Your videos should be part of every theory lesson in schools and colleges. It is fine to explain it on a chalkboard but to actually see it on test equipment makes the theory sooo much readily understandable. I'm a visual learner as are many others, wish the internet and instructor/techs like you were around 40 odd years ago when I was desperately trying to learn this stuff...BRAVO ZULU
seconded. super useful video. i came across this vid because of a project that i'm working on, but it's gonna have to wait while i go through all of his other stuff.
Fifth'd. Compelling demo. And as a result of watching it, I went straight to a homebrew receiver project with a Mosfet RF amp that was unstable above 7mhz. Added 2 turns thru a 43 bead, soldered it right on gate 1, and guess what? It worked!
Best ferrite bead video I've found! I'm an engineer trying to get up to speed to help solve a signal noise problem with equipment at work. Thanks for the great info!
I have used these ferrite beades before and i have known that they do sth by frequencies but i have not seen their waves on the oscilloscope,now i have beter veiw,how a great video was that🙏🙏🙏
I've used ferrites on occasion, but I never realized just how much loss they could create. There you go again teaching something I didn't know! :) Great Job! RW
Thanks again for your great videos! You are an excellent teacher and I for one very much appreciate you taking the time to make each one of your video lessons with such great demonstrations, examples, and experiments to help convey the concepts you are teaching!
This is great. I loved the cross referencing to the 'scope. One area where it does get confusing is the use of various mixes dependent upon the application: use as a choke against use as a transformer. This leads to folks arguing at cross purposes on forums and elsewhere about which mix to use. A mix that works as an RF choke at a given frequency will most likely not be a suitable mix for a transformer at the same frequency for obvious reasons when you stop to think about it. I do enjoy your videos Sir.
I know this vid is old, but gold ! clear demontrations, didn´t know osilators have oscilatotions on the base, I thought it only happened on tube circuits where the cheap and effective solution is a grid stopper resistor, most tubes where deigned for high frec. did´t know that bipolar transistor suffered the same issue. Now I know thanks to you! In fact 2N2222 is a high bandwith transistor (relative to say a BC548).
Excellent video Sir. You and thesignalpath are prob my favorite posters of educational info here. Thanks for sharing with us your knowledge, i look forward to more of your content.
Your channel is high quality , very interesting channel , it is a must have channel for any electronics person / engineer . I wish i had more time to see all of them several times over .
I always wondered how effective those filter beads were. Many products have those inside and I always ask myself "how much are these tiny ferrite beads going to help"... Thank you for showing us and making it clear! :)
I worked as an engineering technician for a large op amp maker 45 years ago and we were always looking to increase the bandwidth of our opamps and multipliers. These were discreet devices that were about 1-1/2" square and had 7 to 9 pins on the base (I still have a few in my parts bins). The circuitry was on small printed circuit cards, these were put into a potting shell and then filled with epoxy. A cheap way to increase the bandwidth was to slide a small ferrite bead over the output pin -worked every time.
"thank you for this" its always better when an there's a coherent instructor explaining a thing for me sometimes the concepts don't leap off the page for me on top of the fact i don't speak electrical engineer so again thank you.
Indeed very well demonstrated, these filters and suppression of unwanted frequencies both within circuits and power supplies as these can directly affect other sensitive electronic equipment through power lines or other interconnections as well as radiate electromagnetic radiation as radio frequency interference, (RFI) so today you would not be able to market any product unless you meet all RFI regulation under the EMC rules, and only then you could place any product on the market and obtain a CE marking requirement.
I always thought that ferrite beads were electrically conductive. When I saw you put that bead directly on the lead I was sure a short was imminent:)). Thanks, opened my eyes and put ferrite beads on mosfet gates on my current project working at 300v, very clean switching right now. (Also added capacitors very close to the half bridge).
Fred Garvin you can’t just say never. applications may require to add a reactance to any location depending on its application. For example sometimes your biasing network may require inductors near the gate specially in radio frequency designs. Besides it is all relative to what your gate sees and its switching speed. You could put a a tiny inductor (fH) and if your frequencies are in KHz it simply won’t see it.
I understand the principle of why it works... didn't realize it could have that magnitude of affect on at higher frequency. My question, how do you determine when you need to use this filter? What would be some symptoms? This question stemming from the fact that all of the computer related cables have them. AWESOME video!
1) I'm really enjoying your videos 2) What is your profession? Does it involve teaching, because you deliver the material really well 3) Ever though of elmering?
Thanks for a practical demo, I always wanted to see. My idea is that supply decoupling and EMI suppression are 2 different use cases of ferrite bead. 1. Supply decoupling = ferrite bead in series and acts attenuates high frequency noise to pass through, hence decoupling. 2. EMI suppression = ferrite bead as a transformer (not in series), basically provides a low impedance for high frequency noise, so that they do not radiate through parasitic antennas. Or, is 1. and 2. same???
