Most magazines like to review the top ten most viewed articles this time of year and Interference Technology is no different. We think our readers and authors are awesome and enjoy highlighting some of the most popular articles to date.
So, here we go:
- What is differential and common mode current, by Ron Brewer. Unwanted conductive and radiative emissions can be caused by differential or common mode currents. This article explains how they are generated.
- New EMC requirements for commercial avionics: RTCA/DO-160G, by Erik Borgstrom. DO-160G covers standard procedures and environmental test criteria for testing airborne electrical and electronic equipment (avionics). The tests specified in DO-160G are typically performed to meet Federal Aviation Administration (FAA) or other international regulations covering electrical or electronic equipment that is installed on commercial aircraft.
- The HF current probe: theory and application, by Kenneth Wyatt. This article describes one of the most valuable tools in the EMC engineer’s “bag of tricks” – the high-frequency current probe. Current probes are invaluable for measuring high-frequency common-mode (or “antenna”) currents flowing on wires or cables. Experience has proven that poorly terminated (bonded or filtered) cables are the no. 1 cause for radiated emissions failures at a test facility. By measuring the common-mode (CM) currents (sometimes referred to as “antenna” currents) on these cables it’s possible to troubleshoot and apply fixes to a product right there in your development lab. You can also predict, to a good degree of accuracy, whether a given cable current will pass or fail in the measurement chamber.
- The international medical device EMC standard – IEC 60601-1-2, by Daniel Hoolihan. The standard was most recently released as the Third Edition in March of 2007. The Standard is currently under review by Maintenance Team 23 of Subcommittee 62A (Common Aspects of Electrical Equipment Used in Medical Practice), which is part of the International Electrotechnical Committee – Technical Committee 62 (Electrical Equipment in Medical Practice). NOTE: this standard was recently updated to the 4th edition and reviewed here.
- Radiated emission measurements at 1/3/5/10/30 meters, by Daniel Hoolihan. Radiated emission measurements are unique in that they must always state “the horizontal distance from the Equipment-under-Test (EUT) to the receiving antenna.” This horizontal distance, which can be 1, 3, 5, 10, or 30 meters, and the standardized limits associated with those distances, are the subject of this article.
- Designing electronic systems for EMC: grounding for the control of EMI, by William Duff. There are two primary reasons for grounding devices, cables, equipment, and systems. The first reason is to prevent shock and fire hazards in the event that an equipment frame or housing develops a high voltage due to lightning or an accidental breakdown of wiring or components. The second reason is to reduce EMI effects resulting from electromagnetic fields, common impedance, or other forms of interference coupling.
- Review of IEC 606010102:2014 (4thedition), by Darryl Ray. IEC 60601-1-2:2014 Edition 4 was published February 2014 and replaces IEC 60601-1-2 Edition 3 published on 2007. It pertains to EMC for medical electrical equipment and medical electrical systems. The European version (EN60601-1-2:2015) is identical to its IEC counterpart with exception of references to the EN versions of the 61000-4-x series and the addition of an Essential Requirements annex. The motivation behind the 4th edition was to create a safety standard that pertains to electromagnetic disturbances in order to align with the general requirements of IEC 60601-1 Edition 3. The previous version of IEC 60601-1-2 did not adequately address the safety aspects as related to electromagnetic interference. In addition, the differences between edition 3 and 4 with respect to immunity are substantial.
- Assembling a low-cost EMI troubleshooting kit – Part 1 (radiated emissions), by Kenneth Wyatt. Those of us who are either in-house or independent EMC consultants can benefit greatly by assembling our own EMI troubleshooting kit. I’ve depended on my own kit for several years and it has proven not only valuable but depicts a sense of professionalism in dealing with your own product development engineers, their managers, or your clients, as the case may be. This article will summarize what I’ve included in my own kit, and because everyone’s needs might be a little different, you’ll want to use this information as a guide. Feel free to add or subtract tools and test equipment as desired. You should expect to spend about $3k to $5k for the complete kit, depending on whether you make a lot of DIY probes or buy commercial, but this price range includes a spectrum analyzer.
- Electromagnetic interference sources and their most significant effects, by Anthony DiBiase. As the density of the electromagnetic environment continues to increase, the concern about its effects from sources producing EMI also increases. Advances in technology and the number of products produced are having a significant effect on the efforts aimed at maintaining the required operation and interoperability of products and systems used in our society. These events had added challenges for those who are responsible for keeping pace with the effort needed to maintain the required level of electromagnetic compatibility (EMC) in these products and systems.
And finally…
- Rise time versus bandwidth and applications, by Mekonen Buzuayene. In measurement instruments such as oscilloscopes and spectrum analyzers, the maximum rise time (tr) that can be measured with reasonable amplitude accuracy is directly related to the instrument’s 3 dB bandwidth (B). Rise time is usually specified as the transition time for a signal to go from the 10% to the 90% level of the steady maximum value. However, bandwidth describes the range of frequencies over which the majority of the energy of a signal is contained. Specifically, it is defined as the frequency range over which the frequency response of a signal degrades by 3 dB, assuming a single-pole high-pass frequency response.
Well, that’s a wrap for 2018! I hope you all enjoyed these, as well as all the articles published by our fabulous authors and bloggers this past year.
This will be my final blog as your senior technical editor, as I will be turning my full attention to my clients starting January 1st. Writing and editing for Interference Technology has been a wonderful journey, but with consulting business on the rise in a big way, I find I need to say goodbye to the great staff at ITEM Media and I’d like to thank them for the opportunity I’ve had this last three years to see what publishing looks like from the “other side”.
You’ll continue to see my blogs and articles as I have time to write. Thanks to all the readers for your great support! Signing off, but not out.
Cheers, Ken
