[RFI] LED Bulb RFI

[Gary Johnson]

Nice work, Ken. I'm glad to see someone publishing on the subject of conducted emissions below 30 MHz. Most of the articles on RFI design engineering these days focus on radiated emissions and much higher frequencies. Also it’s helpful to see mention of brand names and to find out that there may be surprises. The tests on LED bulbs that I published are consistent with what you observed. At the time, I found that Feit and GE were excellent, with Cree not quite so good, but of course it was a limited sample and products change over time. LED light fixtures remain universally horrible.

I do wish that the standards called for true common-mode measurements incorporating the ground wire. I include that instrument in my LISN system and my data. Normal-mode voltage noise isn’t always fully correlated with common-mode current! I’ve seen it again and again in a variety of products. It seems that they treat the ground wire as a sewer into which the noise magically disappears when in reality it’s just another antenna.

-Gary NA6O
http://wb9jps.com/Gary_Johnson/RFI.html <http://wb9jps.com/Gary_Johnson/RFI.html>

> 
> Hi All, I just published the results of some measurements I took recently of conducted emissions from LED bulbs. There?s one big surprise at the end...
> 
> https://www.edn.com/comparing-conducted-emissions-from-led-lamps/ <https://www.edn.com/comparing-conducted-emissions-from-led-lamps/><https://www.edn.com/comparing-conducted-emissions-from-led-lamps/ <https://www.edn.com/comparing-conducted-emissions-from-led-lamps/>>
> 
> Cheers, Ken (WA6TTY)
> ________________
> Ken Wyatt