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Verify Thevenin’s Theorem

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Verify Thevenin’s Theorem Powered By Docstoc
					                 The Islamia University of Bahawalpur
                     University College of Engineering & Technology
                              Department of Electrical Engineering
                             EE211 Network Analysis 3rd Term (2nd Year)

                                     (LAB EXPERIMENT NO. 2)


          Name: _______________________________ Roll No. __________________

          Signature: ____________________________ Date: ____________________

To Verify Thevenin’s Theorem

Performance Objectives:

Upon successful completion of this experiment student will be able to:
    Understand the concept of source transformation
    Implement Thevenin’s theorem on complicated circuits to simplify them

Equipment Required:

      Bread Board
      Resistors (Select any three resistors and calculate their Thevenin equivalent resistance)
      DC Power Supplies
      Digital Multimeter
                               R1             R3
                                                               a
                                                              +

                VS                       R2            VTH RTH
                                                           -
                                                               b
                                      Figure 1


                              RTH
                                              c


                VTH

                                                 d

                                      Figure 2

Prior Calculations:
Consider the circuits in figure 1 and figure 2 and follow the steps given below:
   1. Write down the values of the three resistors you have selected for figure 1:
       R1 =                   R2 =                   R3 =
2. Calculate the value of RTH which will be used in circuit of figure 2:
   RTH =
3. Write down the expression for the open terminal voltage Vab which is equal to VTH:
   VTH =
4. If a load resistor (RL1) of 1kΩ is inserted between terminals a and b, what will be the
   expression for the load current IL1?
   IL1 =
5. Write the expression for the power delivered to RL:
   PL1 =
6. If a load resistor (RL2) of 1kΩ is connected between terminals c and d in figure 2, what will
   be the expression for current through this resistor?
   IL2 =
   Procedure:
1. Connect the circuit given in figure 1
2. Insert a load resistor of 1kΩ between terminals a and b
3. By adjusting the value of Vs, measure VL1 and complete the table given below:


                                                        V L1
                       Vs           VL1        I L1           PL1  I L1  V L1
                                                        1k
                       0
                       2
                       4
                       6
                       8
                      10
                      12
                      14
                      16

                                           Table 1


4. Now on the same board connect the circuit given in figure 2
5. Insert a load resistor of 1kΩ between terminals c and d
6. For each value of VS in table 1, calculate the value of VTH and complete the second column
   of table 2 given below
7. By adjusting the value of VTH, measure VL2 and complete the table 2:
                                                                 VL2
               Vs          VTH                VL2       I L2          PL 2  I L 2  VL 2
                                                                 1k
                0
                2
                4
                6
                8
               10
               12
               14
               16

                                              Table 2

8. Your measurements should show the following equalities:
          VL1 = VL2               IL1 = IL2                PL1 = PL2


   Questions:
       1. If VTH  aVS ; calculate the average value of a

                VTH
           a       
                VS
       2. Write the expression for a in terms of R1, R2 and R3
           a
       3. If we set VS = 200V in circuit 1, what will be the value of VTH?
          VTH =
       4. What should be the value of VS in circuit 1 to have VTH = -25V?
          VS =
       5. If we replace R1 with a short circuit, what will be the value of a?
          a=
       6. If we replace R2 with a short circuit, what will be the value of a?
          a=
       7. What is possible maximum value of a?
       8. What is possible minimum value of a?
       9. If we replace R3 with a short circuit in figure 1, will power delivered to load resistor
          increase or decrease?
       10. Convert the circuit in figure 2 to a Norton equivalent if VTH = 10V and RTH = 4kΩ
                          IN =                             RN =

				
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