It was a great pleasure to support and accompany you at our location in Munich! The video turned out really cool! We are already looking forward to your next visit! :)
Thank you @wuerthelektronik for facilitating this great video. As you can see in the comments, there is much interest in this topic and many people are simply unfamiliar with EMC test procedures and EMC as a whole. I salute you for raising awareness and educating this community, and I look forward to watching the next visit to your facilities.
I know that you are just some marketing heini responsible for public relations propaganda and have nothing to say, but could you atleast bring the idea of Open-Access into the company? For me personally this is the worst about this property based ideology, that we have no access to means of science and engineering, besides that all human knowledge is locked behind "intellectual property".
I have been designing products for 35 years and I have always had excellent experiences with Würth Elektronik components. They are excellent. In such a design as this DC-DC converter I would immediately switch to a 4 layer PCB, but I would use both layers 2 and 3 for ground with plenty of via stitching. I would also flood any unused space on layers 1 and 4 and stitch those to ground too. It's a crazy rabbit hole. Robert Feranec is an excellent resource for expert lectures on EMC and PCB design.
@@Gastell0 Vias are inductors in those frequencies and would affect negatively more than the incomplete faraday cage you get from outer layer GND pour would help.
@@Gastell0 That's a recipe for cross-talk. The primary goal is to have a matching return path. You get that with internal ground planes, and additional isolation with two ground planes. You can often do a quite a bit to improve two layer circuit boards, but it does take far more design time and perhaps additional circuit board area.
@@Gastell0 In addition to the other replies, you cannot put your components into these inner layers. They would sit on top of the ground layers and every signal has to go down with vias and you rip your solid ground planes apart.
Here's a funny story. The office where I work was using several consumer-grade Wi-Fi routers as access points. We are in a research campus near a company that works with satellites. One day the CRTC (Canada's telecom regulator) showed up with a rather expensive RF spectrometer looking all over our building like they were witching for water. Turns out one of those AP's radios was putting out too much energy into adjacent frequencies and those frequencies happened to be what they were using to communicate with the satellites. Every time they had to turn their dish towards our building, they got a bunch of noise. Just goes to show how important it is to meet EMC requirements!
@@reverse_engineered I worked for a company that supplied computers to schools. The management wernt happy about the time and money spent on ensuring the kit met EMC standards. Then one day they recieved a call from a school saying that a child with a pacemaker was getting heart palpitations when he walked past one of our computers. An engineer was dispatched to investigate where upon it was discovered the problem was a monitor supplied by a third party not our kit. We gave them one of our CE approved monitors and breathed an enormous sigh of relief. The Technical Director never complained about signing cheques again.
I remember there being a news story years ago of a radio-telescope here in Australia that kept picking up random bursts of interference around the 2.4GHz spectrum at regular times throughout the day but they couldn't pinpoint what it was or where it came from. Eventually they figured out that it was caused by employees opening the door to the microwave oven in the break room to stop it whilst it was running. Just enough microwave energy would leak out in-between the time the door opened and when the oven turned off to be picked up by the telescope.
A couple of comments from an old PSU & EMI guy... Sometimes the worst source of EMI is the gate drive current spike inside the chip (assuming the MOSFETs are integrated), which typically needs to be dealt with caps at the chip supply pins. Also, a single uF-range cap isn't enough in most applications. I'll use tiny caps in the 330pF-3300pF range as close to the device pins as possible, with larger bulk caps a bit further away where there is more room. Remember, it is the high-frequency edges that matter most when it comes to suppressing EMI, and larger bulk caps don't do a great job at high frequencies.
Good point. No matter how small the bypass cap, it still has SOME "ESL" (equivalent series inductance) to it, not to mention SOME ESR, too. These stray inductances and resistances create zeroes in the impedance curves, thus limiting the ability of bypass capacitors to do their things. Too many of our fellow engineers assume that a capacitor's impedance curve keeps decreasing as frequency rises, but the zero causes this curve to flatten out at 1/(2πRC) so that the R (esr) limits the upper frequency. Usually the R is about the same for each family size of capacitor (0603, 0402, 0201, etc.), so by using a smaller value C, the break point of the curve is at a higher frequency, thus improving matters. ESL is more problematic because once the break point is reached, then the impedance actually rises as the impedance changes from being a capacitor being an inductor!
Some things never change. Old rules still apply. The only thing that changed up to this day is that you can now very easily get 100nF in a 0402 SMT case size, which is the smallest of the widely used types. 0201 and 01005 are, of course, also obtainable, but then you're getting into "diminishing returns" territory, where it's not gonna be much closer to the IC die if it's *that* much smaller. In any case, I believe it's important to address the common misconception that you need to parallel 100pf || 1nF || 100nF for the decoupling to be good. People often do it with the same case size (e.g. 0603) for all 3 parallel capacitors, thereby entirely missing the point of parallel caps: tiny ones to be as close to the pins, and then the physically larger ones can go somewhere a bit further to cover the bulk.
Full time PCB designer for 10 years here. For EMC reduction, i would start at better layout. Its usually the cheapest solution when it comes to volume production. Component changes should be done if you really need it, since you can save money and space. Nowadays virtually every board is a multilayer board for this reason as well as complexity. For 4 layer boards the "traditional" stackup of Signal - GND - Power - Signal is better than a 2 layer board, but its till quite bad. The main reason is that when you switch the signals from top to bottom, you also have to switch the reference layer, and you cant connect GND and Power for obvious reasons. There are some kludge ways to improve this, but its a lot better to go to a better stackup. Now days what is recommended is a stackup is Signal + Power - GND - GND - Signal + Power. This is an amazing way to minimise radiated emissions and it really doesn't take all that much space. As others in the comment section have pointed out Robert Feranec has great videos on this topic. My personal favorite are with Eric Bogatin and Rick Hartley. Great video i loved it.
Reducing EMI from power supplies is an art. Every switcher in my house has some kind of noise suppression. Over the years I've become adept at finding the cheapest and most effective solution. I do this, of course, to minimize noise to my ham radio receivers. The real question is, how to I get my crazy neighbor to let me fix his noisy military grade radio jammer power supply.
I can relate to that, i am a Ham Operator my self, in the winter time i almost know where a heating system is powering on, or when the neighbours are switching on their cheap LED Roomlights. But til now the PV Systems around here quite silent. For your neighbour, ask the local authorities for assistance. I don't know where are you from. In Germany it is the Bundesnetzagentur, if you file a complaint the will make a appointment with you at the location and take measurements and if the owner of the HF source will not comply the BnetzA can prohibit the use. Maybe it is a Power supply before thermal self destruction, a fellow Ham found something like that in his neighborhood, in this case is was a almost molten power supply from a WiFi Router.
@@mariom.9472 I'm not sure things here work the same as in Germany. Here in the U.S. the government usually only takes action if you are doing something annoying to them (the government), while I doubt very much they would bother to correct my crazy neighbor for annoying me. For example, last year I discovered a local construction site (~4 miles away), employing unlicensed illegal aliens using Baofeng HT's and talking all day long, every day, in the middle of the 70cm ham band, interfering with amateur satellite downlinks. I filed an official complaint including recordings of the radio traffic to the FCC, and although they did send me confirmation, it has been almost a year and they have done nothing. For finding noise, I built a portable magnetic loop on a stick, hooked up to a Tiny Spectrum Analyzer with waterfall display. So I can traced the location of a noise and triangulate its exact position, even if I'm a hundred feet away. In this case the neighbor let me scan the outer walls of his house and I know exactly what is causing the noise, only he refuses to do anything about it, even if I supply him with a replacement power supply.
