Q:  Determine Norton's current in given the circuit.

Solution:

            First Inject a 1A current source into the port and declare V_x across 200Ω so that

            For node 1

                                    1= (V₁/100) + (V₁-V_x)/50

                                     100=V₁+2V₁-2V_x

                                                 3V₁-2V_x=100 .......... (i)

                        For node 2

                                                -0.1V₁=(V_x/200)+(V_x-V₁)/50

                                                -20V₁=V_x+4V_x-4V₁

                                                                    5V_x+16V₁=0 ..............(ii)

By Solving out simultaneously A & B we have

                                                             10V_x+32V₁= 0

                                                            -10V_x+15V₁= 500

                                                                        47V₁= 500

                                                                            V₁=10.64V

                                                                        Also R_th= R_n =V₁/1A =10.64Ω

As no independent source is involved in the circuit, therefore I_N=0