# Determining the distribution of voltages in a given rectangular grid

1. Nov 13, 2008

### blandonfrank

1. The problem statement, all variables and given/known data
Hi,
I need to calculate the voltage drop in an n by m grid. There are resistors 4 resistors connected to a square; R1 for horizontals and R2 for verticals. There's a voltage applied at point B and point A is grounded.

I need to create a MATLAB function that will solve for the voltage and display it in a matrix.

2. Relevant equations
Kirchhoff Law
V= IR

3. The attempt at a solution

I1R1 - I2R2 - I3R1 + I1R2 =0 (That's the equation for one of the squares), using this logic to solve for one, I can solve for all. But, how can I automate it for a n x m grid?

2. Nov 14, 2008

### Staff: Mentor

You know the voltages at B and A, so you need to write the (m X n - 2) simultaneous KCL equations to solve for the voltages at those other nodes. The good news is that you have MATLAB to solve the simultaneous equations (set it up as a matrix equation?). The bad new is I don't know MATLAB, and am not sure what kind of scripting capability you have in it.

Is your question more about whether to use the KCL equations, or do you already know that is the way to go, but are looking for a way to generate general code in MATLAB where you put in different n and m values to see how the voltage maps of the nodes change?

3. Nov 14, 2008

### blandonfrank

berkeman,

Thanks for the response.

I know that KCL would be the way to go to solve this problem. My question is more of how I can do it on MATLAB, I have a bunch of currents I and to solve for voltage, I would have to know those currents to see how the voltage maps out.

Once I solve for the voltage, I need to print out the solution as a matrix.