• • • • • TECHNICAL BULLETIN Conductive elastomers • Knitted wire mesh Conductive coatings, sealants, adhesives Cable shielding products • EMI/ESD shielding laminates Shielded vents and windows Commercial and military EMI testing LEADER IN EMI SHIELDING INNOVATION, DESIGN, AND TEST TECHNOLOGY 203 ® CHO-STRAP INSULATED GROUND STRAP FEATURES • Low RF impedance • Passes all requirements of UL specification 94V0* • Reduces EMI radiated emissions • Very flexible • Simple installation • Tinned contacts for corrosion resistance • Flame retardant adhesive system • High dielectric strength exterior • Wide range of standard sizes CHO-STRAP® grounding straps are flexible, double-insulated laminates of copper (inside) and polyester film (outside), with punched and tinned ends to facilitate termination. They provide low-impedance ground paths at RF frequencies, thereby reducing radiated EMI problems caused by ordinary wire grounds. They are generally more cost-effective than braided ground straps. ™ Grounds made with ordinary wire (e.g., #18 copper wire) will have high impedance at RF frequencies, and can actually act as an antenna, thereby increasing radiated emission levels. Braided ground straps are costly and inconvenient because their ends generally require tinning or hole punching by the user, and they must often be insulated to avoid shorting problems in tight quarters. CHO-STRAP ground straps are supplied in a variety of standard widths and lengths (see Table 1). Standard construction is 5-oz. rolled annealed copper, laminated on both sides to 1-mil polyester film with a flame retardant polyester adhesive. Ends are punched with 0.187” dia. holes (4.75 mm dia.) for ease of installation with #10 screws. A 1/2” (12.7 mm) tinned area at each end prevents oxidation of the termination contact area. TABLE 1 STANDARD CHO-STRAP SIZES These ground straps are recommended wherever board-to-chassis or chassis-tocabinet grounding is required. Common applications include: Part No. L-1011-3 L-1011-6 L-1011-9 L-1011-12 L-1011-15 L-1011-18 L-1012-3 L-1012-6 L-1012-9 L-1012-12 L-1012-15 L-1012-18 • Tying a CRT driver board to chassis (very low impedance ground required); • Tying one sub-chassis to another; • Tying a sub-chassis to main chassis ground; • Tying cabinet panels to chassis ground. Nominal Dimensions, inches (mm) A 3.0 6.0 9.0 12.0 15.0 18.0 3.0 6.0 9.0 12.0 15.0 18.0 B (76.2) (152.4) (228.6) (304.8) (381.0) (457.2) (76.2) (152.4) (228.6) (304.8) (381.0) (457.2) 0.500 0.500 0.500 0.500 0.500 0.500 1.000 1.000 1.000 1.000 1.000 1.000 C (12.7) (12.7) (12.7) (12.7) (12.7) (12.7) (25.4) (25.4) (25.4) (25.4) (25.4) (25.4) 2.5 5.5 8.5 11.5 14.5 17.5 2.5 5.5 8.5 11.5 14.5 17.5 (63.5) (139.7) (215.9) (292.1) (368.3) (444.5) (63.5) (139.7) (215.9) (292.1) (368.3) (444.5) Other sizes available. *Recognized under the Component Program of Underwriters Laboratories, Inc. Chomerics, Div. of Parker Hannifin 77 Dragon Court Woburn, MA 01888-4014 Tel: 781-935-4850 FAX: 781-933-4318 www.chomerics.com Parker Hannifin PLC Chomerics Europe Parkway, Globe Park Marlow, Bucks, SL7 1YB, United Kingdom Tel: (44) 1628 404000 FAX: (44) 1628 404090 France Freephone Tel: (0590) 8170 Germany Freephone Tel: (0130) 818074 Parker Hannifin Hong Kong Ltd. Chomerics Sales Department 8/F King Yip Plaza 9 Cheung Yee Street, Cheung Sha Wan Kowloon, Hong Kong Tel: (852) 2428 8008 Fax: (852) 2480 4256 NOTICE: The information contained herein is to the best of our knowledge true and accurate. However, since the varied conditions of potential use are beyond our control, all recommendations or suggestions are presented without guarantee or responsibility on our part and users should make their own tests to determine the suitability of our products in any specific situation. This product is sold without warranty either expressed or implied, of fitness for a particular purpose or otherwise, except that this product shall be of standard quality, and except to the extent otherwise stated on Chomerics’ invoice, quotation, or order acknowledgement. We disclaim any and all liability incurred in connection with the use of information contained herein, or otherwise. All risks of such are assumed by the user. Furthermore, nothing contained herein shall be construed as a recommendation to use any process or to manufacture or to use any product in conflict with existing or future patents covering any product or material or its use. © Chomerics, div. of Parker Hannifin Corp., 1999 Printed in U.S.A. 1M599SG-200R Rev.1-599