UNSUBSCRIBE si-list-digest, for more help, put HELP. si-list archives are accessible at http://www.qsl.net/wb6tpu
RE: Safety: Hi-Pot Suppression for TNV lines
Chris, Clear away the ground plane to give you the proper clearance. You need to be able to pass the tests without an external protector. You didn't mention Part 68 in your message. You do need that as well, plus an FCC Registration Number (although what you have to do to file for it may be changing very soon), manual verbiage, etc. If all else fails, you could supply a remote modem switch that would control power to your product. There are a few manufacturers but they can be a little pricey. Dave Spencer Oresis Communications -Original Message- From: Eric Petitpierre [mailto:eric.petitpie...@pulse.com] Sent: Monday, May 22, 2000 10:14 AM To: emc-p...@majordomo.ieee.org; Maxwell; Chris Subject: Re: Safety: Hi-Pot Suppression for TNV lines Chris, Usually the hi-pot tests done during the safety evaluation are meant to verify spacings and insulation. The hi-pot tests I have seen usually allow intentional paths to ground to be disconnected. It is the trace separation,etc, you are interested in, not how well the MOV conducts. Both MOV's are considered intentional paths to ground. Both should to be disconnected at the ground side during the test. If only one is disconnected, you may still have a path, whether it is direct, or through the contacts (open or closed) of the hookswitch. Eric Petitpierre Pulsecom Herndon, VA eric.petitpie...@pulse.com __ Reply Separator _ Subject: Safety: Hi-Pot Suppression for TNV lines Author: chr...@gnlp.com (Maxwell; Chris) at smtp List-Post: emc-pstc@listserv.ieee.org Date:5/22/00 10:33 AM Group, Is there an in-line adapter that we can install on a TNV line (in our case, a typical RJ12 phone line) to our product that will provide a second layer of hi-pot protection? The whole explanation follows for those who think they can help. Others can press delete right now and get on with their day. We produce a piece of fiber optic test equipment that is rack mounted and operates from 48VDC. Most of our typical equipment does not have TNV connections, however this does. We have designed a remote reset option. The remote reset consists of an RJ12 jack on the back of the unit. The user can plug a phone line into this jack. Once installed, the user can perform a 5 second power down on the unit by dialing the unit's phone number and letting the line ring 5 times. This has proved valuable to customers because the units are designed for remote installation. If the unit hangs up, they don't have to drive, fly, hike or swim out to where the unit is installed to perform a hard re-boot. This remote reset line only takes in the TIP and RING signals (the RJ12 only has pins 3 and 4 populated). Both TIP and RING have MOV's going to chassis ground. We have had the unit safety tested. During safety testing, the MOV's were cut (creating a single fault condition). When the MOV's were cut, the hipot test caused an arc to ground on a circuitboard within the unit. This arc was considered a failure. My guess is that the arc is caused by the fact that the tip and ring signals run close to a piece of the ground plane on the top layer of the board. My first stab at fixing this would be to clear out the ground plane so that it is furthur away from tip and ring. Now, even minor changes to circuitboards can cost thousands. It can also mean scrap. This unit is a very low volume product (hundreds annually). It may be more cost effective for us to add some sort of in-line suppressor external to the unit as opposed to revising the circuitboard. Given that the unit is rack mounted, I am assuming that there would be room in the rack to mount such a device, if it existed. Hence my question. Anybody have any ideas? Thank you for your time. Chris Maxwell, Design Engineer GN Nettest Optical Division 109 N. Genesee St. Utica, NY 13502 PH: 315-797-4449 FAX: 315-797-8024 EMAIL: chr...@gnlp.com --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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: Jim Bacher:
