1. Electric Circuits 5 Advanced Circuit Analysis

2. Advanced Circuit Analysis Question 1 Because 1A = 1000mA i.5 mA = 0.005 A ii.150 mA = 0.15 A iii.0.3 A = 300 mA iv.0.042 A = 42 mA ??

3. Advanced Circuit Analysis Question 2 Because 1k  = 1000  i.3.5k  = 3500  ii.25000  = 25 k  iii.0.45k  = 450  iv.22  = 0.22 k  ??

4. Advanced Circuit Analysis 3. If the current through the circuit opposite is 600mA, what is the EMF of the battery? V = ? I = 600mA = 0.6A R = 20  V = IR V = 0.6  20 V = 12V V I R

5. Advanced Circuit Analysis 4. What power is being dissipated in the resistor opposite?

6. Advanced Circuit Analysis 5. What is the resistance of a globe rated at 200mW when it is being driven by a 6  0V battery?

7. Advanced Circuit Analysis 6. What is the power (in mW) being used by an LED that has 0.70V across it and a current of 5.0mA flowing through it? P = ? V = 0.70V I = 5.0mA = 0.005A P = VI P = 0.7  0.05 P = 0.035W P = 35mW

8. Advanced Circuit Analysis 7. How much heat is dissipated in the resistor opposite in 3 minutes?

9. Advanced Circuit Analysis 8. What is the total resistance of the parallel resistors opposite?

10. Advanced Circuit Analysis 16 

11. Advanced Circuit Analysis 10. Assuming the battery opposite is ideal? (a) What is the total resistance of the circuit? R tot = 2 + 4 R tot = 6  44

12. Advanced Circuit Analysis 44

13. 10. Assuming the battery opposite is ideal? (c) What will be the power dissipated in the 2  0 ohm resistor? P = ? I = 2A R = 2  P = I 2 R P = 2 2  2 P = 8W 44 From q2b I = 2A

14. Advanced Circuit Analysis 10. Assuming the battery opposite is ideal? (d) What will be the power drain on the battery? P = ? I = 2A V = 12V P = VI P = 12  2 P = 24W 44 I = 2A

15. Advanced Circuit Analysis 10. Assuming the battery opposite is ideal? (e) What will be the potential drop across the parallel components? V = ? I = 2A R = 4V V = IR V = 2  4 V = 8V Or use one of the voltage divider techniques. 44 I = 2A

16. Advanced Circuit Analysis 44 I = 2A From q8f 8V

17. Advanced Circuit Analysis 11. What is V out ?

18. Advanced Circuit Analysis 12. What is R? Method 2 – Ratios on the diagram Using the ratios on the diagram R = 100  2 = 500  2V 55 55

19. Advanced Circuit Analysis 13. What is R? Method 2 – Ratios on the diagram Using the ratios on the diagram R = 2k  5 = 10k  25V 55 55

20. Advanced Circuit Analysis 2.0  6.0  12A

21. Circuit Design

22. Circuit Design Question 1 100V

23. Circuit Design Question 1 The circuit below has a string of 5V 1W globes. (b)What is the current flowing in the circuit? circuit current = current on 1 globe 100V I = ? V = 5V P = 1W

24. Circuit Design Question 2 The circuit for a small set of Christmas tree lights is shown below. The voltage supply (shown as a DC battery) is 240V. The complete circuit is designed to consume a total of 160W. Which of the following best describes the correct labelling for the lights in the circuit? A.20W; 30V B.20W; 240V C.160W; 30V D.30W; 20V

25. Circuit Design Question 3 Arrange the following items into a circuit designed to give a total light intensity of 200W. All items must be connected into the final circuit. 100V 50V 25W 100V, 150W 50V 25W

26. Circuit Design Question 4 (b)How much current will be flowing through each battery? 100V 50V 25W 100V, 150W 50V 25W Find I in 150W Globe I = ? V = 100V P = 150W Find I in 25W Globe I = ? V = 50V P = 25W Total Current = 1.5 + 0.5 = 2.0A So current through each battery will be 1.0A 1.5A 0.5A 2.0A 1.0A

27. Circuit Design Question 5 – Q18 2011 All the lights in the circuits below are operating normally. Identify which of the circuits, A or B, uses more power and explain why this is the case, using numerical calculations in your answer? P = VI P = 12 × 2 P= 24W P = ? V = 12V I = 2.0A P = VI P = 12 × 3 P= 36W P = ? V = 12V I = 3.0A Circuit B uses more power In Circuit A In Circuit B Examiners Comment Series and parallel circuits continue to cause difficulties for some students. Many were unable to work out how much current was flowing in each circuit. It was common for circuit A to have 4 A and circuit B to have 1 A. Other students tried unsuccessfully to obtain the total effective resistance of the circuits 55%

28. Circuit Design Question 5 – Q18 2011 All the lights in the circuits below are operating normally. Identify which of the circuits, A or B, uses more power and explain why this is the case, using numerical calculations in your answer? OR

29. Circuit Design Question 5 – Q18 2011 All the lights in the circuits below are operating normally. Identify which of the circuits, A or B, uses more power and explain why this is the case, using numerical calculations in your answer? P globe = VI P = 6 × 2 P= 12W P globe = ? V = 6V I = 2.0A P globe = VI P = 12 × 1 P= 12W P globe = ? V = 12V I = 1.0A P total = 2 × 12 = 24W 55% P total = 3 × 12 = 36W Examiners Comment Series and parallel circuits continue to cause difficulties for some students. Many were unable to work out how much current was flowing in each circuit. It was common for circuit A to have 4 A and circuit B to have 1 A. Other students tried unsuccessfully to obtain the total effective resistance of the circuits

30. Circuit Design Question 6 – Q 13 2010 Complete the circuit opposite to show the connections when the heater is set to provide a heating power of 600 W. Find R required for 600W R = ? P = 600 V = 240V RMS For 96Ω the resistors need to be connected in series. Note: draw your line in black pen so that it photocopies clearly. Do not use pencil or red pen. 58% You could have also worked out the power for series and parallel connections to see which gives 600W