Source: cirosantilli/electromagnet

= Electromagnet
{wiki}

<Electromagnets> allow us to create controllable <magnetic fields>, i.e.: they act as <magnets> that we can turn on and off as we please but controlling an input <voltage>.

Compare them to <permanent magnet>: on a magnet, you always have a fixed generated magnetic field. But with an <electromagnet> you can control the field, and even turn it off entirely.

This type of "useful looking thing that can be controlled by a voltage" tends to be of huge importance in <electrical engineering>, the <transistor> being another example.