expert insights: emc bench notes
Just Starting Out in EMC?
By Kenneth Wyatt
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ith all the many pressures you have as a product designer, does electromagnetic compliance (EMC) always seems like a stumbling block to delaying product sales? Is your product exhibiting one of the top three failures; radiated emissions, electrostatic discharge or radiated immunity? Are you continually cycling between design/fixing – running to the compliance test lab – failing again – and back to shot-gunning more fixes? Wondering how to attack these issues earlier in the design cycle? Would you like to learn how to characterize and troubleshoot simple design issues right on your workbench? Then this is monthly column is for you!

Unfortunately, most colleges and universities fail to include courses on electromagnetic compatibility, so most product designers are forced to “learn the hard way” through multiple compliance failures. In today’s world of multiple digital products and wireless wearables, product‑to‑product compatibility becomes important. Products must be designed so they don’t interfere with other products or communications system (limits on emissions) and must continue to work in an environment with radiated fields (ex., two-way radios) and power line transients (immunity). Compliance testing must be performed for the U.S and worldwide markets before sales can start. Compliance failures are often a roadblock to sales.

This series of articles will help you with some resources, go through some basic EMC design concepts and help you create your own EMC troubleshooting kit to use for in-house characterization and troubleshooting. We’ll also discuss simple ways of using these new tools to perform your own in-house emissions and immunity pre-compliance testing.

To start off, I’d like to provide you a list of my most recommended books, web sites with educational content and publications, along with short descriptions.

Do your product emissions look like this? Uh oh, not good!
Chart showing product emissions
Recommended Books
Yes, I’m biased, so have included my three recent books, The “EMC Trilogy”, in the listing. In my opinion, those listed in red should be the first to consider adding to your library if you’re just starting out in the field.
  • ANDRÉ AND WYATT – EMI Troubleshooting Cookbook for Product Designers, SciTech Publishing, 2014. Includes chapters on product design and EMC theory & measurement. A major part of the content includes how to troubleshoot and mitigate all common EMC test failures.
  • ARMSTRONG – The Physical Basis of EMC, Nutwood UK Publications, 2010. An excellent treatment of EMC basics and theory and includes emissions, immunity and coupling/crosstalk.
  • ARMSTRONG – EMC Design Techniques for Electrical Engineers, Nutwood UK Publications, 2010. This 460-page handbook covers all aspects of product design for EMC compliance.
  • ARMSTRONG – EMC for Printed Circuit Boards, Nutwood UK Publications, 2010 (2nd edition). Practical aspects of PC board design for EMC.
  • BOGATIN – Signal & Power Integrity – Simplified, Prentice-Hall, 2018 (3rd Edition). Great coverage of signal and power integrity from an electromagnetic fields viewpoint.
  • BOGATIN – Bogatin’s Practical Guide to Prototype Breadboard and PCB Design, Artech House, 2021. This is a practical textbook used for his students at University of Colorado – Boulder on taking designs from breadboard to final PC boards incorporates all aspects of power integrity, signal integrity and EMC.
  • MONTROSE – EMC and the Printed Circuit Board, IEEE Press, 1999. Describes basic EMC theory and design for PC boards.
  • MORRISON – Grounding and Shielding – Circuits and Interference, Wiley, 2016 (6th Edition). The classic text on grounding and shielding with up to date content on how RF energy flows through circuit boards.
  • MORRISON – Fast Circuit Boards – Energy Management, Wiley, 2018. A brand-new book explaining how digital signals, in the form of electromagnetic energy, moves through circuit boards. Destined to be a classic.
  • OTT – Electromagnetic Compatibility Engineering, Wiley, 2009. The “bible” on EMC measurement, theory, troubleshooting and product design. The content is somewhat dated (examples are through-hole technology, for example) and the suggested PC board stack-ups are no longer recommended (unless all six of his rules are followed), otherwise his theory is sound.
  • PAUL – Introduction to Electromagnetic Compatibility, Wiley, 2006 (2nd Edition). The one source to go to for an upper-level course on EMC theory. Again, the content is dated, but the theory is sound.
  • SANDLER – Power Integrity – Measuring, Optimizing, and Troubleshooting Power Related Parameters in Electronics Systems, McGraw-Hill, 2014. The latest information on measurement and design of power distribution networks (PDNs) and how the network affects stability and EMC.
  • SMITH AND BOGATIN – Principles of Power Integrity for PDN Design – Simplified, Prentice-Hall, 2017. Getting the power distribution network (PDN) design right is one key to reducing EMI.
  • WYATT – Create Your Own EMC Troubleshooting Kit (Volume 1), WTS Publishing, 2022 (2nd Edition). Lists of test equipment, probes and accessories for performing your own EMC troubleshooting in-house.
  • WYATT – Workbench Troubleshooting EMC Emissions (Volume 2), WTS Publishing, 2021. How to use the tools in Volume 1 to troubleshooting radiated and conducted emissions.
  • WYATT – Workbench Troubleshooting EMI Immunity (Volume 3), WTS Publishing, 2021. How to use the tools in Volume 1 to troubleshoot the most common immunity issues; radiated immunity, ESD and EFT.
Recommended Web Sites
These are some of the leading EMC-related web sites with educational content:
Recommended EMC Consultants
I know many companies often need a little help towards the end of their design in achieving EMC compliance. Here is a listing of recommended consultants from In Compliance’s Consultant Directory: https://www.incompliance-directory.com/onlinedirectory/listing-category/consulting. Some listed here are EMC Test labs (some of which have technical competence in consulting), some are providers of EMC components, and some are independent consultants.
Summary
This is probably more information than possible to digest in the next month, but was much more than I had when just starting out as an EMC engineer for Hewlett-Packard back in 1986! Next month, let’s start gathering the minimal tools to start evaluating products earlier in the design cycle.
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