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Some more on Jeff's never ending saga to tackle home grown EMI

Adrian Godwin All Messages By This Member #1498 On Sun, Jan 29, 2023 at 2:36 PM Jeff Green <Jeff.L.Green1970@...> wrote: ? BTW, every 120V LED screw in incandescent light bulb I tested failed the FCC Part 15 conducted EMI limits by a very large margin. Interesting. What's the spectrum ? Is it the switching converter or the rectification ? ?Big Clive recently did a teardown of an LED bulb with no switcher :
Gary Johnson All Messages By This Member #1500 Check out my LISN design. It includes a wideband current probe that CORRECTLY measures common-mode EMI, something that has never been properly addressed in the measurement standards. They all ignore the role of the grounding conductor as a path for conducted emissions...? 90% of the EMI cases we all deal with can be completely solved with a properly-designed common-mode choke encompassing all AC line conductors. Packaged EMI filters often will not solve the problem because the EMI current is carried via the grounded conductor, which is simply carried through the filter. That being said, installing such a filter inside the offending equipment, with its case bonded to the equipment case, is more likely to be effective than placing the filter in an external enclosure. As for LED bulbs, I have characterized a number of them and detailed reports are on my RFI web page. There are many screw-in bulbs that are indeed compliant. The ARRL RFI lab has similar data which they will eventually publish. In contrast, I have yet to find an LED fixture (with their ghastly switchmode converters) that comes close to being Part 15 compliant. ? Gary NA6O
i2NDT Claudio All Messages By This Member #1501 not exactly a "professional" equipment but good enough for our amatorial purposes: best 73 de i2NDT Claudio
Matthias All Messages By This Member #1502 开云体育 Chiao Claudio, ? I have built something similar also based on Thilo’s inputs and it is very helpful: ? ? Sorry it is only in German but I am sure the pics and sketches together with an online translator should help to understand ? ? Kind regards ? Matthias ? ? ? Von: [email protected] <[email protected]> Im Auftrag von i2NDT Claudio via groups.io Gesendet: Montag, 30. Januar 2023 09:22 An: [email protected] Betreff: Re: [Test Equipment Design & Construction] Some more on Jeff's never ending saga to tackle home grown EMI ? not exactly a "professional" equipment but good enough for our amatorial purposes: best 73 de i2NDT Claudio
Jan Boutsen All Messages By This Member #1503 开云体育 Hello all, ? This DC-LISN ( WURTH design) is only for DC but works very well. ? ? Jan ON4MMW ? toggle quoted message Show quoted text From: [email protected] <[email protected]> On Behalf Of Matthias Bopp Sent: Monday, January 30, 2023 12:30 PM To: [email protected] Subject: Re: [Test Equipment Design & Construction] Some more on Jeff's never ending saga to tackle home grown EMI ? Chiao Claudio, ? I have built something similar also based on Thilo’s inputs and it is very helpful: ? ? Sorry it is only in German but I am sure the pics and sketches together with an online translator should help to understand ? ? Kind regards ? Matthias ? ? ? Von: [email protected] <[email protected]> Im Auftrag von i2NDT Claudio via groups.io Gesendet: Montag, 30. Januar 2023 09:22 An: [email protected] Betreff: Re: [Test Equipment Design & Construction] Some more on Jeff's never ending saga to tackle home grown EMI ? not exactly a "professional" equipment but good enough for our amatorial purposes: best 73 de i2NDT Claudio
Matthias All Messages By This Member #1505 开云体育 Hi Jeff, ? thank you very much for your advice. ? I generated an English version which can now be downloaded here: ? ? This should make life easier for most participants in this forum. ? Kind regards ? Matthias ? ? ? Von: [email protected] <[email protected]> Im Auftrag von Jeff Green via groups.io Gesendet: Montag, 30. Januar 2023 13:14 An: [email protected] Betreff: Re: [Test Equipment Design & Construction] Some more on Jeff's never ending saga to tackle home grown EMI ? toggle quoted message Show quoted text On Mon, Jan 30, 2023 at 06:29 AM, Matthias Bopp wrote: Download the German PDF somewhere you can easily locate it: Go to: Select the German PDF Wait a few seconds, download a fairly comprehensible version in English.
Arie de Muijnck All Messages By This Member #1506 开云体育 Hi Matthias, A nice design and well build. I have used equipment like this professionally and one item that I added are clamping circuits over the output to the spectrum analyzer. The input of that expensive equipment often cannot withstand the switching spikes when the LISN's output load is switched on or off. Just check it with a scope, the transient on that BNC output can be very high. Regards, Arie de Muijnck On 2023-01-30 12:29, Matthias Bopp wrote: toggle quoted message Show quoted text Chiao Claudio, ? I have built something similar also based on Thilo’s inputs and it is very helpful: ? ? Sorry it is only in German but I am sure the pics and sketches together with an online translator should help to understand ? ? Kind regards ? Matthias ? ? ?
Matthias All Messages By This Member #1507 开云体育 Hi Arie, ? very good point. ? Indeed I have built also a limiter circuit with a BNC jack and a plug. I simply plug this onto the BNC port of the LISN to protect the test equipment. ? I guess I should add that information eventually to my description. ? Kind regards ? Matthias ? ? ? Von: [email protected] <[email protected]> Im Auftrag von Arie de Muijnck via groups.io Gesendet: Montag, 30. Januar 2023 14:40 An: [email protected] Betreff: Re: [Test Equipment Design & Construction] Some more on Jeff's never ending saga to tackle home grown EMI ? Hi Matthias, A nice design and well build. I have used equipment like this professionally and one item that I added are clamping circuits over the output to the spectrum analyzer. The input of that expensive equipment often cannot withstand the switching spikes when the LISN's output load is switched on or off. Just check it with a scope, the transient on that BNC output can be very high. Regards, Arie de Muijnck toggle quoted message Show quoted text On 2023-01-30 12:29, Matthias Bopp wrote: Chiao Claudio, ? I have built something similar also based on Thilo’s inputs and it is very helpful: ? ? Sorry it is only in German but I am sure the pics and sketches together with an online translator should help to understand ? ? Kind regards ? Matthias ? ? ? ?

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