Why do electromagnets always need a coil to generate a magnetic field, and why do you need a AC current to generate inductance?
In: Physics
You don’t. Any electricity creates a magnetic field. It’s just usually easier to reuse the same current over and over again to get a stronger field, by having the same wire wrapped up over and over again. The simplest inductors are [ferrite beads around a wire](https://i.stack.imgur.com/llejr.jpg) and you see them everywhere.
Inductors interact with a *change* in current. Switching a DC current on or off will cause it to interact with inductors. Technically any electricity that changes is AC, so you’re technically correct, but inductors are used in “DC” circuits all the time.
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