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In the past, I have crammed a couple of 10nF capacitors into a 9-pin D connector housing, wasn't particularly fiddly - but I guess the point of the seal is that is quick and easy to install...

It has been around in various forms since 1970s.

Hi Ralfbaechle, that's really good feedback. To be honest, as you can see, our videos are mainly focused on EMI, EMC and high-speed measurement, I have been very surprised to see so much interest in this particular video, which is not even one of my personal favourites. But it does highlight the issues we face in our job and life, we have some more videos coming on co-aixal cables, in which I used two different methods measuring the performance of co-axial cables, which are scheduled for November 21st and 28th. It will be interesting to hear your feedback by then!

Electrical conductivity is similar, but aluminium is much cheaper and it doesn't change as much as pure copper in open air.

I used to study the possiblity of using Aluminium wire to replace copper wire in EV charging cables, because aluminium is a lot cheaper and lighter, but at least at the time i studied it, there were big challenges.

Many thanks Rubhern, we will try to make more on this subject for sure. As i mentioned to the other viewer, this video took me by a massive surprise. I was not expecting so much interests, but we have more videos schedueld on cables and connectors in the following weeks and months. Typically, our vidoes address different issues related to EMI, not just cables and connectors, but we do take great advice from our viewers and we often make videos according to your need. Thanks

@@MachOneDesignEMC The "lighter" property would be appreciated. I was surprised when I fond out an extension cord for a 12V batteri charger had aluminium conductors. The problem is you can't solder it and if you clamp it there needs to be a spring in the clamp because aluminium deforms with time.

Hi David, i guess that is related to radios, it would then depend, here is a better resource for you incompliancemag.com/cable-antennas-and-ferrite-cores/

@@MachOneDesignEMC Wow. Very interesting. Thank you very much for your time. Yes, it was about common mode currents on a coax cable of an HF antenna, amateur ham radio. I always use multiples of 1/2 WL coax cable to see the same impedance of the antenna at the end of the line and I wonder if the line being resonant is good or bad, or if resonance can be avoided using ferrite chokes, and where to put them on the cable. I will study your videos and the document of your link. Thanks again.

Indeed! It’s the little things like this that people overlook when questioning why they’re not seeing top performance at the edges of performance envelopes. This is going to get increasingly important for data exchange/infrastructure.

Glad you enjoyed it!

Exactly, and if you want to buy a really good quality one, then you have to pay incredibly high price. I think there should be a standard in the industry to regulate this.

Noted! We will definitely improve this in our future videos!

Thanks, indeed, I was shocked when I opened the clamp shell. But I shouldn't be surprised! Perhaps you can get much better ones from trusted distributors such as Digikey, mouser, etc, but I bet the price will be four times more than this one. I spent 15 GBP on this one.

Indeed, this is especially concerning for everyday use. I often receive emails from people who are into sound systems, music, and gaming, sharing horror stories about their experiences with EMI.

I believe that one of the issues is that most of the consumers aren't qualified to have an opinion on the EMC side of things. Therefore, manufacturers focus on easily visible things such as the feeling the cable gives when touched, or how good connectors look, but the invisible things, such as if the shield is properly connected, are the good RF gaskets inside and so on, all of that is not visible to average consumers, and therefore gets cut to save on costs, or to increase profits. It's very similar for Ethernet cables, for computer video cables and so on.

Hi Torito, I think it should be a combination of good grounding and shielding work together to reduce ambient EM noise. The problem we found in the industry is that electricians are not taught about grounding for EMI, they are familiar with the HV safety aspect, but not EMI. Shielding wise, unless you shield the whole house/office, otherwise, I would focus on improving the grounding of the system and use good filters on the mains.

@@MachOneDesignEMC Thank you Mr Zhang. I have shielded the whole house with conductive graphite paint from Yshield. All that shielding is grounded. I also installed some Graham-Stetzer capacitive filters. I want to try some inductive filters connected in series on the main circuit baut I have this weird electrical installation with two phases and no neutral. I measure 133V between each of them and the ground and 230V between the two phases. So all those inductive filters are supposed to work in series with both phase and neutral. What do you think the approach would be in this case please? I would like to measure the frequencies present in my wiring but most spectrum analyzers only go as los as 9 KHz and I need something to cover everything between 1 Hz- 500 MHz. Also i'm not sure haw to connect it to be able to visualize the noise present.

It is going to be very tricky to explain this in a RUclips video, you can find this either on proper text book, or attend an EMC training workshop/seminar. We have a few follow up videos, which we hope to cover some basics. We do a great deal of detailed explanation in our training programme.

It is just some switching MOSFET, you can design the gate drive turn on resistor (make it close to 0 R), so the rise time is sub nanosecond

There are many ways of measuring the effectiveness of a shielded cable. Using a current probe is just one of these methods. As I mentioned, when it comes to shielding effectiveness of a screen, the theory often doesn't match with the reality. So a current probe method measures the current on the outer surface of the shield, which should be zero if the shield is really good and terminated properly. if not, you are gonna see significant CM current on the outer shield. I would recommend watching this ruclips.net/video/bKaBWkOyMe8/видео.htmlsi=ZmWBJIa7sG2z7WPT

@@MachOneDesignEMC Thank you for your reply. But that is actually a question. In that video, you provoke high CM current by attaching an extra piece of wire to the central conductor. In this case, you measure CM current that is just because of extra displacement current from the central conductor to external room ground. But here you measure the effectiveness of the shield using a similar approach but not connecting anything to the central conductor.

