EMC tutorials - Magnetic field shielding

[@johnwest7993]

I tend to think I know a whole lot about electronics when I watch KZbin videos. But then I watch a FesZ video and I feel like a newbie.

[@seshansesha7645]

Thank you for keeping the presentation simple and easy to make the subject understandable....best videos and presentation i have seen in the EMC world...Thank you

[@BlackRedDead1943]

5 marketing videos before i finally found a useful one - thanks :-)

[@kennymanchester]

Outstanding primer for our increasingly noisy noisy world! Thank you

[@satviksharma1146]

How delightful! Thank you!!

[@shubhamnayak9369]

Nice video... I always enjoy your content.

[@roberttso1079]

Nice demonstration to show how theory comes to life in real measurements!

[@mahditaheri7600]

Awsome, pretty narrated, complete content! Thanks alot...

[@longdongsilver4719]

That's heavy material. Thanks for sharing your work.

[@seshansesha7645]

The best presentations in the EMC world...thank you

[@logicalfalse]

Great video, and perfect timing for my current transformer project! Thanks for making so much great content.

[@mohammad-mahditaghipour4307]

Thank you for this video. I would like to mention that conductive shielding depends on the coupling of the sheet and the source. Higher the coupling, lower the effectiveness.

[@coconutman5854]

If you could make an experiment using faraday cages with AM/FM Radios inside to see which of those radio frequencies don't penetrate certain types of materials, that would interest me a lot. Great video, by the way.

[@johnmacmillan627]

Thank you. Very clearly presented

[@zhitailiu3876]

Such a joy to what this series of videos! Thx, Frez!

[@Atheistic007]

SOLID content, thank you.

[@jluke6861]

Great Video. Thank you for sharing.

[@roliveira2225]

Excellent! Congrats!

[@manoA98A]

That's really quality content!

[@BjornV78]

Hi Fesz, nice video. what about placing a complete steel/alu/copper "box" round each coil like a "Faraday cage", while there still be "leakage" to each other ? Can you also do a video about the use of Ferrite beads arround cables and miniature beads arround leads of components, when these beads have effect, when not etc.... Great video, thx . Gtrz

[@tedzone5544]

This was a very cool video. Thanks

[@lornemalvo2045]

Excellent! Highly informative and explained with clarity. It seems that a few layers of aluminium foil won't be enough to keep ALL of the monsters at bay.

[@KidCe.]

Damnn, i recently came across your channel and gotta say, i love it! In depth videos like these are such a raritey on youtube and are always so helpfull

[@paulpaulzadeh6172]

Great video ,

[@binong7366]

Brilliant! The test result matches what my senior colleague says, and very well explained

[@FesZElectronics]

Happy I could help! Cheers!

[@michelfrance75]

Thank you, this is another very interesting video. In this field of magnetism, I would be delighted if you could one day explain and illustrate to us the construction and operation of a small flux gate magnetometer, or even a proton procession magnetometer. The articles on the internet website are all very confusing on this subject.

[@stanislavsubrt886]

Great tutorial. Thank you very much! I was hoping (after seeing paper from N. Bowler) that you will introduce the concept of complex permeability and how it affects the shielding vs frequency, but I guess it would add 30 more minutes to the video duration. From there I guess next step would be to move to ferrite beads. Again thank you!

[@FesZElectronics]

I did start talking about this topic in an older video ( kzbin.info/www/bejne/Y3bUnn2uadd9isU ) but I guess its a topic that needs a bit more exploring. In the mean time I added a "card" in the video at the time I show the N. B. paper)

[@mumbaiverve2307]

Very good Sir.

[@jamestyrer6067]

Excellent video. Thanks

[@gregvisioninfosoft]

This was exactly what i was seeking to find. My interest here is how closely spaced coils within a speaker passive crossover network may cause unwanted crosstalk between the coils. Few people discuss this subject in the realm of designing crossover networks. In some cases I see the physical orientation of the centers of the coils are 90 degrees apart. But now that youve shown this test rig, I will try to duplicate to see how the orientation and spacing of coils might affect this. Might I ask, what type of 'amplifier' are you using here? An audio amplifier?