When I was a kid my neighbour had a kitchen mixer that jammed all tv and radio on both am and fm in the whole street when he turned it on. I can't imagine the hassle of trying to receive weak signals when people are running their cheap motors in badly designed products for everything day and night.
Useful note: It is possible to 'self certify' for CE by making a DOC (declarationof conformity). The CE mark covers both electrical safty (usually under the Low Voltage Directive) as well as intentional and unintentional radio frequency emission (EMC). You dont need to do anything more than the DOC, but if things go wrong and an inquiry is made, you really want some evidence to back your declaration. This can be in the form of a emc 'pre-cert' lab report that will be less expensive to obtain than going to a full blown certification body. For the US I understand there are no strictly required electrical safty regs but there is FCC which covers EMC. Self certification is less common here, but you can import up to 3 items at a time for personal use with FCC form 740 pt.II item 7. 😀
I went to a Würth EMC expo (by invitation) at Duxford some years ago. Half a day listening to some very interesting theory and sales (genuinely....Würth really are good at this) and half a day looking at the aircraft in the Museum. Thanks Würth...a great day.
I made some simple indicator lights for my friend's bike (e-bike / pedelec). We used a cheap MT3608 boost converter to convert the 6V I got from one pin of his battery controller to 12V for the lights. We tested it in his garage and it worked great, except for the fact that his DAB+ radio briefly lost reception every time the indicator lights were turned on :D
So good to see how much the industry has changed. I got into EMC testing over 30 years ago when the radiated testing was all done outside on an open area test site, normally with a manually tuned receiver system. So much easier these days with a screened room blocking out all of the extraneous noise.
EMC sometimes feels like voodoo and certainly is very close to magic. A few things I learned over time: 1. Use fully shielded inductors whenever possible. 2. Inductor orientation matters: you want the start of a coil to be closest to switching element 3. Avoid long loops 4. C0G caps can really help with higher harmonics 5. Feed through caps are better than shunt ones
You also have to keep in mind the shape of the traces on the board themselves too. I didn't realize it until I had gone into radio that 90° angles emit RF like hoses.
at JLCPCB and similar manufacturers, there's almost no price difference between 4 and 2 layer boards, especially compared to shipping and assembly so just always start with 4 layers for DIY projects unless it's a super duper simple design. You make your life layouting easier, it'll work better for EMC as well as general performance, and you can make it fit into the size you want more easily. The stackups of PWR/DATA GND GND PWR/DATA or PWR/DATA GND PWR/DATA GND are typical recommendations that work for many applications
I designed my first 4 layer board earlier this year and really enjoyed it! Layout is so much easier and clean when you have easy access to ground and power. 😊
I totally agree and I quite like that first stackup for most applications. Excellent advice to send beginners in that direction. 👍 Power can be run as traces without issue and the ground plane is by far the most important to have uninterrupted.
A 4-layer board is rapidly approaching unfixable though. Any major corrosion damage to vias or inside layers is basically a death sentence. Conformal coating would be very much recommended out in the field.
I'm glad you've brought this subject to our attention; it's often ignored and causes headaches trying to work out why circuits are misbehaving. A few years ago I was fortunate to be involved in setting up both types of EMC lab at my workplace - it was nice to see the equipment again in this video, it brought back some memories!
Würth not only deliver great components, the also share their knowledge about it. I love their books and "the Trilogy of magnetics" is one of the books I own and use a lot. We had this book at a previous job so as soon as I got a new job, I had to buy this book myself. I refused the gesture from my current boss to buy this with company money. The book is that good that I want to have it on my own bookshelf in my own workshop 😁 And yes: Würth components are not always the cheapest but the capacitor and inductor kits saved me that much development time that they are worth their money
This episode reminds me of my old job at a company that makes HiFi speakers. One of our engineers was an absolute genius at making crossovers. I started building own speakers and he did the final touch with just a few caps and coils. The results where always mind blowing.
Great video! As an amateur radio operator I am fully aware of the issues that poorly designed electronic devices have on the electromagnetic spectrum. From PWM LED drivers, to switch mode plug packs and USB chargers, Ethernet networks and right up to my VDSL2 modem... all the RF soup makes listening to weak HF radio signals a challenge. It takes a lot of work to design a fully EMC compliant product and many manufacturers take shortcuts to save costs.
Exactly 6 years ago I started to watch your videos 😊. Till this date you have shared so many knowledge to your viewers. Thank a lot for creating such informative videos ❤. Your basics video and diy and buy helped me a lot. If RUclips never suggested me your videos probably most of house electronic items would have become part of scrap yard or electronic waste 😅. Thanks a lot 😊 for such lovely and for informative videos although some part of your videos goes over my head if I have no knowledge about it 😂 but I getting better day by day 😉
You can also shield components and/or parts of circuit board to reduce EMC emissions. Also, even if the board itself doesn't pass, the final products could pass in a suitable grounded metal enclosure. Im pretty sure you could do a "EMC shield board", 2 layer with a top 100% plane and then edge solder connections all around, looking like a postage stamp. Then mill out bottom of this board so it fits on top of the board you want to "protect". Voila, you have now shielded emissions. This works as long as no component is higher than the thickness of the shielding board, but if a single component is higher, you coukd make a hole in the shield for that component and still have a good shield - as long as the high component is not the radiating culprit.
One solution you skipped for radiated emissions is shielding. The simplest solution is to put your project in a metal box but that is not the only way to do shielding. If you look at some PCBs that have RF transmitters/receivers you will notice that some of the circuits are in metal boxes that solder to the PCB. Another approach is to coat the inside of the plastic enclosure with metalized paint. BTW, I designed a pacemaker programmer that passed the medical EMC directive. I did initial testing at SWrI in Texas and final testing at TÜV.
But then you should add input and output filters, otherwise it just creeps out along the cables and your shield is useless. And shields are expensive, so first try other solutions.
I spent a number of years on getting my designs to pass EMC requirements, and then spent some years in my employer's EMC lab helping folks test their designs and fix problems. Wurth produced some nice ferrites and other devices for addressing EMC issues. I have to say that Fair-rite makes some nice stuff too. Switching converters are one of the biggest offenders in regards to generating noise, and board designers should follow the converter manufacturer's guidelines (and there are often board layout suggestions). EMC is an interesting and complicated subject, and certainly not intuitive.
This field was what Siegfried Linkwitz' (Linkwitz transform) worked in at Hewlett Packard. His work on audio and LS design was fascinating and controversial.
Месяц назад+4
Hey I work in this building :) Wish I knew you were there, I am big fan! Next time, step by Würth ICS office to see some amazing embedded projects.
This is a really helpful video! It's difficult to find introductory material on this topic, since it tends to be an advanced practice and not that relevant to most hobbyists. While I was vaguely aware of some of these, pointing out specific causes and solutions really helps to understand more generally what to consider. Thanks!
Very informative. Keep it up. A potential series on covering certification is not at all a bad idea. Will be cool to see how you solve each hurdle. Whenever there's a DC DC converter, going with atleast a 4 layer board is necessary. We usually go with 4 layer board with 2nd and 3rd layer GND, any left over space on top & bottom will be made as GND pour with via stitching.
