Note: This is an excerpt from the book, EMI Troubleshooting Cookbook for Product Designers, by Patrick André and Kenneth Wyatt. See Reference 1. Introduction Radiated emissions are by far your highest risk when performing compliance testing at the test facility. With all the high-speed digital circuitry inside electronic products today, it becomes all too easy for harmonics … [Read more...]
Using An Oscilloscope To Verify EMC Tests For Automotive Electronics
Consumer demand for more entertainment, safety, and communication options within automobiles has significantly increased both the density of electronic components and the number of on-board wired and wireless signals. The result: an ever-expanding range of signals contained within the same car-sized fixed space. USING AN OSCILLOSCOPE TO VERIFY EMC TESTS FOR AUTOMOTIVE … [Read more...]
Good SI, PI and EMC require this most of all…
Good SI, PI and EMC require a proper, grown-up understanding of electricity... Instead of what circuit designers are taught! As electronic designers, we were taught the children’s version of electricity at school, college, university, etc. This is the version that pretends (just as the SPICE simulator does) that electricity flows as little packets of charge totally inside … [Read more...]
Plugging into a Power Source 93 Million Miles Away
Harwin Gecko-MT 1.25mm pitch Mixed Layout Connectors Connect with confidence with Harwin’s Gecko-MT range; the smallest and lightest mixed-layout connector available for high-reliability applications. The Gecko-MT range combines the 1.25mm pitch Gecko signal connector system with mixed technology layouts, which adds 10A power contacts to the range, providing additional … [Read more...]
An Isotropic Probe for Radiated Susceptibility Measurements from 10kHz to 18GHz and 5V/m to 220V/m
Abstract: Isotropic probes are available for radiated susceptibility test level measurements from 100kHz to 6GHz, 2MHz to 18GHz, 2MHz to 40GHz and 2MHz to 60GHz. For MIL-STD-461 and DO-160 testing a frequency range of 10kHz to 18GHz would be better and a possible solution is presented here. Introduction The probe described in this paper has three separate sections, … [Read more...]
Functional Safety, Risk Management, EMC and EMI
What is Functional Safety? The safety of products, systems and installations can be split into two parts: i) ‘Basic’ safety: electric shock, excessive temperatures, excessive radiation, fire, explosion, implosion, bruising, pinching, crushing, cutting, emissions of toxic fumes, etc. ii) ‘Functional’ safety: when things being controlled don’t function correctly … [Read more...]
Doing Things That Usually Do Not Work
“If you’re not making mistakes, then you’re not doing anything.” — John Wooden Over the years, I have seen several things that make me scratch my head. Many of them are things I have done (there, I admitted it). I would like to look at these situations to (maybe) help not to make the same mistakes. So, to be clear: Do not do these things. Concerning Shielding One would … [Read more...]
EMC Confidence Checking
I was recently working with a manufacturer of stand-alone ticket machines, who had big problems with Ethernet-related emissions. Long story short – it was the Ethernet hub they had incorporated in their machine. They had assumed that all CE-marked Ethernet hubs would be equally good for EMC, and they had several different types lying around their design department. We tested … [Read more...]
Mains Harmonic Current Emissions are Always Bad – It is Risky to Rely on the Limits or Exclusions in the Standards
Many (perhaps all) of EMC standards that are listed under the EMC Directive, that set limits for mains harmonic emissions, have exclusions (‘let-outs’) for certain types of equipment, especially: (these examples are from IEC/EN 61000-3-2 Ed.5:2018) Lighting equipment with a rated power of less than but not equal to 5W Equipment with a rated power of 75W or less, e.g. … [Read more...]
Review: EMI Devices Harmonic Comb Generator
Harmonic comb generators are handy tools for validating open area test sites or semi-anechoic chambers and I've written extensively on how to use these for various other applications (see References). Harmonic comb generators produce a range of narrow band harmonics that are typically very stable in amplitude and frequency. One of the major uses is to position one in place … [Read more...]