I was right as my guess it was some kind of filter. I asked Best Buy and Office Depot and no one knew. Your explanation is very good. I am trying to find the same length power supply cord for my adventure cam without the ferrite bead on it. The cord came with a ten year old Cannon camera but works on my Ultra Pro X 10. The length is 18". My next step is to try Radio Shack for the cord I need. Subbed and liked.
Really like these videos. What i like the most is the comments from guys that feel they have to mention that they themselves are engineers or graduates of M I T . The only thing that they engineer is a burger onto a bun at the golden arches for an 8 hour shift. Nevertheless....good video Thanks
Thank you for posting this excellent video! It has helped me to understand (on a QUALITATIVE basis) exactly how ferrite beads work. Though I am currently interested in filtering out barely-AUDIBLE-frequency noise (in the 10 KHz to 20 KHz range), I am now prepared to do some trial-and-error testing with different split ferrite beads, installed on both the power cord and audio signal cables of our A/V system. Thanks again!
Very well explained Alan. I have a topic suggestion - back to basics video on filters. Something that shows multiple order passive/active filters and their performance. Thanks for making these wonderful videos.
Very instructive video. Now I am thinking that maybe for the cases that the operational frequency of the circuit is in much lower ranges, it is even better to use bids made up of iron, instead of ferrite. Because if I know correctly, the "cutoff" frequency of iron is much less than ferrite. Though I have never seen any iron bids around a wire for noise cancelling ...
Is the added inductance the cause of the loss that you keep referring to, or is that a property of the material like dielectric loss? And how would a coil inductor behave differently than a ferrite bead? Awesome channel btw
Thank you! I fix CB radios and have one that has a touch of parasitic oscillation. I am putting a bead on the base of the final or driver later to see if it'll alleviate it.
As a former Instrumentation Technician, we usually get deliveries of industrial instruments with those things loosely bouncing inside the box. I usually pick it up and turn it this way and that not knowing what those darns are for. Now I know. Thanks.
Thank you for sharing your knowledge. I was reading through the manual for a new video camera I had bought, and it mentioned this thing I'd never encountered before, that snaps around the power supply cable. Of course my curiosity was piqued, so I had to find out more. Thanks to your video, it all makes perfect sense: suppression of high frequency electromagnetic radiation, by encouraging lossy inductance. My questions is: is this to protect the camera itself or is it just bundled in to comply with regulations to prevent other devices from picking up interference? Is the operation of the camera likely to be affected if I don't bother putting it on? The cord is supposed to be wrapped around the bead (in parallel) so that the cord passes through the middle part twice. The design of the supplied bead is such that it is a very tight fit and I am concerned that I will damage the insulation of the cord if I were to clamp it shut. If I simply left it off, what's the worst that could happen? (I would be filming on battery power 99% of the time anyway. Very seldom using the power cord while filming. Only there for charging the batteries.) Thanks again for the clear explanation.
It is likely needed for the camera to meet some emissions standard. It is highly unlikely that you'll have any problem whatsoever if you only pass it through once or leave it off entirely.
I like your informative video. I never suspected that a simple PSO would break into oscillation at 200 MHz. I've built quite a few, but even if they did oscillate, my 20 MHz scope would never know it. Thanks.
Hi there, first of all let me thank you for your video, it has educated me to no end. I have a rfi problem I would like your advice with. I run a professional music studio and am always trying my best to cut down on noise. Recently I have had a dimmer switch installed on the studios lights. The dimmer switch is an old school MK type double switch not a new led one.. One dimmer for each rooms lighting circuit. I am using new Phillips led warm white bulbs which are great for my studios lighting bills and have been designed to work/dim with regular old dimmers. Indeed the Phillips led bulbs dim perfectly and smoothly, even better using the old mk dimmer than the Chinese led dimmer I had before. However, now it seems that with the dimmer installed I am picking up much more interference in the room while recording. The classic one is a single coil pickup in a guitar. It goes crazy with interference when the lights are on and then shuts up when I turn the lights off. Same with guitar amplifiers. Of course I know that guitar pickups and tube amps always pickup interference anyway it's just that the audible volume of said interference has got much louder since I fitted the dimmer. Please is there any way I can choke/suppress or isolate the dimmer switch in order to reduce the noise/interference without having to sacrifice the dimmer and go back to the standard on full of off switch? Perhaps ferrite beads on the connections to the dimmer? Or do I have to spend a lump on a 1:1 isolating transformer and completely isolate the lighting circuit from the rest of the power in the studio. Any help would be much appreciated. Thank you.
