PROBLEMS 244 SERIES-PARALLEL NETWORKS. FIG C response to an analysis of the ladder network of Fig without the elements R 5 and R 6.

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1 244 R-PARALLL NTWORK FG C response to an analysis of the ladder network of Fig without the elements and. PROBLM CTON 7.2 Descriptive xamples 1. Which elements of the networks in Fig are in series or parallel? n other words, which elements of the given networks have the same current (series) or voltage (parallel)? Restrict your decision to single elements, and do not include combined elements. (a) (b) R2 R7 (c) (d) FG Problem 1.

2 PROBLM Determine for the networks of Fig (a) (b) (c) (d) FG Problem For the network of Fig. 7.66: a. Does 6? xplain. b. f 5 A and 1 2 A, find 2. c. Does 1 5? xplain. d. f V 1 6 V and 10 V, find V 2. e. f,,, and R 1, what is? f. f the resistors have the values given in part (e) and 10 V, what is the value of in amperes? g. Using values given in parts (e) and (f), find the power delivered by the battery and dissipated by the resistors and. 4. For the network of Fig. 7.67: a. Calculate. b. Determine and 1. c. Find V For the network of Fig. 7.68: a. Determine. b. Find s, 1, and 2. c. Calculate V a. 1 2 V 1 3 FG Problem V 2 6 s V V V V a FG Problem 4. FG Problem 5.

3 246 R-PARALLL NTWORK 6. Determine the currents 1 and 2 for the network of Fig V V 25 FG Problem a. Find the magnitude and direction of the currents, 1, 2, and 3 for the network of Fig b. ndicate their direction on Fig *8. For the network of Fig. 7.71: a. Determine the currents s, 1, 3, and 4. b. Calculate V a and V bc. 24 V V a 2 c b 8 V V 5 1 s FG Problem 7. FG Problem V 1 9. For the network of Fig. 7.72: a. Determine the current 1. b. Calculate the currents 2 and 3. c. Determine the voltage levels V a and V b. 2 V a V b 3 FG Problem 9.

4 PROBLM For the network of Fig. 7.73: a. Find the currents and 6. b. Find the voltages V 1 and V 5. c. Find the power delivered to the 6-k resistor. 9 k 6 = 28 V V 1 3 k 12 k 12 k 6 k V k FG Problem 10. *11. For the series-parallel network of Fig. 7.74: a. Find the current. b. Find the currents 3 and 9. c. Find the current 8. d. Find the voltage V ab. 80 V 5 3 R 7 8 a V ab R 9 b 9 = R 8 FG Problem 11. *12. Determine the dc levels for the transistor network of Fig using the fact that V B 0.7 V, V 2 V, and C. That is: a. Determine and C. b. Calculate B. c. Determine V B and V C. d. Find V C and V BC. R B V CC = 8 V C 220 k R C 2.2 k B V B B C V C V B V BC V C V = 2 V R 1 k FG Problem 12.

5 248 R-PARALLL NTWORK V G = 1.75 V G = 0 A D = V DD = 16 V 1 2 M R D V G G 2 G V G 270 k R D 2.5 k D V 1.5 k *13. The network of Fig is the basic biasing arrangement for the field-effect transistor (FT), a device of increasing importance in electronic design. (Biasing simply means the application of dc levels to establish a particular set of operating conditions.) ven though you may be unfamiliar with the FT, you can perform the following analysis using only the basic laws introduced in this chapter and the information provided on the diagram. a. Determine the voltages V G and V. b. Find the currents 1, 2, D, and. c. Determine V D. d. Calculate V DG. FG Problem 13. *14. For the network of Fig. 7.77: a. Determine. b. Calculate V a. c. Find V 1. d. Calculate V 2. e. Determine (with direction). 15. For the network of Fig. 7.78: a. Determine the current. b. Find V. 400 V V 1 = 9 V 32 V 400 V V a V 5 7 FG Problem 14. V 2 = 19 V FG Problem k 1 k V b *16. Determine the current and the voltages V a, V b, and V ab for the network of Fig V 2 k 0.5 k V a 1.5 k FG Problem 16.

6 PROBLM For the configuration of Fig. 7.80: a. Find the currents 2, 6, and 8. b. Find the voltages V 4 and V 8. V V 2 30 R 7 R 8 8 V 8 FG Problem Determine the voltage V and the current for the network of Fig V V FG Problem 18. *19. For the network of Fig. 7.82: a. Determine by combining resistive elements. b. Find V 1 and V 4. c. Calculate 3 (with direction). d. Determine s by finding the current through each element and then applying Kirchhoff s current law. Then calculate from / s, and compare the answer with the solution of part (a). V 1 1 V V s FG Problem For the network of Fig. 7.83: a. Determine the voltage V ab. (Hint: Just use Kirchhoff s voltage law.) b. Calculate the current. 6 V a b 5 20 V FG Problem 20.

