Magic of Magnetism & Inductors (ElectroBOOM101-007)

hi do you want thanks to Skillshare for sponsoring this video and helping share knowledge more about them later in the video okay do you want to do magic you can try this at home no really I have a one and a half volt battery I have a white LED here that requires around three volts to turn on so my battery can't turn it on now I put three of these LEDs in series which means they need nine volt to turn on the battery can't douche now I have a regular transformer wall adapter not connected anywhere you can use it as ease or you can tear it apart and pull one coil of winding out either way is fine now the positive of the battery goes to the coil that goes to the positive of the LEDs and returns to the battery the battery you still can't do but now if I short across the LEDs with a piece of wire and let go BAM I have nine volt pulses across them and they turn on and here I can replace the coil with the wall adapter and doing the same thing it's even brighter deep magic I wonder if it can shock me here instead of the LEDs I put my fingers across the wires and short across my fingers yeah I mean I can feel it so there are pulses of high voltage there's a new way to get shocked I've shown you before that new media magnets drop like a rock in air but if you drop them through a roll of aluminum foil they drop very slowly but similarly look this frame is also made of aluminum and my magnet has north and south on the surfaces and if I put it on and let go it goes down slowly magic you can make a few turns of winding and connect an LED to its end and drop it on a wireless charger and bam magic you stick a battery on a magnet and short the battery using a piece of wire like this and it starts churning magic you connect two parallel reverse LEDs across a coil and pass a magnet through it and ping pong ping pong ping pong ping pong magic of course I joke it's not magic it's magic oh it's magnetism stay with me to the end to understand what's going on stay magnetism is quite simple at noob level which we strive for here when you have charges moving in a direction you have current and magnetic fields wrap themselves around that path like this going to infinity these follows one of the right-hand rules where the thumb shows the direction of current which is the flow of positive charges or reverse of electron flow and other fingers show the direction of fields wrapping around the wire so if the current runs in a loop like this magnetic fields wrap themselves all around the wire like this and that's why some metals like iron have stronger magnetic properties and are called ferromagnetic it's because this cloud of electron turns around the Aten core in a more defined direction and turns the atom into a tiny magnet but see when the molten iron cools down it solidifies and crystallizes into this patchy crystal form with every tiny patch having a random magnetic direction so all these random directions cancel each other and the iron is neutral if you bring a strong magnetic field close you force these to rotate and align with the field which not only magnifies the original field it turns the iron into a magnet but it's like these tiny magnets are stuck on a spring and if you bring external field close they try to align themselves and the stronger the field the further they align until they fully align this is when the magnetic material is saturated meaning that stronger external field won't make any difference in their magnetism and when we try to remove the external field they try to spring back unless too much force has bent them permanently out of shape so when you have a piece of ferromagnetic material and you connect a magnet to it it becomes a magnet too and if your source field is strong enough you can bend those tiny Springs out of shape and make a more permanent magnet of course heat is the enemy of determinants magnets because their structure shakes out of alignment and the magnet dies forever there so don't overheat your magnets goodbye love not everything hot is kissable it was Michael Faraday who was first able to imagine an observed magnetic fields as these invisible lines and then later with the help of Maxwell and some other scientists they put together these complex equations to describe electromagnetism talk about this I'm supposed to be educated to be able to use these equations but just seeing them hurts my brain learn them at your own risk but here I'd like you to really feel magnetism in your heart observing magnetism is quite simple like my examples at the beginning except that magnetism is fake it's like the shadow of electric fields and it has something to do with Einstein's theory of relativity don't worry I'm not going there especially since I don't know what the hell is going on if you're a professor with clarity on the subject please help me and put me out of my misery but for now forget about everything complex and let's stick to primitive ways knowing that the concept of magnetism is correct and makes our calculations very efficient and simplified so magnetism is like an annoying partner it resists any change like let me just know leave okay then give me a kiss what the hell are you doing your animal the hell let me just go don't leave of sex what the clip is trying to say is that in magnetism according to Lenz law anything that's created due to magnetism opposes any changes in its creator you raise current through a wire it induces changing magnetic fields around the wire that create opposing currents in the wire to reduce the changes in the source current you change the magnetic fields around the wire and they induce a changing current in the wire that creates opposing magnetic