Great video on an important topic! One thing I never quite understood is why multi layer boards don't ever seem to put the ground plane on the outsides and the traces inside to minimize radiation. I'm imagining that the components could go directly to the inner layer through vias, which would make troubleshooting harder, but might help in specialized applications.
Funny thing. Some 35 years ago. Though being a mechanical engineer, I had the task of designing an industrial multiprocessor board with lots of I/O. Size approx. 10 by 10 inches. To be fitted in electrical cabinets with 3 phase contactors and other noisy stuff. To simplify board design, I used 4 layers boards with ground and power planes on the outside. Hundreds made, working flawless. Seems I did a clever thing.
More of these EMC topics and videos from Wurth lab. Now i know where to buy components for my power supplies. This is a gem🎉🎉🎉 will be checking out Lorandt youtube channel. Great to see people sharing knowledge on such a complex area making it motivational. Sometimes these labs a very difficult to access but great to see what goes inside looking at all the setups.🎉🎉🎉
Fun stuff. Most of what I work with is up in the 30 GHz range but when testing our products we have to perform both the conducted and radiated tests as required by the applicable ENs before we can declare conformity for our product. On the home front, we had some landscaping work done which included some lighting that was powered by the available 24 VAC for the existing low voltage lighting. The landscaper finished the work and left before dark and when I returned home a bit later the lights were on and it all looked very nice. However, I couldn't open my front gate using my remote control and had to resort to the gate's keypad which is hard wired to the gate opener. Long story short, I traced the problem to a new up-light with LED bulb that had been set up near by gate opener. The LED bulb was generating enough RFI up in the 315 MHz range to prevent the receiver from detecting my opener unless I walked up and stood right next to the gate. The landscaper wouldn't believe me until he saw the problem with his own eyes. The solution was to move the up-light further away from the gate opener and to replace the LED bulb with a different model that didn't spew RF all over the place. Unfortunately the landscaper forgot to leave the noisy bulb for me. I had really been looking forward to having a look at it with my spectrum analyzer and SDR receivers to see where and how much RFI was being sent out. Anecdotally, I hear from a lot of amateur radio operators about problems from switching power supplies, solar array micro inverters, and LED bulbs that really cause problems with receive noise in the HF bands.
There is actually a conducted immunity EMC test you can do probably at home. The DPI (Direct Power injection) test. All you need is a signal generator, a power amplifier and a oscilloscope. (IEC 62132-4)
3:30 honestly, that is factually not accurate. Some converters have their worst EMI at the 50% or 99% point. I know you had to simplify for time constrains and low and high load are good compromises, but some products have strange resonance effects only at certain load points.
You forgot 50% of the EMC equation: There are also requirements for what you need to accept and handle when it comes to incoming noise as well. A lot of cheap audio amps are not properly immunized for conducted noise on power. Many also amplify common mode noise directly due to single-ended inputs too.
Würth has some very nice lab space! The place I’ve gone for EMI/EMC testing was a dungeon relative to that! (Haven’t been there in a few years and my understanding is that it’s been renovated since, but I bet it still pales by comparison.)
This video was so fun, I have no clue what was going on with all the electronics logic, but I'd love to learn, I'm currently trying to expand my knowledge into embedded software.
These boards are legal in any case, at least regarding Europe with its CE. Except of rare cases such boards count as "components", as like a chip, capacitor or resistor. None of them need to fullfill the CE requirements (there are requirement regarding RoHS and REACH tho). CE decleration is only required for a PRODUCT. Therefore the board integrator have to validate and fix any kind of EMC/EMI issue. This always have to be done - no matter if the used components are certified by itself. So, as a general rule (as I said, there are exceptions), such project boards don't have to fullfill the emission regulations. The final product created with it have to.
@@askLorandt it has not changed, because it is technical not possible nor relevant. Parts are parts by definition. CE applies to products, but parts can be products if some characteristics apply. To be clear at this point: In some cases it is strictly forbidden to make a CE marking on parts, because it's not legal according to the compliance guidelines. As some kind of exception, I already noted this, are RoHS/REACH declerations, as part of the CE process. You might ask why I wrote it is technical not possible. You, as manufafturer, will define the "intended operation state", which is measured afterwards. Let's be a little bit sarcastic here: You, the manufacture, decripe the intended operation state "no power". You will measure nothing. True, this is nonesens and can't be declared this way. But a part can be used in countless possible veriants and this can't be measured. For example: This sepcific DC/DC converter you try to sell here, just declare in your datasheet: Put common mode chokes on input and output, a bank of capacitors and put it all together in a metal can.... well, you can rediate whatever you want. Accodring to your "intended use" it doesn't matter. That's why the majority of parts are not part of any kind of EMI/EMC measuring. How they behave is defined by there use in the product where it gets implemented. That is, why even you, as manufacterer, integrate some kind of CE approved part - let's say a common brick power supply for example - need to measure the whole product/machine/assembly afterwards, because the part itself may comply, but how you are using it in your product may not.
Thanks for this! My company uses NCEE in Lincoln, NE to do all our testing. And our equipment is located in the middle of a corn field! (Middle of Nowhere!) : )
LOL as a kid i used to create "FM" transmitters with old ECC85 vacuum tubes. They were excellent sideband generators all the way to our television (before cable so with an actual antenna on the roof) Pretty sure my transmitter would have blown up that measuring antenna :D Awesome vid! And thanks @wuerthelektronik!
Thanks for going to the effort to make such complex and specific videos about specialised topics. While the DIY or BUY option here - as far as testing labs are concerned - is definitely on the buy side of the scale, the knowledge gained from your experience there provides practical lessons to improve our own designs regardless. :)
I'm so glad you are taking on this topic as it is generally ignored. I would be very interested in a follow up video that tries out more solutions. In particular, I wonder what difference 4 layer design makes. Maybe more information about what the EMC tests involve and the limits.
The most significant example of EMC problems I've seen is from a cheap HDMI cable I bought that prevents the TV from receiving digital broadcasts when it's plugged in at both ends.
Apparently here in the USA, FCC are obviously strict about RFI and EMI, yet they allow some hobbyists to get away with it, at least up to four or six projects, that's it. I am sure it might be the same elsewhere, you gotta look at RFI / EMI rules for where you live at, they differs somewhat. If you wanna sell the completed boards to somebody else, you definitely want to have a decent oscilloscope so you can rework and / or respin the board once you find out why. It's your responsibility to make sure it doesn't disturb TVs and any other electronics. If you work with SMD components, it's a bit easier to manage RFI with solderable Faraday cages which phones almost always use. It's kinda recommended to use the shields with DIY RF circuits in order to get the cleanest signals possible as outside RFI and EMI would mess with it making it a bit harder to discern via oscilloscope.
EMC topic is voodoo for many people, but as the frequencies of consumer electronics interfaces increase, it is rapidly becoming an issue. For example, in terms of required product testing before market, a failed EMC test means lost money and time, which is initially not expected by the board designers and product developers. This vid teaches us that even products on the market may have their pitfalls outside of the basic usage scenarios.
