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Learn firsthand what a capacitor is and how it works right here!!
Covered in this Episode:
- Electric Forces
- Capacitor Theory
- Capacitor Structure
- Polarized and Non-Polarized Capacitors
- Capacitor Voltage and Current Relation
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By: Mehdi Sadaghdar

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. 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 cannot 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 tell the blood people to use, Express VPN and go around the filters to access what they need securely. You can use Express VPNs, app or software on your phone or computer with a click of a button.
It encrypts your data, secures it and transmits it through one of their many servers from 94 countries to choose from so it looks like you're connected from a different place and, most importantly for me, when I travel and connect to unsecure Wi-Fi networks, expressvpn make sure my Connection from my computer to their servers is safe. Imagine if my passwords were stolen so go to my link and get three months free James out.

15 thoughts on “How CAPACITORS Work (ElectroBOOM101-006)”
  1. Avataaar/Circle Created with python_avatars Ralph Meltsner says:

    A capacitor is like a plumbing pipe with a rubber diaphragm across the middle.

  2. Avataaar/Circle Created with python_avatars Josh Young says:

    Mehdi, nobody LITERALLY thinks that AC current is zig-zagging through the plates… it's just a technique for memorizing which type of current can pass through. Don't judge people's memorization techniques!

  3. Avataaar/Circle Created with python_avatars Sizzlik says:

    Whats the pain difference between a capacitor with low voltage but high capacitance versus one with high voltage and low capacity? What hurts more, what will rip off my finger? Got to know before i zap myself..

  4. Avataaar/Circle Created with python_avatars D0ggyF1zzl39 says:

    ElectroBOOM, you make learning electricity in physics II look very fun. I Thank you with your professional explosive wisdom

  5. Avataaar/Circle Created with python_avatars uSE yOUR hEAD says:

    Hey electroboom can i ask? Why wire doesnt burn out when you winding the wire and connect each end to the battery or powersupply?

  6. Avataaar/Circle Created with python_avatars Best way to Learn coding says:

    I saw your video everytime and I also didn't know your videos are over I thought that the video was small but than I realized that your videos are of full of knowledge so I don't think about time while seeing this videos!!

  7. Avataaar/Circle Created with python_avatars Indrajeet M says:

    After watching this I solved my JEE advanced question even faster 😃

  8. Avataaar/Circle Created with python_avatars Morphasella says:

    The best teacher. Thank you. It seems like you know what newbie don't know.

  9. Avataaar/Circle Created with python_avatars Ali Zafar says:

    Dear Sir , I have a question. What called fluid or oil electrolytic inside the polar capacitor ?

  10. Avataaar/Circle Created with python_avatars Ryan Ringer says:

    peep the derivative of voltage to get current at the end. God tier

  11. Avataaar/Circle Created with python_avatars idk who says:

    I'm getting addicted to his videossss….. They're sooo gooood

  12. Avataaar/Circle Created with python_avatars Shubham Upman says:

    Damn never understood dielectrics so well. Thanks Mehdi. The jail example was hilarious btw, lol

  13. Avataaar/Circle Created with python_avatars JAW Media says:

    Excellent video once aging Mr. BOOM.
    PS. can u tell us how transistors are getting to be so absolutely tiny?

  14. Avataaar/Circle Created with python_avatars Az Anyad says:

    Fabulous, thank you for educating us. My last oscilloscope had a CRT…I don't have it anymore.

  15. Avataaar/Circle Created with python_avatars CCJ's Random Videos says:

    I'm intending to replace a capacitor for my spoilt fan. Somehow learned abit of how to solder wires to it and discharging them first before connecting to the main circuitboard?

    Could you make a video on how to use a multimeter for each and every of its functions? Learning from other videos makes me less interested in learning.

    Got a Fluke Digital Multimeter 175 as a gift and I wish to learn more on how to use it.

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