As a consultant, I'm seeing an increasing number of manufacturers wanting to add or retrofit wireless into new or existing products. Products typically include mobile, household, industrial, scientific, and medical devices. Also, the trend toward the “Internet of Things” (IoT) or the Industrial Internet of Things (IIoT) adds to the problem. This transition towards "everything … [Read more...]
Get the Job Done – Pocket-Sized 20 MHz Wireless Oscilloscope
In photography, they say the best camera is the one you have with you. The same may be said for simple electronic test equipment. For example, I was recently working with a client and we needed to verify Vcc voltage on one of their boards. Not having a DMM quickly available in their lab, I pulled out a tiny DMM from my troubleshooting kit, no larger than a pack of cigarettes. … [Read more...]
Developing an In-House EMC Troubleshooting & Pre-Compliance Test Lab
While investing in your own full in-house EMC test laboratory may seem difficult to justify, most companies should be able to afford to implement some level of pre-compliance testing capability. Outside compliance test labs can cost upwards of $2,000 per day. The advantage of being able to perform some of the key tests in-house is that you can quickly determine whether your … [Read more...]
Review: EMC – Methods, Analysis, Circuits, and Measurement
Electromagnetic Compatibility - Methods, Analysis, Circuits, and Measurement, David Weston, CRC Press, 2017 (3rd edition) While I've reviewed many books on EMC, this one by David A. Weston, is the most complete in coverage yet. The 1157-page book covers not only basic and advanced theory of EMC, but includes product design, commercial and military measurement techniques, and … [Read more...]
Measuring Common Mode Versus Differential Mode Conducted Emissions
When faced with excessive conducted emissions from switching power supplies, one of the first things to investigate and to determine the adequacy of is the power line filter. Line-powered switching supplies generally have both common mode and differential mode sections of the filter as shown in the generalized schematic in Figure 1. When using a line impedance … [Read more...]
ESD Effects of Digital ICs
One issue I see fairly often with unshielded consumer or commercial products is CPU resets during periods of immunity testing, such as during electrostatic discharge (ESD) testing. Untreated, this can lead to field failures and associated customer satisfaction issues. The remedy is usually quite simple and IC manufacturers even mention the solution, but it’s usually buried … [Read more...]
Narrowband Versus Broadband Harmonic Signals
Radiated and conducted emissions measurements are often comprised of both narrowband and broadband sources. So what differentiates “narrowband” and “broadband” signals? Narrowband Versus Broadband Signals The definition of whether a signal is narrowband or broadband as measured using a spectrum analyzer, depends entirely on the receiver bandwidth (resolution bandwidth, or … [Read more...]
Assembling A Low Cost EMI Troubleshooting Kit – Part 2 (Immunity)
This article concludes the two-part series, Assembling Your Own EMI Troubleshooting Kit – Part 1, which included a listing of the major components of a complete EMI trouble shooting kit that can be easily transported where needed. Most of the probes and tools listed in Part 1 were useful for troubleshooting radiated emissions. In Part 2, we’ll discuss several other useful … [Read more...]
Gaps In Return Planes – Bad News for EMI
Currently, there is an ongoing discussion among SI and EMC engineers on the fine points of PC board design for best signal integrity and EMI performance. Among the topics it seems designing in gaps or slits in ground return planes always comes up. Gaps can also occur mistakenly due to the addition of some connectors or other object that creates gaps in the copper. In fact, … [Read more...]
Interference Technology’s Top Ten Articles From 2005 to 2016
Each year, I like to capture the top “clicked on” articles. Knowing this will help me determine what topics readers feel are most engaging. The data will help me as technical editor round up articles for 2017 that will be equally compelling. Some of these topics include EMC basics, product design for compliance, EMC standards updates, medical EMC, vehicular EMC, and military … [Read more...]