Fabulous video. Since you have made the first video about your design, I ordered the China man version 3.3Volt version as I don't have components for your design. I use it for my Xiaomi temperature / humidity devices with a Lithium Iron cell. The CR2032 cells don't last long. So, thank you very much for introducing me
If you took your staircase light project from a few months ago where you had a very long switching trace do a whole lap around the board and scrambling your digital communications to the EMC lab, I bet it would make the DC-DC converters look great in comparison.
Any power supply or voltage converter should be placed inside a shielded enclosure to prevent EMC issues. If they have DC outputs, filtering of the outputs should be done to remove any noise on them. You aren't going to make a buck or boost converter that doesn't make EMF noise. Same goes for inverters and rectifiers. There is going to be noise from the circuitry. You can make an enclosure using plastic and conductive paint if weight is a concern, just remember that you need to make electrical contact on all seams of it and to ground it so the EMF is being sent directly to the chassis ground of the circuit of the equipment, vehicle, or building so it is dissipated instead of being passed through the enclosure.
This reminds me of the interference heard on Ham Radio, caused by some L.E.D bulbs and fluorescent light fixture. Actually- If you put rj45 connectors on each end of telephone cable then interference can be heard on FM radio between 85.5Mhz - 87.7Mhz and this all reminds me of back in the day a simple break in a overhead communications cable resulted in the AM radio's & ham radio's being blasted with noise and not even JPO? (Called Ofcom nowadays) knew until someone complained about their landline not working and tired engineer had rectified a break and the noise went away.
I would like to see more information on preliminary in-house testing, instead of "you can't do it without all this specialized equipment." Those labs are extremely expensive and as small scale designers, this would quickly bankrupt us. There must be a way to get a "feel" for whether your circuit will pass before wasting time and money on this expensive process.
Well the best advice I can give u Get urself AM radio Take ur product, portable power source and your radio deep into nature (like a forest), so u get away from all the city noise Sweep acros am band while ur device is powered and observe if u hear any change in sound on the radio while the device operates If u hear noise, then device is bad AM doesnt lie, AM shows all ur mistakes Fix ur product, if u dont hear noise ur good PS: regular am radio usualy operate on lower frequencies, but there usualy problems are so if u fix for lower frequencies, u fix for higher frequencies If u want to test vhf, then u can get airband receiver
You can do some rough pre-compliance testing for sure. Get a metal table, 1-2 LISNs, and a 1-2000$ spectrum analyzer for conducted emissions. You can use a big Zarges aluminium box as a "poor man's GTEM cell" to get a rough house number where you are with radiated emissions. But esp. the last one will not be a proper measurement of course. More like you are looking for anything that sticks out in the spectrum and attenuate it as much as possible before attempting a certification run. In Europe I have also made good experience with the RF departments of local universities being willing to help for relatively small money. Not sure how that works with for-profit schools in other parts of the world though. The reality is also that if you want to sell a product in a market that requires CE or something comparable, it is often enough not worth the trouble as a small-scale guy. Those tens of thousands of €/$ are just a fraction of the potential costs including electrical waste, legal risks and other cost factors.
Great video! I really found the PCB design optimization segment interesting. Can I suggest a video on PCB design best practices? Your videos motivated me to create my own PCBs and I have made many over the last few years
In past decades much of this information was known only by old men with white hair and beards who were called the wizards or the bears. Video such as this are excellent and I hope to see more here. If you would like to dive down this rabbit hole more, I recommend Robert Feranec's videos with industry experts. One thing to remember is that there is one set of rules for DC to maybe 10-20kHz, another set of rules between 10-20kHz and 6GHz, and a very different world above 6GHz.
I learnt something new today! I was designing my own budget smart speaker a few weeks ago, using cheap buck boost which coincidentally was the problem when i was troubleshooting it as my speaker output sounded just like the one in your video what are the chances that i get my answer to why it was happening so soon! Thank you! It was very puzzling why it was behaving so weirdly😊
A proper isolated booster from 5V to 12V that had low emi would be super helpful! Then you can use a bt source and amp share the same ground/battery without ground loop noise.
Was a pleasure for me to assist you! 🤩
Glad you like the video😉 And thanks for helping out👍
Super cool guys!
I dont see any EM videos in your channel, have you hidden it?
@@yoppindia they were on the companies channel
Thank you sir
It was a great pleasure to support and accompany you at our location in Munich!
The video turned out really cool! We are already looking forward to your next visit! :)
Thank you @wuerthelektronik for facilitating this great video. As you can see in the comments, there is much interest in this topic and many people are simply unfamiliar with EMC test procedures and EMC as a whole. I salute you for raising awareness and educating this community, and I look forward to watching the next visit to your facilities.
I know that you are just some marketing heini responsible for public relations propaganda and have nothing to say, but could you atleast bring the idea of Open-Access into the company? For me personally this is the worst about this property based ideology, that we have no access to means of science and engineering, besides that all human knowledge is locked behind "intellectual property".
hello wuerth elektronik I bought some capacitors of yours a few days ago and they look nice
Great to see the in depth approach and the background information. Before this video i only knew Würth of the calenders, wich where a bit shallow.
I have been designing products for 35 years and I have always had excellent experiences with Würth Elektronik components. They are excellent.
In such a design as this DC-DC converter I would immediately switch to a 4 layer PCB, but I would use both layers 2 and 3 for ground with plenty of via stitching. I would also flood any unused space on layers 1 and 4 and stitch those to ground too. It's a crazy rabbit hole. Robert Feranec is an excellent resource for expert lectures on EMC and PCB design.
Thanks for the feedback and tips. I bet with 35 years of experience, you have seen some crazy designs.
What kind of difference can it make if opposite is done, both outer layers used for ground, and 2,3 for current and signaling?
@@Gastell0 Vias are inductors in those frequencies and would affect negatively more than the incomplete faraday cage you get from outer layer GND pour would help.
@@Gastell0 That's a recipe for cross-talk.
The primary goal is to have a matching return path. You get that with internal ground planes, and additional isolation with two ground planes.
You can often do a quite a bit to improve two layer circuit boards, but it does take far more design time and perhaps additional circuit board area.
@@Gastell0 In addition to the other replies, you cannot put your components into these inner layers. They would sit on top of the ground layers and every signal has to go down with vias and you rip your solid ground planes apart.
Here's a funny story. The office where I work was using several consumer-grade Wi-Fi routers as access points. We are in a research campus near a company that works with satellites. One day the CRTC (Canada's telecom regulator) showed up with a rather expensive RF spectrometer looking all over our building like they were witching for water. Turns out one of those AP's radios was putting out too much energy into adjacent frequencies and those frequencies happened to be what they were using to communicate with the satellites. Every time they had to turn their dish towards our building, they got a bunch of noise. Just goes to show how important it is to meet EMC requirements!
@@reverse_engineered I worked for a company that supplied computers to schools. The management wernt happy about the time and money spent on ensuring the kit met EMC standards. Then one day they recieved a call from a school saying that a child with a pacemaker was getting heart palpitations when he walked past one of our computers. An engineer was dispatched to investigate where upon it was discovered the problem was a monitor supplied by a third party not our kit. We gave them one of our CE approved monitors and breathed an enormous sigh of relief. The Technical Director never complained about signing cheques again.
