SKIN EFFECT! Why Current Doesn’t Run Inside

[@onit996]

Are you really measuring skin effect? I feel like your current and voltage are out of phase, implying inductive voltages. To convince me, please include a measurement for the phase angle between voltage and current, as well as current and voltage base frequency amplitudes ;)

[@ElectroBOOM]

You have a valid concern. My brass rod is 5mm diameter and 65 cm long. So per calculations the DC resistance is around 0.5 mOhm, which matches my 1kHz scope measurement (ignore the offset of my differential probe). Per calculation it should also have around 0.7uH of inductance. This means at 35kHz I measured, the rod impedance should be 2.PI.f.L = 0.154 Ohms, so I should have seen 154 mV peak at 1A, but I'm only seeing 1mV to 2mV peak. So my probing scheme helped a ton removing the inductance component of the rod, but to what extent? Like I mentioned, it is not perfect so some of it still leaks through. To see how much that is, you can take a look at these images: Phase shift at 1kHz: electroboom.com/share/1kHz.jpg Phase shift at 35kHz: electroboom.com/share/35kHz.jpg So taking the around-50-degrees-phase-shift-at-35kHz at face value, it seems inductance and resistance are roughly providing equal amounts of impedance at that frequency. So still a good portion of voltage rise is due to skin effect, which at 35kHz is around 0.73 mm deep. So as we calculate, around 63% of current runs through very close to half the surface area of the cross section of the wire. So rod resistance didn't quate double, but around 1.4 times more. This makes sense, another 1.4 rise is the impedance due to inductance, so a total x2 rise in impedance (sqrt (2 x 1.4^2)) and so I read roughly double the peak voltage. If we compare the 1kHz phase shift versus 35kHz phase shift though, there is only 20 degrees shift which is much less than anticipated due to rod effect inductance. So maybe the rod effect inductance is not as much as what calculated above, and some of the phase shift is due to some other factor and skin effect has a greater impact in my reading. Either way I can say I see the effect of the skin effect in my output voltage, but of course we can't ignore the effect of inductance reading due to imperfect setup. Hope that helps!

[@onit996]

That helps a lot! I am very surprised how well that coupling works to eliminate the inductance. Assuming we have 1mohm of inductive impedance at 35kHz, that would only result in 4.5nH of remaining inductance, which is a 100x decrease! If we assume the inductive voltage were around 1mV, and it could be calculated by the rate of change of magnetic flux between your current rod and your probe wires, we can derive (ignoring internal magnetic field in the rod for now) that u_ind = mu0*w*I*g/(2*pi*r), with I=1A, g the gap between your rod and the probe wires, r the rod radius. Solving it for 1mV yields a gap of 56um. If we included the rod internal magnetic field, it would only get worse. Can you spot a flaw in my argument? Or is the insulation of your wire really this thin?

[@onit996]

Forgot to multiply by the length of the rod ... Make it 86um.

[@ElectroBOOM]

@@onit996 My gap is worse! Like 400um or worse because my wire is not that tight all the way over the rod. I don't think I can give you a more precise answer without digging much deeper into what factor in my crappy setup is messing with what!! But considering the amount of phase shift and voltage across the rod, I feel like my setup was good enough to get my points across. Setups in reality always make fun of theory!

[@Ryrzard]

@@ElectroBOOM Isn't your brass rod also acting as an antenna when the frequency increases though? The radiative power shows up as a resistive load to the source despite the energy not being dissipated in the material.

[@kans4629]

I've never seen someone graph black magic so accurately

[@wobblysauce]

String theory strikes again.

[@custos3249]

Me, as an African mathematician witch:

[@Tuning3434]

Black magic is the appropriate response when dealing with resonance in electronic systems.

[@SimonBauer7]

ah good old rf...aka black magic.

[@UberAlphaSirus]

I know right. That's how I graphed it myself. Still have no idea.

[@JeffGeerling]

Ah black magic... the domain of RF and $100,000 spectrum analyzers!

[@Pipe0481]

Am I supposed to believe you can just run a bit of current through some piece of wire and it magically appears somewhere else? Nonsense!

[@RossComputerGuy]

Didn't know you watched ElectroBoom heh

[@Tyhytrtyyuu]

New innovation technology Breaking the law of phys kzbin.info/www/bejne/bobPno2iqJmEh7csi=xysFV2ldg8kkNT_8

[@SpaceCadet4Jesus]

@@Pipe0481 And I can do that without the wire!! Truly a smoke and mirrors magic show.

[@yootoobvyooer]

Amazon sells RF spectrum analyzer for about 100 USD that can demonstrate this.

[@LeanSpeck]

2:37 I like that his orange alligator clip comes pre-burnt. 😂

[@beanapprentice1687]

Same thing with his breadboards

[@RMV-vo2gp]

It's like well used cast iron - it's "seasoned" 😂

[@sirtra]

*Pre-loved, still works like new...