It is possible that these snap-on ferrite cores might help - installed in the wiring box for the dimmer or light fixture, or both. But there are no guarantees. It may help to understand which device is the major contributor. If the dimmer is replaced with a switch using your Phillips LED bulb, is the noise lower? Or, if regular incandescent bulbs are used with the dimmer, how is the noise? Some of the manufacturers have written information on reducing noise/interference: www.lutron.com/TechnicalDocumentLibrary/360484.pdf
Ok, one turn in a ferrite bead, cylinder or toroid put losses at very high frequency. My question is: it is only due the reactance coming from inductance or also for an other phenomenon ? If yes, which one and where it is measured in the toroids datasheet? TNX in advance for your answer and for your fine explanations. 73s.
another great video! just one question though. you explained and showed how the ferrite bead blocked parasitic oscillations at the base of BJT. i can see how the ferrite bead's inductance can filter high freq. noise at that point, but you also mention you have added a series resistor before to achieve the same goal. i dont understand how adding a resistor can filter the high freq. components. is that something to do with RC circuit coupled to it? thanks
Wow! I saw this link in the comments of a 3-part decoupling tutorial at allaboutcircuits, despite being a good article, your video explained more in 12 minutes than a month of reading online! I will definitely check out some of your other videos, I would love to see some more on choosing the correct part for different applications! (If you haven't already) Excellent video, and I'm shocked that this was done in one take - unless you have Hollywood level editing skills ;)
Trying to diagnose weird wiring on my old Nissan and I am considering adding ferrite cores on some of the finicky sensor wires. I've added some to the LED retrofit headlights and I actually think it made a difference in drivability. I have a feeling the fans on the heatsink was creating enough RF and maybe that combined with no isolated ECU grounds it might be enough to distort a 5v cam signal, which I have had issues with in the past.
Good information. Very helpful. I have a wireless mic set up and at times I get very bad RFI. I suspect it's a cell phone of one of my neighbors. The cord from my lapel mic to the transmitter acts like an antenna and picks up the very high frequency of the phone. I ordered some ferrite beads off Ebay. Hope that solves the problem...
Very nice video. Once again a super job in using instrumentation to explain and show the behavior. I wish the ARRL Handbook has such videos embedded in the pdf versions!! Dave, AA6RE
Thank you. I've got an older DC voltage standard I've been trying to repair. It has 4 "VN66AK or 2N6660" transistors, 2 of which have berrylia washers on them... after watching your video I'm guessing those washers act as EMI filters on the high speed VMOS transistors.
Great info!!! thank you !! I'm powering my gopro camera from a accessory outlet on my Harley Davidson and wondering if I would benefit in employing a bead on the usb power supply line to reduce any noise it might generate?
Will a ferrite bead disrupt the data traffic on a cat 6 data cable running from a switch to a phone or PC? We are getting what we think is EMI interrupting phone calls. I need a way to filter it, but not kill the needed data traffic on the cable. Great video and explanation.
Very practical and useful explanation, I have an axial ferrite bead inductor with the following inscription: 1W0_()_33J How should I understand this inscription? ._()_ = ohm symbol
W2aew, when they use a CHOKE a series transformer coil in the power supply, what does this Choke do to the AC ripple? The Choke changes the discharging and charging of the filter caps or doesn't affect it? Without using a Choke the AC ripples can cause "harmonics" added to the circuit?
I have probably several hundred ferrite beads salvaged in the process of scrapping out various bits of equipment. Can you suggest any way for me to characterize them? Determine which ones might be best in which applications?
The AC cord plug into the back of an a piece of equipment, inside before the power supply there is a silver square box that filters out RFI/EMI from the AC outlet. Is there ferrites beads inside this RFI/EMI box or what kind of filters are inside these RFI EMI filters for the AC outlets. EE engineers have told me these AC RFI/EMI filters cause a lot of current leakage issues i'm guessing from the AC hot wire to the earth ground. I have tried opening up these silver box RFI/EMI filters but looks like filter cavities or something.
Any suggestions on eliminating noise from a BLDC cooling fan in RF circuits? I have read and observed that this noise emanates from the fan's ground wire. The only solution I've found that really works is to use a seperate power supply for the fan, that is a seperate ground reference. The question is, can I create a truly isolated supply for the fan if it is using the same AC wall outlet voltage source as the RF circuit? I haven't figured out how to do this yet. Any suggestions would be appreciated. Thanks always.
Thanks for the lesson sir… if i use emi ferite bead at end of grounding wire in motorcycle or car engine, is that can improve eletrical circulation and can get better performance?
Great video. I was wondering if you could assist me. Ever since installing a new router I'm hearing a pop noise from my pc speakers. I was instuctedvia a forum to put ferrite core on the leads to no avaail. I'm just learning to use an oscilloscope and was hoping you might lead me to a tutorial that would help. Thank you!
It is the common mode (versus differential) signals that are attenuated by the bead on the USB cable. Common mode signals cause the entire USB peripheral to act like a monopole antenna.
