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...]
Securing New 5G Physical Assets with Electronic Access Control
The 5G era of mobile computing and communications is rapidly moving forward. 5G stands for the fifth generation of wireless infrastructure—a massive upscale of network technology. It will provide data transfer rates faster than the blink of an eye, reducing latency for even the most data-hungry applications, high bandwidth, and greater opportunities for connectivity and … [Read more...]
A Simple Method for Estimating Radiated Emissions
A simple method for estimating radiated emissions I recently received the following question: How to calculate the radiated E field with following test conditions with an antenna placed 1 meter away from the test setup?: A commercial equipment under test with metal housing Equipment placed on the grounded metallic table/plane LISN installed (and also placed … [Read more...]
Comparison of PWM VFDs versus Resonant Link Converters – Part 2
In Part 2 of this blog, the harmonic current distortion of a typical Variable Frequency Drive (VFD) is discussed, as well the possible solutions to the problems that this causes. Active Front End or (AFE) units are also discussed and some of the issues that they themselves … [Read more...]
Comparison of PWM VFDs versus Resonant Link Converters – Part 1
AC variable frequency drives (VFDs) have been in existence in a number of forms since the early 1970s. In the early 1980s the “pulse width modulated” (PMW) VFD versions began to appear. This form of motor control produced less motor rotor and stator harmonic heating and delivered smoother torque control at slow motor speeds. Thirty years on PWM VFDs are still the most … [Read more...]
Insertion Loss and Filter Performance
Background Filters are almost always a part of electronics design. Design engineers design a filter to achieve certain attenuation in specified frequency range. There are many types of filters, such as high pass, low pass or bandwidth. Popular filter configurations include L-C, C-L-C (π) or L-C- L (T). It is safe to say that when it comes to filter design, the discussion of … [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...]
Instrument Hardware to Ensure Accurate Measurements Using NFPA 5lb Weights for ESD Control
Authored by: Gene S. Monroe, iNCE, NASA Langley Research Center, Hampton, VA Bob Vermillion, CPP, Fellow, iNCE, RMV Technology Group, LLC, NASA Ames Research Center, CA INTRODUCTION Proper verification of an Electrostatic Discharge (ESD) Protected Area (EPA) relies heavily on the use of the National Fire Protection Association (NFPA) 5lb weights. These 5lb weights … [Read more...]
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