We want to find Vth for the given circuit using nodal analysis. We need to create a supernode. I have drawn the directions the currents. How do I proceed? Please help me out. Thank you
1: I was just wondering that whether you followed the whole procedure explained in the following link to deal with supernode: https://img840.imageshack.us/img840/1959/img0002qc.jpg
You see the author also applied KVL.
I think the author overcomplicated the subject too much.
I also apply KVL in this equation V1 = Vo + 2*Vo
So as you can see we don't need to know the polarities of V3 and V2
All we need is this simply KVL equation
V2 = V3 + 5V or V2 - V3 = 5V or V3 = V2 - 5V
And if we change the polarity of a 5V voltage source
We will write
V3 = V2 + 5V ; V3 - V2 = 5V; V2 = V3 - 5V
This is all we need form KVL when we dealing withe supernode.
Normally when we deal with supernode and start writing KCL but first we virtually short V1 and Vo and then start to write down KVL equations.
But of course your equation are good.
I was wondering one thing. In this post of yours you used the attached clipped diagram. Your attached diagram in your mentioned post has the polarities of voltage supply reversed. My linked scanned diagram has the +ve polarity on the left side. This point really confused me in some of the post. Please clarify this if possible. Thanks a lot.
But can you tell me withe part of my post confuses you?
As I said for figure 1
We don't need to know the polarities of V3 and V2 to be able to write KVL equations. V2 = V3 + 5V or V2 - V3 = 5V or V3 = V2 - 5V
And if we change the polarity of a 5V voltage source figure2
We can write KVL without knowing V2 and V3 polarity.
V3 = V2 + 5V ; V3 - V2 = 5V; V2 = V3 - 5V
And of course if we assume the current directions for I2 and I3 we already (immediately) know the polarity of V2 and V3.
Actually what had confused me was that you had used different polarities for the battery. By the way, did you swapped the polarities of the battery because my scan has +ve polarity on the left? Just curious.