Thanks for another great video. After seeing the action of the chokes in your demo it makes me wonder whether adding chokes to each side of a horizontal dipole antenna could change the resonant frequency of the antenna. So, for instance, if I had an antenna where each side was of length L, could I make the antenna resonate at double the original frequency by adding chokes at the L/2 points of each side of the antenna. In effect I guess I’m asking if the antenna could be made to appear to be shorter through the scheme described above. If such a thing could be done I can imagine moving the two chokes to whatever position was needed to have a half-wave “effective length”. Since I’ve not heard of such an approach I’m guessing there is a fundamental flaw in my logic. After watching many of your videos, I feel that if anybody can set me straight it’s you. - Thanks! - Jim
Thank you for this great video. In electricity, when we wind electric wire on a ferrite core, we can translate the electromagnetic effect to an electrical circuit by impedance which is jwL ( j, omega the angular frequency, L the induction). But here, the ferrite is on the wire. How do you translate that in electricity terms like impedance (maybe it is still jwL, with induction L computed differently) ?
I think its because even a simple wire has a parasitic inductance. When you add the core this inductance gets bigger (ferrite is more permeable than air), making this parasitic inductance bigger and changing its impedance
Can you use a ferrite bead over the shielding of a power cord with three conductors, or is it required to use a ferrite bead on each individual conductor? My intention is to reduce any chance of RFI noise that may possibly occur on the power strip for my guitar effects pedalboard.
could you possibly use this to mitigate AFCI trip nuisance for some appliances? My understanding is that EMI/RF surge protectors on some appliances helps prevent them from tripping some AFCI breakers.
Would a ferrite bead on a USB cable cause bandwidth losses, or would it be fine because both of the ground and signal cables are inside the ferrite? Ferrites have always confused me, since they act like inductors yet have no coils of wire (apart from in some).
Great as always, wonder what the freq. was in that burst? Looked kind of sinister and a real trouble maker but easy to fix. Glad to learn something new as always. Dave.
Great video, well done, covers a lot of material without any wasted time. I so dislike the videos where the presenter is ill prepared and spends half the video hemming and hawing before getting to the point.
At timeline 7:55 you showed parasitic oscillations of about 200 Mhz at the base of the 2n2222 transistor. Why didn't those parasitic oscillation appear at the collector of the transistor. This was before you placed the ferrite beat at the base of the transistor.
I am curious if the scope was set for 50 ohm input impedance, or the nominal high impedance during the ferrite bead tests? It would seem to require 50 ohm input on the scope to get the voltage division associated with the filter, but maybe this is wrong...
... and you have another subscriber. Great video and thanks for showing demos on the 'scope. I've been looking for a good video on ferrites and I believe I found it.
Thank you, you made me a better engineer than I was 10 minutes ago
Hello dear Sir. Could you please tell is it possible to check it with "multimeter"? If yes how?
@@SingTodayi No, you need at least an oscilloscope. Multimeters are not precise enough and they don't go high enough in terms of frequency.
Your videos should be part of every theory lesson in schools and colleges. It is fine to explain it on a chalkboard but to actually see it on test equipment makes the theory sooo much readily understandable. I'm a visual learner as are many others, wish the internet and instructor/techs like you were around 40 odd years ago when I was desperately trying to learn this stuff...BRAVO ZULU
I think I just learned more in ten minutes than a month of physics class.... and if I'm not mistaken you did this in one take as well. Excellent work!
seconded. super useful video. i came across this vid because of a project that i'm working on, but it's gonna have to wait while i go through all of his other stuff.
fourthed.[?].
Fifth'd. Compelling demo. And as a result of watching it, I went straight to a homebrew receiver project with a Mosfet RF amp that was unstable above 7mhz. Added 2 turns thru a 43 bead, soldered it right on gate 1, and guess what? It worked!
I also concur.
Sixthed, very good live explanation
The bead on the base demonstration was almost magical. Great demo.
I liked your practical oscillator example.
I been a Ham since 1979 and this is the most awesome video I have ever seen!! 👍👍👍
Excellent tutorial. You packed more useful info in a few minutes than hours of dry text from the library. Many thanks.
This is the best video I've seen on ferrites and how effective they can be.. excellent.
Best ferrite bead video I've found! I'm an engineer trying to get up to speed to help solve a signal noise problem with equipment at work. Thanks for the great info!
Thank you for another one of your excellent teaching moments. You are blessed with the ability to say just what needs to be said, no more, no less.
I have used these ferrite beades before and i have known that they do sth by frequencies but i have not seen their waves on the oscilloscope,now i have beter veiw,how a great video was that🙏🙏🙏
I've used ferrites on occasion, but I never realized just how much loss they could create. There you go again teaching something I didn't know! :) Great Job! RW
Thanks again for your great videos! You are an excellent teacher and I for one very much appreciate you taking the time to make each one of your video lessons with such great demonstrations, examples, and experiments to help convey the concepts you are teaching!
your 10 min videos are like summary of 1hour engineering class, but better and enjoyable.
