When designing an electronic system, it is important that it function as intended; this requires an understanding of many aspects of EMC including signal integrity (SI). One of the principal ways we can learn to understand SI is by knowing where our currents are flowing, as they move from one area on the circuit board to another and return. It is always easy to know where the intended signal flows, as it will be contained in the trace you place on a circuit board, but where does the return signal current flow? If you have a ground plane, the signal is “expected” to flow under the signal trace, as mirror current. At higher frequency “most” of the return current will flow under the signal trace, but at lower frequencies this is not necessarily the case. The unsuspecting designer might be surprised to learn the return current at lower frequencies might take a totally different path than expected.

There are many aspects of EMC a design engineer needs to understand when designing electronics. Signal Integrity is just one. Members can get a more detailed understanding of this and other technical concepts in the upcoming three-day course EMC By Your Design: An EMC Practical Applications Seminar and Workshop being held Tuesday, October 26 – Thursday October 28, 2010, at the Hilton Hotel, in Northbrook, IL. The course includes: Lecture, discussion and hands-on workshop; two textbooks and a large workbook of slides used in class; take-home proprietary EMC design software; free optional design evaluation of your product; and instructors with over 75 years combined engineering experience. For registration information, contact Carol G. at cgorowski@dlsemc.com or at (847) 537-6400. D.L.S. Electronic Systems Inc., 1250 Peterson Drive, Wheeling, IL 60090, www.dlsemec.com.