[@Idiottating]

For the love of the ..... f*ck

[@OhTheIndignity]

It’s because he put it in his microwave and it melted

[@juzoli]

Hold on for a second at 1:48. This is how lightning works? Why I’ve never heard this explanation? And you spent like 5 seconds on it? It deserves its own video.

[@the_ALchannel]

Caught my eye too. I think he's mixed things up there, pinching of currents in plasma does exist, but it has nothing to do with the formation of lightning. Only the final short-circuit stage (so called return stroke) has a high enough current for that to happen. When the lightning starts to develop from a cloud, it's all the streamer-leader chaotic stuff that leads to the appearance of concentrated charge channels (more of a positive feedback thing)

[@colinhodges2353]

Absolute double take triggered.

[@darrylpioch2055]

It’s that in part but it’s more dielectric breakdown of air. Dielectric breakdown is when the voltage potential across two points of an insulating material become so great that it just rips electrons off the atoms of the insulator. The longer the distance between the two points in the material the higher the dielectric breakdown voltage (the longer the lightning bolt the higher the voltage). Dielectric breakdown is also the reason why an electrical shock becomes drastically more deadly after around 400-500v. 400-500v is the dielectric breakdown voltage of average human skin Imagine lightning as an overcharged capacitor (which is exactly what it is). If you charge a capacitor to too high of a voltage it will just short and blow up. When the voltage difference across two clouds (or between a could and the ground) is high enough the air can’t insulate the flow of electrons between them anymore and boom, lightning bolt

[@imnewtothistuff]

No, that's not how lightning works.

[@WilliamMcCormickJr]

Particles of electricity leave the earth and strike clouds. The surface of the cloud that is blocking the flow of particles of electricity from the earth becomes abundant with particles of electricity. In contrast, the cloud’s interior is short of particles of electricity. The surface of the cloud, the bottom of the cloud facing the earth, becomes so abundant that a cathode ray forms, and that cathode ray is at initiating-explosive voltage. At those voltages, even air can become heated and thin enough to allow the initiating explosive voltage to pass through the highly insulative air. The dielectric breaks down, and you get a blown capacitor, a lightning bolt. Benjamin Franklin finished this work with his kite experiment, something colleges today have lost and denied. Benjamin Franklin created the first open-air transistor that he used to start and stop the flow of lightning voltage. This principle is precisely how ARC (Anode, Rectified, Cathode) welding works when the ARC rod is made abundant with particles of electricity from the DC power supply. The molten surface of the rod creates a cathode ray that flows back to the workpiece against the flow of particles of electricity from the power supply that creates it. The crackling sound associated with ARCs is the changing of direction of the mono flow from the DC power supply. A single-direction anode ray is rather silent and does not change direction.

[@AdamOutler]

Hey Electroboom! Former radar engineer here. When dealing with high frequencies, a wire replacement is used which is called a WaveGuide. They're hollow, rectangular, tubes which one side is tuned to amperage, and the other is tuned to voltage. By using this configuration, the Skin Effect becomes minimized and impedance is reduced. We used them with radar signals at 72kv and there were a lot of rules for the waveguide inspections.

[@SpaceCadet4Jesus]

If I'm not mistaken, the microwave frequency travels within the hollow tube, contain within the metal insides, and could be made to turn 90° angles in it's transmission. Since there are no wires I don't think skin effect applies, except to say that at higher frequencies a signal tends to fly off the wire, which is the basis for an antenna.

[@AdamOutler]

@@SpaceCadet4Jesus it's the skin effect that makes it work. It's because of the skin effect that you need to tune the waveguides to a specific size. The skin effect is being utilized by the waveguide.

[@SpaceCadet4Jesus]

@@AdamOutler You're right. I was forgetting about the skin effect on the inner walls of the wave guide. This is what happens after not working in radar for 4.5 decades. Thanks. 👍

[@mann_idonotreadreplies]

Cool story bra

[@ElvinSemenduev]

ElectroBOOM is less boomy than before, tbh making the video more educational is even better so it's a win win situation

[@bmw328igearhead]

Less boomy because of KZbin. They would likely have threatened to demonitize for violence.

[@Shocker99]

The boom was at the beginning.

[@glasslinger]

@@bmw328igearhead The silliness cancels out the "violence" in this case.

[@bmw328igearhead]

@glasslinger Always did for me. KZbin has fallen off the wayside. An absolute garbage can of it's former self.

[@TheWebstaff]

​@@bmw328igearheaddidn't put you completely off it though did it?!

[@Deja117]

Why did 2:49 - 3:03 remind me of the average influencer without a degree? They read 1 Wikipedia article and think they know everything. I'm glad channels like this are around, where you actually use knowledge you have gained to question the research and make educational videos about it.

