1. ELECTRIC POWER

2. POWER AT HOME When you plug in a device, you are using alternating current (AC) Both (+) and (-) … alternates at 60x /second (60Hertz)

3. POWER AT HOME When you plug in a device with a battery, you are using direct current (DC) Rechargeable = AC/DC Cell Laptop Electric toothbrush Electric car

4. ELECTRICAL DEVICES Transformer – changes between high and low voltage

5. ELECTRICAL DEVICES Special Power Cords -

6. SAFETY DEVICES Fuses & Circuit Breakers

7. SAFETY DEVICES Ground-Fault & Arc-Fault Interrupters

8. POWER Electric Power – The rate of energy used by an appliance Measured in units of Watts (W) or kiloWatts (kW). Kilo = 1000 1 kW = 1000W Equations:

9. POWER The more Watts a device uses, the more expensive it is to use. **Most expensive move heat in or out.**

10. EFFICIENCY

11. FROM THE POWER COMPANY When you get your electric bill, you get charged in units of kilowatt  hours. kWh = how many kW multiplied by hours ran Ex: A 100W lightbulb ran for 10 hours = 1 kWh $ = kW  hrs  rate (set by power company)

12. EXAMPLE Assume your rate = $0.10 / kWh

13. POWER BILL GAS

14. POWER BILL - ELECTRIC

15. POWER BILL – DAY TO DAY ELECTRIC

16. POWER BILL – HOUR BY HOUR ELECTRIC

17. POWER BILL – COMPARED TO NEIGHBORS