The Accuracy of Measurements in Lumped R-C Cable Circuits as Used in the Study of Transient Heat Flow

This paper deals with certain aspects of the accuracy of measurements on a lumped R-C cable, and contains definite suggestions as to the desirable number of lumps to be used in such measurements. The effect of capacitive leakage and the influence of sectioning (that is, the influence of the number of lumps) are considered in their relation to the accuracy of measurements of potential and current. The increasing importance of lumped R-C circuits in heat-transfer research is pointed out, and the analogy between the flow of electricity in such circuits and the flow of heat, particularly unsteady-state or transient heat flow, is treated. The investigations described in this report were carried out at Columbia University on the heat and mass flow analyzer, which is essentially an R-C circuit. The results can be used in the appraisal of errors encountered in heat flow and similar problems solved by the analogy method, that is, by lumped R-C circuits.