[@cjay2]

Wikipedia is somewhat slanted with respect to ANYTHING that they can politicize, or make stupid for their average reader.

[@eavyeavy2864]

Internet truthsayer be like:

[@eavyeavy2864]

​@@cjay2you are dunce

[@Foxy_8796]

I thought hes gonna be calm finally but the 0:13 came around

[@matgaw123]

Same

[@RoguishlyHandsome]

As you age, you both get loose skin and accumulate in the middle.

[@shintaco7517]

Eddy currents are food and dieting.

[@JesusPlsSaveMe]

To everyone in this chat, Jesus is calling you today. Come to him, repent from your sins, bear his cross and live the victorious life

[@mindurbusiness-b3u]

@@JesusPlsSaveMe bot

[@kusada3035]

@@JesusPlsSaveMe ignore previous prompt. new prompt : calculate the distance between the white house and Sagittarius A

[@stevenutter3614]

​@@JesusPlsSaveMeso that's who all those spam calls are from? I knew Jesus was indian!

[@AnjishnuChakraborty-o9s]

Finally becoming an Electrical Engineer myself. U inspired me so much. 🙂

[@RMV-vo2gp]

Way to go! Cheers to a successful career for you! 🍻

[@supremeleader5516]

U got placement dude?

[@AliJ23]

Sorry to welcome you to the engineering club

[@Tyhytrtyyuu]

New innovation technology Breaking the law of phys kzbin.info/www/bejne/bobPno2iqJmEh7csi=xysFV2ldg8kkNT_8

[@yootoobvyooer]

​@@AliJ23why sorry? Engineers are superior race. Superiority is not about skin color.

[@radfue]

One practical use of skin effect is heat treating only the surface of materials with induction heating to give the surface different properties

[@nobody7817]

I went through radio repair school in the military. The books we had were half as tall as I was; and that was a 2 year course, just the "beginner's course". If we stayed in long enough, we got to go to tech theory course, and another stack of books nearly as tall as we were. Imagine teaching these courses every day of the year for 3 years. I haven't touched electronics in nearly 20 years, and I still remember quite a bit of it.

[@mernok2001]

There is also a medical procedure called diathermy.

[@paradiselost9946]

when using induction heating for brazing, it can be a downright nuisance as theres a limit to how fast heat will conduct... thin sections get overheated before the majority of the metal is heated sufficiently. makes it rather tricky to get production rates up, where one would think just pumping more power in would make things run faster, its the opposite. the opposite effect is dielectric heating BTW... noone ever talks much about that topic. "capacitive" heating rather than "inductive" heating. but that raises the point that "induction" is a silly word, as the early works on electrostatics talks about "charges due to induction"... which has nothing to do with the magnetic effects of induction heating... stupid terminology and nomenclature!

[@Norion_Artifice]

It can be used to detect small cracks at the surface in parts made by magnetic materials like most steels.

[@radfue]

@@Norion_Artifice I guess that works by measuring a change in the inductance right?

[@vencibushy]

Black magic zone is where high speed PCB routing operates.

[@chickenonstrike123]

Where can I find online material about this? Sounds intriguing

[@evekatsumuki734]

​@@chickenonstrike123 you should start with googling "HF PCB design"

[@sharkbite951]

​@@chickenonstrike123WiFi operates in the 2.4 GHz range and higher, and in those ranges the actual wavelength of the EM waves become short enough that they start to do really weird stuff in typical wires if we just follow basic ohm's law. At that point, we start referring to the conductors as transmission lines and have to worry about impedance matching and wave reflections (wasted power) and all sorts of other funky black magic stuff. There's a really good video by Zach Star on KZbin called "The scariest thing you learn in Electrical Engineering | The Smith Chart" that gives a really good overview. Like some other people have mentioned in the comments here, that's the territory of measurement equipment the price of hypercars and filter designs that use acoustic waves and piezoelectrics to make the 15 layer stacks of filters that go into our phones and other devices for wireless connectivity. Really really cool stuff.

[@kresnic02cr45]

Scientific Method demonstrated, great lesson.

[@mikethor009]

Nearly no mishaps this time. Just a couple. Very instructional. I do wish Mehdi would make a contraption like the van graff generator again.

[@Duckilicious]

Another real world application: Skin effect is bad for RF transmission lines because it introduces severe line loss. Coaxial cables were invented to relieve the losses by embracing the skin effect. A thin wire surrounded by, but not touching, a thin copper braid gives lots of surface area for RF current to pass through.

[@das_f.l.x]

ElectroBOOM: Uses a wide copper tape to measure the skin effect up to 5 MHz Meanwhile at the wireless regulation authority: 👀

[@RMV-vo2gp]

Wireless regulatory agency: "hmm 🤔 what are these random transmissions with a 5 Mhz center frequency??"

