Howto repair switch mode power supplies #5: Magnetic core materials, ferrite vs steel

In the fifth video in the Switch Mode Power Supply (SMPS) repair series we continue with a bit more background in the magnetic core materials. In this episode we focus on the fact of why in the case of SMPS one need to use high frequency switching circuits paired with ferrite core material. Furthermore, the ferrites are directly compared to the traditional humming transformers with iron cores containing silicon. Silicon is added to change the magnetic properties of the cold rolled steel core material, making it electronically less conductive, and also to shift the material towards to be soft-magnetic. The magnetic loss is explained in SMPS in terms of the magnetic hysteresis loops in hard-magnetic vs. soft-magnetic materials.
Namely, in SMPS one must use expensive core materials with soft magnetic properties containing rare-earth metals like cobalt, rhodium and neodymium. This is because the magnetic core loss is directly proportional with the operational frequency. Therefore, old low frequency transformers from linear power supplies operating at 50-60Hz can use cheap steel/iron core material, because they operate at the low frequency regime of the power grid.
Via experiments the AC sine wave and the alternating current from the electric grid is explained, together with small experiments and figures.
From the experiments with a simple mechanical spring, it is easy to see that the smaller the spring, the higher the frequency will be at which it oscillates. This is a very important design consideration also for SMPS, since the smaller the chopper transformer/inductor, the higher the pulse-width-modulation (PWM) must be. Thus, making smaller and lightweight SMPS means, that one must go to higher switching frequencies.
Also, this means, that in the case of SMPS one must use complex electronic circuits to feed the small chopper transformer with high frequency pulses, which is not necessary for humming 50-60Hz transformers.

[@shvideo1]

No one has explained this topic an intuitively as you have. I can learn so naturally the principles that you are so patiently conveying in your videos. You are an excellent teacher. Please continue and do not stop! Thank you!!

[@tiborfarkas3205]

I fully agree

[@peckelhaze6934]

I have not enjoyed such a series of videos for a long time. I have learn't so much. Thanks for these.

[@peterduxbury927]

It is a real pleasure to see and listen to your tutorials. The best part - is that we can all keep going back over your tutorials until it all becomes clearer! You are providing a great service to the world. It seems that most electronics such as TV's Sound Systems and Computers etc all have the Switchmode Power Supply in common, and the majority of faults are attributable (due to higher voltages / frequencies / heat) to the components in the SMPS. Please keep up your great work. Greetings from Australia.

[@DonkeyLearningIT]

Many thanks for your kind comment! Also, now I really hope to get back and uploading new content again on the channel.

[@n0yxl]

Many thanks for producing this series about Switch Mode Power Supplies. I have gained much more respect for these otherwise seemingly "cheap little power supplies".

[@MLX1401]

Appreciating the way you - with great patience and humour - go through all the basic circuit components and explain why they are needed in the signal path. Those "how-it-works-for-donkeys" -descriptive parts with graphs and analogies are the best! Thank you so much for putting your time and eh, energy in these, helping out us entry-level elecronics enthusiasts :)

[@DonkeyLearningIT]

I like your feedback, many thanks for taking your time and watching the video! Though, I would never call my viewers donkeys. Instead, *I am the donkey myself* who needs to learn new tricks ;)

[@RideFree245]

Great teaching style, love the depth and ability to get true natural science in to the complex electronics. Bravo!

[@DonkeyLearningIT]

Thanks for the positive comment. Most people commented that the presentation is too slow, and I repeat things too many times. So in the future videos I will try to speed things up a bit, and reduce repetition.

[@MemoriesRR]

I feel like I’m back in college again only I don’t have to squint to see the presentation. Wonderful. Thank you.

[@olajideoyekunle9044]

I really do not know how to thank you. I am learning in an entirely new and better way what I have always thought I already well understood. Again, many thanks.

[@FrancisRodgers]

I came here looking for information on power supplies. But you have also given one of the best explanations I have seen on inductors. Thank you for sharing this information.

