- #1
cuallito
- 95
- 1
Homework Statement
This problem propped in my head yesterday related to a project I'm working on (not homework, I'm not in school, but I thought this was the best place for it) and I just can't figure out how to crack it! If we have a large plate made up of nxn smaller plates, what is the resistance of the whole plate? For simplicity, let's say each sub-plate is either a perfect conductor, regulator conductor (resistivity=1 in some units), or a perfect insulator.
Would it be possible to write a closed form solution so that if we knew the arrangement of the smaller plates, we can calculate the total resistance of the larger plate?
What I'd like to have is a formula, that given an arbitrary matrix rho representing the arrangement of the sub-plates, it gives me the top-to-bottom resistance of the whole plate.
$$
\rho=
\begin{pmatrix}
0 & 1 & \infty & 1 & 1 \\
\infty & 1 & 0 & 0 & 0 \\
0 & 0 & 1 & \infty & \infty \\
\infty & 1 & 0 & 1 & \infty \\
1 & 0 & \infty & \infty & \infty
\end{pmatrix}
\longrightarrow
\Omega\ ?
$$
2. Homework Equations
Kind of lost on where to start, but maybe differential forms of maxwell's equations?
The Attempt at a Solution
I can figure out some simple cases:
If it's all one material, the resistance would just be the height (top to bottom) times the resistivity of the material.
Likewise, if we limit ourselves to horizontal "stripes" of different materials, the total resistance would just be the height of the first stripe times the resistivity of its material, plus the height of the second times it's reistivity, etc.
Finally if we had a big plate that was one sub-plate high vertically by n plates horizontally, it seems like it'd reduce to a parallel resistors problem? But I'm not sure...
It seems that for more complicated configurations, you'd almost have to find the path of least resistance in each case?