actually , i don't know how to start . I can solve the independent sources's questions. But there is a dependent current source . I've tried to solve this five or six times and different ways but i couldn't get close to the answer.
Try to use a superposition and find Vth voltage http://forum.allaboutcircuits.com/t...rrent-and-voltage-sources.101488/#post-764893 Ix = 6V/(5 + 3 + 4) + 1.5Ix* 5/12 (current divider rule) 12Ix = 6 + 7.5Ix 4.5Ix = 6 Ix = 6/4.5 = 1.3333A So Vth = Ix * 4 ohm = 5.33V Next you need to find a Rth, so you need to short A with B and find Isc current. Ixsc = 6V/(5 + 3 ) + 1.5Ixsc* 5/8 Ixsc = 12A Rth = Vht/Ixsc = 5.333V/12A = 0.444Ohm