[@hernancoronel]

I am not sure I want to know so much about transformers... wasn’t this a series about switched mode power supplies? Thank you for the videos!

[@Aman-sj5pl]

I am getting more and more addicted to this tutorial of yours. You're doing an awesome job, keep up the great work! Thank you a lot.

[@DonkeyLearningIT]

I am glad that you liked it! Some people complain that the series is "too theoretical" in spite that I am covering the very basics. After one knows this basic stuff, it is more easy to explain a practical repair and to show what is the thought process going into figuring out the broken component.

[@graemelinsdell2361]

Very detailed graphical description of reasons behind uses for the inductor material in switch mode supplies. thank you very much for the effort in this tutorial

[@DonkeyLearningIT]

Thanks for watching! I know my videos are somewhat too long, but I try to give information to people and explain the reasons why things are done in the way they are done instead of just putting techno music below the clip.

[@jelmar8740]

I have downloaded this SMPS series, really usefull and I’ve learn more than when I was in University, I needed basic electonic knowledge for modern HVAC especially those equipped with inverter. Thanks a lot for the video. I can’t believe this is free

[@DonkeyLearningIT]

You are welcome! Also, I am sorry that I was not able to produce new content in the meantime, but hopefully I will be able to get back on the horse (I mean on the donkey). HVAC is a good thing to study now, as far as I heard, one can easily get jobs with it. Wish you good luck!

[@extremelocura]

I am hooked.. I can watch you all day.. Thank You.

[@lisuraoi]

This summarizes my Power Electronics subjects in my college.

[@evil17]

Brilliant series you have created here Donkey, very precise and educationally informative, thanks for sharing.

[@tk2life]

Please go on with this amazing work !

[@DonkeyLearningIT]

Thanks for encouraging me. I am a baaad lazy donkey! I promised myself, tomorrow I must upload the new episode, no matter what.

[@youawa7dsa133]

Ya we are waiting go a head

[@DonkeyLearningIT]

Finally, the 6-th video is up on Linear Regulators, which is an important topic. Namely, linear regulators are used both for providing reference voltages, and for supplying ICs from high voltage DC.

[@EkholmAndreas]

wow! I'm just started to learn myself a little electronics and have started to watch videos on KZbin. Your videos I absolutely among the best I've seen. thanks for making me interested to learn more!

[@DonkeyLearningIT]

Thanks for the positive feedback! There are probably other very good videos out there, but I could not find them specifically in this topic, so this is why I am creating this series. Have fun with the upcoming vids in this series as well, though I can produce contents only on the weekend due to my job.

[@rosco4659]

Blown away by this series, watched up this ep back to back but now I need a break for an hour because my brain is coming out of my ears

[@DonkeyLearningIT]

I hope that you will learn things as you go through the videos!

[@brucewilliams6292]

Excellent explanation of how the system works. This is very clear.

[@BomJimmy]

This is the most important video on transformers. Thank you so much.

[@Conservator.]

Hi, I’ve watched your video’s a long time ago but went through them too quickly. In the mean time I’ve watched several other video’s about SMPS. Today I’m binge watching your video’s for the second time and boy they are good. You have given me a profound understanding of how smps work, especially the part where the field collapses and the current is reversed. Up until now this has always been a bit of a mystery to me. Thank you very much!

[@Dickard66]

Thank you for this series of videos. They have increased my knowledge and understanding 10 fold and I'm only up to vid number 7. You have an amazing gift for teaching. Thank you & Merry Christmas. xx

[@quest2718]

Great video series. I really liked the analogy with spring and the inductor.

[@DonkeyLearningIT]

This is why I have included the mechanical spring, since it is easier to see the basic concepts with a spring, and then gradually transfer those concepts to the inductor.

[@imansudrajat3297]

woooowwww.....soooo detailed....thanks for your patient in making this very clear..

[@kd5inm]

So far I have enjoyed watching your videos, one thing I will point out is that on the part where you discuss the 12 volts DC from the battery you have the flow of current backward. Current and voltage flows from negative to positive, not from positive to negative. The reason is that electrons flow from negative post where less electrons are, hence negative - to positive + post where more electrons are. Electron flow is from negative to positive on a battery.

