Electromagnetic Interference Shielding
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- Опубліковано 21 сер 2024
- Here is a not-too-long tutorial about Electromagnetic Interference and ways to get rid of them.
Shielding for electromagnetic interference or EMI, is usually a hot topic when building audio and radio frequency equipment. Also, with the increase of clock speeds for digital devices in the order of the gigahertz, EMI shielding, or EMS for short, has become a hot issue also in the digital world. In fact, digital devices can generate EMI that needs to be shielded to prevent it from invading our leaving space.
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Thank you for watching!
Thank you for the time spent explaining this topic. Very useful video!
After searching for hours, I found your video...really helpful...you covered the entire topic...😌😌😌..Thanks 😊
Glad it was helpful!
The explanation is really comprehensive. Thanks!
Fantastic source of information my friend. Well done contribution.
Glad you enjoyed it!
Thanks for sharing the valuable knowledge.
You are very welcome!
Thank you for your teaching
Thank you for watching!
Sei assolutamente bravo sgnore,, da Africa; you are so cear
Thank you
any ideas about mineral shielding such as the often promoted Shungite and some other crystals?
Shungite and similar minerals are no good for emi shielding. Shielding requires a highly condutive material and these minerals are not. Furthermore, to.make effective shields you need materials that can easily adapt to various shapes. Shungite, as well as other similar materials, are basically stones and the only way to adapt them to surfaces is to melt them at high temperatures. Why would someone do that, if you can easily work with metals like copper and aluminum in sheets easily pliable?
Thank you
What are the Shielding techniques for Battery Management System (BMS)
The answer is much more complicated than you may think. I'll just give you a few hints. Are we talking about a battery that powers some sort of electronic device? Like, foe example, a laptop computer? Or a we talking a battery that powers a switching system to generate alternate current at high voltage, like in the UPS devices, which are devices that use a battery to provide electrical energy when the power grid is down? Or maybe the BMS in an electric car? In these three examples the needs are very different and the shielding will be, accordingly, very different. The principle is always the same, though: we need a metallic enclosure connected to ground that prevents the electric part of the electromsagnetic field to go through. Depending on the amplitude of the EMI that needs to be shielded, the thickness of the shield must change and sometimes, in addition to shields we need to provide filtering on the cables that go through the shield, to connect the device inside the shield to some other circuit outside. This filtering is normally done by putting rings of ferromagnetic material around selected places along the wires, to increase the inductance of the wire which will act as a low pass filter. In other cases, actual low pass filters need to be used instead. And yet in other cases, you may need to do both at the same time.
Very informative 👍
Thank you!
Hello thank you for video. I understand this shielding applies to transverse waves. But how can longitudinal waves be shielded? From what I’ve heard longitudinal waves make shielding very hard. Eager for your reply as it has become very important to me to block these. Thank you.
We are talking about electromagnetic waves, which do not need a medium to propagate. Such wave can be of three different kid:
1) TEM: Trasverse electromagnetic where both fields are perpendicular to the direction of the motion.
2) TE: electromagnetic waves where only the electric fields in perpendicular to the motion, while the magnetic field is in the same direction.
3) TM: electromagnetic waves where only the magnetic field is perpendicular to the motion and the electric field is in the same direction.
You can see how, for electromagnetic waves, it is not possible to have an electromagnetic wave purely longitudinal. Actually, in general, when electromagnetic waves propagate in the open space, they are usually only TEM. It is necessary the interaction with a material to trasform them in TE or TM.
For a wave to be purely longitudinal, it has to be a mechanical wave, that uses the mechanical properties of the medium to propagate, like the waves in the ocean, or the sound waves in the air. Electromagnetic waves are not of such nature.
Because of the above, the shielding methodologies I have presented in the video, are always valid, for either TEM, TE, or TM wave. For purely TM wave (veru unlikely to happen in the open air), you would have to thicken the shield more then for the TE or TEM waves, but that's about it.
Thank you Great video
Thanks
The reason why it is so difficult to shield against kinetic magnetic flux is because "the stuff" (EM field) that magnetic flux is made of is EVERYWHERE and in EVERYTHING. It's like trying to dam water with water...The best way to shield against magnetic fields is using an active shielding method - a magnetic field perpendicular to the field lines you are attempting to shield. "The stuff" theory is not a very popular one in our current physics establishment! 😉😉
16:12 what do you mean by that? Can you please give me an example?
Here an example that should clarify the issue.
Assume you have a circuit on a PCB and assume you need to shield the back of the PCB with a conductive plate.
In order for the shield to work properly, you will need to connect the ground of the PCB to the plate.
Let's assume you do that by connecting a wire between a corner of the plate and a PCB ground track close to it.
The plate is connected to ground and everything works fine.