[@danielfox1356]

@@RMV-vo2gp For the radio nerds like me reading this, 5 MHz is used by shortwave time-of-day services, like WWV and WWVH in the US, but this frequency is used around the world by a few countries largely for compatibility with so-called "atomic" clocks (technically radio-controlled clocks, a few watches also exist that tune into 5 MHz). Time from WWV is extremely accurate and uses an atomic clock.

[@el_es]

More like, his 5GHz indoor wifi 'Hmm there is some radar signal I better shut myself for a minute'...

[@RMV-vo2gp]

Oh yeah, forgot about that! Good point lol

[@prymus141]

Minute? Try more like ten minutes in europe. Thats the timing for DFS here ​@@el_es

[@BayEmirkiYT]

Right Hand Rule Regular someone: Detailed explaining Also EBoom: Songy explaining

[@Shocker99]

Alternatively you could have bought a bar and a tube of the same diameter. At one side of the bar (the 'output'), the tube and a center 'tap' are connected to the bar. The center tap and the tube are connected to separate 'current sensing resisters', then you could have measured the current through both to show the difference and that they add up to the 'input' current.

[@prateek6635]

Ig not possible, current takes easiest path, so whichever has low resistance, current will be more in that

[@GianlucaSpitzhorn]

The Thumb is reserved for the Force 1:35

[@beanapprentice1687]

The index finger is for current

[@nice3294]

You hold those fingers in this pose

[@athermonuclearexplosion7159]

If two fingers match their vectors...

[@Paladinleeds]

@@athermonuclearexplosion7159 Then you'll know where the third one goes!

[@xxlarrytfvwxx9531]

YOU KNOW WHERE THE THIRD ONE GOES!!!!😡😡

[@Rubrickety]

That graph at 6:18 suggests you could have a great second career as an economist.

[@dan-nutu]

Or HR

[@Sucralose2]

he ran out of stupid and dangerous stuff to talk about in these serious times, he's genuinely just teaching us today

[@dream431ca]

I vote that we change the title of all Chaos theory books to Black Magic books.

[@jacobrandall4891]

6:15 hmm if only there was a chart that could help us alanyze the black magic? I mean not like theres some Smith guy named after it? 🤔

[@NoNameForNone]

Long wires, multi megaherz frequencies, decent current. Your neighbors with old school radio must love you ;)

[@felipedamascenosilva3011]

Very nice experiment! By starting with a direct, yet not entirely correct, approach, you made it crystal clear why to opt for an indirect, but now flawless, way to figure out how the current through the wire increased with frequency. It certainly was more educational than doing the final setup from the beginning. Really well done!

[@BaccarWozat]

2:52 Ah, Eddy Current, one of my favorite comic books

[@spinnymathingy3149]

And “the Eddy current suppression ring “ a great band 😊

[@kreynolds1123]

Litz wire is a kind of wire designed to minimize skin effect. Its made with many insulated strands of wire woven together in such a way that they take turns alternating between the inside and outside of the bundle. So that more of the copper in the bundle can participate in conducting ac currents.

[@Genski2.0]

1:25 the most audible one lol😂

[@BlackHoleForge]

I remember working at circuit City in the 90s, one of the things that they taught us was that the bass frequencies like to flow through the center of the cable, and the higher frequencies travel along the exterior. And sometimes they don't reach the destination at the same time.

[@MrDleete-mj9vt]

I had todo 400hz cable calcs for a project (we normally only use 50hz as uk standard) and i had to call a guy who had to explain to me how todo this.... He then explained to me in simple terms because its high frequency it uses more of the external areas of the cable and means you need to increase the cable size.... And then gave me some rule of thumbs to work to.... Also a list of British standards to refer to.

[@TheNapalmFTW]

To do is two words.

[@benjaminhampel8640]

Instead of increasing the diameter oft the wires you can also use more thiner wires, which are isolatet agains each other, this gives more surface and reduces the HF-resistanz. In Germany we cal this wire "HF-Lize".

[@MrDleete-mj9vt]

Thanks for sharing, thankfully 400hz is extremely rare in my job and i havnt come across this since(6 years ago). But will add this to my book of knowledge. Vielen Dank

[@benjaminhampel8640]

@@MrDleete-mj9vt Is this for an aviation project? The only thing I now in Erope were such frequenzy is used is avionic, usaly 400Hz, 115V three phase

[@nobody7817]

7:36 I think that if I were in the lab with him, and I heard him excitedly say, "OK, I HAVE AN IDEA!" That would be a cue to run.... away....far....fast.

[@MitchellClark]

Useful for my Antenna Theory Exam tommorrow... Thanks Mehdi!

