Engineering Thevenin Equivalent for circuits with dependent sources

[shanrei]

Hi!

Good day! I was studying Circuit Theorems when I stumbled upon this circuit that has a dependent current source asking for a Thevenin equivalent. Up until now, I was only familiar with solving circuits with independent sources so this has me having a hard time. I tried using superposition theorem to solve for Vth but my answers don't match with the given answers. Can anyone please help me with this? Here is the pic for the circuit.

http://img230.imageshack.us/img230/3359/picture1um7.th.jpg


Thanks in advance!

 

[Corneo]

Did you do KCL at node X (where the dependent current source is going into)? Can you see the relationship of voltage at this node to the current going out of the node? (Ix going into 3 and 4 ohms)

 

[mplayer]

First I would remove the sources and solve for the R_th.

Next I would use Node-Voltage analysis on the original circuit:
-use the node on the negative side of the voltage source as your reference node
-now the only nodes with unknown voltages are the upper-middle node and upper-right node, label as V₁ and V₂, respectively.
-write the constraint equation for I_x
-write the KCL equations for nodes V₁ and V₂
-solving these 3 equations for the 3 unknowns should give you the information needed to find this circuit’s V_th


I hope that helps you get the correct answer, and that I described it correctly