7 250 R-PARALLL NTWORK *21. For the network of Fig. 7.84: a. Determine the current. b. Calculate the open-circuit voltage V. *22. For the network of Fig. 7.85, find the resistance if the current through it is 2 A. V 20 V 18 V 120 V 20 2 A FG Problem 21. FG Problem 22. *23. f all the resistors of the cube in Fig are, what is the total resistance? (Hint: Make some basic assumptions about current division through the cube.) *24. Given the voltmeter reading V 27 V in Fig. 7.87: a. s the network operating properly? b. f not, what could be the cause of the incorrect reading? V = 27 V 6 k 12 k 6 k 45 V 36 k FG Problem 23. FG Problem V V 3 5 V 5 1 V 7 R 7 7 CTON 7.3 Ladder Networks 25. For the ladder network of Fig. 7.88: a. Find the current. b. Find the current 7. c. Determine the voltages V 3, V 5, and V 7. d. Calculate the power delivered to R 7, and compare it to the power delivered by the 240-V supply. FG Problem 25.

8 PROBLM For the ladder network of Fig. 7.89: a. Determine. b. Calculate. c. Find 8. 2 V R 7 R 8 1 FG Problem *27. Determine the power delivered to the 10- load of Fig V 2 P FG Problem 27. *28. For the multiple ladder configuration of Fig. 7.91: a. Determine. b. Calculate 4. c. Find 6. d. Find 10. CTON 7.4 Voltage Divider upply (Unloaded and Loaded) 29. Given the voltage divider supply of Fig. 7.92: a. Determine the supply voltage. b. Find the load resistors R L2 and R L3. c. Determine the voltage divider resistors,, and. R 9 R 8 R V = 1 = s = 72 ma 40 ma 6 48 V 12 ma R L1 1.6 k FG Problem V 8 ma R L2 R L3 FG Problem 29.

9 252 R-PARALLL NTWORK 120 V 10 ma *30. Determine the voltage divider supply resistors for the configuration of Fig Also determine the required wattage rating for each resistor, and compare their levels. 40 ma 180 V 20 ma R L2 40 V R L1 100 V R L3 36 V 4 ma 60 V FG Problem V 1 k Pot. R L 10 k 3 V CTON 7.5 Potentiometer Loading *31. For the system of Fig. 7.94: a. At first exposure, does the design appear to be a good one? b. n the absence of the 10-k load, what are the values of and to establish 3 V across? c. Determine the values of and when the load is applied, and compare them to the results of part (b). FG Problem V Pot. FG Problem 32. a 1 k V ab b 10 k V bc c *32. For the potentiometer of Fig. 7.95: a. What are the voltages V ab and V bc with no load applied? b. What are the voltages V ab and V bc with the indicated loads applied? c. What is the power dissipated by the potentiometer under the loaded conditions of Fig. 7.95? d. What is the power dissipated by the potentiometer with no loads applied? Compare it to the results of part (c). CTON 7.6 Ammeter, Voltmeter, and Ohmmeter Design 33. A d Arsonval movement is rated 1 ma, 100. a. What is the current sensitivity? b. Design a 20-A ammeter using the above movement. how the circuit and component values.

10 PROBLM Using a 50-mA, d Arsonval movement, design a multirange milliammeter having scales of 25 ma, 50 ma, and 100 ma. how the circuit and component values. 35. A d Arsonval movement is rated 50 ma, a. Design a 15-V dc voltmeter. how the circuit and component values. b. What is the ohm/volt rating of the voltmeter? 36. Using a 1-mA, 100- d Arsonval movement, design a multirange voltmeter having scales of 5 V, 50 V, and 500 V. how the circuit and component values. 37. A digital meter has an internal resistance of 10 M on its 0.5-V range. f you had to build a voltmeter with a d Arsonval movement, what current sensitivity would you need if the meter were to have the same internal resistance on the same voltage scale? *38. a. Design a series ohmmeter using a 100-mA, movement; a zero-adjust with a maximum value of 2 k ; a battery of 3 V; and a series resistor whose value is to be determined. b. Find the resistance required for full-scale, 3/4-scale, 1/2-scale, and 1/4-scale deflection. c. Using the results of part (b), draw the scale to be used with the ohmmeter. 39. Describe the basic construction and operation of the megohmmeter. *40. Determine the reading of the ohmmeter for the configuration of Fig (a) (b) FG Problem 40. CTON 7.9 Computer Analysis Ppice or lectronics Workbench 41. Using schematics, determine V 1, V 3, V ab, and s for the network of Fig Using schematics, determine s, 5, and V 7 for the network of Fig

11 254 R-PARALLL NTWORK Programming Language (C, QBAC, Pascal, etc.) 43. Write a program that will find the complete solution for the network of Fig That is, given all the parameters of the network, calculate the current, voltage, and power to each element. 44. Write a program to find all the quantities of xample 7.8 given the network parameters. GLOARY d Arsonval movement An iron-core coil mounted on bearings between a permanent magnet. A pointer connected to the movable core indicates the strength of the current passing through the coil. Ladder network A network that consists of a cascaded set of series-parallel combinations and has the appearance of a ladder. Megohmmeter An instrument for measuring very high resistance levels, such as in the megohm range. eries ohmmeter A resistance-measuring instrument in which the movement is placed in series with the unknown resistance. eries-parallel network A network consisting of a combination of both series and parallel branches. Transistor A three-terminal semiconductor electronic device that can be used for amplification and switching purposes.