HEY... give it to me, I dont care if its legal or not, I dont even give it a thought, likely the more suspect THE BETTER .... compliant this... smFh
I remember there being a news story years ago of a radio-telescope here in Australia that kept picking up random bursts of interference around the 2.4GHz spectrum at regular times throughout the day but they couldn't pinpoint what it was or where it came from. Eventually they figured out that it was caused by employees opening the door to the microwave oven in the break room to stop it whilst it was running. Just enough microwave energy would leak out in-between the time the door opened and when the oven turned off to be picked up by the telescope.
@@mos8541 I guess you don't need to rely on a pacemaker :-)
That's not EMC
A couple of comments from an old PSU & EMI guy... Sometimes the worst source of EMI is the gate drive current spike inside the chip (assuming the MOSFETs are integrated), which typically needs to be dealt with caps at the chip supply pins. Also, a single uF-range cap isn't enough in most applications. I'll use tiny caps in the 330pF-3300pF range as close to the device pins as possible, with larger bulk caps a bit further away where there is more room. Remember, it is the high-frequency edges that matter most when it comes to suppressing EMI, and larger bulk caps don't do a great job at high frequencies.
Good point. No matter how small the bypass cap, it still has SOME "ESL" (equivalent series inductance) to it, not to mention SOME ESR, too. These stray inductances and resistances create zeroes in the impedance curves, thus limiting the ability of bypass capacitors to do their things. Too many of our fellow engineers assume that a capacitor's impedance curve keeps decreasing as frequency rises, but the zero causes this curve to flatten out at 1/(2πRC) so that the R (esr) limits the upper frequency. Usually the R is about the same for each family size of capacitor (0603, 0402, 0201, etc.), so by using a smaller value C, the break point of the curve is at a higher frequency, thus improving matters. ESL is more problematic because once the break point is reached, then the impedance actually rises as the impedance changes from being a capacitor being an inductor!
Some things never change. Old rules still apply.
The only thing that changed up to this day is that you can now very easily get 100nF in a 0402 SMT case size, which is the smallest of the widely used types.
0201 and 01005 are, of course, also obtainable, but then you're getting into "diminishing returns" territory, where it's not gonna be much closer to the IC die if it's *that* much smaller.
In any case, I believe it's important to address the common misconception that you need to parallel 100pf || 1nF || 100nF for the decoupling to be good.
People often do it with the same case size (e.g. 0603) for all 3 parallel capacitors, thereby entirely missing the point of parallel caps: tiny ones to be as close to the pins, and then the physically larger ones can go somewhere a bit further to cover the bulk.
Full time PCB designer for 10 years here. For EMC reduction, i would start at better layout. Its usually the cheapest solution when it comes to volume production. Component changes should be done if you really need it, since you can save money and space. Nowadays virtually every board is a multilayer board for this reason as well as complexity.
For 4 layer boards the "traditional" stackup of Signal - GND - Power - Signal is better than a 2 layer board, but its till quite bad. The main reason is that when you switch the signals from top to bottom, you also have to switch the reference layer, and you cant connect GND and Power for obvious reasons. There are some kludge ways to improve this, but its a lot better to go to a better stackup.
Now days what is recommended is a stackup is Signal + Power - GND - GND - Signal + Power. This is an amazing way to minimise radiated emissions and it really doesn't take all that much space.
As others in the comment section have pointed out Robert Feranec has great videos on this topic. My personal favorite are with Eric Bogatin and Rick Hartley.
Great video i loved it.
Best comment I've read so far :)
Reducing EMI from power supplies is an art. Every switcher in my house has some kind of noise suppression. Over the years I've become adept at finding the cheapest and most effective solution. I do this, of course, to minimize noise to my ham radio receivers. The real question is, how to I get my crazy neighbor to let me fix his noisy military grade radio jammer power supply.
Thanks for the feedback :-)
Extraneous RFI makes ham radio folks cry 😂😂 so many cheap power supplies are very noisy!
I can relate to that, i am a Ham Operator my self, in the winter time i almost know where a heating system is powering on, or when the neighbours are switching on their cheap LED Roomlights. But til now the PV Systems around here quite silent.
For your neighbour, ask the local authorities for assistance.
I don't know where are you from.
In Germany it is the Bundesnetzagentur, if you file a complaint the will make a appointment with you at the location and take measurements and if the owner of the HF source will not comply the BnetzA can prohibit the use.
Maybe it is a Power supply before thermal self destruction, a fellow Ham found something like that in his neighborhood, in this case is was a almost molten power supply from a WiFi Router.
@@mariom.9472 I'm not sure things here work the same as in Germany. Here in the U.S. the government usually only takes action if you are doing something annoying to them (the government), while I doubt very much they would bother to correct my crazy neighbor for annoying me. For example, last year I discovered a local construction site (~4 miles away), employing unlicensed illegal aliens using Baofeng HT's and talking all day long, every day, in the middle of the 70cm ham band, interfering with amateur satellite downlinks. I filed an official complaint including recordings of the radio traffic to the FCC, and although they did send me confirmation, it has been almost a year and they have done nothing.
For finding noise, I built a portable magnetic loop on a stick, hooked up to a Tiny Spectrum Analyzer with waterfall display. So I can traced the location of a noise and triangulate its exact position, even if I'm a hundred feet away. In this case the neighbor let me scan the outer walls of his house and I know exactly what is causing the noise, only he refuses to do anything about it, even if I supply him with a replacement power supply.
When I was a kid my neighbour had a kitchen mixer that jammed all tv and radio on both am and fm in the whole street when he turned it on. I can't imagine the hassle of trying to receive weak signals when people are running their cheap motors in badly designed products for everything day and night.
These boards are components, and as such are outside the scope of CE marking, so meaningless to say they are not legal.
Ah, someone already said it!
I guess you meant to say: "not illegal"
@@ArnDroidtv The CE mark goes to finished assemblies and not components so saying either does not apply.
@@Peter_S_ I know that, but that means: such components are never "illegal".
@@ArnDroidtv To repeat both myself and Mike, such designations are outside the scope of components.
Useful note: It is possible to 'self certify' for CE by making a DOC (declarationof conformity). The CE mark covers both electrical safty (usually under the Low Voltage Directive) as well as intentional and unintentional radio frequency emission (EMC). You dont need to do anything more than the DOC, but if things go wrong and an inquiry is made, you really want some evidence to back your declaration. This can be in the form of a emc 'pre-cert' lab report that will be less expensive to obtain than going to a full blown certification body.
For the US I understand there are no strictly required electrical safty regs but there is FCC which covers EMC. Self certification is less common here, but you can import up to 3 items at a time for personal use with FCC form 740 pt.II item 7. 😀
That is an interesting tidbit that will be stored in the memory banks. Thanks for sharing!
I went to a Würth EMC expo (by invitation) at Duxford some years ago. Half a day listening to some very interesting theory and sales (genuinely....Würth really are good at this) and half a day looking at the aircraft in the Museum. Thanks Würth...a great day.
Good for you, I actually fell asleep during one of their presentations
I made some simple indicator lights for my friend's bike (e-bike / pedelec). We used a cheap MT3608 boost converter to convert the 6V I got from one pin of his battery controller to 12V for the lights. We tested it in his garage and it worked great, except for the fact that his DAB+ radio briefly lost reception every time the indicator lights were turned on :D
So good to see how much the industry has changed. I got into EMC testing over 30 years ago when the radiated testing was all done outside on an open area test site, normally with a manually tuned receiver system. So much easier these days with a screened room blocking out all of the extraneous noise.
