Cheap basic conducted EMC tester for offline 60W SMPS LED driver

[ocset]

Hi,
Does anyone know if there's a video like this one for using the DSA815 spec anal for an offline 60W smps (LED driver)  conducted emissions test?...


We like the idea of just having the small metal sheet under the DUT, rather than a completely shielded room, which we cant afford
(its only to act as a basic guide, not for  the actual accreditation)


I believe the HM6050 is the cheapest LISN to use.
http://www.farnell.com/datasheets/1851611.pdf?_ga=1.216594710.1679746183.1489787856

[tautech]

It ain't rocket science as the EMI testing part in this video demonstrates:

https://youtu.be/ZjO5hKPwcEY

[nctnico]

Please skip Tautech's off-topic infomercial because a) the methods shown in there aren't going to help pass emissions testing first time at all b) it doesn't even show measuring conducted emissions.

For conducted emissions testing you don't need a shielded room but a LISN suitable for mains and a spectrum analyser which goes up to 100MHz.

[T3sl4co1l]

This works, more or less;
https://www.seventransistorlabs.com/Images/DistAmp2.jpg

The important part being the metal plate underneath everything, and the LISN on the left, into which the power supplies connect.  Its RF ports are terminated as shown, since I was using it as a filter in this case, but yeah, that's where you'd measure things of course.

Testerizing conducted susceptibility requires a modestly powerful amplifier and a sweep generator; which, interestingly enough, is the main intended application of the above mentioned amplifier (the shiny stuff on the right side).  You will need more than a few watts to reach useful output levels (3 or 10V are typical), times a fair factor to account for the attenuator required (to help isolate the amplifier from reflected power at unlucky frequencies), and you will also need a cable clamp signal injector of some sort, to deliver common mode conducted energy to cables that aren't simply wired into a LISN.

A similar setup is used for EFT testing, and surge (where applicable) is coupled in with a CDN as well.

Tim