EMC tutorials - The HOT Loop

#139 In this video I continue looking at the noise coming from switching converters. I look at the various circuit loops in converters and check which of the loops generates the most amount of noise, so which needs to be kept small when compromises need to be taken.
Previously on Circuit Loops:
SMPS loops: • About CIRCUIT LOOPS in...
Amplifier loops: • About CIRCUIT LOOPS in...
Field probes:
Magnetic: • EMC debugging - Near f...
Electric: • EMC debugging - Near f...
References:
www.analog.com/media/en/techn...
Circuit schematic: drive.google.com/file/d/1JoKX...
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[@monoki8708]

fire hot loop explanation yo

[@alexengineering3754]

This is not just any cookie box, its Fesz's cookie box :D very nice

[@pa4tim]

I repaired a coertivity meter and when repaired the owner demonstrated what happened with the coertivity from metal if you bend it. The effect was big. He told me that was the reason you never should bend or dril mu-metal after its heat treatment. Thanks for an other interesting video

[@weinihao3632]

What was the working principle of the coercivity meter you repaired?

[@pa4tim]

@@weinihao3632 I do not exactly know because part of the system was a black box (no schematics from those boxes) and known to be good. It is a 19" amplifier/controller/PSU and 3 external cabinets. One is a big extremely heavy cabinet on wheels (size dog-house) with a huge coil inside used to magnetize the sample. There is also a "probe" inside. As far as I know it is a small coil used to measure the remanent magnetic field (If I use the correct term ) In short, it generates a magnetic field and measures the BH curve of metal samples. The meter has several modes, the one they used gave a value in A/m (if I remember well) The company who owns it develops things like electric motors for third parties. Something very rare, they had schematics, so there was no need for reverse-enginering. (95% of what I have too repair (my day-job) has no schematics)

[@nargizatoboeva1287]

Related to EMC: it would be very interesting to see how to simulate active EMI filter in LTspice

[@ChainsawDNA]

Excellent!

[@rjordans]

Interesting analysis, thanks!

[@Stefanev]

Another great video! Thanks.

[@barjan82]

I like your cookie-box based emc chamber 😀😁

[@mrechbreger]

Thank you for your videos!

[@sirousmohseni4]

Good video

[@shams350z]

Please do a video on various snubber circuits on switching power supplies. Pros/Cons of snubbing and substitute of it.

[@FesZElectronics]

That's an interesting topic! I will try to get to that at some point. Thanks for the suggestion!

[@MrThoriam]

Can you make a video about your near field probe? Its awesome! ;).

[@FesZElectronics]

I did something a while back :D kzbin.info/www/bejne/omO8hGSpa62rfrc and kzbin.info/www/bejne/iWOaq56VfM9spLc

[@aboukhaleed1340]

Hi I want from you a video about how I can design a stereo modulator for fm transmit using none ic cheap

[@user-uq4ly2lk1n]

how did you print your boards??

[@FesZElectronics]

I use the tonner transfer method. I tried covering this a long long time ago kzbin.info/www/bejne/i5rFmX-tqcd1h7M

[@user-uq4ly2lk1n]

@@FesZElectronics ok, thanks.

[@davidaz4933]

add a guard ring layout

[@AntonioDellaRovere]

Sorry, isn't it the non-linearity of the diode that is causing all the noise? Just think of diode ring-mixer, where the high frequency mix products are actually wanted..

[@FesZElectronics]

I guess that is a different way of looking at things - in the diode mixer, you start off with a sine wave and process it using the diode; with a switching converter, you start off with DC and chop it into bits using switches (either mosfets or diodes); it does not have to be a diode, it can be a mosfet and you will get the same amount of noise.