# Node Voltages Problem

1. Oct 30, 2014

### k_squared

1. The problem statement, all variables and given/known data
We are told to analyse the circuit in the diagram (ignore the texts) with the method of node voltages.

Here is the answer:

2. Relevant equations
Kirchhoff's Current Law
Kirchhoff's Voltage Law

3. The attempt at a solution
So far, all I have been able to get is the equation described by the top line of the matrix relation. However, there is no 0 by the resistance!

Worse, the bottom equation looks to me like (1-alpha)*v_2. And I have no idea where v_2 is even defined, or how this is a valid KCL equation without the value or R_2 anywhere....

Thank you in advance for any help!

2. Oct 30, 2014

### Staff: Mentor

Your diagram has labelled the nodes 1 and 2. So it is reasonable to assume that v1 corresponds to node 1's voltage and that v2 corresponds to node 2's voltage.

It could be that when you are trying to recover the individual node voltage expressions that you are not correctly carrying out the matrix times vector operation?

I do see one typo in the text's solution though. The resistor in the matrix's first term should be R1, not R.

Why don't you try writing out the nodal analysis equations from scratch. They can always be be wedged into matrix form afterwards.