ELECTRICITY AND MAGNETISM Friday, February 26, 16 ELECTROMAGNETS • An electromagnet is a current-carrying wire wrapped around an iron core. • To increase the strength: • Increase the current • Using a larger core • Increasing number of coils • The magnetic field of an electromagnetic is turned on or off when the electric current is turned on or off. • Doorbells and high-speed trains use electromagnets to operate Friday, February 26, 16 MAGNETS PUSH AND PULL CURRENT • Current-carrying wires produce a magnetic field that acts the same way as a magnet’s magnetic field. • Two current-carrying wires can attract or repel each other as if they were two magnets. • The magnetic field around a wire causes it to be pushed or pulled by a magnet, depending on the direction the current is flowing in the wire. • An electric motor (device that converts electrical energy into kinetic energy) runs by using the magnetic field formed by a current-carrying wire formed into a loop. Friday, February 26, 16 USING MAGNETS TO CREATE CURRENT •A generator uses a magnetic field to turn motion into electricity. • An alternating current (AC) changes from positive to negative due to a looped wire changing direction of motion. •A direct current (DC) electrons flow in one direction •A generator can produce both DC and AC current. • Large Friday, February 26, 16 power plants produce AC current.