1. Transformers

2. ► Electric Generators- the main function of an electric generator is to convert mechanical energy to electrical energy. ► Electric motors- main function of an electric motor is to convert electrical energy into mechanical energy.

3. Transformer ► A device that increases or decreases the emf of alternating current. ► Reminder: emf is the energy per unit charge supplied by a source of electric current.

4. AC Transformer ► consists of two coils of wire wound around a core of soft iron. ► The coil on the right has N 1 turns and is connected to an input ac potential difference source. This is called the primary winding.

5. ► The coil on the left is connected to a resistor R and consists of N 2 turns, is the secondary. ► The difference between the two is the amount of turns N

6. Transformer equation ►ΔV2=N2 V1►ΔV2=N2 V1►ΔV2=N2 V1►ΔV2=N2 V1 N 1

7. Step-up ► When N 2 is greater than N 1 the secondary emf is greater than the primary making it a step up transformers.

8. Step Down ► When N 1 is greater than N 2 the secondary emf is less than that of the primary making it a step-down transformers. Examples