And what is induction, anyway?
In: Engineering
When a wire experiences changing magnetic pull, voltage is generated in that wire. This is called induction.
When electricity runs through a wire, it becomes a magnet, temporarily.
So when you try to pass electricity through a wire, especially a coiled one where each loop magnetically interacts with the other loops because they’re right next to eachother, it’s kind of difficult. The electricity takes time to build up in the loop, as the voltage from the magnetism fights against the voltage you’re using to push electricity through the wire. Then, when you stop applying a voltage, it takes a while for the electricity to stop as the voltage from the magnetism is now keeping it going
Another way to put this: Inductance is a ‘force’ that fights to keep the same amount of electricity running through a wire. If you want more or less electricity to flow, you need to use a voltage. A coil of wire has more inductance than a single wire, and a coil of the same size with more loops has more inductance.
You can measure inductance pretty easily. You try to pass electricity through a wire and see how long it takes to get going.
If you bring a magnetic material like iron near the loop, it amplifies the magnetic strength of the wire and so increases the inductance. If you bring a non-magnetic conductive material like copper near the loop, it allows electricity to freely flow which reduces the inductance.
Traffic signals put a big loop of wire in the ground and repeatedly test its inductance, and when this inductance changes enough they know that a large metal object is nearby.
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