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...]
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...]
Key Points to Remember While Choosing PCB Assembly Company
Once you have designed a PCB and have completed everything that needs to be done before the assembly process, you would require a PCB assembly company to assemble your PCB without any problems. After all, you've been working considerably hard to assemble the layout and the design of the PCB. You would want to be convinced that your PCB gets well-assembled. To ensure that the … [Read more...]
ESD Testing Needs to Change to Reflect Real-Life
Semiconductor die shrinking means that 0.7ns risetimes are now too slow Electrostatic discharges in the real world cover a very wide range: from relatively slow high-voltage events (say, > 1kV peak) to extremely fast low-voltage events (say, < 1kV peak). The figure shown is of the transient field radiated by a micro-gap discharge between two coins – more on this … [Read more...]
Ground / Power Bounce Cause Noise Emissions From All IC Pins
Ground and power bounce are often ignored as sources of CM noise emitted from all integrated circuit (IC) pins, even if they are static inputs or outputs, digital or analogue, and even sometimes emitted as radiated noise directly from the body of the IC (especially when its physical structure resonates). CMOS ICs use ‘totem-pole’ logic switching gates that momentarily short … [Read more...]
For Remote Patient Monitoring Systems, Wireless Coexistence Can Be Lifesaving
The demand for wireless medical applications such as remote patient monitoring, real-time diagnostic analysis, smart surgical systems, and implantable sensors have grown significantly over the last couple of years. Thanks to implanted medical devices, many patients live an almost normal life without having their mobility compromised. Popular implants include cardiac pacemakers, … [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...]
Don’t Rely on the Stability of the Mains Frequency
My old colleague and good friend Tim Williams sent me the story below for inclusion in EMI Stories/Banana Skins, and I found it so interesting in so many ways that I decided to publish it as a Blog. In so very many EMC standards and other meetings on EMC, we hear that the stability of the AC mains power frequency is either ‘not an EMC issue’ or is ‘never a real EMC … [Read more...]
MIL-STD-461G Implications with RE102 Changes
Introduction: MIL-STD-461G was issued in December 2015 incorporating many changes throughout the document prompting user questions or interpretations. Laboratory situations arise where the generic guidance requires specific situational decisions and the most common tests such as RE102 are included. The user quickly realizes that the given direction does not make sense for a … [Read more...]
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