[@DonkeyLearningIT]

Well, the issue is that in electronics we are still talking about the *conventional* current flow, which is exactly the opposite to the actual electron flow. This is because the conventional current was fixed before the time when physicists have discovered electrons. At that time it was already too late to change the nomenclature in older books, so it lived on until this day, and it will stay for generations to come.

[@adamsacad8265]

very informative videos keep it up. waiting next videos.

[@revoshimini1433]

I quite appreciate your teaching skill and right knowledge of SMPS. Great Job! More grease on your elbow.

[@DonkeyLearningIT]

Thanks for the comment. Some people complained that the video was way too theoretical, but I think it is important to understand why SMPS use different smaller transformer cores.

[@REMEMBERFINCH]

This is the first video I've seen of yours, I've subscribed and will go back and watch what i've missed. Thanks for sharing your knowledge.

[@DonkeyLearningIT]

I am glad that you liked the material. Btw, good feedbacks like these are giving me some will to finally produce new videos and finish this series.

[@REMEMBERFINCH]

I hope you do. Quick question for you. What causes some DC motors to stutter or pulse with some power supplies? The motors I've seen it with are in as low as 3vdc and as high as a 48vdc drill motor. and everything in between? If powered with a battery there is never a problem but when using various power supplies from old devices such as a 12vdc 2a supply from an old router, one motor rated for 12v might pulse or stutter and another rated the same will run fine. Thanks

[@DonkeyLearningIT]

DC motors have not just a voltage rating, but also a current rating. Voltage multiplied by current will provide the power in Watts. Now the issue is, that especially switch mode power supplies tend to totally drop out (meaning they go well below the rated voltage) when they are loaded with a higher current compared to which they were designed. After the PSU drops out, it will start up again, than drop out, and this will repeat over and over, causing the pulsing you mention. In contrast to a power supply, a battery can provide very high current until the battery heats up, and even a hot battery is still providing a smooth voltage which slowly decays over time due to discharge of the battery and due to heat.

[@Sekhar_Home]

Finally able to know why there is a small transformer in smps mobile charger..

[@dr.bharatbapodara3223]

Am speechless.!! What a learning..!!!

[@zikermu]

Dear Sir, I congratulate you for this lesson which is really educational both in terms of electronics and in terms of physics (electromagnetism, frequency).I would have liked to see it before because for 3 months, I have been trying to troubleshoot an AC adapter for a laptop with a power of 330W. The problem I encounter is the identification of the Coil of the active PFC. This one has a secondary winding which is on one side connected to the ground of the 2 MOSFETs of the PFC (they are in parallel) but I cannot find where the other side is connected. I told myself that it must be connected to an integrated circuit to detect a current crossing at zero (ZCD) but none of the legs of the 2 closest ICs correspond (the other ICs are on the 19.5V side (An OP2990 and a TEA 1995 ).In addition, these ICs are unreadable.The other problem is the identification of the primary of the output transformer.I followed the tracks with the ohmmeter and the inductancemeter but my diagram is not consistent with an LLC assembly The choke which is between the 2 MOSFETs has several connections (which I don't understand) and is surmounted by a radiator (which I understand) I am not looking for the values ​​(x milliHenry, etc.) of these materials but their installation and wiring I wrote to the company DELTA from whom I bought 5 of these power supplies but, despite my reminders, they do not even have the decency to answer me. Do you know where I can find this information? .Thanks in advance

[@praviama]

Superb tutorial on SMPS. Expecting other soon.

[@DonkeyLearningIT]

Hopefully it will be up this weekend if all goes right. It takes a lot of time to produce videos, since my editing skills are not the best.

[@sheremon5646]

Excellent Explanation 💯

[@osamahnajjar2824]

keep up teacher you are better then my university doctors and prof's :)

[@DonkeyLearningIT]

Thanks for the comment! However, I had couple of Indian colleagues at the university, and also I have watched some lectures from the Indian Institute of Technology, and they were really good. They go right into the important concepts, without much fuzz and unnecessary mathematics. This is why soon India and China will produce better engineers than Europe or the US was doing 20 years ago.

