An Investigation into Electrical Resistance

Background Knowledge Resistance, in electricity, is a property of any object or substance to resist the flow of an electrical current. The quantity of resistance in an electric circuit determines the amount of current flowing in the circuit for any given voltage applied to the circuit. The resistance of an object is determined by the nature of the substance of which it is composed, its resistivity, accounting for its dimensions and its temperature. Resistivity is …

…bridged across the other two points. When all four of the resistances bear a fixed relationship to each other, the currents flowing through the two arms of the circuit will be equal, and no current will flow through the galvanometer. By varying the value of one of the known resistances, the bridge can be made to balance for any value of unknown resistance, which can then be calculated from the values of the other resistors.