[@arthurm7846]

Great Video, thanks!

[@michaellove7912]

thumb up first then watch

[@shivendradhakariya6241]

sir very useful for me

[@lostmarble0318]

Great demonstration. How does the resonant frequency of the shield affect the shielding? The steel seemed to show a hump about half way across. Trying to understand what caused that.

[@mavamQ]

I would like to see both a copper plate and a copper plate together. Also, Can you try painting a sheet of plastic with Lowes Chalk board (magnetic) paint? Try one coat or several. I read it works, but how well? Try painting it on a copper sheet. Does grounding the sheet to the input signal ground help? Also, set you coils such that they don't move between tests so each test is the same. maybe start with 1000mv so we can easier calculate the attenuation of each item rested. Thanks for the video. The question is because someone ask, can I line the inside of my plastic box with copper tape for shielding? You show iron is better, so how about iron paint, and how many coats, and should you use copper tape and then paint it with Lowes Magnetic paint? I think It would have much more attenuation if you completely enclosed one coil, but you do need to leave an insulated seams to prevent the one turn shorted problem. Also pretty sure larger sheets would have more attenuation. I would like to see more experiments in this area. I subscribe, hoping to see it. Thanks.

[@vipinpnair]

Good one. Can you also check the shielding effectiveness if the material is connected to ground( copper & steel)?

[@FesZElectronics]

Of course, that will be in part 2 with electric field shielding.

[@matheusdosreisbravim1483]

Nice video

[@joachimloretz3697]

Sensationell

[@thghho]

Hello, regardless of budget, what can be the best magnetic field shielding material, which can block magnetic field and at same time does not attract by the magnetic?

[@DreamhouseVideography]

Thank you for the info! Great video. Could you tell me: Can I block emf from the Smart Meter (attached to the outside of my home) by placing a piece of galvanized sheet metal between myself and the Smart Meter? Thanks.

[@birdman1843]

I just use metal sheets to protect me against my evil gang stalker

[@p_mouse8676]

Would it also help to ground the shielding? What about hybrid solutions, so combining iron with copper for example?

[@FesZElectronics]

Grounding any shield is very important, but its not necessary if we purely talk about magnetic fields, any currents induced into a shield, usually stay in the shield. I do want to talk about this in more detail in a future video focused on electric field shielding - there grounding becomes essential.

[@p_mouse8676]

@@FesZElectronics Thanks, looking forward to it! :)

[@AdityaMehendale]

A good "razor" to ever answer this kind of question is "ground, with respect to _what_?" In inductive coupling, the eddy-currents are not referred to any external reference, so grounding cannot help. With E-field (capacitive) coupling, it surely will!

[@Andrii_V]

2 seconds to realize that this is hight quality video. How are you achieving this? ))

[@dalenassar9152]

GREAT VIDEO, as always.... I have a pair of 3" spiral wound copper pancake coils...one above the other (spaced at 1/4" to 1/2") connected in series and arranged so that they tend to attract when pulsed. They are pulsed with a capacitor. They are parallel, and one directly above the other. I would like to shield about half of the circular coils so that there is somewhat less attraction between a portion of the two...do you have any suggestions? THANKS MUCH --daLE

[@ttkoh123]

Copper is Used in Transformers, Inductors etc. So, the question is: What If you Ground the Copper to enable the Copper to Generate EMF Counter Forces to Shield? Like the Flux Band Video you posted. It means will the device of interest be riding on the Ground Ref and disturbances and will not be affected by it because of common mode?

[@Luau_1957]

Resumed CPAP Airfit N20 mask has magnets 350-400 mV and they recommend for those with body implants not to use mask with magnets. I have a cochlear implant slightly over 6” above the magnet location in the mask which appears to be ok for me to continue using this mask as it works well with me. I am trying to find some antimagnetic insulator I can wrap around the magnet to shield or lower mV to a safer reading? So I found your video. Any suggestions, thanks

[@milesprower6641]

So we know about permeability now, but what about complex permeability?