[@MiracleMAX]

Well done on a clearly explained series. I look forward to your explanation of repairs in the near future.

[@DonkeyLearningIT]

Thanks for the comment. Now the summer is over and the rainy days started, so I should have more time to produce videos.

[@MiracleMAX]

As a creator myself, I know how much time is spent in filming and especially editing. Working full time seems such an inconvenience! Keep up the good work!

[@wahabfiles6260]

You have very good gift of teaching! Subscribed and liked!

[@pwasanthatube]

thanx for your teaching methods. small points of electronics also useful. i known that from you. thanks again.

[@BAPAVEDIO]

Amazing work dude, thanks a lot.

[@jp040759]

Great series. Glad I ran across your channel.

[@daviddrake6989]

I know virtually nothing about electronics , yet I have always been fascinated bit. Unfortunately I was directed away from this interest. Knowing virtually nil I now enjoy your site very much . I am amazed at your command of English. English is very odd to the non native . May I suggest that when you pronounce 'circuit ' just say circit" in English the u is not pronounced. I Remain your fascinated Australian watcher. AMAZING

[@abdulganichairil1203]

Thanks for your tutorials are clearing understanding me.

[@DonkeyLearningIT]

I am glad that you liked it. Due to lack of time, I did not mention iron powder core coils, which are mainly used in the filtering part of an SMPS. In later videos I will talk about those as well.

[@silviuguseila2552]

Amazing teaching skills!

[@hanilokam1217]

pure explanation

[@xrqtv2540]

You are just awsome keep going. You will be fenomen.

[@frikkiejacobs8858]

Really great videos. Thank you!

[@manaharlotia7233]

thanks for nice video part 5.

[@robinsonedwardnnaji4703]

I love this video and would like to become your student. Well done!

[@DonkeyLearningIT]

Thanks for the feedback. Just watch the series and hopefully it will help you with your repairs. Due to health problems I was not producing videos in the last months, but hopefully I will be able to take time and get new videos uploaded.

[@787cb]

Excellent video. Very clear explanations. What country did you learn English in? It is very good.

[@kentvandervelden]

Really wonderful explanation and series.

[@DonkeyLearningIT]

I appreciate your feedback. I must say that your videos look professionally made on your channel. I will never reach that video quality, but at least I can try to provide some basic concepts instead. Also, I am glad that you managed to quit the rat-race and make it on your own as a small business/entrepreneur. I'm getting closer to 40, and still not there yet...

[@kentvandervelden]

You're exceptionally kind to say that. I agonize over small details in appearance that are not nearly as important as the information. You do it correctly, in my opinion, focusing on the education. I agree with the other comments here, that your explanations exceed many university professors I had. Regarding the new work, I now work 80hrs/wk to avoid working 40hrs/wk, but most it can be shared and that's closer to my heart. I'm a little over 40 and life is good :) Best of success to you, Kent

[@alok20001]

First of all thanks for your nice and knowledgeable information on SMPS which has cleared many of my doubts about power supply. Kudos to you for the same . I need your help in buying a good screw driver set which will be useful for SMPS and other electronic products Along with this also share the brand of soldering iron which will be useful in removing transformers , inductors and MOSFETs in power supply

[@DonkeyLearningIT]

Just let me know the pricerange, and I can give you some tips. Btw, you can watch my two videos where I present most of the stuff which I use for soldering, that might be useful for you as well.

[@alok20001]

Donkey Learning IT I have a budget of around $80 for screw driver set and same amount for soldering station. May I know the name of episode where you have mentioned about soldering station

[@DonkeyLearningIT]

I would spend less on the screwdrivers. On the other hand, for $80 it is almost impossible to get a decent soldering iron, especially if you need to remove large components which require good heat capacity. Is your budget really this tight, or you could eventually extend it a little?