Easy, yes. Cheap, no ... But heck even back then you would still need calibrated equipment, that kind of ruins cheap
30 years ago we rented time and equipment deep underground in a salt mine in the UK.
@@ColinWatters yeah I recall some of the clients of the lab I worked went there a few times. Never had a chance to visit it myself
@@TalpaDK oh definitely not cheap, annual calibrations and the cost of the equipment certainly add up
This kind of research and experimentation can solve a lot of problems in more complex or sensitive electronic devices. More videos like this, please.
EMC sometimes feels like voodoo and certainly is very close to magic. A few things I learned over time: 1. Use fully shielded inductors whenever possible. 2. Inductor orientation matters: you want the start of a coil to be closest to switching element 3. Avoid long loops 4. C0G caps can really help with higher harmonics 5. Feed through caps are better than shunt ones
You also have to keep in mind the shape of the traces on the board themselves too.
I didn't realize it until I had gone into radio that 90° angles emit RF like hoses.
Yes, it is always better to use 45 degree chamfers until you reach 6 GHz where angles are no longer tolerable and you need to use smooth curves.
at JLCPCB and similar manufacturers, there's almost no price difference between 4 and 2 layer boards, especially compared to shipping and assembly
so just always start with 4 layers for DIY projects unless it's a super duper simple design.
You make your life layouting easier, it'll work better for EMC as well as general performance, and you can make it fit into the size you want more easily.
The stackups of
PWR/DATA
GND
GND
PWR/DATA
or
PWR/DATA
GND
PWR/DATA
GND
are typical recommendations that work for many applications
Thanks for the tip and feedback :-)
I designed my first 4 layer board earlier this year and really enjoyed it! Layout is so much easier and clean when you have easy access to ground and power. 😊
I totally agree and I quite like that first stackup for most applications. Excellent advice to send beginners in that direction. 👍
Power can be run as traces without issue and the ground plane is by far the most important to have uninterrupted.
😮
A 4-layer board is rapidly approaching unfixable though. Any major corrosion damage to vias or inside layers is basically a death sentence. Conformal coating would be very much recommended out in the field.
Excellent explanation of the electromagnetic effect of electronic circuits.
Thanks :-)
Würth Elektronik München is just 1km away from me, so it was you the day i thought i saw you, now i feel bad for not stoping the car and meet you
I'm glad you've brought this subject to our attention; it's often ignored and causes headaches trying to work out why circuits are misbehaving.
A few years ago I was fortunate to be involved in setting up both types of EMC lab at my workplace - it was nice to see the equipment again in this video, it brought back some memories!
Würth not only deliver great components, the also share their knowledge about it. I love their books and "the Trilogy of magnetics" is one of the books I own and use a lot. We had this book at a previous job so as soon as I got a new job, I had to buy this book myself. I refused the gesture from my current boss to buy this with company money. The book is that good that I want to have it on my own bookshelf in my own workshop 😁
And yes: Würth components are not always the cheapest but the capacitor and inductor kits saved me that much development time that they are worth their money
@askLorandt Awesome to see you both making this colab. Thank you guys!
Obrigado! 🤗
This episode reminds me of my old job at a company that makes HiFi speakers. One of our engineers was an absolute genius at making crossovers. I started building own speakers and he did the final touch with just a few caps and coils. The results where always mind blowing.
I would love to see more collabs like this! Thanks for this!
What a lucky guy! Glad you were able to share your visit with us.
Great video! As an amateur radio operator I am fully aware of the issues that poorly designed electronic devices have on the electromagnetic spectrum. From PWM LED drivers, to switch mode plug packs and USB chargers, Ethernet networks and right up to my VDSL2 modem... all the RF soup makes listening to weak HF radio signals a challenge. It takes a lot of work to design a fully EMC compliant product and many manufacturers take shortcuts to save costs.
It's an annoying problem but kind of fun hunting down the offending source 😂
Dit dit
Exactly 6 years ago I started to watch your videos 😊. Till this date you have shared so many knowledge to your viewers. Thank a lot for creating such informative videos ❤. Your basics video and diy and buy helped me a lot. If RUclips never suggested me your videos probably most of house electronic items would have become part of scrap yard or electronic waste 😅. Thanks a lot 😊 for such lovely and for informative videos although some part of your videos goes over my head if I have no knowledge about it 😂 but I getting better day by day 😉
Very welcome EMC videos. Meet him again!
A release of a new video from you is always a highlight of my week. Thanks. Chris
Awesome :-) Thanks for watching :-)
@@greatscottlab can I share my EMC test video with you ruclips.net/video/hr4RVqUHXjY/видео.htmlsi=wCipY3wUzbHmuzNS
@@greatscottlab could it be possible for a weekly upload?
love watching your videos as your very chill and explain things well.
Thanks for discussing RFI in an electronics context. Those of us who are radio hobbyists are appreciative...
I love that you leave in your failures, or shortcomings. It's very relatable and makes the video a lot more genuine. Keep up the great work!
You can also shield components and/or parts of circuit board to reduce EMC emissions. Also, even if the board itself doesn't pass, the final products could pass in a suitable grounded metal enclosure.
Im pretty sure you could do a "EMC shield board", 2 layer with a top 100% plane and then edge solder connections all around, looking like a postage stamp.
Then mill out bottom of this board so it fits on top of the board you want to "protect".
Voila, you have now shielded emissions. This works as long as no component is higher than the thickness of the shielding board, but if a single component is higher, you coukd make a hole in the shield for that component and still have a good shield - as long as the high component is not the radiating culprit.
one of the best videos I saw on this topic for quite a while, please make more of these!
One solution you skipped for radiated emissions is shielding. The simplest solution is to put your project in a metal box but that is not the only way to do shielding. If you look at some PCBs that have RF transmitters/receivers you will notice that some of the circuits are in metal boxes that solder to the PCB. Another approach is to coat the inside of the plastic enclosure with metalized paint. BTW, I designed a pacemaker programmer that passed the medical EMC directive. I did initial testing at SWrI in Texas and final testing at TÜV.
But then you should add input and output filters, otherwise it just creeps out along the cables and your shield is useless. And shields are expensive, so first try other solutions.
Mr. Faraday approves your comment.
Awesome video. EMC is a field that more people should know about!
finally a sponsor i'm actually interested in!
actually JLPCB also rules!
I spent a number of years on getting my designs to pass EMC requirements, and then spent some years in my employer's EMC lab helping folks test their designs and fix problems. Wurth produced some nice ferrites and other devices for addressing EMC issues. I have to say that Fair-rite makes some nice stuff too. Switching converters are one of the biggest offenders in regards to generating noise, and board designers should follow the converter manufacturer's guidelines (and there are often board layout suggestions). EMC is an interesting and complicated subject, and certainly not intuitive.
Not gonna lie, when I see "Wurth" on a product I know I'm working with something well built and reliable.
Great to see my friend Lorand here. Cheers from Bulgaria
Thank you my friend!🤗 Hope see you soon
Thank you so much Würth for letting this happen!!!
I learn so much from your videos. Thank you for making things understandable.
Confession: I sometimes watch your videos for your penmanship 😅
One of the most interesting video ive seen from this dude, im following Scott since a lot of years.
Great timing. I was looking into the EMC issues for a BMS.
