# Norton's Theorem Question (with dependent sources)

#### inkosi

Joined Dec 10, 2013
35
Hello friends,

I have trouble solving the attached question. How exactly do you solve this? I did it with nodal analysis and got 2.18 V which I think is correct but the question specifically says solve it using Norton's Theorem. I know you have to find Voc and Isc, but what is Voc? How do you find it? And what is Isc? Is it the current flowing to the 4k resistor on the right hand side?

Help would be appreciated.

#### Jony130

Joined Feb 17, 2009
5,316
First you need to find Vo voltage, using whatever method you like or use.
And Vo = Voc
Next you need to short Vo terminals and find short circuit current Isc.

#### inkosi

Joined Dec 10, 2013
35
I'm a bit stuck finding Isc. Here are the nodal equations I made:

-6-Vo / 6k = (Vo / 2k) + (-3 / k) + (V1 / 4k)

And Vo / 2k = 2kIx and V1 - Vo = 2kIx. I get Isc as 3/7 mA, but apparently the answer is -1mA.

What have I done wrong?

#### Jony130

Joined Feb 17, 2009
5,316
Isc = Vb/R3

#### WBahn

Joined Mar 31, 2012
26,398
Hello friends,

I have trouble solving the attached question. How exactly do you solve this? I did it with nodal analysis and got 2.18 V which I think is correct but the question specifically says solve it using Norton's Theorem. I know you have to find Voc and Isc, but what is Voc? How do you find it? And what is Isc? Is it the current flowing to the 4k resistor on the right hand side?

Help would be appreciated.
I'm a bit unsure what is being by "solve this"? In other words, I see several things that the problem may be asking for and am not sure which it actually is.

Are you JUST being asked to find Vo for this circuit as given? If that's the case, I don't see how Norton's Theorem really helps you that much. You really can't walk across doing source transformations and transforming the one that you can do (on the left hand side) really doesn't buy you a whole lot.

I'm just guessing here, but I think what you might be expected to do is to treat the 4kΩ across the output as a load and then find the Norton equivalent circuit for everything else and then apply that equivalent circuit the to 4kΩ resistor and solve for Vo. But that's just a guess and I can think of a few other things that would be just as reasonable.