How CAPACITORS Work (ElectroBOOM101-006)

hi it is time for you to learn about the basic components well I've already told you about resistors a while back so all is left is capacitors and inductors there are quite simple really and I won't dive too deep I promise the capacitor theory is quite simple really atoms have cores and electrons that turn around them electrons have negative charge while cores have protons that are positive opposing charges attract each other while the same charges repel each other all thanks to electric fields that's all you need to know for now and it bit more see you can't just shove an electron into a conductor because there is no room and they repel each other and push back unless you bribed them with some positive charge like get into yourself dad I'm not getting in there are you afraid I'm not afraid I can't stand this guy I'll tear it apart you don't want these blood on my hands the cell beside you is filled with girls hello there okay I go in there or like imagine hackers work alone unless you are a great target and they all work together to steal your data take it away James that's why you should use expressvpn the sponsor of this video to protect against hackers go to expressvpn comm / electro boom and get three months of free service and encrypt your data and make it secure hide your location and bypass the filters to access the data you need securely back to you Mary I made a plexiglass container with a thin gap between the surfaces and fill it with no d-mail magnets with the same direction so they repel each other I learned it from Cody's lab now imagine these are electrons repelling each other let's assume this is the neutral state of a conductor and electrons and protons are equal and we can't fit any more electrons in there like there is five electrons on this side now imagine this magnet is a positive ion core stripped of its electrons if we bring this positive charge to our electrons it pulls them close to each other so now there is more room on that surface and more electrons can fit there like six now and that's how capacitors work you have two conductive surfaces overlapping but not cutting isolated by a nonconductor called a dielectric that can be air or better and now if you put a power supply across the surfaces like a battery you can push electrons into one surface and suck them from the other surface of course the electric current is defined as the reverse of the flow of electrons the electric force between these charges keeps them together so even when you disconnect the battery the capacitor keeps its charge and just like that you can charge a capacitor of course it only takes a fraction of a second to charge which depends on dama right connects it backwards I think I did you would think having two conductors side by side wouldn't care about the voltage polarity which is true for some capacitor types like ceramic but apparently in some like electrolytic it matters see capacitors are made with different structures like ceramic electrolytic tantalum or others and each one has its own pros and cons the chemistry and structure of some of them like electrolytic or tantalum makes them polarized it's like having a very fluid across your capacitor as soon as you put reverse voltage or too much positive voltage across your capacitor it starts conducting extra current and blows up which makes for great pyrotechnics let's look at it again [Music] in any case a charged capacitor has this potential energy in it where the charges like to get together but they can't because of the dielectric and are held in position by the attracting electric fields but as soon as you put a load across it the charges say you can stop our love now there's a new way you wasn't burden tell me about it so well I didn't care what I can't just let things penetrate me so the charges passed through the load and the capacitor discharges now you might ask why would we need solid dielectrics between plates instead of air there are three good reasons one is that they make sure plates won't touch second is that they can isolate against leakage and arcing much better than air so you can bring the place much closer and third similar to ferromagnetic material that we make our inductor and transformer cores from because they improve magnetic fields good dielectrics also improve electric fields based on their electric permittivity and result in higher capacitance now you might ask what's a good reason to bring the plates as close as possible well the electric forces between charges is very small over long distances so we have to bring them close for increased attraction and that increases the amount of charges we can put in a capacitor and so increases its capacity but too high of a voltage over too small of a gap will break the dielectric and short the plates that's why every capacitor has a specific voltage rating and also the larger the plates the more charges can fit in them and so the higher the capacitance so the capacitance is equal to epsilon which is a constant for dielectric permittivity times the area of the overlapping plates divided by their distance the unit of capacitance is ferret named after Michael Faraday and the amount of charge in coulombs you can put in a capacitor is equal to its capacity hands times the voltage across it so more voltage or more capacity means more charge now you might have heard some idiots say that when there is a DC signal like this it hits the capacitor plates like this and gets blocked while an AC signal can zigzag between the plates like this and pass through well that's wrong when you place a DC voltage across a capacitor the voltage across it rises as the charges flow into it until the electric field in the capacitor is the same as the field in the battery and their voltages are equal and as you know like temperature the electric current only flows from a higher voltage to a lower voltage and if the voltages on both sides are the same then there is no current so when you connect the DC across a capacitor it charges to the same voltage and the current stops but when you have AC you constantly raise and lower the voltage which pushes and pulls the charges in and out of the capacitor so if you look at your capacitor as a black box it looks like that the electric current goes in one side and out of the other side then returns in the next cycle so from outside it looks like an AC current is passing through the component although the actual charges never passed through the capacitor and only accumulate on the plates so that's the capacitors for you now let me tell you some interesting wisdom around what was it going to say all right capacitor is like a cop it's voltage rises as you pour charges into it its voltage rises faster if you pour more charges per second or more currents into it this is when the capacitor blows up although the current through a capacitor can change instantly the voltage across it can not jump from one value to another because it would mean in that moment of time the current was Infinite because some charge went into the capacitor in no time and that just doesn't happen in real life I told you the charge in a capacitor is equal to the voltage across it times its capacitance so it kinda bit of change in charge can change the voltage that crosses by a tiny bit if you watch my previous electro boom 101 episodes you know that current is equal to the amount of charge passing per second so in a tiny bit of time only a tiny bit of charge passes if we rearrange these we see that the current through a capacitor is equal to its capacitance times the rate at which the voltage changes in time voltage and current both being a function of time well this is pretty much all you need to know about capacitors so for example if you shove a constant current into the capacitor then the rate of voltage change is constant meaning that the voltage changes in a straight line that's not straight tray straight line never mind or if your voltage changes like this in time and you can approximate a piece of it as a straight line then the slope of that piece times the capacitance gives you the approximate current that runs through the capacitor between these two points it's all so simple wink if you have a sine wave voltage across a capacitor then at zero crossing we have the maximum voltage change a positive rate here so we have a peak current positive here and here we have a peak negative current and at the peaks of voltage the rate of voltage change is zero and so the current is zero in these spots so the current through the capacitor looks like this always leading the voltage by 90 degrees okay we have had enough for one episode I'll give you more details as we go forward into electro boom 101 next stop inductors so make sure to like my videos and subscribe to my channel and if YouTube is blocked in your country then use Express VPN drains if YouTube is blocked then they won't be able to see this message then somehow 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Channel: ElectroBOOM

Views: 1,090,948

Rating: 4.9724975 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, capacitors, metal plates, permittivity, electric fields, dielectric, electrolytic, tantalum, ceramic

Id: rbCXKhhzBN0

Length: 10min 56sec (656 seconds)

Published: Fri Feb 07 2020