The key to identifying the location of an ESD source is by measuring the time of arrival between the two antennas. ESD discharges are tough to locate because they don’t occur periodically. Rather, they occur intermittently. I earlier wrote an application note on how to use an oscilloscope to trace the path of ESD current […]
How to compare EMI absorption materials with a cookie tin
Product enclosures have frequency resonances that can produce unwanted EMI. Absorption materials in the cavity can reduce EMI. Use a cookie tin to compare materials before inserting them into your product. As operating frequencies approach microwaves, enclosures can appear as resonant cavities and amplify EMI emissions. When I was working on space shuttle communications systems, […]
Characterize EMI from dc-dc converter ringing
Switching power supplies produce radiated and conducted emissions caused by ringing. Oscilloscope and spectrum-analyzer measurements let you see them. DC-DC converters are ubiquitous in most electronic products. While more efficient than linear regulators, they can also produce considerable amounts of interference that can affect nearby circuits. The measurements in this article show how ringing occurs […]
Review: Micsig TO3004 tablet oscilloscope
If you’re looking for a portable oscilloscope for field troubleshooting or for demonstrations, look at the Micsig TO series. Here’s my take on the four-channel 300 MHz variant, TO3004. The Micsig TO3004 oscilloscope (Figure 1) is an 8-bit, four-channel, tablet-sized portable oscilloscope that’s also available with 100 MHz and 200 MHz varieties with two or […]
EMI from LED light fixture often exceeds regulatory limits
Conducted emissions from LED light fixtures at frequencies from 1 MHz to 30 MHz can interfere with amateur radio and several broadcast bands. Radiated emissions reach into the lower cellular bands. After recently moving to northern Colorado and setting up my EMC lab and amateur radio station in the basement, I wanted to update the […]
Review: PCBite circuit board holder and probe kit
The PCBite kit holds your circuit board in place while you probe it, reducing the risk of short circuits. Recently, I’ve had to test and characterize many small PC boards, including embedded processors, DC-DC converters, and other wireless-related products, for EMC issues. I’ve never really had an easy way to keep these boards from moving […]
Review: Tekbox TBCG4 harmonic comb generator
The Tekbox TBCG4 harmonic comb generator produces a wide range of known frequencies for EMC immunity testing and routine checking of EMC chambers. I’ve used harmonic comb generators for decades in various applications, including antenna measurements, cable resonance measurements, and shielding-effectiveness testing. I also find them useful for checking the daily consistency of test chambers […]
Free and low-cost online EE tools aid in design
Downloadable and online free and low-cost EE tools help engineers design and analyze circuits.
New products at the EMC & Compliance International Conference
At the annual UK event, Tekbox, Y.I.C. Technologies, and Harogic Technologies were among the companies exhibiting new EMC measurement equipment. The EMC & Compliance International conference and training was held again in Newbury, UK, from May 22 to 23 this year (Reference 1). This was my first opportunity to attend this annual conference hosted by […]
Spectrum measurements shed light on sign malfunctions
Interference in the 900 MHz band appears to produce random errors in a gas station price sign. Spectrum analyzers help track it down. I received a call recently from a former client who manufactures electronic signs. A gas station was experiencing intermittent loss of wireless control of its signs, which displayed the price of various […]
