Section 14.3

I. Electromagnetic Induction Faraday’s Law- An electric current can be produced in a circuit by a changing magnetic field When the loop moves in or out of the magnetic field a current is induced in the wire When the wire in a circuit moves perpendicular to a magnetic field the wire is maximized (parallel –no current)

2 Generators convert mechanical energy to electrical energy Generator- device that uses electromagnetic induction to convert mechanical to electrical energy

Electricity is produced in a generating plant Electricity is produced in a generating plant. The simplest type of generator has two main components: a rotating magnet called the “rotor” which turns inside stationary coils of copper wire called the “stator.” When the rotor rotates through the magnetic field, it generates a flow of current through the copper coils of the stator. Generating plants must use some form of energy or fuel to turn the rotor

Alternating current Generator that changes direction at regular intervals Currents in the outlets in your home are AC

3. Large power plants use generators to convert mechanical energy to electrical

4. Dams are built to harness the kinetic energy of falling water

5. Coal power plants use heat from burning coal Coal-fired power plants currently provide more than 50 percent of the U.S. electricity

II. Transformers A device that can change one alternating current voltage to different current voltage Primary and secondary circuits in a transformer each turn one time, then voltage across each is about equal

1. Step – down transformer Transformers like this one are used to reduce the voltage across power lines are safer to use