Magnetism from Electricity 18.2

Electromagnetism Oersted discovered that a wire carrying a current makes a magnetic field. Electromagnetism is the interaction between electricity.

Using Electromagnetism A solenoid is a coil of wire that produces a magnetic field when carrying an electric current. It concentrates the weak magnetic field of current running through a wire into one area. An electromagnet is a solenoid that has an iron core. That iron core becomes magnetized by the magnetic field when the wire is carrying current. A magnet can exert a force on a wire carrying a current.

Applications In a door bell, pushing the doorbell closes a circuit that pushes an iron rod activating the bell An electric motor is a device that changes electrical energy into mechanical energy. A rotating coil of wire and a reversing direction of current causes reversing polarity of the magnetic field. This reversal of polarity keeps the coil turning over, creating the mechanical energy. Galvanometers measure current using a combination of permanent magnets and rotating electromagnet when the current flows. This rotating electromagnet operates the pointer.