Page 46 - NETWORK ANALYSIS
P. 46

39
                                                                                                                       Thevenin Theorem

                       Step 2


                       Calculate the value of Thevenin voltage, Vth by removing the load (2 + j4) Ω from the

                       circuit. There are two different ways to solve for the Thevenin voltage, Vth.
















                                                        Figure 2.4(d)



                       Method #1

                                    Vth = V4Ω = i x 4Ω



                              By using Current Divider Rule (CDR),
                                           −j5
                                     i  =         x 30A = (15 – j30) A
                                        (4 + j3 – j5)

                                  Vth    = V4Ω =   i x 4Ω = (15 – j30) x 4   = (60 – j120) Volts




                       Method #2

                                    Vth = iT x (25 – j30) = (0.18 + j0.24) x (25 – j30) = (11.7 + j0.6) V
                       Simplify the circuit diagram.

















                                   V = IR = 30 x (–j5)     Figure 2.4(e)
                                        = –j150 V
   41   42   43   44   45   46   47   48   49   50   51