[@brunofigueiredo230]

Very nice video! Can you tell me more about the type of copper wire you're using to mount the inductors? How many meters or loops on the plastic frame are you using?

[@riverli3594]

very helpful

[@orveclenunivsa9975]

good video! thank you! However, I was wondering... when magnetic field lines are redirected thru the shielding material, y that magnetic field is variable, shouldn´t that create and electric field that propagates too on the shielded side? And shouldn´t that variable electric field create another magnetic field in the shielded area?

[@lupoal4113]

Great!

[@LowellAlb]

The shielding sheet must be getting hot due to the induced current. That's how induction heating work. But then what happens in the case of Ferrite which is not a good conductor of electricity? How is the energy dissipated that is fed as electrical energy to the primary coil?

[@FesZElectronics]

A conductive material will behave as you said - similar to induction heating; a current gets generated. With a ferrite, there is a similar principle at play but rather than conducting current, the ferrite (or any magnetic material for that matter) will conduct the magnetic field; at high frequency, the material becomes lossy and turns the magnetic flux to heat;

[@bluebarnflowers]

Hello, what would work best to shield EMF from a power wheel car it's DC.

[@ilovefreeski]

Very good information would anyone happen to know what frequencies a solar flare emp or nuclear emp would generate? Looking to make a faraday cage

[@objection_your_honor]

Is that why I found a copper band going around the switching transformer in a UPS? The one I took apart was connected to ground! Why? I saw a DIY EMP shield made of galvanized steel garbage can available from your local home center, it too was only connected to earth ground through a thick copper wire! What does earth ground do? To ground the induced voltage and current caused by the EM event?

[@vrushaliparkale9451]

Which type of steel must be used for high frequency shielding?

[@khemrajramsamooj9334]

Can you find the resonant frequency of the coil by just using the oscilloscope and function generator?

[@FesZElectronics]

Yes; the measurement is based on the fact that at resonance, the impedance of the coil is at a maximum value - if you inject signal from the generator trough a fixed resistor into the coil and measure the amplitude of the signal present on the coil using the oscilloscope, the frequency at which the signal value is at a maximum will be the coils self resonance. Keep in mind though that because the oscilloscope probe has non-negligible capacitance, the resonance frequency might shift a bit.

[@alexzemaitis]

I really need advice. I currently live in a motel room with a kitchennet and there is a 5g tower 4 blocks away in one direction and 1 mile in another direction. I want to sheild my room from emfs using reflectix, aluminum window screen and galvanized steel but I need advice on how to do it safley without making emfs worse. Should I put it on every single wall from floor to ceiling or just the 2 walls that the 5g is coming from? Also since I live in this room if I'm on my laptop or using my phone which i usually am in the room will it make it dangerous and start ping ponging around the room? Will I still be able to use electronics in the room without it being dangerous? I basically want to limit emf exposure as much as possible especially the 5g is the main concern, if there's a little bit of rf for now it's fine but my goal is to just limit emf as much as possible especially from the outside but I want to do it safely because there will still be electronics being used in the room until night time. Would it be best to just do like 2 or 3 sides of the room or even a faraday cage section of the room separate? Also will ot become an electrical trap of I don't ground it? Any advice helps on how to shelid this room. Thank you and God bless 🙏❤️

[@mejrimouhamedali]

thanks

[@ilkin9558]

so which material is best for block ?

[@مجداسماعيل-ف8ق]

Hi dear sir What if we use a vacuumed space in between the plates; ferrite plates for example which have high permeability and conductivity?

[@thorbennielsen3845]

What if you grounded the shield. What effect will it have?

[@hugovillegas8973]

Thanks for the very informative and well explained video. My question is, what about aluminum? Have you tried it?

[@FesZElectronics]

I did not try it in this video, but it does not have magnetic proprieties, and its less electrically conductive than copper; however its cheap. You will find shields built from aluminum - its a rather low cost material, and its light so you can make it relatively thick.

[@olaruionut2250]

Salut ! Foarte bun tutorialul! Felicitări! Care este părerea ta despre banda de izolare de la 3M, EM80KM ?