Nice to see you being sponsored by Würth!
I'm happy for you!
This field was what Siegfried Linkwitz' (Linkwitz transform) worked in at Hewlett Packard. His work on audio and LS design was fascinating and controversial.
Hey I work in this building :)
Wish I knew you were there, I am big fan!
Next time, step by Würth ICS office to see some amazing embedded projects.
Hey, how could you suppress your name? Never saw this in RUclips.
@@baxbanni2226 weird😅, no idea
This is a really helpful video! It's difficult to find introductory material on this topic, since it tends to be an advanced practice and not that relevant to most hobbyists. While I was vaguely aware of some of these, pointing out specific causes and solutions really helps to understand more generally what to consider. Thanks!
Very informative. Keep it up.
A potential series on covering certification is not at all a bad idea. Will be cool to see how you solve each hurdle.
Whenever there's a DC DC converter, going with atleast a 4 layer board is necessary. We usually go with 4 layer board with 2nd and 3rd layer GND, any left over space on top & bottom will be made as GND pour with via stitching.
Great video on an important topic! One thing I never quite understood is why multi layer boards don't ever seem to put the ground plane on the outsides and the traces inside to minimize radiation. I'm imagining that the components could go directly to the inner layer through vias, which would make troubleshooting harder, but might help in specialized applications.
Hey I would love if you can keep this series up. Maybe once a month it’s super interesting.
Funny thing. Some 35 years ago. Though being a mechanical engineer, I had the task of designing an industrial multiprocessor board with lots of I/O. Size approx. 10 by 10 inches.
To be fitted in electrical cabinets with 3 phase contactors and other noisy stuff. To simplify board design, I used 4 layers boards with ground and power planes on the outside.
Hundreds made, working flawless. Seems I did a clever thing.
Very cool, not an easy subject to deal with but the summary was very useful (even if I can't do it 'at home').
This is the way to take us to a higher level of expertise!
it's just math hell
More of these EMC topics and videos from Wurth lab. Now i know where to buy components for my power supplies. This is a gem🎉🎉🎉 will be checking out Lorandt youtube channel. Great to see people sharing knowledge on such a complex area making it motivational. Sometimes these labs a very difficult to access but great to see what goes inside looking at all the setups.🎉🎉🎉
I don't run my own channel but you could try #askLorandt 😁
Good job explaining this complex matter, well done.
Fun stuff. Most of what I work with is up in the 30 GHz range but when testing our products we have to perform both the conducted and radiated tests as required by the applicable ENs before we can declare conformity for our product.
On the home front, we had some landscaping work done which included some lighting that was powered by the available 24 VAC for the existing low voltage lighting. The landscaper finished the work and left before dark and when I returned home a bit later the lights were on and it all looked very nice. However, I couldn't open my front gate using my remote control and had to resort to the gate's keypad which is hard wired to the gate opener.
Long story short, I traced the problem to a new up-light with LED bulb that had been set up near by gate opener. The LED bulb was generating enough RFI up in the 315 MHz range to prevent the receiver from detecting my opener unless I walked up and stood right next to the gate. The landscaper wouldn't believe me until he saw the problem with his own eyes. The solution was to move the up-light further away from the gate opener and to replace the LED bulb with a different model that didn't spew RF all over the place.
Unfortunately the landscaper forgot to leave the noisy bulb for me. I had really been looking forward to having a look at it with my spectrum analyzer and SDR receivers to see where and how much RFI was being sent out.
Anecdotally, I hear from a lot of amateur radio operators about problems from switching power supplies, solar array micro inverters, and LED bulbs that really cause problems with receive noise in the HF bands.
Lorandt is the best! You should have had him given him a speaking roll! 😀
I was just the "stunt man" in this video 😂
There is actually a conducted immunity EMC test you can do probably at home.
The DPI (Direct Power injection) test.
All you need is a signal generator, a power amplifier and a oscilloscope.
(IEC 62132-4)
3:30 honestly, that is factually not accurate. Some converters have their worst EMI at the 50% or 99% point. I know you had to simplify for time constrains and low and high load are good compromises, but some products have strange resonance effects only at certain load points.
Super video! Many thanks for the great work and cool explanations! All the best, Rob in Switzerland
Great video and topic (I suggest you put _EMC_ into the title...!)
You forgot 50% of the EMC equation: There are also requirements for what you need to accept and handle when it comes to incoming noise as well.
A lot of cheap audio amps are not properly immunized for conducted noise on power. Many also amplify common mode noise directly due to single-ended inputs too.
Love the "NO COLIN FURZE" sign at 2:30
Watching your video from Brazil. Very interesting See WE lab in action!
Thanks for watching! :-)
You need a podcast as well. I could listen to your EMC and other design tips while working.
Well, now I have something more to consider for my projects. Thank you, as always!
Würth has some very nice lab space! The place I’ve gone for EMI/EMC testing was a dungeon relative to that! (Haven’t been there in a few years and my understanding is that it’s been renovated since, but I bet it still pales by comparison.)
This video was so fun, I have no clue what was going on with all the electronics logic, but I'd love to learn, I'm currently trying to expand my knowledge into embedded software.
These boards are legal in any case, at least regarding Europe with its CE.
Except of rare cases such boards count as "components", as like a chip, capacitor or resistor. None of them need to fullfill the CE requirements (there are requirement regarding RoHS and REACH tho). CE decleration is only required for a PRODUCT. Therefore the board integrator have to validate and fix any kind of EMC/EMI issue. This always have to be done - no matter if the used components are certified by itself.
So, as a general rule (as I said, there are exceptions), such project boards don't have to fullfill the emission regulations. The final product created with it have to.
this is not like you describe anymore... As soon you place to market should be CE compliant, else you will pay for the "lesson"
@@askLorandt it has not changed, because it is technical not possible nor relevant.
Parts are parts by definition. CE applies to products, but parts can be products if some characteristics apply. To be clear at this point: In some cases it is strictly forbidden to make a CE marking on parts, because it's not legal according to the compliance guidelines.
As some kind of exception, I already noted this, are RoHS/REACH declerations, as part of the CE process.
You might ask why I wrote it is technical not possible. You, as manufafturer, will define the "intended operation state", which is measured afterwards. Let's be a little bit sarcastic here: You, the manufacture, decripe the intended operation state "no power". You will measure nothing.
True, this is nonesens and can't be declared this way. But a part can be used in countless possible veriants and this can't be measured. For example: This sepcific DC/DC converter you try to sell here, just declare in your datasheet: Put common mode chokes on input and output, a bank of capacitors and put it all together in a metal can.... well, you can rediate whatever you want. Accodring to your "intended use" it doesn't matter.
That's why the majority of parts are not part of any kind of EMI/EMC measuring. How they behave is defined by there use in the product where it gets implemented. That is, why even you, as manufacterer, integrate some kind of CE approved part - let's say a common brick power supply for example - need to measure the whole product/machine/assembly afterwards, because the part itself may comply, but how you are using it in your product may not.
Thanks for this! My company uses NCEE in Lincoln, NE to do all our testing. And our equipment is located in the middle of a corn field! (Middle of Nowhere!) : )
And BTW, this lab is big enough to drive a Tractor inside for the same type of testing ; )
LOL as a kid i used to create "FM" transmitters with old ECC85 vacuum tubes. They were excellent sideband generators all the way to our television (before cable so with an actual antenna on the roof)
Pretty sure my transmitter would have blown up that measuring antenna :D
Awesome vid! And thanks @wuerthelektronik!