But now you want to do a better ground connection between the plate and the PCB, so you choose a second corner of the plate and you use another wire to connect it to the closest ground track on the PCB.
It is at this point that you start getting a lot of noise. Why? Becaue you have created a loop that behaves like an antenna (like the loop antenna that in the past were so common for the UHF channels of the old TVs). This antenna captures all the possible noise present in the environment and injects it on the PCB through the ground connections.
The loop I'm talking about is made out of the following elements. The first wire connected between the plate and the track, the plate itself, the second wire connecting the other corner of the plate with the PCB track, and finally the ground tracks on the PCB itself.
You have basically transformed what it was supposed to be a shield in to a concentrator of noise that affects your PCB.
Hope this helps.
Greetings of the day sir,
I just wanted to know what measures can prevent Voice to skull, Remote Neural Monitoring(RNM) and energy weapon signals and waves from reaching you. Will the Faraday cage work? Any help would be really appreciated. Thank you.
The Faraday cage works only with EM fields. Voice is a mechanical wave.
@@eleneasy How do I block Remote Neural Mnitoring signals? Also, is it possible to deflect them?
Brain signals are extremely low power and low voltage. To capture those signals we need to put electrodes directly on the scalp of the subject. I don't believe there is a technology capable of doing that over a distance (Remote Neural Monitoring). Even it it existed, it couldn't just do it with any kind of obstacle between the apparatus and the subject person. The simple walls of your house are more than enough to shield against the possible usage of these apparatuses against your person. Therefore, I would not worry, if I were you.
So we need one shield (magnetic or electric) to block these two fields?
It depends on the situation.
For a static field, you need a shield that is specific for it. A magnetic filed requires a ferromagnetic material to act as a shield. An electrostatic field requires a good conducting material to act as a shield.
For a dynamic filed is different. A dynamic electric filed cannot exist without the presence of a corresponding dynamic magnetic field. And, viceversa, a dynamic magnetic filed cannot exist without a corresponding eletctric field. That's why we do not really distinguissh dynamic magnetic fields and dynamic electric fields. They have to be there togther, at the same time. For this reason, rather than considering two separate fields, we consider a single field, which we call electromagnetic field. Ti shield from such a field we can use either a ferromagnetic material or a good conductor because, the moment we stop one of the two components, the other one ceases to exist as well.
The video concentrated more on electromagnetic fields. In that context, the answer is therefore yes, we just need one type of shield to block the whole thing. And, usually, we choose a good conductor, because is it easier to handle than a ferromagnetic material which, by the way, needs to have a good magnetic permeability to be able to work as a good magnetic shield.
Thanks for the information, do you know any relation between EMI on human body devices (like the human hearing system)?
No, sorry, i don't have enough background to answer questions on the effects of emi on human physiology.
I have a cable that is shielded against electric field (equipment generating high voltage) by using grounded shield. But it's creating issues against magnetic field(with an equipment having high current). What can be done in this case ? Will a shield having high magnetic permeability help?
I don't think so. If the high current is constant, it will not cause any interference with your cable. If the current is spiking periodically or randomly, then the spikes themselves produce high frequency electromagnetic fields. If the cable is already shielded against electromagnetic fields, then it looks like the amplitude of the field generated by the high current exceeds the shielding capability of the cable. There are two possibilities to fix the problem.
1) Use a cable with a thicker shield and make sure that not only is grounded, but it is also connected to the ground of the electronic circuit to which is connected. The ground connection must be done with a thick cable, to allow for enough charges to move through it to actually be able to work as a shield.
2) The device that is generated the high currents should be shielded as well, possibly enclosing it in a Faraday cage connected to ground as well.
In other words, both the source of the electromagnetic noise and the deviced that receive the noise should be well shielded. A magnetic shield with high magnetic permeability seems useless to me, in this case, because the problem is not a magnetic field but instead is a variable electromagnetic field. To shield electromagnetically a device, it is enough to create electrostatic shields around it.
Yours is a problem that has been studied for a long time, especially by car makers. In the case of a car, there are enormous electromagnetic fields generated by the spark plugs, and they have to use state of the art shields to prevent the fields to reach the electronics in the car, which is sited close to the engine, and thus difficult to handle. Sometimes, the solution to avoid this kind of problem can be very costly.
I live near a power line. I am looking for proper shielding. Is copper or stainless steel mesh curtain good shielding?
Well, leaving close by a power line is not necessarily a bad thing. How close are you? is that a high voltage power line? Or low voltage? How far is it from your house? Remember that radiating power decreases with the third power of the distance.
If you really would like to shield your house against the electromagnetic interference coming from the power lines, copper or stell mesh is fine, as long as it is grounded. But there rae two problems:
1) you should shield the entire perimeter of the house, curtains at the windows are definitively not enough.