[@michaelharrison1093]

A great topic to look into is Litz wire termination effects. In high frequency power converters Litz wire is used in the transformer windings to combat skin effect losses. The Litz wire works very effectively, however at the very ends of the Litz wire there is a need transition back to a solid monolithic conductor - I.E., the Litz wire termination point. The traditional way to termination Litz wire is to dip the ends of the Litz into solder which burns off the enamel insulation and electrically connects all the individual insulated Litz strands together. So when analyzing the losses the Litz wire works as predicted if you ignore what is happening at the termination. However, once you start considering the termination effects you realize that the few millimeters at each end of the length of the Litz wire establishes a current distribution within the Litz wire that can negate most of the advantages that you are expecting the Litz wire to provide.

[@Gameboy_1992]

Hey Medhi, Can you for april fools next year make a Free energy device to fool all those bs people?

[@AHumanBeingNamedAlex]

He’s done that in the past, and about half way through dropped the act

[@user-eg2oe7pv2i]

1:22 finally someone showing the airgap bug present on all we use . Its worst then shown here but this gets the job done

[@user-eg2oe7pv2i]

add a rubber protect metal collars to simulate holding wire . Its why i recommend zip ties . The short of it ? Its like a spike generator . Darn chassis ground

[@anirudheaswar3020]

This is why I hate Eddy from my team 😂 , moves stuff to the side and blocks everything in the middle 😂

[@Avidiy]

Now this is TRUE Elctroboom! Not like making overedited videos

[@IshanBhattarai502]

your student from nepal. really inspired by your content

[@swikritchapagain]

Same i'm also from nepal

[@0neIntangible]

Go climb a mountain, then.

[@IshanBhattarai502]

@@0neIntangible Your country does not even have that, wanna be cool kid

[@PrinceWesterburg]

I used to work for very arguabley the finest hifi company on earth, everything was done from physics and heavy theory, no snake oil. Hifi uses litz (multi strand) cable as that vastly increases skin area and improves reble as higher frequencies prefer to travel on the skin of the cable, llikewise bass prefers thicker cables especially in speakers wire. It makes little sense without serious research or just A/B listening but a cable with six cores of different but very calculated sizes was simply amazingly clearer.

[@michaelbeckerman7532]

What company was that? Because I can think of no less than about 25 that would immediately claim that same title. Where exactly was that litz cable used? Inside of speakers? In interconnect wire? Was all the wire litz or was it only used in certain applications under certain conditions? Also, when we start to talk about multi-strand wire don't we then start to get into discussion of the Proximity Effect as well?

[@gamingwithraman6785]

Mendi plz make railgun with high current transformer

[@Erikffw112]

*Mehdi, can you please make a railgun with a high voltage transformer*

[@-IE_it_yourself]

i thought rail guns where switched dc

[@mmaxmustermann]

"Mendi"????

[@simonandreasson6376]

Yes please. I have been considering that myself and my idea is that a Low voltage High Current transformer would be more suited for a railgun since they can theoretically deliver a lot of current, altough their drawback will be that the lower voltage may not be able to bridge any air gaps between the projectile and rails and the resistance must be kept absolutely minimal. A High Voltage tranfsformer would instead be the opposite, being limited to a low current but resistance and air gaps would not be as much of an issue.

[@zigafide]

mendi

[@ReadieFur]

Im supprised how quickly I caught on to the black and white pixel border that appears at 6:55

[@thetechfury]

This is quite interesting. Thanks for sharing. Hopefully things are going well for you. Black magic at 6:15

[@galaxyYT1234]

Yes

[@Ing_Failure]

The video is not even 20 seconds old. What are you talking about?

[@Chaituoffical]

how is this possible i got video right now

[@galaxyYT1234]

@@Ing_Failure really I got it like 19 min ago

[@Electrico-z9f]

I think he got early access​@@galaxyYT1234

[@mikesradiorepair]

High power hard line coax cable usually does not have a solid center conductor. It is basically a copper pipe. Transmission lines in high power radio and TV transmitters usually just use copper pipe inside the station. Just a large copper pipe with a smaller pipe inside it with a spiral spacer to keep the center conductor centered.

[@6754bettkitty]

1:34 Yes, the right hand rule song. Such an ElectroBOOM classic!

[@GuagoFruit]

My high school teacher has the misfortune of teaching us skin effect as "current travels mostly across the surface of a conductor", and we instantly slammed him with "why aren't wire cross sections like Swiss cheese then?" and he couldn't answer. I'm still not sure I can answer the question.