The demonstration for suppressing a parasitic oscillation was brilliant!
This is the best primer on ferrites I have ever seen. I really appreciate your videos.
good info. I always wondered how effective those ferrite cores were and if they did anything. Thanks for clarifying!
This channel is GOLD MINE and the videos are Nuggets.
Thank you sir, this solves a few problems I've been fighting. You have an outstanding way of explaining things.
Excellent coverage. Hams (W2AEW) often have extensive, job related, knowledge and experience to share. I suspect that's the case here. Thanks, AA4BQ.
This video has earned yourself a subscriber sir. Very well done.
This is great. I loved the cross referencing to the 'scope. One area where it does get confusing is the use of various mixes dependent upon the application: use as a choke against use as a transformer. This leads to folks arguing at cross purposes on forums and elsewhere about which mix to use. A mix that works as an RF choke at a given frequency will most likely not be a suitable mix for a transformer at the same frequency for obvious reasons when you stop to think about it. I do enjoy your videos Sir.
I know this vid is old, but gold ! clear demontrations, didn´t know osilators have oscilatotions on the base, I thought it only happened on tube circuits where the cheap and effective solution is a grid stopper resistor, most tubes where deigned for high frec. did´t know that bipolar transistor suffered the same issue. Now I know thanks to you! In fact 2N2222 is a high bandwith transistor (relative to say a BC548).
Excellent! Covered so much in a small Video... A must watch for all electronics related engineers. Thanks for a great refresher course.
Great video, learned something new
Excellent video Sir. You and thesignalpath are prob my favorite posters of educational info here. Thanks for sharing with us your knowledge, i look forward to more of your content.
Your channel is high quality , very interesting channel , it is a must have channel for any electronics person / engineer . I wish i had more time to see all of them several times over .
I always wondered how effective those filter beads were. Many products have those inside and I always ask myself "how much are these tiny ferrite beads going to help"... Thank you for showing us and making it clear! :)
Other online sources only gave me some vague description of these mystery components but your demonstration made things very clear for me!
I worked as an engineering technician for a large op amp maker 45 years ago and we were always looking to increase the bandwidth of our opamps and multipliers. These were discreet devices that were about 1-1/2" square and had 7 to 9 pins on the base (I still have a few in my parts bins). The circuitry was on small printed circuit cards, these were put into a potting shell and then filled with epoxy. A cheap way to increase the bandwidth was to slide a small ferrite bead over the output pin -worked every time.
"thank you for this" its always better when an there's a coherent instructor explaining a thing for me sometimes the concepts don't leap off the page for me on top of the fact i don't speak electrical engineer so again thank you.
Indeed very well demonstrated, these filters and suppression of unwanted frequencies both within circuits and power supplies as these can directly affect other sensitive electronic equipment through power lines or other interconnections as well as radiate electromagnetic radiation as radio frequency interference, (RFI) so today you would not be able to market any product unless you meet all RFI regulation under the EMC rules, and only then you could place any product on the market and obtain a CE marking requirement.
This was the most informative and actually answered the questions I've had for years! Massive kudos w2aew!
I always thought that ferrite beads were electrically conductive. When I saw you put that bead directly on the lead I was sure a short was imminent:)).
Thanks, opened my eyes and put ferrite beads on mosfet gates on my current project working at 300v, very clean switching right now. (Also added capacitors very close to the half bridge).
They are electrically conductive.
Never put an inductor on a FET gate.
That's the last thing a switching fet wants.
Fred Garvin you can’t just say never. applications may require to add a reactance to any location depending on its application. For example sometimes your biasing network may require inductors near the gate specially in radio frequency designs. Besides it is all relative to what your gate sees and its switching speed. You could put a a tiny inductor (fH) and if your frequencies are in KHz it simply won’t see it.
Great video!
Thank you very much for your excellent explanations about ferrite beads. The clearest explanations! Thank you!
I understand the principle of why it works... didn't realize it could have that magnitude of affect on at higher frequency. My question, how do you determine when you need to use this filter? What would be some symptoms? This question stemming from the fact that all of the computer related cables have them. AWESOME video!
1) I'm really enjoying your videos
2) What is your profession? Does it involve teaching, because you deliver the material really well
3) Ever though of elmering?
Thanks for a practical demo, I always wanted to see.
My idea is that supply decoupling and EMI suppression are 2 different use cases of ferrite bead.
1. Supply decoupling = ferrite bead in series and acts attenuates high frequency noise to pass through, hence decoupling.
2. EMI suppression = ferrite bead as a transformer (not in series), basically provides a low impedance for high frequency noise, so that they do not radiate through parasitic antennas.
Or, is 1. and 2. same???
I had an idea what those beads around transistor legs were for, but so good to see a demonstration. Thanks
+Malcolm Hunter Was that like witchcraft, or what?
I was right as my guess it was some kind of filter. I asked Best Buy and Office Depot and no one knew.
