2. McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. Electricity Principles & Applications Eighth Edition Chapter 5 Multiple-Load Circuits (student version) Richard J. Fowler McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. 5 - 1

3. McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. INTRODUCTION Voltage Regulation (Page 128) Parallel-Circuit Calculations (Page 116) Parallel-Circuit Measurements (Page 114) Series-Circuit Calculations (Page 109) Series-Circuit Measurements (Page 107) Series-Parallel Circuits (Page 123) 5 - 2

4. McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. Dear Student: This presentation is arranged in segments. Each segment is preceded by a Concept Preview slide and is followed by a Concept Review slide. When you reach a Concept Review slide, you can return to the beginning of that segment by clicking on the Repeat Segment button. This will allow you to view that segment again, if you want to. 5 - 3

5. McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. Concept Preview Voltage drops in series are additive. There is only one current in a series circuit. Resistances in series are additive. Powers in a series circuit are additive. Ohm’s law, Kirchhoff’s voltage law, and the power formulae are used to solve series-circuit problems. 5 - 4

6. McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. kk mAmVVA + V A  COM - d c a c R T = V T  I T =90 V  0.1 A = 900  P T = V T x  I T = 90 V x 0.1 A =9 W R T = 900  P T = 9 W B 1 90 V R1R1 R2R2 R3R3 0.1 A Series-Circuit Relationships (Page 00) 5 - 5

7. McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. kk mAmVVA + V A  COM - d c a c Series-Circuit Relationships R 1 = V R1  I T =20 V  0.1 A = 200  P R1 = V R1 x  I T = 20 V x 0.1 A =2 W R T = 900  P T = 9 W B 1 90 V R1R1 R2R2 R3R3 0.1 A R 1 = 200  200  P R1 = 2 W V R1 = 20 V 5 - 6

8. McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. kk mAmVVA + V A  COM - d c a c Series-Circuit Relationships R 2 = V R2  I T =40 V  0.1 A = 400  P R2 = V R2 x  I T = 40 V x 0.1 A =4 W R T = 900  P T = 9 W B 1 90 V R1R1 R2R2 R3R3 0.1 A R 1 = 200  200  P R1 = 2 W V R1 = 20 V P R2 = 4 W 400  R 2 = 400  V R2 = 40 V 5 - 7

9. McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. kk mAmVVA + V A  COM - d c a c Series-Circuit Relationships R 3 = V R3  I T =30 V  0.1 A = 300  P R3 = V R3 x  I T = 30 V x 0.1 A =3 W R T = 900  P T = 9 W B 1 90 V R1R1 R2R2 R3R3 0.1 A R 1 = 200  200  P R1 = 2 W V R1 = 20 V P R2 = 4 W 400  R 2 = 400  V R2 = 40 V V R.3 = 30 V R 3 = 300  300  P R3 = 3 W 5 - 8

10. McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. Series-Circuit Relationships R T = 900  P T = 9 W B 1 90 V R1R1 R2R2 R3R3 0.1 A R 1 = 200  200  P R1 = 2 W V R1 = 20 V P R2 = 4 W 400  R 2 = 400  V R2 = 40 V V R.3 = 30 V R 3 = 300  300  P R3 = 3 W Check total values against individual values 9 W = 2 W + 4W + 3 W 90 V = 20 V + 40 V + 30 V 900  = 200  + 400  + 300  5 - 9

11. McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. 4V 3V 5V Voltage Drops for Normal and Open Loads Without an open load, the measured voltages are: With one load open, 0V, and 12V. 5V,4V, and 3V. the measured voltages are: 0V 12V 5 - 10

12. McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. A Series-Circuit Problem R 1 2 k  R2R2 B 1 90 V V R2 = 50 V V R1 = V T - V R2 =90 V - 50 V = 40 V I R1 = V R1  R 1 = 40 V  2 k  = 20 mA R 2 = V R2  I R2 =50 V  20 mA = 2.5 k  R T = R 1 + R 2 = P T = I T x V T = 0.02 A x 90 V =1.8 W P R1 = I R1 x V R1 = P R2 = I R2 x V R2 = Check for errors: P T = P R1 + P R2 =0.8 W + 1.0 W =1.8 W 2 k  + 2.5 k  =4.5 k  0.02 A x 40 V = 0.8 W 0.02 A x 50 V =1.0 W 5 - 11

13. McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. Concept Review Voltage drops in series are additive. There is only one current in a series circuit. Resistances in series are additive. Powers in a series circuit are additive. Ohm’s law, Kirchhoff’s voltage law, and the power formulae are used to solve series-circuit problems. Repeat Segment 5 - 12

14. McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. Concept Preview (Page 114) Currents in parallel are additive. Only one voltage exists in a parallel circuit. Resistances in parallel are not additive. Powers in a parallel circuit are additive. Ohm’s law, Kirchhoff’s current law, and the power formulae are used to solve parallel-circuit problems. 5 - 13

15. McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. kk mAmVVA + V A  COM - d c a c Parallel-Circuit Relationships (Page 00) B1B1 R1R1 R2R2 R3R3 30 V V T =V R1 =V R2 =V R3 =30 V 5 - 14

16. McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. kk mAmVVA + V A  COM - d c a c Parallel-Circuit Relationships 2 A R 1 = V R1  I R1 = 30 V  2 A = 15  V T =V R1 =V R2 =V R3 =30 V B1B1 R1R1 R2R2 R3R3 5 - 15

17. McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. kk mAmVVA + V A  COM - d c a c Parallel-Circuit Relationships 1 A R 2 = V R2  I R2 = 30 V  1 A = 30  V T =V R1 =V R2 =V R3 =30 V B1B1 R1R1 R2R2 R3R3 2 A R 1 = V R1  I R1 = 30 V  2 A = 15  5 - 16

18. McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. kk mAmVVA + V A  COM - d c a c Parallel-Circuit Relationships 3 A R 3 = V R3  I R3 = 30 V  3 A = 10  V T =V R1 =V R2 =V R3 =30 V B1B1 R1R1 R2R2 R3R3 2 A R 1 = V R1  I R1 = 30 V  2 A = 15  R 2 = V R2  I R2 = 30 V  1 A = 30  1 A 5 - 17

19. McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. kk mAmVVA + V A  COM - d c a c Parallel-Circuit Relationships 3 A V T =V R1 =V R2 =V R3 =30 V B1B1 R1R1 R2R2 R3R3 2 A R 1 = V R1  I R1 = 30 V  2 A = 15  R 2 = V R2  I R2 = 30 V  1 A = 30  1 A R 3 = V R3  I R3 = 30 V  3 A = 10  4 A 4 A = 1 A + 3 A 5 - 18

20. McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. kk mAmVVA + V A  COM - d c a c Parallel-Circuit Relationships 3 A V T =V R1 =V R2 =V R3 =30 V B1B1 R1R1 R2R2 R3R3 2 A R 1 = V R1  I R1 = 30 V  2 A = 15  R 2 = V R2  I R2 = 30 V  1 A = 30  1 A R 3 = V R3  I R3 = 30 V  3 A = 10  4 A 4 A = 1 A + 3 A 6 A I T = 2 A + 1 A + 3 A = 6 A 5 - 19

21. McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. kk mAmVVA + V A  COM - d c a c Parallel-Circuit Relationships B1B1 R1R1 R2R2 R3R3 30 V 15  30  10  Measured R T = 5  Calculated total resistance is R T = 1 1 R1R1 1 R2R2 1 R3R3 ++ = 1 1 15 1 30 1 10 ++ = 30 6 = 5  5 - 20

22. McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. Circuit Measurements Quiz There is only one voltage to measure in a ____ circuit. There is only one current to measure in a ____ circuit. Measuring ____ requires physical interruption of a circuit path. The easiest measurements to make in a circuit are ____ measurements. Measuring individual resistors requires modification of the circuit when the resistors are in ____. parallel series current voltage parallel 5 - 21

23. McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. Concept Review Currents in parallel are additive. Only one voltage exists in a parallel circuit. Resistances in parallel are not additive. Powers in a parallel circuit are additive. Ohm’s law, Kirchhoff’s current law, and the power formulae are used to solve parallel-circuit problems. Repeat Segment 5 - 22

24. McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. Concept Preview Ohm’s law, Kirchhoff’s current law, formulae are all used to solve series- parallel circuit problems. Kirchhoff’s voltage law, and power Powers in a series-parallel circuit are additive. Multiple currents and voltages exist in a series-parallel circuit. Two or more resistances are either in series or parallel in a series-parallel circuit. 5 - 23

25. McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. Solving Series-Parallel Circuits 33  8  B1B1 R1R1 R3R3 88 V R2R2 R4R4 48 V 1 A I R4 = I R3 =1 A V R4 = 1 A x 33  = 33 V VR1 =VR1 = 88 V - 48 V = 40 V V R3 = 48 V - 33 V = 15 V R3 =R3 = 15 V  1 A = 15  I R1 = 40 V  8  = 5 A I R2 = 5 A - 1 A = 4 A R2 =R2 = 48 V  4 A = 12  P R1 =5 A x 40 V =200 W P R2 = 4 A x 48 V =192 W P R3 = 1 A x 15 V =15 W P R4 = 1 A x 33 V = 33 W PT =PT =5 A x 88 V =440 W RT =RT = 88 V  5 A = 17.6  Cross-check PT =PT =200 W +192 W +15 W + 33 W =440 W 5 - 24

26. McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. DETERMINING THE REGULATION OF A ZENER CIRCUIT Determine the output voltage with the lightest load to be served. The output voltage is 12.046 V when the load is 1000 ohms. Notice that the 1000-ohm load draws 12 mA. In other words, the zener provides 12.046 V when the load is 12 mA. R 2 100  R 3 1000  R 1 100  12 V D 1 V 1 25 V S1S1 Next change the load to the heaviest load to be served 5 - 25

27. McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. R 2 100  R 3 1000  R 1 100  12 V D 1 V 1 25 V S1S1 Notice that S 1 has been toggled to change to a 100-ohm load. The output has reduced from 12.046 V to 11.916 V while the load current has increased (by a factor of ten) from 12 mA to 120 mA. The % of V reg = [(12.046 – 11.916) / 11.916] x 100 = 1.1 % The voltage source for this circuit has 5 ohms of internal resistance. Therefore, the source voltage decreases as the load current increases. Thus the zener is compensating for both increased load current and decreased source voltage. 5 - 26

28. McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. Circuit Calculations Quiz Kirchhoff’s ____ law is most useful in solving series circuit problems. Kirchhoff’s ____ law is most useful in solving parallel circuit problems. Both of Kirchhoff’s laws are used in solving ____ circuit problems. When a 10-  resistor and a 40-  resistor are parallel connected to a 24-V source, the total power is ____ watts. When a 20-  resistor and a 30-  resistor are series connected to a 25-V source, the total power is ____ watts. voltage current series-parallel 72 12.5 What type of diode provides good V regulation?Zener 5 - 27

29. McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. Repeat Segment Concept Review Ohm’s law, Kirchhoff’s current law, formulae are all used to solve series- parallel circuit problems. Kirchhoff’s voltage law, and power Powers in a series-parallel circuit are additive. Multiple currents and voltages exist in a series-parallel circuit. Two or more resistances are either in series or parallel in a series-parallel circuit. 5 - 28

30. McGraw-Hill © 2013 The McGraw-Hill Companies Inc. All rights reserved. REVIEW Series-Circuit Measurements Series-Circuit Calculations Parallel-Circuit Measurements Parallel-Circuit Calculations Series-Parallel Circuits Voltage Regulation 5 - 29