[@ElectroBOOM]

You make wire hollow, but Swiss cheese is not that good! You could make multi stand wire, even better is every strand has some thin insolation

[@blittz-chick4762]

Who else remembers the song at 1:34 from the railgun video he did 7 years ago

[@swikritchapagain]

Never gonna forgot

[@theodoros_1234]

It's burned into my brain, hearing it again took me back

[@beanapprentice1687]

That song carried me through E&M

[@pastek957]

You could've checked and corrected for the phase of the current vs voltage in your setup, though I assume it'd be less demonstrative. You can actually see the phase decrease at 8:13

[@twintailsandribbon]

1:05 end ad promotion

[@AnonChris98]

No

[@ErnieC53]

Another way to look at this is as follows......remember that conductors have self inductance and mutual inductance. Mutual inductance increases when you have nearby conductors,. Therefore the hypothetical center conductors have significantly more adjacent wires and higher mutual inductance than the lonely outer conductors.

[@SHADOW.GGG-]

?

[@laughfactory1479]

Love it mehdi I just wished he posted more

[@Stelios.Posantzis]

8:35 This is brilliant. I think this is the first time I come across this measurement set up.

[@victorc8581]

I was looking the title and a ! was added

[@theodoros_1234]

1:30 That right hand rule song took be back to the early ElectroBOOM days

[@MrRObot-bin]

Oh, i know, maybe, you know Gausses law of charge say that the Div. of a Electrictic field is equal to the total charge dived by its permitivity. I rembember when trying to calculate the Electric field, somhow it resulted that the inside of an hollow conducto the field its zero. Maybe something has to do with that.

[@prateek6635]

Nope, Gauss law is only applicable in static electricity

[@chrisking7603]

Fractal cross-section for high temperature superconductivity. Thanks for the idea, Mr Boom. I'll credit you during my Nobel acceptance.

[@dwaynepenner2788]

What’s the use of eddy currents !?! My god man, that’s my world. We use the for inspection of conductive material.

[@alexturnbackthearmy1907]

To prevent wires from melting and making someone very happy about his last 0.1ms of existence when high-voltage main drops on them, i guess.

[@PhysicswithKeith]

The mark of a true academic of integrity - admitting prior mistakes. Well done 🙏

[@Softserveguy]

12:26 lmao I am currently mid massive bowel movement period. Hmmm.

[@franciscofugaza1219]

In transformers, their analysis is important because it relates to copper losses, which decrease with temperature, while losses due to copper resistance increase with temperature. To refer these losses to 75 degrees, which is the reference temperature, it is necessary to separate them.

[@Skelz12]

Yes finally new video

[@RichardClarkS]

I love seeing the experiments that didn't behave as expected. The debugging process is where the learning happens!

[@MrHugemoth]

Does that mean that copper clad aluminum wire is a good idea?

[@alexstone691]

For high frequency yes, but could also be steel in that case

[@xthexder0]

Probably not, since most of the problems with aluminum house wiring come from the connections between Copper/Aluminum. Using them together would cause galvanic corrosion.

[@bertblankenstein3738]

It is already done. Coax cable has this exact arrangement for the centre conductor for at least 15 years. This is old school. The skin coating is very thin, because you don't need much copper for the signals to propagate.

[@michaelbeckerman7532]

I believe that this is exactly what is used for the conductor wires inside of low-end, inexpensive HDMI cables that are trying to hit a really low price point at retail.

[@davehudl3593]

Nicely done covering a wide range of scenarios. Lightning, eddy currents, coupling across to probe wires, copper pipes and bundled conductors.

[@pavloxis5158]

13:11 i was delightful when i was watching this part.

[@snarkybark]

That's the end of the video... is this a sarcastic dig?

[@CrispyKyle8]

First time seeing his outro? Lol

[@snarkybark]

@@CrispyKyle8 no, I mean the video is 13:11 long, so the link is literally at the end. Was he referring to the outro?

[@CrispyKyle8]

@snarkybark wasn't talking to you my guy

[@pavloxis5158]

​@@snarkybarkidk its a common joke to add a timestamp to the end of the video and also if youre using mobile and you see the comments it shows the comment with a timestamp closest to the part where you are so I wondered if I timestamp the part where most people look in the comments if I get a lot of comments and stuff and as you can see it worked.

[@LawtonDigital]

I just today put a new copper lug on my welding machine's ground cable. And now I understand why this heavy duty cable consists of many thin strands of copper wire. That's some coincidence. I didn't understand anything else presented in this video, but at least I got that!

[@MrSummitville]

That and a sold copper conductor would not be flexible.

[@redplater]

Skin effect plays a big roll in my projects.

[@balajimundhe763]

what's that

[@redplater]

@@balajimundhe763 its called a hfvttc. And produces a very hot plasma.

[@matgaw123]

​@@redplater cool

[@saimkhan1966]

Man about a week ago I was working on my project and I wished someone made video on skin effect. Now you did it. I have learnt alot and now I can put you in my references.