Your explanation is very good. I am trying to find the same length power supply cord for my adventure cam
without the ferrite bead on it. The cord came with a ten year old Cannon camera but works on my Ultra Pro X 10.
The length is 18". My next step is to try Radio Shack for the cord I need. Subbed and liked.
LOL you asked Best Buy...You so funny.
Nice video, straigh to the point ! More intuitive than hundred pages of unreadables applications notes...
Nice Job;thank you
Alan, your videos are a must for everyone involved in electronic engineering.
Thanks a lot
Really like these videos. What i like the most is the comments from guys that feel they have to mention that they themselves are engineers or graduates of M I T . The only thing that they engineer is a burger onto a bun at the golden arches for an 8 hour shift.
Nevertheless....good video
Thanks
Thank you for posting this excellent video! It has helped me to understand (on a QUALITATIVE basis) exactly how ferrite beads work. Though I am currently interested in filtering out barely-AUDIBLE-frequency noise (in the 10 KHz to 20 KHz range), I am now prepared to do some trial-and-error testing with different split ferrite beads, installed on both the power cord and audio signal cables of our A/V system. Thanks again!
Very, very well done vid with clear/concise info/presentation.
Job well done Sir.......
Very well explained Alan. I have a topic suggestion - back to basics video on filters. Something that shows multiple order passive/active filters and their performance. Thanks for making these wonderful videos.
Very helpful. Thank you! I'm planning on doing a CNC plasma later this year and the UA-cam algorithm sent me here.
Very instructive video.
Now I am thinking that maybe for the cases that the operational frequency of the circuit is in much lower ranges, it is even better to use bids made up of iron, instead of ferrite.
Because if I know correctly, the "cutoff" frequency of iron is much less than ferrite. Though I have never seen any iron bids around a wire for noise cancelling ...
Wow, I didn't realize how effective the ferrite could be. I will need to do some experiments myself.
Are those frequencies showing on 4:00 timeline got chopped off the higher frequency or compressed it.
The higher frequencies get attenuated (higher loss).
Is the added inductance the cause of the loss that you keep referring to, or is that a property of the material like dielectric loss? And how would a coil inductor behave differently than a ferrite bead? Awesome channel btw
Thank you! I fix CB radios and have one that has a touch of parasitic oscillation. I am putting a bead on the base of the final or driver later to see if it'll alleviate it.
Be careful with your choice of ferrite material or you'll likely affect the operation at 27MHz too.
Thank you
Great video...I always enjoy the way you explain things in such a simple manner...
As a former Instrumentation Technician, we usually get deliveries of industrial instruments with those things loosely bouncing inside the box. I usually pick it up and turn it this way and that not knowing what those darns are for. Now I know. Thanks.
Very good, you are very clear to explain, despite of my bad english you are a good teacher, thank you very much!!!
Excellent presentation visuals are worth a thousand words ..
Great examples, the only thing I would add is side-by-side shots of before and after so that the results are even more obvious.
Thank you for this excellent 10 minutes (11:51 actually) of video that teaches a lot.
Thank you for sharing your knowledge.
I was reading through the manual for a new video camera I had bought, and it mentioned this thing I'd never encountered before, that snaps around the power supply cable. Of course my curiosity was piqued, so I had to find out more.
Thanks to your video, it all makes perfect sense: suppression of high frequency electromagnetic radiation, by encouraging lossy inductance. My questions is: is this to protect the camera itself or is it just bundled in to comply with regulations to prevent other devices from picking up interference?
Is the operation of the camera likely to be affected if I don't bother putting it on? The cord is supposed to be wrapped around the bead (in parallel) so that the cord passes through the middle part twice. The design of the supplied bead is such that it is a very tight fit and I am concerned that I will damage the insulation of the cord if I were to clamp it shut.
If I simply left it off, what's the worst that could happen? (I would be filming on battery power 99% of the time anyway. Very seldom using the power cord while filming. Only there for charging the batteries.)
Thanks again for the clear explanation.
It is likely needed for the camera to meet some emissions standard. It is highly unlikely that you'll have any problem whatsoever if you only pass it through once or leave it off entirely.
I like your informative video. I never suspected that a simple PSO would break into oscillation at 200 MHz. I've built quite a few, but even if they did oscillate, my 20 MHz scope would never know it. Thanks.
I remember watching some weird twisted bits of sinusoid from homemade audio oscillator shown on my 5 MHz scope, now I got what those shapes mean.
Hi there, first of all let me thank you for your video, it has educated me to no end. I have a rfi problem I would like your advice with.
I run a professional music studio and am always trying my best to cut down on noise. Recently I have had a dimmer switch installed on the studios lights. The dimmer switch is an old school MK type double switch not a new led one.. One dimmer for each rooms lighting circuit. I am using new Phillips led warm white bulbs which are great for my studios lighting bills and have been designed to work/dim with regular old dimmers. Indeed the Phillips led bulbs dim perfectly and smoothly, even better using the old mk dimmer than the Chinese led dimmer I had before.
