IEC61000-4-2 has been around for a long time. About 30 years ago myself and others presented to tc-77b improvements that were (and still are) needed. Those concerns still need to be addressed. Our current standard has us addressing ESD stresses that cannot happen and on the other hand ignoring stresses that do happen. I touch on these in detail in my classes to help my clients.
Layer on this trying to arrive at a good model for real world conditions, an issue in all EMC related standards. I would like to address the human body model for a small piece of metal in the hand. My personal discharge, as measured by the instrumentation at Barth Electronics (right here in Boulder City, Nevada) is completely different than the model in 61000-4-2. The Barth instrumentation is the best in the world and I feel fortunate to be near them, about a 15 minute run away. My small metal discharge is very different in two ways. First, the body wave after the first peak has much less energy in it than in the standard. This most likely is easily explained because I have an athletic body from 45,000 miles of running and most likely does not affect test results all that much. However, my initial peak current is more than twice that in the standard using a 5 GHz bandwidth. Since the speed of light is one foot per nanosecond, nothing further away than my elbow can affect this part of the discharge waveform. And, this will affect test results. I think we need new data taken at a 5 GHz bandwidth. Separate from the above, we would like to minimize field issues from environmental stresses. So, I developed an interesting apparatus using an instrument from the chemical/materials industry coupled with an easy to make "antenna" that generates radiated EMI that is very severe. It takes out HDMI and other signals in the room when it is in use. But if it does not affect a design one can be reasonably sure one's device is not going to have problems in the field or at least you will know what the product response is, and if it is dangerous. I just finished building a better antenna from parts in our local Ace Hardware store. Starting now I will be demonstrating it for my attendees as part of my seminars, including one coming up. It will be interesting to see how it affects different products. Doug Smith Sent from my iPhone IPhone: 408-858-4528 Office: 702-570-6108 Email: [email protected] Website: http://dsmith.org - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to [email protected] All emc-pstc postings are archived and searchable on the web at: https://www.mail-archive.com/[email protected]/ Website: https://ewh.ieee.org/soc/pses/ Instructions: https://ewh.ieee.org/soc/pses/list.html (including how to unsubscribe) List rules: https://ewh.ieee.org/soc/pses/listrules.html For help, send mail to the list administrators: Mike Sherman at: [email protected] Rick Linford at: [email protected] For policy questions, send mail to: Jim Bacher: <[email protected]> _________________________________________________ To unsubscribe from the EMC-PSTC list, click the following link: https://listserv.ieee.org/cgi-bin/wa?SUBED1=EMC-PSTC&A=1