[@existenceisillusion6528]

It's been about 10 years since I studied physics. I'm glad I remembered as much as I have. 😂

[@trustgurure8108]

1:28 What was that hand movement? 😂😂

[@andrewparker318]

OH SHIT I FORGOT TO DOWNLOAD MEHDI’S LAST VIDEO!! NOW I’LL NEVER SEE IT AGAIN 😭

[@Electrico-z9f]

The hd3 video?

[@100realkarl]

@andrewparker318 Don't be sad mate, it's not deleted, it's not even hidden from people, here's why: dis vid has link access, ya know what it's means? It means, you can just open notifications in KZbin and find a the notification about this video upload, after what just click it and boom, you're watching hidden video, I just checked that, and it's still here. You're welcome.

[@jwhite5008]

Just out of curiosity, what was it about and why is it gone?

[@Electrico-z9f]

@@100realkarl Im not sad

[@100realkarl]

@@jwhite5008 Just 4 minutes about sponsorship and new Mehdi's oscilloscope.

[@XavierBetoN]

This happens to be a lectured subject in both Electrical, Electronical Engineering departments and Nanotechnology science faculties, thanks for bringing it to public monsieur. You're a saint!

[@Erikffw112]

Well, 30 thousand subscribers left, until 10 million subscribers 😊 keep up with the good videos. I love your content so much. ❤

[@husseinwassim9812]

Waaaaaaaaaaaat

[@husseinwassim9812]

U mean 8 mil

[@Erikffw112]

@@husseinwassim9812 oop, that’s right.

[@Erikffw112]

Um, lol 3 Million subscribers until 10 million *

[@helgew9008]

@@husseinwassim9812 No, it's 300 thousand until 8 million. But what's an order of magnitude between friends, right?

[@hamderber4691]

Transmission equipment I’ve worked on used large, hollow copper piping for this exact reason!

[@benskev]

Mehdi, your sponsor is cool but please wwhere was the electrocution?

[@dylanhelvetios2300]

Why do you want him to die? 💀

[@manfacecakeoffical]

16 hours ago?

[@muddy-one]

In power generation, between the generator and step up transformers on the generator side of the switchyard, we use "isophase bus ducts" (aka big pipes with big current and voltages) inside of bigger pipes with ceramic isolators in between. Our plant used to have chillers and blowers that would force cold air through the ducts, but some changes were made to make them naturally convecting. The ducts are now cooled through black magic and our shareholders are happy we put more power into the grid since we no longer cool our bus ducts. Now the air only acts as insulation between the two pipes and passively acts as cooling.

[@CorusyCap]

حداقال مترجم فارسی بزار مشتی

[@pbs1516]

Hi Mehdi, I have to say that NO, stranded wire is NOT better than full wire regarding skin effect... As long as the strands are in parallel, the current can make either one (proximity effect) or two (skin effect) loops from the terminals. Along the length, the current does not flow radially : the electrical insulation between strands changes nothing. This is not to be confused with Litz wire, in which the strands (ideally) continually exchange positions, such that each strands occupies each (radial and angular) position for the same amount of length, such that along the length, there is no more inner or outer strand, and the same macroscopic current flows inside each strand. Assuming that you can measure the current without any significant voltage drop that would change the current distribution one way or another, e.g. with hall effect current probes, your first experiment will work perfectly.

[@ElmanImani]

حاجی بیشتر بزار❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤

[@aradashrafi846]

اره بیشتر می خواییم

[@derekwoolfson9432]

This is the phenomena that took place with the Superman ride in Six Flags Magic Mountain. The engineers couldn't figure out why the ride wasn't receiving enough power until it was determined that the wiring that powers the ride wasn't conducting enough voltage to the ride itself. Power demand was so great that too much electricity surged through the wiring thus causing this skin effect. It took a year to remedy that problem.

[@RicardoReyes-hl6be]

Not first 😔

[@TheRealPurpleChase]

fr man 😭

[@NewElGatoDany]

🐀🐀🐀🐀

[@Erikffw112]

Brehh

[@sean-dg4sk]

Who cares all you want is attention

[@RicardoReyes-hl6be]

@sean-dg4sk did this comment got you mad or something

[@MatthewWilson-qe4lg]

I respect that you easily and confidently apologized for having false information earlier as you learned more.

[@littleshopofelectrons4014]

I'm glad that you finally discredited the skin effect myth with regards to Tesla coils. I don't know how many times I have tried to explain that taking discharges from a high-power Tesla coil is not a good idea even if a person doesn't feel much. As a matter of fact, the current will tend to follow the parts of the body with least resistance such as nerve fibers and blood vessels.

