1. Circuit Electricity

2. Circuit Builder Interactive: http://www.physicsclassroom.com/Physics-Interactives/Electric-Circuits/Circuit- Builder/Circuit-Builder-Interactive

3. Batteries  Batteries push electrons through circuits. The pressure with which they push is called voltage (V).

4. Current  The rate at which positive charges flow through a circuit.  Unit is Amperes (A)

5. Resistors

6.  They slow the rate at which charges move through a circuit.  Unit is Ohms (Ω)

7. Ohm’s Law  An equation for simple circuits…

8. Parallel circuit:  When electric current divides into two paths, then recombines.

9. Resistors in Parallel

10. Series Circuit  A portion of a circuit in which current follows one path.

11. Resistors in Series

12. Series or Parallel?

13. Example 1:  Determine the equivalent resistance in the following circuit.

14. Example 2:  Determine the equivalent resistance in the following circuit. R 3 = 1.0 Ω R 2 = 2.0 Ω R 1 = 1.0 Ω

15. Homework: Draw the following circuits, and determine the equivalent resistance for each one R 4 =2Ω R 1 =3Ω R 2 =3Ω R 3 =1Ω

16. Important Observations  Resistors cause electric pressures (voltages) to drop

17. Finding Resistance in Specific Resistors Series:  When resistors are connected in series, they all carry the same current. Parallel:  When resistors are connected in parallel, they all cause the same change in voltage.

18. Power  The amount of power at a point in a circuit is given by…

19. Example 1:  Determine the current running through an 8Ω speaker that is plugged into an American power outlet.

20. Example 2:  Determine the resistance of the filament within a 60W lightbulb.