[@DonkeyLearningIT]

Btw, I forgot to ask: what kind of repair do you do most? SMD, through-hole, high power amplifiers, low power digital electronics? Just asking, since the type of application will determine the soldering iron you need.

[@alok20001]

Donkey Learning IT Is it possible to share your email ID so that I can share some picturesque

[@solewalk]

16:12 "Then I remove the magnet, and automatically here the magnetization have dropped down and it completely collapsed". I don't want to be nitpicking, but want to point out a mistake. According to the graph on the right hand side, when the magnetic filed is removed, the magnetization of the material doesn't immediately disappear as you say in the video. Your mouse pointer should have stopped where the top of the graph meets axis M. That's where it indicates magnetization of the material when magnetic field is removed. When you go into the area on the left side of axis M, it means you are applying reverse magnetic field.

[@DonkeyLearningIT]

Well, even so many people complained that the videos are "way too theoretical", so I do not dare to make an actual physics course on magnetism. Those people who notice these oversimplifications/mistakes know more than the average repair technician will ever need to know about the topic, so for them it is of course not detailed enough. Trust me, it is almost impossible to make a video for a broad audience where you try to explain basic concepts without going into detail.

[@solewalk]

@@DonkeyLearningIT I am in no way criticizing you. I just wanted to point out a small mistake. By the way, why did you stop making more videos on this series? I really enjoyed your videos, and I am sure there are tons of people who did. Thank you.

[@kmalnasef1512]

Great series thank you, but I have a question : what do you mean by saying "at the end of the day"? is it like saying "at last"?

[@surgingcircuits6955]

It is like saying "When all is said and done.".

[@allanpatterson7653]

Ferrite has lower Eddy current losses.[3:00] The windings can be subjected to a Ring test,when you test with a pulse across one of the windings it should Ring.

[@DonkeyLearningIT]

You are right, that is an other advantage of the ferrite material. Though, people complained that the video was even so too theoretical.

[@allanpatterson7653]

@@DonkeyLearningIT Theoretical? Thing with KZbin videos you can pause ,rewind, screen save, review against technical journals.

[@DonkeyLearningIT]

@@allanpatterson7653 Well, it seems that many people are not aware of this. If a video is not short, funny and entertaining like a "Thug Life" video, than people do not like to watch it.

[@alejom.depuch831]

I am sorry for the criticism in this and the former videos. Your explanations regarding the operation of a SMPS is great and is very useful. But.... please, pleeeease.... stop comparing inductors with springs. In this video you are comparing the inductor’s CORE with a spring, which may be compared, but the core is not the actual inductor itself. This analogies only lead to confusion for those who are beginning their ways into electronics although they can’t see the confusion yet. Here are the actual mechanical analogs for passive components (LCR): L, the inductor -> a MASS, for example, a car (it will have inertia) C, the capacitor -> a SPRING, for example the springs in that car’s suspension (it will try to keep the car in the same position) R, the resistor -> the FRICTION, for example the shock absorber in that car’s suspension (it will dissipate the energy when the car hits a bump, because, without the shock absorber, the car would continue oscillating due to its mass (inductor) and its springs (capacitor) both fighting each other Having said that, now, I have to say I really enjoy your SMPS explanations.

[@justsean5160]

Another excellent video!

[@DonkeyLearningIT]

Thanks for the comment. As I wrote to an other subscriber, I did not had time to talk about iron powder cores, since the video would have been even longer. In the upcoming videos I will mention it, since those are frequently used as filter coils in SMPS circuits.

[@tochipaul8232]

Thanks, looking forward to it

[@tochipaul8232]

Your videos are superb, can't wait for the rest. When are the rest coming?

[@DonkeyLearningIT]

Thanks for the interest in the follow-up videos. I have the slides made long ago, but my last weekend were really busy. Hopefully this Saturday I can produce the contents, and on Sunday edit/upload it.

[@javiersuarez385]

thanks for your video. It was really clear and has many explanations. I had a question: What happen if we use 50Hz current in a ferrite transformer? will it work as transformer?

