i am an engineer and i want to know what an inductor does because they look really intresting
Gary's answer is excellent, but it more layman's terms, essentially, while a capacitor's purpose is to store voltage, an inductor's purpose is to store current. At steady state (time infinity), an inductor acts like a short circuit.
An inductor allows passage of DC current but resists AC. AC loads become current shifted with respect to voltage by up to 90 degrees in the negative direction. It also stores energy as magnetic energy in it's core when the current is disconnected the magnetic field begins to collapse and the energy is released as an electrical current in the same direction as the original flow. An inductors complement is a capacitor.
