Rocky Mountain Chapter EMC Society |
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Our last meeting was.. Techniques for solving EMC problems in various industries. Download the presentation
here Presenter: Dr. Tom VanDoren University of Missouri-Rolla. Date : September 19 2001 What we saw: Dr Van Doren drew on his extensive experience and presented five EMC problems from four different industries. Before getting into the specifics of the problems, Tom first reviewd the four noise coupling mechanisms that plague EMC engineers - Conducted, Magnetic Field, Electric Field and Electromagnetic Wave - and presented simple equivalent circuits to describe them. Tom then reviewed some of the causes of electromagnetic interference problems - unintended current paths, poor field containment, resonance, and impedance imbalace. Tom then held up a small hand-held PC as an example of a radiated emissions problem at 400MHz . He described the problem and the solution. Some spirited discussions about alternative fixes then ensued to the benefit of all. Toms next example was a Temperature Controller that had a suseptibility problem at the blazing frequency of 60Hz. Using simple math Tom led us on a step by step approach on the solution of the noise issue. Tom then changed gears once again and we went from solving problems with fairly unsophisticated equipment to Avoincs gear. We examined the RF Susceptibility of a Flight Controller. Interestingly enough, the controller actually had EMC protection added but Tom showed the weakness in the implementation that allowed the RF to penetrate the electonics. From flying high to wheels - Tom then displayed a automotive pressure sensor. In this problem featured a "hidden" circuit element that allowed the rectified RF to shift a DC level, with unpleasant results. Also from the automotive worls, Tom showed us a timing sensor that had self induced noise. In summary Dr. Van Doren showed that even though the industry might be different, the physics of EMC coupling can be understood. Biography: Dr. Tom Van Doren, a Professor of electrical and computer engineering at the University of Missouri-Rolla, has over 32 years of teaching and industrial experience in the areas of electronic data aquisition, microwave communication systems, semiconductor processing and electronic circuit design. His experiences in these areas have involved the solution of numerous grounding and shielding problems. He has received two outstanding teacher awards from the University of Missouri-Rolla, is an experienced short course director and instructor, and has the ability to lead participants in informative discussions. Over the past 17 years, Dr. Van Doren has taught more than 355 courses related to electrical noise reduction. More than 12,000 engineers and technicians have attended his courses. He has presented in-house courses for 105 corporations and governments. Contact Information: Dr. Tom Van Doren PICTURES
FROM THE SEPTEMBER MEETING
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