Node Voltage problem

Thread Starter

prast

Joined Apr 15, 2008
5
Hello, I'm trying to write node voltage equations for Node A and B in the following circuit.





My issue is that all of the circuits I've done so far have had obvious "mutual conductance". This circuit however, I'm unsure of. Do they even have a mutual conductance through the unnamed node in the middle?

If there is no mutual conductance I'm thinking the equations will be something like this:

Node A: (0.75 mS)Va = 2mA
Node B: (0.5 mS)Vb = -2mA

So if this were the case Va = 2.67 V and Vb = -4 V

However I feel like there should be some type of mutual conductance here. Maybe something like:

Node A: (0.75 mS)Va - (0.5 mS)Vb = 2mA
Node B: -(0.5 mS)Va + (0.5 mS)Vb = -2mA

This would give Va = 0V and Vb = 4V

Any help would be greatly appreciated, thanks!

John
 

hgmjr

Joined Jan 28, 2005
9,027
If there is no mutual conductance I'm thinking the equations will be something like this:

Node A: (0.75 mS)Va = 2mA
Node B: (0.5 mS)Vb = -2mA

So if this were the case Va = 2.67 V and Vb = -4 V

However I feel like there should be some type of mutual conductance here. Maybe something like:

Node A: (0.75 mS)Va - (0.5 mS)Vb = 2mA
Node B: -(0.5 mS)Va + (0.5 mS)Vb = -2mA

This would give Va = 0V and Vb = 4V
Neither of the sets of equations you have formed, account for the 10V dc source in the problem.

hgmjr
 

hgmjr

Joined Jan 28, 2005
9,027
You did not mention in your initial post in this thread if a specific method to be used in finding the solution to the problem had been stipulated either by your instructor or in the problem statement.

Is the method to be used in solving the problem constrained in any way?

hgmjr
 

Thread Starter

prast

Joined Apr 15, 2008
5
Sorry, the questions are:

a) Formulate node-voltage equations for the circuit.
b) Use these equations to find Vx and Ix
 
Ya, it's kind of hard to tell your methods here. If you give a little more of your work, it'll be easier to find out where (if at all) you're going wrong. I agree with hgmjr, you should read up a bit still. I'd just apply kcl a the unknown nodes. You'd come up with two equations, two unknowns... and voila!
 
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