I assume here that with a bad cable, the skin depth is relatively high so return path current density is also presented on the outer layer of the cable, and due to finite conductivity and inductance, the is some voltage drop on the outer side of the cable, that causes the CM current... Thank you.

Thanks Tomas, you are very kind. Yes, there are so many myths about terminating the shield, which we hope to answer in future videos, stay tuned. I just need to find/build some circuits to prove the point.

@@MachOneDesignEMC Super!

@@MachOneDesignEMC As someone who has to terminate shielded cables daily, I eagerly anticipate your video on this in order to dispel some of those myths and let me know the best way to terminate them. For this reason you have another subscriber.

And Tesla, not the EV!

I think we will start designing some really fun EMC SIPI related shirt and sell them, just for fun or charity.

Glad it is not a 🤌. Lol

Hi, the point is to demonstrate that a ferrite works the best when it is placed in the low impedance point, in this case, it is the radio side. As you can see from the video, close to the tip of the antenna, we have almost zero current, that means at the tip side, it is high impedance (because of low current), therefore, if you place the ferrite on the tip end, it will do nothing. Also see ruclips.net/video/bflbmTCVKk0/видео.htmlsi=z8PSYyEhk9kjGXAO

@@MachOneDesignEMC thank you for that explanation. i will go look at the video you have linked

Thanks Felix, will do

Lol. No worries. We only care if the content is interesting to watch or not.

Good Idea, Koelie, to do that, I need to buy one first :).

That is correct, I have cited his article in my early videos. I should have cited his article in all videos that I used the spark generator.

Are you trying to do jamming? If so it would help to know if you are just trying to be a nuisance or is this for a strategic reasons.

@@Xsiondu lol no. I was thinking if would actually be better to have a poor clock frequency for a micro( lots of variation ) if that would improve emc noise levels by not having a peek be so high, or if it would make it worse by essentially having your peek move around.

@@Cydget This sounds like poor mans spread spectrum clocking, which purposefully spreads clocking instead of relying on (essentially defective) behaviour. Spread spectrum clocking allows multiple devices to communicate while also maintaining the benefits.

What you described is spread spectrum, we have made a video, but recently when I attended the EMC Europe, I attended Prof Bernd Deutschmann's presentation, it was so good, now I think the one I made is not good.... But I think it serves some basics, which we hope to release the video soon.

Jamming and RF weapons are hot topic, when I was in this year's UK, US and European conference, such subjects were really popular. I will try to do some videos in the future. Well, thanks for suggesting all these, because it keeps giving us good video ideas.

Thanks for supporting us. We hope to make more!

Hi, no problem, it is www.mouser.co.uk/new/texas-instruments/ti-ucc28780evm-002-eval-module/?srsltid=AfmBOopoODwIxL2kVqKsavr8RTruF6-oP9KR8A8FtQuaTwDbkJf5utpT

Thanks for the support. We will try our best.

Correct Tomas, but I failed to find a way of finding the rest of the CM current. You know, I thought the CM on the primary side and the secondary side should be more or less the same level, but, as shown in this video, the primary side of the current is a lot less. I suspect it is due to the CM filtering on the AC side. But how can we prove this without taking all the filters out? If our assumption is correct, then there must be another path returning the CM current back to its source, just before the filter. Difficult to measure in this case!

@@MachOneDesignEMC Hi again, if the CM-current was exactly the same on primary and secondary side, wouldn't that mean that there is no radiation at all from the primary side? The radiation that is common between the primary and secondary side consist of what the stray-capacitance is able to transfer. Ideally, without stray-capacitance, the radiation from the primary- and secondary side may look totally different I suppose?

Hi, you really know your stuff! I am not fortunate enough to have the Tektronix probes, I know they must be well constructed. The issue I found, even when using top class Hall effect probes, is the random noise pick up in the ambient. About 10 years ago, when I was working for a big company, we used to clamp a probe on the body of a handheld product and left it there overnight for measuring the CM current. The following morning, we noticed lots of random noise pick-up due to the E field noise. I guess, when it comes to very high frequency event, such as an ESD event, it is always tricky to shield the E field. I remembered D Smith used to do lots of experiments on this subject.

Ok, we may need to create a path for the magnetic field for inductive coupling. The copper shield is increasing the 'overlap area' and 'parasitic capacitance', so that the voltage built up on it is reduced. So we don't need a closed surface. Is this correct?

Exactly!

Hi Bill, no problem at all. I am sure we will see each other again very soon!

Well spotted, 6p and 20p are not so much difference for the results (for Low frequency), I think I may have two sim models there and I chose different values when I was building the models. I should have used the same value for consistency. Many thanks

Will do! It is in the plan

Hi Simba, i have a video on this. see ruclips.net/video/jYR49UghNj4/видео.htmlsi=r94yUgrOPxvVn9wV

@MachOneDesignEMC Yes, I saw it a few months ago, and I still don't think ferrites can prevent RF interference from penetrating. also, do you think toroidal cores (iron powder cores) would work better for lower frequencies?