eli5 how do Tesla coils work?

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I know it has something to do with magnets and copper? I’m not sure. I find them super fascinating though. I love seeing the little lightning sparks. Nikola Tesla is one of my favorite people of all time.

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Anonymous 0 Comments

A tesla coil generates high voltage power through a series of AC transformers. When you change the current going through a piece of wire you will actually create a current in any nearby wires. So if you put two loops of wires close to each other and then alternate the current in one of them the other will also have alternating current at the same voltage, this is called induction. What you can do is to have three loops and then connect the two passive loops in series generating twice the voltage, but half the current. That is the basic design of the transformer. A tesla coil will typically have two or three of these transformers to get the voltage high enough with lots of windings each. The last one tends to be visible as its windings go all the way up the tower creating a massive transformer.

In order to create the alternating currents that this requires the original design calls for a spark gap AC generator. You charge up a capacitor and coil with a battery and when it gets to high enough voltage it will short circuit across a gap specifically designed to create sparks at the exact voltage. Because the plasma in the spark is more conductive then air it will maintain the spark until the capacitor and coil is drained completely. So you get an alternating current from the battery source. This can also be used to create higher frequency power from the relatively slow frequency of a power grid. However modern designs will often use electronics instead of the spark gap.

Anonymous 0 Comments

Electricity and Magnetism are mostly the same thing. While they often seem completely different, the details of the physics are the same.

When you have an electric current in a wire, it makes a magnetic field. If the current changes, like in a wall outlet, the magnetic field changes. This seems unusual because we thing of magnets as static, but that’s actually only true for bar magnets because they are a special case.

When a wire moves in a static magnetic field, or a wire stays in the same place and the magnetic field changes, an electric current is formed in the wire. This is the concept used by generators and motors.

A Tesla Coil combines these two ideas. A small coil is connected to an alternating current, from a wall outlet. A large coil, with very many wires is mechanically mounted to the small coil. This is also very similar to the concept behind a transformer. The Tesla Coil trick is that the ends of the large coil are not connected in a loop. When the small coil makes a magnetic field, the large coil can’t conduct because the ends of the coil of wire don’t touch.

You might think this is a stalemate, because air doesn’t conduct electricity (that’s why unplugging things turns them off). But, it turns out that this isn’t true if the voltage is large enough. Just like Lightning, if you put enough turns in the large coil you can make the voltage high enough to break down the molecules of air and turn the air into a conductor. This gives the lovely sparks that come off the Tesla Coil.