[@FesZElectronics]

Salut! Multumesc mult! Din pacate nu am o parere despre banda respectiva, nu am folosit-o niciodata...

[@Marzenable-ch7dm]

Qi Shield - do you think it works or its a joke? Appreciate your help.

[@june-gl6dy]

thanks for the great explaination! I could not catch the part at @6.52 which is explaining about shielding effect into a conductive material. You mentioned "something" current?

[@FesZElectronics]

I was trying to say "Eddy Current"; these are also referred to as Foucault's current;

[@june-gl6dy]

@@FesZElectronics thanks a bunch! I really learn so much from this.

[@domtom128]

Great video! Why are there two resistors connected to the coils when you were using the power amplifier in the beginning? I assumed that it was to reduce the loading of the amp/match the output impedance, but why is there also a resistor connected to the RX coil?

[@FesZElectronics]

Hello! You are right, I was trying to reduce impedance mismatch issues between the coil a the amplifier ( the resistor is 9R); in the past I had issues with the amplifier output starting to ring because of this. anyway, there is no special reason to keep the resistor on the RX coil other than having a symmetrical system.

[@lichtgestalt9540]

for high efficient shielding often „mu metal“ is used.

[@gerritcoetzee9075]

But nu-metal is only effective at low or weak magnetic field due to its relative saturation level.

[@Graham_Wideman]

Great video about this topic! What is the reason for the low effectiveness of the ferrite sheets in the initial example? Is it insufficiently high permeability coupled with thin material? Or is it possible that the flux density exceeded the ferrite saturation, and that actually a lower _percentage_ leakage would be seen with lower primary coil current?

[@FesZElectronics]

I guess the big issue of the ferrite sheet is that its not specifically designed for such low frequencies. I mean even the datasheet starts giving characterization curves above 1MHz. That, together with the very small thickness 0.05mm (x4 pieces) and of course some saturation should occur as you correctly pointed out, should be enough to explain the result.

[@goncalomarreiro8559]

hello, can i use g-iron armoflex to pass through metal detector with smartphone? we have to drop it off at school

[@Parirash123]

Premium content.

[@jackfrederick874]

Hi. Does the kemet polymer ferrite sheet change the value or normal functionality of the inductor that's being shielded? Great videos, thanks.

[@FesZElectronics]

If the inductor is of shielded type, there should be no impact since only a very small amount of magnetic flux is actually escaping.

[@smollande]

❤

[@jagdishsawant3469]

I could not define SCR for my simulatiun idea.can you suggest the way (buttons from drop down list) scr can be defined

[@ferdind1]

Nice video. I am wondering however, a lot of EMC guidelines suggest bonding and grounding of the shield. Why is this nescessary if the shielding effect is due to diverting magetic fields, or due to eddy currents creating opposing fields?

[@FesZElectronics]

The shield has 2 purposes - when talking about magnetic fields, the grounding does not matter; however the shield will also help with electric fields - there grounding is mandatory - the lower the ground connection impedance the better the electric field shielding.

[@ferdind1]

​@@FesZElectronics Thank you! What about if you ground the shield at both ends? The ground, groundwires and the shield would then form a conducting ground loop. Wouldn't the induced currents in this loop from the magnetic field we are trying to mitigate create an opposing magnetic fied thus mitigating the noise further? For example grounding a cable tray at both ends?

[@ferdind1]

Upon further investigation my assumption seems to be correct. Grounding the shield in both ends is vital to reducing magnetic field noice, at least according to the book "electromagnetic compability engineering" by Henry W. Ott

[@FesZElectronics]

@@ferdind1 Thats a great book! I also agree - even though multi point grounding can have the downside of creating loops which could resonate and make thigs worse at some particular frequency, the overall behavior will be better.

[@falconhawker]

A discussion of magnetic fields due to transformers SHOULD include the magnetic field created by pot cores transformers , which are designed to MINIMIZE external magnetic fields. Pot core transformers must operate at high frequencies , they CAN NOT operate at 50,60, or 400 cps .