However, now it seems that with the dimmer installed I am picking up much more interference in the room while recording. The classic one is a single coil pickup in a guitar. It goes crazy with interference when the lights are on and then shuts up when I turn the lights off.
Same with guitar amplifiers. Of course I know that guitar pickups and tube amps always pickup interference anyway it's just that the audible volume of said interference has got much louder since I fitted the dimmer.
Please is there any way I can choke/suppress or isolate the dimmer switch in order to reduce the noise/interference without having to sacrifice the dimmer and go back to the standard on full of off switch? Perhaps ferrite beads on the connections to the dimmer? Or do I have to spend a lump on a 1:1 isolating transformer and completely isolate the lighting circuit from the rest of the power in the studio. Any help would be much appreciated. Thank you.
It is possible that these snap-on ferrite cores might help - installed in the wiring box for the dimmer or light fixture, or both. But there are no guarantees. It may help to understand which device is the major contributor. If the dimmer is replaced with a switch using your Phillips LED bulb, is the noise lower? Or, if regular incandescent bulbs are used with the dimmer, how is the noise?
Some of the manufacturers have written information on reducing noise/interference:
www.lutron.com/TechnicalDocumentLibrary/360484.pdf
A day where you learn something new is a good day. Thanks for making it a good day for me :-)
Thanks for the wonderful & practical explanation, of the usage of the Ferrite Beads.
You earned my subscription. Very basic but a good refresher!
Ok, one turn in a ferrite bead, cylinder or toroid put losses at very high frequency.
My question is: it is only due the reactance coming from inductance or also for an other phenomenon ? If yes, which one and where it is measured in the toroids datasheet?
TNX in advance for your answer and for your fine explanations. 73s.
another great video! just one question though. you explained and showed how the ferrite bead blocked parasitic oscillations at the base of BJT. i can see how the ferrite bead's inductance can filter high freq. noise at that point, but you also mention you have added a series resistor before to achieve the same goal. i dont understand how adding a resistor can filter the high freq. components. is that something to do with RC circuit coupled to it? thanks
The resistor isn't acting as a filter, it it simply adding a little loss (de-Q'ing) the complex impedance looking into the base.
Wow! I saw this link in the comments of a 3-part decoupling tutorial at allaboutcircuits, despite being a good article, your video explained more in 12 minutes than a month of reading online!
I will definitely check out some of your other videos, I would love to see some more on choosing the correct part for different applications! (If you haven't already)
Excellent video, and I'm shocked that this was done in one take - unless you have Hollywood level editing skills ;)
Yes, one take - after LOTS of prep, practice, and previous attempts....
Absolutely perfect presentation. So clearly explained and demonstrated.
Good explanation, thank you. You sound like a good analog engineer.
Trying to diagnose weird wiring on my old Nissan and I am considering adding ferrite cores on some of the finicky sensor wires. I've added some to the LED retrofit headlights and I actually think it made a difference in drivability. I have a feeling the fans on the heatsink was creating enough RF and maybe that combined with no isolated ECU grounds it might be enough to distort a 5v cam signal, which I have had issues with in the past.
Good information. Very helpful.
I have a wireless mic set up and at times I get very bad RFI. I suspect it's a cell phone of one of my neighbors. The cord from my lapel mic to the transmitter acts like an antenna and picks up the very high frequency of the phone. I ordered some ferrite beads off Ebay. Hope that solves the problem...
Very nice video. Once again a super job in using instrumentation to explain and show the behavior. I wish the ARRL Handbook has such videos embedded in the pdf versions!!
Dave, AA6RE
Thank you. I've got an older DC voltage standard I've been trying to repair. It has 4 "VN66AK or 2N6660" transistors, 2 of which have berrylia washers on them... after watching your video I'm guessing those washers act as EMI filters on the high speed VMOS transistors.
Great info!!! thank you !! I'm powering my gopro camera from a accessory outlet on my Harley Davidson and wondering if I would benefit in employing a bead on the usb power supply line to reduce any noise it might generate?
Very good introduction.
What about energy loss in bead? How much can it dissipate?
Will a ferrite bead disrupt the data traffic on a cat 6 data cable running from a switch to a phone or PC? We are getting what we think is EMI interrupting phone calls. I need a way to filter it, but not kill the needed data traffic on the cable. Great video and explanation.
It most likely will not affect the data on the cat6 cable, since that data is sent differentially. It's certainly worth a try.
Love the analog scopes mmmk, love the frequency response mmmk, superb content Mackey!
Superb video. Very well prepared, I loved all the practical examples.
thanks, I will try it. Im a bit worried that the top frequencies of the audio are going to be effected though.
