Conducted EMC Pre-Compliance with Tekbox DC LISN and Rigol DSA815. Fake LM2596S Exposed.
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- Опубліковано 15 жов 2024
- A Rigol DSA815 spectrum analyzer in conjunction with a Tekbox DC LISN is used to examine line conducted emissions. An eBay purchased LM2596 circuit board is used as the noise source and different types of capacitors/filters are used to reduce emissions. Along the way a fake LM2596S Simple Switcher is discovered. The design and schematic of a CISPR 25 LISN is discussed.
Items used in this video can be purchased from Amazon. All items in this video were personally purchased. As an Amazon Associate I earn from qualifying purchases.
Tekbox LISN: amzn.to/47T4JuH
Tekbox Limter: www.tekbox.com...
Rigol DP832 Power Supply: amzn.to/3YSqoii
Rigol DL3021A Electronic Load: amzn.to/45rnaVE
Rigol DSA815-TG Spectrum Analyzer: amzn.to/45nYD3C
Very interesting!
Thank you for the video. Very useful
Glad it helped.
The grounds on your LISN and DUT should be tied locally to the ground plane and the DUT needs to be raised an inch or two above the plane (not just a cardboard thickness away as that introduces capacitive elements which aren't good in RF measurements!). Also, to ensure the PSU is not affecting the readings, it's wise to place ferrites on the supply cables into the LISN so that the only conducted RF your measuring is from the DUT. The load also needs to be a self powered passive load to ensure that it is not introducing any mains or load regulation switching noise into your DUT measurements. You also need a transient suppressor on your analyser input to prevent the overload conditions you had in this video. Too many of those will shorten the lifespan of your analysers front end!
Good points. Purpose of this video was to demonstrate a quick test. I usually make a comparative measurement with the DUT on and off to see if I am getting external noise through the AC mains. On many occasions I have had too much external noise and have added a common mode filter on the input to the LISN. Note that this LISN has a built-in transient limiter and 10dB attenuator :)
very useful video thanks. Icing on the cake would have been if you had shown the conducted emissions of a genuine LM2596 chip for comparison.
That is a good idea. I'll write that down and put it on the possible "To Do" list. Thanks.