Thanks for going to the effort to make such complex and specific videos about specialised topics. While the DIY or BUY option here - as far as testing labs are concerned - is definitely on the buy side of the scale, the knowledge gained from your experience there provides practical lessons to improve our own designs regardless. :)
I'm so glad you are taking on this topic as it is generally ignored. I would be very interested in a follow up video that tries out more solutions. In particular, I wonder what difference 4 layer design makes. Maybe more information about what the EMC tests involve and the limits.
The most significant example of EMC problems I've seen is from a cheap HDMI cable I bought that prevents the TV from receiving digital broadcasts when it's plugged in at both ends.
Apparently here in the USA, FCC are obviously strict about RFI and EMI, yet they allow some hobbyists to get away with it, at least up to four or six projects, that's it. I am sure it might be the same elsewhere, you gotta look at RFI / EMI rules for where you live at, they differs somewhat. If you wanna sell the completed boards to somebody else, you definitely want to have a decent oscilloscope so you can rework and / or respin the board once you find out why. It's your responsibility to make sure it doesn't disturb TVs and any other electronics.
If you work with SMD components, it's a bit easier to manage RFI with solderable Faraday cages which phones almost always use. It's kinda recommended to use the shields with DIY RF circuits in order to get the cleanest signals possible as outside RFI and EMI would mess with it making it a bit harder to discern via oscilloscope.
R&D often uses tin foil :D
EMC topic is voodoo for many people, but as the frequencies of consumer electronics interfaces increase, it is rapidly becoming an issue. For example, in terms of required product testing before market, a failed EMC test means lost money and time, which is initially not expected by the board designers and product developers. This vid teaches us that even products on the market may have their pitfalls outside of the basic usage scenarios.
Fabulous video. Since you have made the first video about your design, I ordered the China man version 3.3Volt version as I don't have components for your design. I use it for my Xiaomi temperature / humidity devices with a Lithium Iron cell. The CR2032 cells don't last long. So, thank you very much for introducing me
Great topic! It's worth to explore it more in-depth in future videos!
Wow, very nice video you got here! Thanks for caring about these interferences investigations!
Glad you like it :-)
If you took your staircase light project from a few months ago where you had a very long switching trace do a whole lap around the board and scrambling your digital communications to the EMC lab, I bet it would make the DC-DC converters look great in comparison.
more,more EMC video like this, excelent job
Any power supply or voltage converter should be placed inside a shielded enclosure to prevent EMC issues. If they have DC outputs, filtering of the outputs should be done to remove any noise on them. You aren't going to make a buck or boost converter that doesn't make EMF noise. Same goes for inverters and rectifiers. There is going to be noise from the circuitry. You can make an enclosure using plastic and conductive paint if weight is a concern, just remember that you need to make electrical contact on all seams of it and to ground it so the EMF is being sent directly to the chassis ground of the circuit of the equipment, vehicle, or building so it is dissipated instead of being passed through the enclosure.
excellent video, i would love to see more on this topic
Very cool and I think you did an excellent job of explaining this in understandable terms.
This reminds me of the interference heard on Ham Radio, caused by some L.E.D bulbs and fluorescent light fixture.
Actually- If you put rj45 connectors on each end of telephone cable then interference can be heard on FM radio between 85.5Mhz - 87.7Mhz and this all reminds me of back in the day a simple break in a overhead communications cable resulted in the AM radio's & ham radio's being blasted with noise and not even JPO? (Called Ofcom nowadays) knew until someone complained about their landline not working and tired engineer had rectified a break and the noise went away.
Wow that was super cool. Very interesting and wuerth has a pretty crazy set up!
videos about how the industry test are cool!
For that kind of product (SMPS) I would suggest 2 ground planes as reference for top and bottom. You don't need a power plane.
Lol... The filters are already bigger (and surely heavier) than the circuit itself 😂
Great stuff.
For that fundamental frequency, use an LC trap. It will get rid of a lot of it!
I would like to see more information on preliminary in-house testing, instead of "you can't do it without all this specialized equipment." Those labs are extremely expensive and as small scale designers, this would quickly bankrupt us. There must be a way to get a "feel" for whether your circuit will pass before wasting time and money on this expensive process.
Well the best advice I can give u
Get urself AM radio
Take ur product, portable power source and your radio deep into nature (like a forest), so u get away from all the city noise
Sweep acros am band while ur device is powered and observe if u hear any change in sound on the radio while the device operates
If u hear noise, then device is bad
AM doesnt lie, AM shows all ur mistakes
Fix ur product, if u dont hear noise ur good
PS: regular am radio usualy operate on lower frequencies, but there usualy problems are so if u fix for lower frequencies, u fix for higher frequencies
If u want to test vhf, then u can get airband receiver
You can do some rough pre-compliance testing for sure. Get a metal table, 1-2 LISNs, and a 1-2000$ spectrum analyzer for conducted emissions. You can use a big Zarges aluminium box as a "poor man's GTEM cell" to get a rough house number where you are with radiated emissions. But esp. the last one will not be a proper measurement of course. More like you are looking for anything that sticks out in the spectrum and attenuate it as much as possible before attempting a certification run. In Europe I have also made good experience with the RF departments of local universities being willing to help for relatively small money. Not sure how that works with for-profit schools in other parts of the world though. The reality is also that if you want to sell a product in a market that requires CE or something comparable, it is often enough not worth the trouble as a small-scale guy. Those tens of thousands of €/$ are just a fraction of the potential costs including electrical waste, legal risks and other cost factors.
TinySA, a LISN, and an antenna can get you into the ballpark. Having a calibrated RF source helps a lot too
I haven't had luck with my TinySA, the sweep is SOOO slow... what am I doing wrong?
Great video! I really found the PCB design optimization segment interesting. Can I suggest a video on PCB design best practices? Your videos motivated me to create my own PCBs and I have made many over the last few years
Wow, this was "new" informative information I never knew. What a great video to start the day. ☕
Glad you liked it👍
In past decades much of this information was known only by old men with white hair and beards who were called the wizards or the bears. Video such as this are excellent and I hope to see more here. If you would like to dive down this rabbit hole more, I recommend Robert Feranec's videos with industry experts. One thing to remember is that there is one set of rules for DC to maybe 10-20kHz, another set of rules between 10-20kHz and 6GHz, and a very different world above 6GHz.
I learnt something new today! I was designing my own budget smart speaker a few weeks ago, using cheap buck boost which coincidentally was the problem when i was troubleshooting it as my speaker output sounded just like the one in your video what are the chances that i get my answer to why it was happening so soon! Thank you! It was very puzzling why it was behaving so weirdly😊
That was quite an interesting video. A mix bag of items you covered. Enjoyed that.
What a great video.. Thanks from Canada!
Once added a switching clock that had a frequency that moved around the center frequency to spread the energy of the spikes.
Great vídeo !!! And those challenging issues!!!
A proper isolated booster from 5V to 12V that had low emi would be super helpful! Then you can use a bt source and amp share the same ground/battery without ground loop noise.
Fascinating! Thanks a bunch for all the info, dude! 😃
Stay safe there with your family! 🖖😊