Please note that this article was originally published on the old UCT IEEE website by Keoikantse Marungwana. This article can be found here.

On the 3rd of November 2009, the University of Cape Town IEEE student branch was proud to host a talk by Mr Elya Joffe, the IEEE Electromagnetic Compatibility (EMC) Society President, during his visit to South Africa. He is the V.P. of Engineering and works as a Senior EMC engineering specialist and consultant at K.T.M Project Engineering in Israel.

The title of the talk was ‘Current, if not Obstructed, will always Flow in the “Path of Least…” ‘, and discussed the important concept of “Path of Least Impedance” and its relation to EMC principles on grounding. The talk was attended by an audience made up of undergraduate and postgraduate students as well as lecturers from the Electrical Engineering department. Mr Joffe has over 25 years of experience in EMC/E3 (Electromagnetic Compatibility/Electromagnetic Environmental Effects) and has authored, developed and presents many courses on Electromagnetic Compatibility and related topics. He discussed misconceptions on grounding and also highlighted the effect of frequency on return current flow path in electronic circuits.

Mr Joffe engaged the audience by using typical examples and analogies of how water flowing down a hill will take a longer route if this ensures that it is always flowing downhill, and also how hikers will take a longer but easier route climbing a mountain, instead of a shorter but much steeper, thus more difficult, route. He further gave examples of how grounding misconceptions have led to wrong implementations, such as in electronic circuit boards, often resulting in catastrophic failures.

He emphasized that these misconceptions are usually entrenched in the minds of technical and engineering practitioners, making them too difficult to uproot. He discussed an experiment he performed in an effort to uproot a misconception on return current flow path, of which the results were very surprising to his colleagues. Mr Joffe advised the audience that gaining a thorough understanding of the presented material will help them avoid significant losses and failures in their future design projects as engineering professionals. He indicated that the material is original and cannot be found anywhere, but will soon be available in a book he is writing.

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