2) if you succeed in covering all the external walls and the ceiling with the mesh, you would be totally isolated also from the EM fields that you would want (example: radio signals, also those necessary for your smartphone).
Are you sure you really want to do that?
Can you help me with my problem. I'm building a remote control snow blower using an Arduino mega 2560. I properly used shielded wire. But as soon as I start the gas motor the EMI from the ignition system causes the Arduino to freeze up.
Ignition of a ice motor can cause serious emi, at high power. A simple shielded cable is probably not enough to prevent the spikes of energy at high frequency to find their way to the arduino. I would need more details on what that wire is carrying to help you out. With what i have so far, i can only suggest to encase the arduino inside a metal box and make sure that both the box and the cable shield are securely connected to the ground of the snow blower. The negative of the arduino should also ve connected to ground. Then, depending if you are transfering just power or some sort of signal through the cable, you may also need to provide further filtering to it. Finally, when running the ground connections, make sure that you are not creating current loops, which would increase the problem, rather than reducing it. Note also that even after the ignition, the spark plug will continue to produce strong emi bursts. You are basically experiencing the same problem that car manufacturers had to face when electronics found its way to the cars. They had to spend a lot of effort to make that work.
here for honeycomb shielding vents
Hello! I have problem with a home recording studio and what I suspect is EMI from the tram lines close by. It manifests itself as a nasty "buzz" in the audio chain. Is there anything I can do about this? Thanks.
If the buzz is very high, it is probably a problem of missing ground on one or more devices you are connecting together. Before anything else, make sure all the equipment is correctly grounded and there are no audio cables with broken connection to ground.
@@eleneasy Thank you for answering! The noise is relatively low and is only present through amplification, (distortion plugins for use with guitar). The noise is also more active when a tram is speeding up and arriving/departing the station, which lies close by. It could be that the electromagnic induction pickups of the guitars are acting as antennas (?) and picking up EMI from the tram lines and surrounding power lines over the tram. It does not sound like low frequency hum (50/60 Hz), but is rather distributed upwards from around 125 Hz (centre frequency, and upwards to around 4 kHz).
@@iseeu-fp9po if the issue happens only when the guitars are connected, then the pickups could be the issue. You may need to unmount the pickups and lay down some copper tape in their caging in the guitar. The copper them needs to be connected to ground through the audio cable.
@@eleneasy Thank you again!
Grazie! How can I shield off my PC case to stop my single-coil guitar pickup from picking up those nasty HF CPU emitions?
If the pc had already a metal case, there isn't much else you can do. One thing you can try is to use one of those power cord with an RF trap close to the PC side. These cables have a bulge close to the connector that goes on the pc side. It is possible that the RF noise you are experiencing comes from there. If so. The RF trap will help.
@@eleneasy Thank you! I'll try it.
@@eleneasy I've tried it - no luck. I guess, only PC placement can help.
I think so. Try to plug the guitar Amp as far away as possible from the outlet used for the pc.
@@eleneasy There's no amp. I plug guitar to a USB audio interface and use a software amp.
I have a devious neighbor who uses a signal jammer to mess with my garage door signal - even though I have changed the code several times.
I know there are garage doors which have a billion codes, but those can be hacked also.
Any suggestions on what I can use all around my garage to block outside interference? A plug-in device that sends out a signal to protect large areas?
Unfortunately, to block the interference from your neighbor you would block also your own signal from the garage door opener. The only thing that comes to my mind is to eliminate the remote for the garage door and install, instead, one of those devices connected to the wifi of the house. Which can be controlled through Alexa or Google home.
@@eleneasy Yeah. I looked into a few of those. Reviews are saying they are hackable & have all kinds of glitches. Oh well. I will have to keep opening it manually & keep it powered off. Thanks!
@@yumyumkitty2104 have you tried to reason with your neighbor? Also, as far as i know it is illegal to scramble radio waves. Maybe you should check with a lawyer or the local police. The local police may actually be able to reason with the guy.
use padlocks ? manual hahaha......
use manual switch (sensors) and automated motors (mechanical setup)
Good explanations, but the music is annoying.
Thank you for your comment. Maybe you can help me on that. Is the music annoying because it is too loud? Or would you prefer there wasn't any music at all? I normally add it to mask the background noise, especially if using instruments in the lab. Any thought on this would be highly appreciated. Thank you for watching!
I dont know what you just said, but you remind me of Super Mario 🤔
🤣🤣🤣
I love the video and the music brother ✌️
Any wires Look up The Invisible Rainbow: A History of Electricity and Life by Arthur Firstenberg = Biological effects on all life!
the background music is unnecessary
Well, yes, but in four years I only got one complaint. Do you actually feel it annoying or just unnecessary? I'm thinking of running a poll among all the viewers. Would that be OK with you?