1. Circuits

2. SC Standards Covered PS – 6.8Represent an electric circuit by drawing a circuit diagram that includes the symbols for a resistor, switch, and voltage source PS – 6.9Compare the functioning of simple series and parallel circuits

3. Types of Circuits Series and Parallel

4. What is a circuit? Electric Circuit – path that an electric current follows. –Open Circuit – break in path. Electricity can NOT flow through. –Closed Circuit – No breaks. Electricity can flow through.

5. Circuit Diagrams

6. Series Circuits In a series circuit, the current has only one pathway to travel. e-e- e-e- e-e-

7. Series Circuit If one bulb goes out, they all go out Creates an open circuit

8. Series Circuits Current is same throughout circuit (through each resistor). Current in entire circuit decreases with increased resistance (cumulative: add resistance to get total resistance).

9. Checkpoint Series Circuit 1.What is total resistance? 2.What is the current? 3.What happens when one resistor (light bulb) burns out?

10. Parallel Circuit In a parallel circuit, the current has multiple pathways to follow. e-e- e-e- e-e- e-e- e-e-

11. Parallel Circuit Individual path for each item connected If one item goes out the others stay on Still a closed circuit

12. Voltage in each path is same Total current in circuit increases if another path is added, the total resistance is reduced

13. Using Chemical Cells (Batteries) Series Makes “Battery” Increases Total Voltage Parallel Makes “Battery” Total voltage does not change Makes batteries last longer

14. Complex Circuits Combination of series and parallel circuits –In your house

15. If we try to send too much current (too many electrons, too fast) through a circuit, the circuit will get hot and may cause a fire ! A FUSE has a metal strip that will melt if it gets too hot. This prevents the circuit from melting in another spot. Now you must replace the fuse.

16. A CIRCUIT BREAKER has a metal strip that bends as it is heated. When it bends too much, it activates a switch that breaks the circuit. Once reset, the circuit breaker can be used again.

17. Lab 1.Series Circuit with 3 light bulbs 2.Parallel circuit with 3 light bulbs 3.Complex circuit with 2 bulbs in series and the 3 rd in parallel to the other 2.