The ammeter-voltmeter method is a general method for measuring electrical resistances that is widely used in the introductory physics laboratory, mostly for pedagogical reasons. Simultaneous readings of current (I) and voltage (V) allow the calculation of electrical resistance (R) using Ohm’s law: R = V/I. It is implicitly assumed that electrical wire and contact resistances present in the measuring circuit can be neglected. Two measuring configurations are usually proposed, depending on the relative values of R and the internal resistances of the ammeter and voltmeter. In this work, we highlight the deficiencies of this standard approach and propose a modified ammeter-voltmeter method that can be used with more generality and better performance.

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