Very practical and useful explanation, I have an axial ferrite bead inductor with the following inscription: 1W0_()_33J
How should I understand this inscription?
._()_ = ohm symbol
W2aew, when they use a CHOKE a series transformer coil in the power supply, what does this Choke do to the AC ripple? The Choke changes the discharging and charging of the filter caps or doesn't affect it? Without using a Choke the AC ripples can cause "harmonics" added to the circuit?
I have probably several hundred ferrite beads salvaged in the process of scrapping out various bits of equipment. Can you suggest any way for me to characterize them? Determine which ones might be best in which applications?
The AC cord plug into the back of an a piece of equipment, inside before the power supply there is a silver square box that filters out RFI/EMI from the AC outlet. Is there ferrites beads inside this RFI/EMI box or what kind of filters are inside these RFI EMI filters for the AC outlets. EE engineers have told me these AC RFI/EMI filters cause a lot of current leakage issues i'm guessing from the AC hot wire to the earth ground. I have tried opening up these silver box RFI/EMI filters but looks like filter cavities or something.
Any suggestions on eliminating noise from a BLDC cooling fan in RF circuits? I have read and observed that this noise emanates from the fan's ground wire. The only solution I've found that really works is to use a seperate power supply for the fan, that is a seperate ground reference. The question is, can I create a truly isolated supply for the fan if it is using the same AC wall outlet voltage source as the RF circuit? I haven't figured out how to do this yet. Any suggestions would be appreciated. Thanks always.
Thanks for the lesson sir… if i use emi ferite bead at end of grounding wire in motorcycle or car engine, is that can improve eletrical circulation and can get better performance?
Great video. I was wondering if you could assist me. Ever since installing a new router I'm hearing a pop noise from my pc speakers. I was instuctedvia a forum to put ferrite core on the leads to no avaail. I'm just learning to use an oscilloscope and was hoping you might lead me to a tutorial that would help. Thank you!
It is the common mode (versus differential) signals that are attenuated by the bead on the USB cable. Common mode signals cause the entire USB peripheral to act like a monopole antenna.
Thanks for another great video. After seeing the action of the chokes in your demo it makes me wonder whether adding chokes to each side of a horizontal dipole antenna could change the resonant frequency of the antenna. So, for instance, if I had an antenna where each side was of length L, could I make the antenna resonate at double the original frequency by adding chokes at the L/2 points of each side of the antenna. In effect I guess I’m asking if the antenna could be made to appear to be shorter through the scheme described above. If such a thing could be done I can imagine moving the two chokes to whatever position was needed to have a half-wave “effective length”.
Since I’ve not heard of such an approach I’m guessing there is a fundamental flaw in my logic. After watching many of your videos, I feel that if anybody can set me straight it’s you. - Thanks! - Jim
Thank you for this great video.
In electricity, when we wind electric wire on a ferrite core, we can translate the electromagnetic effect to an electrical circuit by impedance which is jwL ( j, omega the angular frequency, L the induction).
But here, the ferrite is on the wire. How do you translate that in electricity terms like impedance (maybe it is still jwL, with induction L computed differently) ?
I think its because even a simple wire has a parasitic inductance. When you add the core this inductance gets bigger (ferrite is more permeable than air), making this parasitic inductance bigger and changing its impedance
Can you use a ferrite bead over the shielding of a power cord with three conductors, or is it required to use a ferrite bead on each individual conductor?
My intention is to reduce any chance of RFI noise that may possibly occur on the power strip for my guitar effects pedalboard.
could you possibly use this to mitigate AFCI trip nuisance for some appliances? My understanding is that EMI/RF surge protectors on some appliances helps prevent them from tripping some AFCI breakers.
Would a ferrite bead on a USB cable cause bandwidth losses, or would it be fine because both of the ground and signal cables are inside the ferrite? Ferrites have always confused me, since they act like inductors yet have no coils of wire (apart from in some).
Hi great video!
How would you what frequency is the cable is putting out and how would you know what type of ferrite would you need for it?
Great as always, wonder what the freq. was in that burst? Looked kind of sinister and a real trouble maker but easy to fix. Glad to learn something new as always. Dave.
Finally ,It all makes sense now!
Thank you!👍
Great video, well done, covers a lot of material without any wasted time. I so dislike the videos where the presenter is ill prepared and spends half the video hemming and hawing before getting to the point.
At timeline 7:55 you showed parasitic oscillations of about 200 Mhz at the base of the 2n2222 transistor. Why didn't those parasitic oscillation appear at the collector of the transistor. This was before you placed the ferrite beat at the base of the transistor.
I am curious if the scope was set for 50 ohm input impedance, or the nominal high impedance during the ferrite bead tests? It would seem to require 50 ohm input on the scope to get the voltage division associated with the filter, but maybe this is wrong...
... and you have another subscriber. Great video and thanks for showing demos on the 'scope. I've been looking for a good video on ferrites and I believe I found it.