Electronics tutorial - Ferrite and Magnetic permeability

#95 In this video I look at magnetic permeability - what it is and how it affects inductor behavior. First I look at how it influences the inductance of an inductor and then I look at just how stable this inductance variation is with frequency.
Tektronix documentation: download.tek.com/document/75W...
TDK datasheet: www.tdk-electronics.tdk.com/d...
Murata Datasheet: www.murata.com/en-eu/products...
Permeability in steel: home.eng.iastate.edu/~nbowler/...
Spreadsheet with formulas: docs.google.com/spreadsheets/...
Special Thanks to all my supporters on Patreon! Especially @afiskon and Xegomen!
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[@hanangonen8732]

I love your videos . They are very useful ...and you have good presentation skills .

[@FesZElectronics]

Glad you like them! Thank you!

[@xDR1TeK]

I don't know what I was studying at the university because this here is far more important than what I already learned there.

[@knowledgetreasure-1523]

the best video on inductors continue in such way of analysis

[@SMV1972]

Узнал много нового. Благодарю Вас!

[@christopherwolford6522]

Awesome I was just refreshing myself on this stuff last night and it popped up 2 hours ago thank you!

[@josephotieno898]

Wonderful explanation and presentation on the subject...

[@jean-pierrebuttet9438]

Thank your for the explanation, I just learned something very useful

[@chifoltz9023]

Very good teacher thank you!

[@bogdansofalca6946]

really appreciate your content. Thank you!

[@omeridan8815]

Yes! Tell us about the discovery!

[@SanjaySharma-pw6ww]

Thanks for the valuable information

[@lucabelvederesi6914]

Very nice video and interesting topic! Should be interesting to see how the ferrite beads and/or inductor have impact for example in an input filter of linear regulator and stuffs like that.

[@sidravi3885]

wonderful.. keep it up...

[@timostheodoru3532]

Top quality content as always...keep it up mate!

[@FesZElectronics]

I'm happy you enjoyed it! Thank you!

[@avisouran2225]

Very very good

[@gharbisalem1254]

Keep the good work your content are awesome also unique 🙂 thank you for passing your knowledge

[@FesZElectronics]

Thank you! Will do!

[@guillermo2044]

Can you do a similar video on “mag amp” saturable inductors explaining their properties and how they can be used as switches in power electronic converters? Thank you for the great video. (Referring to section 8.8.1 of Switch-Mode Power Supplies book by Chris Basso)

[@p_mouse8676]

Excellent video! Maybe as a follow up, it would be very interesting to look at the current vs inductance graph (saturation) as well as doing distortion measurements. Also adding a DC current will drastically reduce performance of many inductors (without an air gap) From an audio point of view it's by far the least linear component.

[@FesZElectronics]

Actually I do plan to look at saturation and temperature effects in the next video of this "series". Its quite a pity that most ferrite bead datasheets have absolutely no current derating curves - I mean you get some curves related to heating, but nothing related to impedance loss.

[@p_mouse8676]

@@FesZElectronics yes. Even in most datasheets of inductors that's missing. Quite an important variable.

[@primateinterfacetechnologi6220]

Since you mentioned it... This air gap thing; It remains confusing to me- I have a sense of when they use it... I have unwound a metric fu(#-tonne of transformers, meticulously: but I haven't heard an explanation that I understand. Nothing unusual here. ... So in the example of a DC bias that you cite, what is it about the air gap that prevents this from being a problem? something to do with saturation?....... I basically don't know what I'm talking about in this area. I struggle to ask a question that I imagine makes sense. I have to deal with this stuff though because I'm an audio guy; I play instruments... often through unusual circuitry, so... there is a big overlap- especially in my case. If you have any idea what I'm asking (more than I do)... I thank you for your insight. peace, and rock on, Mr (or Mrs.) Mouse.

[@moniftormos6881]

Great

[@DiegoColl44]

Thank you!! is the information that I just needed to know now.!! haha!!

[@stephenma2065]

I've just repaired my induction meter. The negative inductance reading is mainly caused by the fuse and fuse holder inside the meter. Just take out the fuse and clean the contact area, it may fix this problem.

[@FesZElectronics]

Thanks for the suggestion! I checked my fuse, it was burned out; but after replacing it, the problem persisted. It seems the inductance measurement does not go trough the fuse with this particular meter...

[@hallkbrdz]

Great presentation. What is puzzling is why then pmsm motors, which use high frequency PWM, are made with laminated silicon steel instead of ferrites. I assume this is mainly due for structural reasons.

[@two_number_nines]

Why are electric motors exclusively using steel sheet cores? I've calculated many brushless motors go at about 16khz per phase, especially electric vehicles. They use bare steel sheet cores in the coils and the rotor (with either magnet or conductor inserts for synchronous or asynchronous mode). CD/DVD and HDD drive motors go between 300 and 400 hz.