fields to stop the changes in the source field you raise current through a wire they create changing magnetic fields around it that oppose the source current those fields wrap around another wire and induce a changing current that create opposing magnetic fields and reducing them so that they can't effectively oppose the source current so the source current rises again creating even stronger magnetic fields so that it can maintain the output current it's an opposition mess but this feature of magnetic fields is what we use to create inductors and transformers see inductance is based on this property that the induced magnetic fields oppose the changing current by inducing an opposing force called electro-motive force so every piece of wire has some inductance associated to it but to increase this effect we loop a longer piece of wire like this so that the fields created from each wire wrap around more wires and this increases the inductance and so the magnetic reluctance against the change of current the overall magnetic fields around such an inductor which is also an electromagnet looks like this with the direction of the fields following the right-hand rule and from north to south on the outside of the electromagnet and south to north inside so increasing the number of turns increases the magnetic fields and raises the inductance also a larger radius increases the length of wire and so the inductance and adding a ferromagnetic core like iron magnifies the magnetic fields and significantly raises the inductance inductance is shown with capital L with unit of Henry named after Henry we can calculate inductance based on the coil geometry and core property which I don't care about you can use online calculators so after all this description what is an inductor good for what an inductor does is that it stores energy in the form of magnetic fields in the space around it like I said those fields oppose the changes in the source current so they have energy to do it it is like an elastic hose if i push water current into it it expands and a steady flow of current goes out of the other side but if I suddenly shut down the input current the hose collapses and keeps pushing current out of the other side so it opposes the sudden change of current at the input and that's why they say a capacitor blocks DC but an inductor blocks AC which is inaccurate as hell what's accurate is capacitor blocks DC but inductor shorts DC so this is important in my previous electro boom 101 episode I told you that capacitors store energy in form of electric fields and oppose the change of voltage now inductors store energy as magnetic fields and oppose the change of current don't forget that and here's what we end up calculating through complex math for a relation between voltage and current of an inductor basically the voltage across an inductor is equal to its inductance times the rate of current change in time if you remember from the capacitor episode the voltage across a capacitor cannot change instantaneously in no time because that would mean infinite current through the capacitor now the current through an inductor cannot change instantaneously because that would mean infinite voltage across it and we can't have this in real life and that explains what happened at the beginning when I turned on LEDs by a one-and-a-half volt battery when I shorted across the LEDs I put a DC voltage across the inductor so the current through it started to rise only limited by the resistance of the inductor and the battery when I open the short though the current through the inductor couldn't change instantaneously as the magnetic fields were collapsing so it pushed current into the LEDs and the voltage across them instantaneously jumped to 9 volts also for example if the voltage across the inductor changes as a sine wave then when the voltage is at the peaks it means that the rate of current change is maximum a positive rate here and a negative rate here and when the voltage is at zero it means that the rate of current change is zero here and here so the inductor current wave looks like this always lagging behind the voltage by 90 degrees unlike a capacitor current that always leads the voltage by 90 degrees and there we have it enough details for one episode inductors of beautiful components like Skillshare the sponsor of this video skill share is a great online learning community where people with great skills share them with curious and creative people who want to learn something new or brush up on their knowledge but wait using my link in the description the first 500 people get two months free trial of Skillshare premium which is more than enough to take many classes and get your feet wet there are tons of classes on arts crafts productivity film and video production music photography and much more you can take them at your own convenience for as low as $10 a month on a one-year subscription after your free trial I finally switch to Adobe Premiere and After Effects to improve my video quality thanks classes like the one by Jordi Banda put on Premiere Pro I started smoother and picked up some good tricks I'm sure you can find something good to help you out to use my link and thank you for watching

Channel: ElectroBOOM

Views: 1,190,882

Rating: 4.9687476 out of 5

Keywords: educational, electrical, ElectroBOOM, science, electronics, engineering, entertainment, equipment, measurement, experiment, mehdi, mehdi sadaghdar, arc, mishap, physics, Sadaghdar, test, tools, circuit, funny, learn, shock, spark, discharge, inductor, transformer, magnetism, magnet, ferromagnetic, induction, induce, boost

Id: ySx84Ca7BFQ

Length: 12min 57sec (777 seconds)

Published: Sun Mar 15 2020