Experiments with electrical resistive networks

Theoretical problems involving equivalent resistances of large or infinite networks of resistors have received substantial attention. We consider two actual networks. In the first, the resistance is measured across one end of a ladder whose number of loops is incremented until the precision of the multimeter is exceeded. In the second, resistances are measured across nodes near the center of a 12 by 12 square grid of resistors. These experiments are useful in the introductory physics laboratory as interesting examples of equivalent resistance, and can be added to a standard Ohm’s law experiment. The square grid apparatus also can be employed for lecture demonstrations. In addition, this apparatus offers approximate experimental confirmation of complicated theoretical calculations for the equivalent resistance between two nonadjacent nodes of an infinite square grid. These experimental results are verified numerically.