1. Even MORE about ELECTRICITY

2. Circuits

3. Circuits There are two kinds of circuits: There are two kinds of circuits:

4. Circuits 1.Series

5. Circuits There are two kinds of circuits: There are two kinds of circuits: 1.Series 2.Parallel

6. Series Circuit

7. In a series circuit there is only one pathway for electrons to follow.

8. Series Circuit In a series circuit there is only one pathway for electrons to follow.

9. Series Circuit

14. In a series circuit when the power is turned off, everything goes off.

15. Series Circuit In a series circuit when the power is turned off, everything goes off.

16. Parallel Circuit

17. A parallel circuit is one where electrons have more than one path to follow. A parallel circuit is one where electrons have more than one path to follow.

18. Parallel Circuit A parallel circuit is one where electrons have more than one path to follow. A parallel circuit is one where electrons have more than one path to follow.

19. Parallel Circuit

22. In p.c. one device can be turned off without affecting the others. In p.c. one device can be turned off without affecting the others.

23. Resistance

24. Resistance In electrical circuits resistors are used to reduce the current. In electrical circuits resistors are used to reduce the current. The unit used to measure resistance is ohms. The unit used to measure resistance is ohms. The symbol is Ω The symbol is Ω

25. Question: How do we figure out what the resistance is?

26. Answer: OHM’S LAW

27. Ohm’s Law Ohm’s Law says that as you increase voltage, current also increases. As you increase the resistance, current decreases. Ohm’s Law says that as you increase voltage, current also increases. As you increase the resistance, current decreases.

28. Ohm’s Law Ohm’s Law says that as you increase voltage, current also increases. As you increase the resistance, current decreases. Ohm’s Law says that as you increase voltage, current also increases. As you increase the resistance, current decreases. In other words... In other words...

29. Ohm’s Law Ohm’s Law says that as you increase voltage, current also increases. As you increase the resistance, current decreases. Ohm’s Law says that as you increase voltage, current also increases. As you increase the resistance, current decreases. In other words... In other words...

30. Ohm’s Law V = I x R V = I x R (V)volts, (I)amps, (R)ohms (V)volts, (I)amps, (R)ohms

31. Ohm’s Law

32. Practice Problems V = IR The starter motor of a car is connected to a 12V battery. If the starter motor has 75A of current going through it to start the car, what is the resistance of the starter motor?

33. Practice Problems V = IR The starter motor of a car is connected to a 12V battery. If the starter motor has 75A of current going through it to start the car, what is the resistance of the starter motor? R = V/I

34. Practice Problems V = IR The starter motor of a car is connected to a 12V battery. If the starter motor has 75A of current going through it to start the car, what is the resistance of the starter motor? R = V/I R = 12V/75A R = 0.16Ω

35. Practice Problems V=IR A flashlight has a filament with a resistance of 10.7 Ω. The batteries provide 2.8V. What is the current through the filament?

36. Practice Problems V=IR A flashlight has a filament with a resistance of 10.7 Ω. The batteries provide 2.8V. What is the current through the filament? I = V/R

37. Practice Problems V=IR A flashlight has a filament with a resistance of 10.7 Ω. The batteries provide 2.8V. What is the current through the filament? I = V/R I = 2.8V/10.7Ω I = 0.26A

38. The End... for now