1. Bellwork Draw a circuit diagram that has one battery and two light bulbs.

2. Bellwork 1) If I remove a light bulb from the below circuit, then what happens to the other light bulbs? 2) If I remove a light bulb from the below circuit, then what happens to the other light bulbs?

3. Two Types of Electric Circuits Series Parallel

4. Series Circuits Provide a single path through the circuit If one bulb is removed all light bulbs turn off

5. Parallel Circuits Each device connects to the voltage source If one bulb is removed others will remain on

6. Noticing the difference Series or parallel? Series Parallel

7. Series or Parallel? Ask yourself: Does the circuit provide more than one path for the current? Yes = Parallel NO = Series

8. Series or Parallel? Parallel Series

9. Once More! Series Parallel

10. Bellwork Label the circuit diagrams below as either parallel or series.

11. Current and Potential Difference across Series Circuits I T = I 1 = I 2 = I 3 = ….  V T =  V 1 +  V 2 +  V 3 + …. ITVTITVT I2V2I2V2 I 3 V 3 I 1 V 1

12. Current and potential difference across Parallel Circuits I T = I 1 + I 2  V T =  V 1 =  V 2 ITVTITVT I2V2I2V2 I1V1I1V1

13. 1 st - Interpret correctly V A

14. V A V V

15. V A

16. Typical Problem If each Volt meter measures a potential difference of 10 V what is the potential difference at the battery? V2V2 V1V1 V3V3

17. In this series circuit, if ammeter 1 shows a current of 1.0 amperes, what will be the reading of ammeter 2? A2A2 A1A1 I2I2 I1I1

18. In this circuit, if voltmeters 1 and 2 both show measurements of 1.5 volts, what will be the reading of the voltmeter V T ? V2V2 V1V1 VTVT

19. In this parallel circuit, if ammeters 1 and 2 both show measurements of 0.5 amperes, what will be the current I T measured by ammeter A T ? A1A1 ATAT A2A2 I2I2 I1I1 ITIT

20. Series Circuit R eq = R 1 + R 2 + R 3 + …. R1R1 R2R2 R3R3 R eq Equivalent Resistance The total amount of resistance of a complete circuit

21. Example What is the equivalent resistance of this circuit? R 1 = 15 ohm R 2 = 10 ohm R 3 = 5 ohm R eq = ?

22. Example Find the resistance in R 2 ? R 1 = 20 ohm R 2 = ? ohm R 3 = 5 ohm R eq = 45 ohm

23. Example: A student needs a 10 ohm resistor to complete a circuit, but only 2 ohm resistors are available. Which of the following should be done to complete the circuit? a.Connect five 2 ohm resistors in parallel b.Connect five 2 ohm resistors in series c.Connect three 2 ohm resistors in series and two 2 ohm resistors in parallel d.Connect two 2 ohm resistors in series and three 2 ohm resistors in parallel

24. Example A student needs a 20 ohm resistor to complete a circuit, but only 2 ohm resistors are available. What should be done to complete the circuit?

25. Parallel Circuit R1R1 R eq R3R3 R2R2

26. Find the equivalent resistance R 1 = 20Ω R eq R 3 = 20 Ω R 2 = 20 Ω

27. Find the equivalent resistance R 1 = 20Ω R eq R 3 = 5 Ω R 2 = 10 Ω

28. Find the equivalent resistance R 1 = 30 Ω R eq R 3 = 10 Ω R 2 = 15 Ω

29. Law of Conservation of current At any junction in a circuit the sum of the currents entering the circuit must equal the sum of the currents leaving the circuit P 7A 3A 4A Toward point P Away from point P

30. Typical Question The diagram below represents currents in branches of a circuit. What should be the reading in ammeter A? P 6A 5A A

31. Example 2 The diagram below represents currents in branches of a circuit. What should be the reading in ammeter A? P2A 6A A 5A

32. Example 3 Which diagram represents the correct current direction in a segment of an electric circuit 4 A 2 A a) 4 A 2 A b) 4 A 2 A c) 4 A 2 A d)

33. One More! What is the reading in ammeter A A 4 A 3 A 5 A