Unlike ordinary magnets, electromagnets can be switched on and off. In a simple electromagnet, a coil, consisting of serveral hundred turns of insulated copper wire is wound around a core, usually of iron or Mumental. When a current flows in a coil, it produces a magnetic field.
Electromagnets can be used in magnetic relays, circuit breaker and magnetic storage. In a way, there are more uses for electromagnets then permanent magnets because electromagnets can be turned on and off.