[@sergiobnu]

I think you are mistaken about the Ferrite composition. It actually also contains Iron, but in oxide form. See en.wikipedia.org/wiki/Ferrite_core But I still am enjoying your video. Have started this Howto series yesterday

[@grzegorz16100]

I'm sick of springs by now;)

[@macan7042]

At the end of the day this is pretty good video :)

[@DonkeyLearningIT]

You mean that I repeated "at the end of the day"? Well, at the and of the day when I am tired that might happen ;)

[@user-ig6tw3yh2z]

excellent tutorial video series

[@DonkeyLearningIT]

Thanks for your positive feedback! Hopefully I will have time this weekend to finish the 6-th video in the series.

[@clems6989]

EXCELLENT JOB !!!!

[@dipakbhalodia7155]

Grating working very good

[@juanitoseme8632]

Thanks

[@batistafrose6009]

Nice video

[@HTCGT1963]

Very ,Very Good info

[@renatorobles7440]

Good morning ! liked and subscribed !! Thanks!

[@poopandfartjokes]

When using inductors in passive audio filters, which core type is best suited for passing 50Hz versus 5000Hz? Also is it different if blocking those frequencies? I’ve always used air core inductors for passing and iron core for blocking. If that makes any sense.

[@DonkeyLearningIT]

For audio applications the inductors tend to *not use any* type of magnetic core. This is because the magnetization/demagnetization cycle will make the sine wave audio to be distorted and appear more similar to a square wave, which is no good for audio signals. Thus, if you dissemble high-end audio filters, they will have massive coils in them without magnetic core wound from thick copper wires. Those inductors are expensive, but they are the right type for audio.

[@carlnikolov]

CIRRRRR QWEETTT!!!!

[@DonkeyLearningIT]

And this is how Dr. Donkeystyle likes it ;) Though, in the meantime I tried to pronounce it better.

[@carlnikolov]

@@DonkeyLearningIT I like cir qweet! It has an unusual Austrian charm

[@incxxxx]

Very good job, but still it is not clear why high frequency needs small core and vice versa. It is mystery, it would need more explanation.

[@Vidya1939]

NICE LECTURE. WE R CATCHING IT TKQ TOO

[@emililie2244]

Interestingly, the differences between the ferrite cores according to color I did not know. Thank you

[@DonkeyLearningIT]

The colors are not really a real indication, but in general this is what I found. However, every manufacturer might use a completely different color scheme, so do not necessarily think that just because a ferrite is blue, it will work at 100MHz. Also, old ferrites were all left black/gray, even the high frequency ferrites, especially in Russian electronic circuits. This is because at that time ferrites were simply not coated with anything.

[@gertjancarina2589]

Hello verry nice educaring videos I have 2 questions. 1 u are europian ( italien ore spanisch? ) 2 can i contact u on some way? I want to ask u somting about switching powersuppys. Thx a lot for your info til now

[@gedeon1980yt]

good job man

[@ganimidis]

If i hear one more time "At the end of the day" i'm gonna be driven mad i think...

[@DonkeyLearningIT]

At the end of the day you can click on the X button in the corner of the video. I am with Louis Rossmann on this one: I try to help people and convey them information, and I do it as good as I can for free of charge.

[@joeysartain6056]

Where is the 4th video in this series?

[@mrsemifixit]

Is it possible to have the soft core ferrite oscillate at lower frequencies like 60hz? Or they have a minimum oscillation in the kHz?

[@DonkeyLearningIT]

Technically speaking, it is possible, but in reality it is not practical. Namely, as I explain in the video, size does matter, at least when it comes to magnetic cores ;) Now because of this, you would need a HUGE ferrite core to go down to low frequencies. In fact, due to the soft-manetic nature of the ferrite core, the equivalent ferrite would be several times heavier and larger than an iron-core at low frequencies.

[@mrsemifixit]

Donkey Learning IT Why would it need to be larger? More surface area to slow down the output frequency?

