1. The problem statement, all variables and given/known data Find thevenin equivelent of this circuit with respect to a and b 2. Relevant equations Mesh Currents 3. The attempt at a solution Here I will try to find V(open circuit) = Vth = Vab ((I think this anyways)) I apply mesh currents (any faster methods are welcome if you know them) iA: -100/V/ + 10/ohm/(iA) + 40/ohm/(iA-iB)=0 iB: 40/ohm/(iB-iA) + 50/ohm/(iB-iC)=0 iC: 50/ohm/(iC-iB) + 20/ohm/(iC) + 200/ohm/(Ix) = 0 iD:-10/A/ iX: iX=iB-Ic I get the folowing values using solve function on calculator: iX=-40A/ iA=210/A/ iB=260/A/ iC=300/A/ iD=-10/A/ And using ohms law with parallel resistors having equal voltages.. Vab = 40/ohm/*(iA-iB) = -2000 = Voc = Vth Now is where I begin to have trouble finding Isc... I draw the short circuit between a and b (which I believe causes R3 and R4 to have no current through them thus making Ix = 0 and vs2 = 0 as well): Simplifying it you gain ((if my previous assumptions are correct reguarding the short circuit)): Now from here I am actually unsure what I should do. I do want to do mesh currents but I dont know if I will recieve a correct answer. I also wondered if I could use a closed surface... something like this perhaps: If I used that I would get an equation like -100/V/ / 10/Ohms/ + Isc = 0 But then again it just doesnt seem quiet right to me. And i have no way to check my answer.