[@NourMuhammad]

From what I see in that video there is a very good base martial to build a good and affordable PC LCR instrument

[@FesZElectronics]

Well, the Analog discovery already has a built in section in its software application that performs the "L" and "C" measurement over frequency. i basically extracts the L, C and R for any component - so for an inductor, you get your inductance, but also the parasitics - ESR and EPC

[@boonedockjourneyman7979]

Analog Discovery is an accessible device from both cost and infrastructure points of view. In that way, it is like your videos. You would be doing a good thing by using and reviewing it more. Many hobbyists and students would benefit.

[@jimkulyk7347]

Great video with very useful information. Could you explore how to minimize low frequency common mode currents on coaxial cable outer surface shield or return conductor? This is a problem when measuring low impedance components or power distribution networks IPDN) on PCBs with a VNA or frequency response analyzer (FRA).

[@lambda7652]

Awesome video! can you please make a follow up about BH loops and what we can tell from them? I was always thinking a small loop the loss is small but this seams not to be true.

[@gacherumburu9958]

👍👍

[@rinkalsutariya3784]

please explain enhanced Howland current source and simulate in LTspice.

[@HL65536]

Is there a list or table of inductor core materials and their losses at certain frequencies and energy storage potential? I am always unsure which of the sort-by-price inductors are suitable for what applications.

[@jmikronis7376]

Ferrite cores are manufactured with a number of ratio mixes and material mixes. They’ve gotten better over the years resulting in smaller cores and lower wire size. Keep in mind - at frequencies higher than 20KHz, the skin effect causes electron flow to concentrate at the outermost layer of the conductors.

[@ahmatrizki5154]

any same kind of measurement for ferrite?

[@levibanuta8381]

Excellent video.. I like the application note from Tektronix, I actually used the same setup for impedance measurements and will use it again in the future for sure. If you don't mind, I would like to ask your opinion on a matter that I came across recently. A 2.6 mH inductor with a ferrite core (cylinder with 10 mm diameter and 7 cm length) is changing the inductance to almost 3 mH in the proximity of a large metal object. Is the permeability of the core changing, or the magnetic field is disrupted by the large metal object? Is there a way to compensate that? Thank you..

[@FesZElectronics]

I guess the issue is that the old core was just the ferrite cylinder and air; that was giving the 2,6 mH; by having the metal object (I guess its ferro magnetic) the magnetic filed pass trough that also, so the new "core" is made from the old and part of the object. That is why the total permeability is slightly larger. You might try increasing the distance between inductor and object, or try changing the material of the object; or if price allows it, change the inductor to have a less open magnetic field - so rather than a rod core, have a ring core or something.

[@levibanuta8381]

@@FesZElectronics Many thanks ! I tried increasing the distance from the metal, which is a 5 ton solid steel block, but I am limited to just 1 cm of room. There are moving parts that restrict the position of my inductor, if I move it more than 1 cm away, it will collide with the moving parts. Also, we tried carving into the steel block to remove some metal, but was insufficient. I'm still looking for solutions and will probably try other core materials. Thank you again ! Multam mult ;)

[@primateinterfacetechnologi6220]

@@levibanuta8381 To be honest; I want to hear more... I think it was the five-ton steel block. Go figure. peace, and rock on.

[@Dc_tech386]

You know for months I have being issues with my mosfet overheats with every ferrite core I buy on Amazon and today I came across the real reason why my mesfet get hot with very little load and it’s the type of material that the ferrite is made with all this time I was using pc40 material ferrite for months I ever give up in ferrite transformer and now my ferrite inverter work will pc40 is for fly back converter only and 3c90 material is for push pull converter

[@SanjaySharma-pw6ww]

Sir kindly make me clear "duty cycle" when it is considered to be 50% and when its 100%.pls co- relate with ic uc3842/uc3845 family.when to choose 3843/3845. Kindly make video on sendust core too. Thanks for your all videos

[@primateinterfacetechnologi6220]

I also find "duty cycle" ratings confusing... It's not what a rational person would think... But something a bit more convoluted and confusing...

[@actyon20]

I wanna buy you a beer Sir :)

[@ChaineYTXF]

You ha Starship's heat tiles on your wall..? Good thermal insulator? 😁

[@FesZElectronics]

Actually the room in which I do my videos does seem to be a bit warmer since I added those. The main reason though why I got the tiles was to create a more interesting looking background (almost anything wound have been better than the white wall); but also the tiles have a textile surface, so they help with reducing sound reflection and echo.

[@primateinterfacetechnologi6220]

I get the feeling you've only scratched the surface of this exact subject- It seems that inductors have more to them than all the other types of electronic components combined... I'm including all silicon junction types in one category here. I don't really know much about this stuff... but then again that's what the experts say as well; if they know what they're talking about. It seems like we've actually got three things here: resistance, capacitance, and the universe of weird inductive behavior... I guess it depends on how you break it down and whether we're talking about practical usage or............. If I were Stephen Hawking or Richard Fayman I would know what I was talking about. But I'm not, and I don't. Peace man, and thank you.

[@dougaltolan3017]

Shame you couldn't do the test with a ferrite transformer core for a side by side comparison. Swapping from your measurement to a datasheet lost me.

[@incxxxx]

I think that your old films without presentation picture of yourself were much much better, because did not distracted from meritum.

[@bogdansofalca6946]

haters gonna hate