[@DonkeyLearningIT]

The concept is similar to energy density: one need to eat a large volume of vegetables to get the same amount of calories as from a small piece of chocolate. Similar example is that a large piece of wood might weight less than a small piece of led. Magnetic energy is mostly about the volume (i.e. m^3) and not about surface area (i.e. m^2). Due to low magnetic energy density in a ferrite, the core would need to be larger. This is because ferrite is soft magnetic, which reaches magnetic saturation at a lower magnetic field as an iron core would. This means, that in order to reach the same total magnetization in a ferrite core, you would need a lot larger volume, since the density is lower.

[@thesupremearchitect1121]

Can somebody point me to where can I sell those ferrite cores in EU?

[@shivaprakashk2395]

clearlt explained the functionality

[@shivaprakashk2395]

clearly...

[@DonkeyLearningIT]

Well, could have been better, but otherwise the video would have been way too long. Also, I am glad that this dry "theory" part is done, but it was important to go through it, so that we can build on those concepts in future videos.

[@aramachandrashenoy7455]

Sir, please arrange to get schematic diagram of SMPS CIRCUIT. Thanking you

[@hadireg]

👍👍😊🙏

[@mixme8655]

great

[@therider3939]

Can i use ferrite core for transformer with 50hz

[@barneygilstrap3388]

Yes, they work just as well at low frequency

[@MrMeskiokas]

considering the accent you must be either from the Estonia or Finland

[@viswanathaniyer2372]

A good viedo

[@DonkeyLearningIT]

Thanks for the feedback!

[@isprithul]

Why bother generating 50 thousand hertz? make the AC from grid 50 thousand hertz, problem solved! Correct if I'm wrong, well I'm probably wrong

[@MrOpenGL]

Here is the problem: Power cables have a capacitance. At 50 Hz, you are charging and discharging the capacitor 50 times a second. At 50000 Hz, you are doing that 1000 times faster, so you are wasting more energy. Not to mention that at high frequencies, a cable becomes an antenna, so instead of a power transmission line, you essentially have a heater that is also a radio transmitter! And finally, skin effect. At high frequencies, electrons flow only on the outer layers of the cable. Therefore, you need much thicker cables than you would need at 50 Hz or DC.

[@DonkeyLearningIT]

When electricity was first used in households, it was a *big competition* between Tesla and Edison. Edison wanted DC, wheres Tesla has realized, that DC is a dead-end for power transmission. Tesla was a smart guy, who also developed the basics of radio transmission, so he knew that one *must stay with low AC frequencies* otherwise losses will be too grate. The issue is, that at 50.000 Hz there would be a *huge loss* of power over any traditional power line, especially if you consider that power is transferred for hundreds of miles of cables, and it goes through at least 6 high power transformers. Practically the power wires would behave like an antenna, dissipating power.

[@isprithul]

Thanks :)

[@dedskin1]

you can put 50Khz in a classic transformer as well , has nothing to do with springs or sound pitch or resonance , its just the fact that higher frequency's deliver less losses hence things can get smaller for same power , its about loses not resonance , sound pitch or wahtever alley you seamed to be lost in there and you are lost no doubt about it , let me remind you you started with SMPS now you are playing with screws

[@DonkeyLearningIT]

Please try to put 50KHz in a classic transformer. You will get an induction heated core which will melt the whole thing.

[@dedskin1]

@@DonkeyLearningIT ridiculous , i will push 300W at 50k though AC transformer big one no problem , wanna bet

[@DonkeyLearningIT]

As Lil Jon would sing: Let me see you do it! Of course, if you put in a massive core of a welding transformer, and you pump in only a couple watt, that might hold for a while just due to heat capacity.

[@dedskin1]

@@DonkeyLearningIT ill do it , but i need to make 50K 300W generator , i dont have that handy , unfortunately , or you know some way to get 50k sine wave of around 300W thats easy and cheap to make

[@luciferx1636]

Too much junk . Important thing ate lost .

[@mehdirezai5347]

to much theories

[@paulmorrey733]

Thanks

[@DonkeyLearningIT]

Thanks for taking your time, and indeed going through the videos. I hope that they will be informative for you.