An inductor is just a coil of wire around some kind of core. The core could be just air or it could be a magnet.
When you apply a current through the inductor, a magnetic field is created around it.
By using a magnetic core the magnetic field will be much much much stronger.
What Does An Inductor Do?Edit
The inductor is similar to the opposite of a capacitor.
In series it will resist alternating currents (AC) and let direct currents (DC) flow free.
It’s like a bully component. It will mess with the alternating currents (AC). But the direct current (DC) he will let be.
So don’t try to mess with the inductor by being alternating. It will beat you down.
How Does An Inductor Work?Edit
A current through any wire will create a magnetic field. The inductor is a wire shaped so that the magnetic field will be much stronger.
The reason an inductor works the way it does is because of this magnetic field. This field does some magic physics stuff that resists alternating currents.
I don’t like to go into the physics and maths. But if you want to read a more detailed explanation, check out Wikipedia’s inductor article.
What Can You Use Inductors For?Edit
I almost never use inductors. Mostly because I tend to stick to digital circuits. But I’ve used them sometimes for creating filters or oscillators.
And that is what they are mostly used for. Filters and oscillators.
You often find inductors in analog AC electronics such as radio equipment.