this post was submitted on 01 Jul 2023
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ELI5
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Explain it to me like I am 5. Everybody should know what this is about.
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Someone else will probably explain this in a much better way, but I'll give it a go. I'll explain DC, AC is a bit more complex.
Current is the flow of charge. Atoms are made up of a nucleus, surrounded by electrons. The electrons are loosely held, meaning they can travel around to other atoms.
In simple terms, batteries have an accumulation of atoms with extra electrons which are lost more easily, meaning the electrons want to move away. This is known as electric potential. Since there is a lack of electrons (aka positive charge) in the opposite terminal of the battery, the electrons move from the negative to the positive terminal, or we say the positive charge moves from the positive to the negative terminal, through the circuit.
Metals are known to let charge flow within them, so they are used as conducting wires in circuits. When electrons flow through the circuit, the energy with which they flow can be harnessed. Example, if we add a resistance to their path which glows, you have a bulb.
Motors work in a different way. When current flows through a circuit, it has a magnetic effect on its surroundings, so it can interact with magnets. This is harnessed to make rotational motion. It helps if you watch videos, as the visual representation is infinitely better.
I am also still learning, so if anyone finds any mistakes whatsoever, please do let me know. I intentionally didn't use the falling water analogy, as that didn't help me at all when I was learning this topic.
@AppleMango
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AC is actually a little easier to explain.
Imagine you're holding each end of a rope that is looped around a pulley. When you pull on the rope with one hand, your other hand goes in the opposite direction and the pulley turns a little bit. You've transfered a little bit of work to the pulley, which can be used to do other things. But "you" have only moved a little bit. You pull your stretched hand in, and you other hand goes out and the pulley does a little more work. Now do this movement 60 times a second (50 in some parts of the world), and you've just discovered alternating current electricity. You don't have to move much in order to send energy over long distances, which is one of the advantages of AC over DC.
So in an AC current the electrons are just jiggling back and forth? How far do they move through a wire, I'd imagine they jump like a few meters back and forth if it's only 50/60 times per second.
It's not really the electrons moving. It's the electromagnetic field potential that's moving. The rope is that field. And the distance it moves isn't measured in meters, but in volts. In most cases, around 240 volts (more or less...but that's a whole other discussion).
A lot of this is hard to wrap your head around because you can't physically see these forces, only measure them with instruments. We'll dive a little deeper while still trying to keep the rope metaphor going.
Imagine each electron in a wire as stationary, and all standing in a line next to each other all the way down the wire, each connected to its neighbour by a loop of rope. If you turn one of these electrons, it causes the one beside it to turn, which causes its neighbour to turn, etc all the way down. Our pulley is attached to one of these electrons. You pull the rope one way, it turns the pulley, which turns the first electron, which transfers that energy all the way down the line. How far you pull in one draw is the voltage. How hard you pull is the amperage.
This is the basis of a generator. A magnet (our pulley) is passed over a coil of wire, which induces an electromagnetic field (our rope) in the wire. It makes the electrons "turn", and sends that energy down the entire length of the wire. Nothing really moves except for the electromagnetic field.