Conformity Magazine - March 2008 - (Page 46)

enclosures and shielding gaskets and barriers. Stainless steel is often used for wire mesh in optical shielded windows, combining high light transmission with high shielding. Lower mesh counts and thinner wire diameter provides higher light transmittance, while higher mesh counts and thicker wire diameter provides better EMI attenuation. Copper as a conductive wire mesh is softer than stainless steel and is very reflective. Its advantages are high shielding and conductivity, with lower cost. Plastic using transparent conductive coated films, such as indium-tin-oxide (ITO) or multilayer conductive coatings, combines high visible light transmission, uniform electrical conductivity and excellent environmental stability. Also, there is no matrix of wires to interfere with the display as with the above meshes. However, the latter offers lower shielding and less consistent attenuation than wire mesh. [4] Compliance Testing and Certification Consumer electronic equipment falls under a wide range of global test standards. The primary markets driving test standards are the U.S., Canada and the European Union (EU). Other market areas can subsequently be reviewed, such as Japan, Taiwan, Australia/New Zealand, etc. For the purpose of this section, major appliances and electric tools are not considered consumer electronics. Usually, the further along a product is in development, the more extensive/difficult/costly are the changes necessary to correct compliance issues. There are two separate critical paths for safety and EMI/EMC certification compliance programs. For EMI/EMC, the primary test standards for consumer electronics are for Information Technology Equipment (ITE) and Audio Video Equipment. The Federal Communications Commission (FCC Part 15) and Industry Canada (ICES 003) regulate the radiated and conducted emissions for this type of equipment in the United States and Canada, respectively. In Europe, radiated and conducted emissions are regulated by EN 55022 for ITE, and by EN 55013 for Sound and Television Broadcast receivers and associated equipment. The EU also regulates the immunity requirements for consumer electronics. Requirements for ITE fall within EN 55024. Sound and Television Broadcast receivers and associated equipment falls under the immunity requirements of EN55020. Both of these “product family standards” provide test levels and methods for immunity tests covering electrostatic discharge (ESD), radiated immunity, conducted transient immunity, conducted surge immunity, conducted RF immunity, magnetic field immunity and voltage fluctuation/ dip immunity. These standards are designated as EN 610004-X or IEC 61000-4-X where “X” is the type of test. For example, the electrostatic discharge test is designated as EN 61000-4-2 or IEC 61000-4-2. There are a number of revisions/amendments to some of these standards. It is best to work with the test facility to determine the accurate series of test standards for your equipment. In the EU, two other test standards exist for the control of power line harmonics and flicker. The standards for power line harmonics, EN 61000-3-2 (IEC61000-3-2), and flicker, EN 61000-3-3 IEC61000-3-3), have wide applicability and are also required for CE marking. For EMI/EMC, the first item on the critical path is to have a test run for radiated and conducted emissions. Once a device meets these requirements, the remaining tests typically fall into place with minor issues, if any. These recommendations are for devices and/or systems which already exist. If a device is still in the design phase, it is still best to have a paper review done with regard to the same aspects. For safety compliance, consumer electronic equipment follows the requirements of UL 60950-1 in the United States and CSA 22.2 No 60950-1 in Canada for ITE. Consumer audio/video equipment follows the requirements of UL 6500 in the United States and CSA C22.2 #1 and C22.2 No. 60065 in Canada. In Europe, EN 60950-1 (IEC 60950-1) is for ITE, and audio/ video equipment follows the requirements of EN 60065 for Figure 6: Typical electromagnetic compliance (EMC) test setup Conformity marCh 2008

Table of Contents Feed for the Digital Edition of Conformity Magazine - March 2008

Conformity Magazine - March 2008 NewsBreaks Editor's Note Adelstein Renominated to the FCC Industry Canada Publishes FAQs On RF Fields FDA Gives Its Scientific Capabilities Poor Marks FDA Offers Guidance On its Product Review Process FDA Publishes Updates to List of Recognized Standards FDA Warns of Patient Risk From Electric Dental Handpieces Complying with the EMC Directive, Second Edition ESD Open Forum Emerging Issues in Standards - Korean "RoHS": Not Like RoHS at All The iNARTE Informer Challenges in Testing - Field-Induced Charged Device Model: What Really Happens Design Fundamentals - EMI Shielding Technologies for Consumer Electronics Equipment Focus On...Compliance Software Buyer's Guide Additional Standards Published for the EU's ATEX Directive Additional Standards for the EU's Medical Devices Directive Also Published China to Require Bar Codes to Enhance Product Safety CPSC Releases 2007 Self-Assessment CPSC Actions in News IEC Standards Update UL Standards Update Product Reviews Telcordia Standards Update From Our "You Can't Make This Stuff Up" Department Looking Back: Items from Past Issues of Conformity Advertisers

Conformity Magazine - March 2008

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