[@byronwatkins2565]

You also need to consider that the parallel component of the magnetic field VECTOR is far easier to contain in a permeable material than the perpendicular component -- your apparatus considers only the perpendicular component. Simultaneously, conductors are far worse at shielding the parallel component. Seldom will noise sources cooperate with your shielding efforts and engineers must design for the worst case.

[@lukiepoole9254]

What they teach you : "Magnetic circuit of an electromagnet and a transformer." What they DON'T teach you : "The special effect of opposing magnetic flux being diverted by two different reluctance cores, which is the same as current flowing through two different resistors proportionately. Except that this occurs on opposing magnetic flux which is assumed to be not possible as it breaks known physics and breaks first thermodynamics law. The effect produce a useless transformer, and also an overunity generator."

[@stripedmark]

Hi FesZ , the link to the coil structure is broken :(

[@FesZElectronics]

It works well on my side... did you try copying the link directly into the browser?

[@stripedmark]

Hi @@FesZElectronics thank you for great content and swift answer. Hmm, doesn't work here I also don't seen the model on your thingiverse account..

[@stripedmark]

@@FesZElectronics Oh now it works ..:)

[@FesZElectronics]

Aaa, I figured it out, it wasn't "published". Please see now if its ok.

[@Mr.Kronk2]

Hey! Sorry for asking, but what type of amplifier are you using for your setup? when I'm looking around for amplifiers all i find is amplifiers used in the music industry or radio frequency amplifiers. would love to be able to use this experiment as a demonstration setup for a Sience fair :)

[@FesZElectronics]

Hello! the amplifier I used in this video is "home-made". Its based around the LT1210. In theory at least it can output about 1A at +/-10v up to ~10MHz.

[@luminousfractal420]

decided to mount crossover parts in small glass domes. then remembered i was using two coils for the woofer🤦 hoping for a solution in this vid 😂. ..well ive got some inch thick steel plate....

[@باباابي-ش1ض]

👍👍👍

[@minahilashraf5617]

what is the maximum limit of frequency in your set up.

[@FesZElectronics]

The spectrum analyzer measurement was performed up to 1MHz, since above that the measurement coils reached their self-resonance; regardless this phenomenon should continue upwards even if I couldn't measure it.

[@hengshihoneycomb]

hopefully metal honeycomb vent can help

[@stanislavcoros]

eddy currents only work when that shielding material is AT MOVEMENT. not stationarry. thats the trick my friends :D so when its shielding, it act on magnet also, and slow it down. It is fair price to maintain no free energy "D

[@kaybhee6]

did u try aluminum foil... hi grade

[@BalogunJoseph-h4j]

Please explain magnetic shell for me

[@SurvivalSquirrel]

Wait! What? You bought expensive ferrite shield, that is worse than cheap steel?

[@krisraps]

And THIS Is The Main Reason We Can`t Use Normal Electric Wires For Our Radios.

[@djcaddypoarta6]

I only came here to find out how to block the back gate from closing all the time cos motherfuckers put an electromagnetic lock and now I can't use the rear gate to go in I have to take a trip 'round the whole building as the neighbours were getting funny for using ''their gate''.... World, 2022.

[@makemoneyrelax]

i measure magnetic fields in nT I really am confused why you use mv? You are not blocking the magnetic I think..

[@FesZElectronics]

I'm not measuring the magnetic flux density directly - I don't have a tool for that, but rather, I'm measuring the voltage induced into a secondary coil - hence the mV. So I'm measuring the effect of the magnetic field, rather than the field its self. With a proper calibration the mV could be converted to tesla, if that is really necessary.

[@dalenassar9152]

GREAT VIDEO, as always.... I have a pair of 3" spiral wound copper pancake coils...one above the other (spaced at 1/4" to 1/2") connected in series and arranged so that they tend to attract when pulsed. They are pulsed with a capacitor. They are parallel, and one directly above the other. I would like to shield about half of the circular coils so that there is somewhat less attraction between a portion of the two...do you have any suggestions? THANKS MUCH --daLE