1. Circuits

2. complete, closed path that electrons flow through
Electric circuit
complete, closed path that electrons flow through

3. Circuits need three basic parts:
 Energy source – battery, photocell, generator

4. Circuits need three basic parts:
Load – something that uses the energy by changing it into other forms

5. Circuits need three basic parts:
Wires – connect energy source to the load

6. A switch can be used to open and close a circuit

7. “on”
circuit is closed and electrons can flow

8. “off”
circuit is open and electrons can’t flow

9. Common Circuit Symbols

10. How would you draw this diagram?

11. Two main types of circuits:

12. all parts are connected in a single loop
Series circuit
all parts are connected in a single loop

13. Series circuit
A break in the circuit stops the flow of electricity to all other parts of the circuit

14. Series circuit
Multiple light bulbs (loads) share the current and make the bulbs dimmer

15. So Why Use a Series Circuit?
Useful in burglar alarms

16. Parallel circuit
parts are connected side by side with more than one path to travel through

17. Parallel circuit
A break in the circuit doesn’t stop the flow to the remaining devices

18. Parallel circuit
Multiple light bulbs will retain the same brightness

19. The more paths the LESS the resistance
Parallel Circuits
The more paths the LESS the resistance
Water example: added pipes coming from a large tank will allow more water to flow out than a single pipe.

20. Parallel circuit
Each pathway can be separately switched off w/out affecting the others

21. Series or Parallel Circuit?

22. Series or Parallel Circuit?

23. Series or Parallel Circuit?

24. Series or Parallel Circuit?

25. Series or Parallel Circuit?

26. Christmas Lights

27. What type of circuit wires your house?

29. A few Questions About Circuits

30. Which circuit has the brighter globe? Why do you think this occurs?

31. Which circuit has the brighter globe(s)
Which circuit has the brighter globe(s)? Why do you think they are brighter?

32. Which circuit has the brighter globes? Why do you think this happens?

33.  If you wanted to light up two globes as brightly as possible using one battery, which is the better way to do it?

34. Which of the circuits will have the brighter globes?

35. Which of the circuits will have the brighter globes?

36. Household Circuit Safety

37. Broken wires, water, or overload can cause circuit failures
… which can do a lot of damage

38. Fuses
contain a thin piece of metal that melts if current is too high, opening the circuit

39. Fuses
Has to be replaced to complete the circuit again

40. Circuit breaker
piece of metal bends when it gets too hot which flips a switch and opens the circuit

41. Circuit breaker
Has to be reset to complete the circuit again

42. GFCI – found in individual outlets and acts like a small circuit breaker