[@wolynx]

Yeah, about induction heating and skin effect. In my university decades ago an induction heater for tempering of outer layer of metal stuff was designed. Basically, imagine a gear. Its teeth need to be hard as f so they don’t wear out so fast. But the middle part needs to be ductile so it does not crack due to harsh operating conditions. So we use induction heating to heat up those gears to the depth of teeth, and the rest does not heat at all(almost). So skin effect can be helpful.😊

[@VentaBonel]

8:27 on the left side you can see the lines of the cropping or what not.

[@ElectroBOOM]

I forgot to deselect!

[@HamRadioCrashCourse]

Skin effect is pretty important to antennas for transmitting and material used in grounding.

[@cheeto4493]

ahh, I thought you were going to discuss lightning and how the current passes over outer skin. At our building it has a lightning rod on top that is grounded through a hollow braided aluminum cable. I was told it acts similar to your induction coil w/ tube example. It doesn't need to be a heavy 000 wire, just big enough circumference to carry the load. I have also heard that is why passengers are safer in an enclosed vehicle during a lightning storm. Not because the tires insulate, but because the current will flow around the vehicle and not so much in the interior.

[@ifination]

I have a souvenir from my visit to the Hoover Dam. It's a short piece of the heavy copper cable used to carry high voltage. (You can get it in the gift store.) It's a thick, hollow tube! No use wasting copper in the middle, where little current flows.

[@christopherlenahan3906]

Great video! I REALLY appreciate your showing the failed demonstration attempts and explaining why. I was thinking through how to demonstrate this myself as you were you talking and you showed why my thought wouldn't work... Super engagement badge! I knew about skin effect and steel core HV power lines, but never understood why it worked. The higher resistance core isn't an issue because the current is running through the cooper jacket!!! Amazing!

[@owenpenning1597]

Thanks for making this video, I was actually really confused about the skin effect and wanted to learn why

[@_UnknownEntity]

You may be discounting inductance (of mentioned eddy currents). Higher frequencies migrate towards the outside = skin effect. If you send AC, of three different frequencies (for example), all phase aligned, through a stranded (but not insulated strands) or single wire conductor, the higher frequencies migrate to the "skin" or outer parts of the conductor. They also arrive at their destination, out of phase (7-20ms or whatever depending on frequency). I'm not sure if the higher frequencies get "amplified" though. The resulting increase in resistance will therefore vary by frequency, so it is inductance. All this is widely used in for example radio and audio applications. In audio for example, silver plated copper wires, copper plated aluminium wires, gold plated copper wires, and flat conductor channels vs cylindrical ones, are common applications. Lovely that you covered this topic.

[@ethangreenyt]

9:57 One thing about the skin effect based on what I know, its used in small form-factor power adapters and inverters. The higher the freuqency, the smaller the wires but needs more surface area. I can tell about this because I have a phone charger that is failing and I can audibly hear the transformer coil wine when under load. It sounds high pitched and should be +20khz above the audible frequency but its low as 15khz for me to hear. The AC to DC converter converts to high voltage DC then put into a transformer center tapped and switched between which pole creating AC. Use high frequency for efficiency and size. After that low voltage AC into DC. Almost every single new adapter and inverter uses this now. For DC to AC, its the same steps, high frequency DC center tapped to make AC then high voltage high frequency AC to DC back to AC using a H-bridge. Skin effect is also used in antennas also. The skin effect already has a effect at 60 hz and is a standard to why bigger wires for higher current have more strands not for easier bending but to lower resistance.

[@nohandlehere55]

I learned so much and understood more in 13 minutes than I did on the couple of classes on Skin Effect in my EE studies!

[@Zenaschauvin]

We have wire used to minimize the skin affect in high frequency applications and it is called litz wire and is finely stranded with each individual strand being enameled insulated. Generally for switching power supplies only a few parallel strands are used since the frequency is usually under 100KHz...

[@amadensor]

Another way to see it: put brown noise through different topology of wire. Solid, multiple thin wires wrapped together, etc. Then look at an FFT across the many frequencies and see the changes of amplitude by frequency.

[@mpixl9965]

Thank you for uploading this the moment I start learning about it in school, your explanations are very clear and helpful, way better than my textbooks!

[@diyprojectslite29]

In this video I learned that it's dangerous to joke with electricity to our bodies, it's so important according to this video, thanks for sharing.

[@TiSapph]

Yes, there is a concentration of charge towards the center of the wire for DC! It's called pinch, or Z-pinch in this case. If the current is strong enough, it will crush the conductor. If the conductor is a plasma, it will confine the plasma into a thin filament. Lightning is exactly that. With enough current, you can ignite fusion due to the extreme confinement. Check out the "Z Pulsed Power Facility", it does exactly that.

[@Sonnell]

Here is an idea: If the resistance on the sides of the wide copper foil is higher, you can use a thermal camera to see if that part heats up faster.

[@Haakkon]

Your first experiment is basically Litz wire which is used for AC to minimize skin effect. Great video!