An ultra low frequency bridge for dielectric measurements

In 1955 Mr. I. R. Weingarten¹ presented before this conference a paper in which he described a bridge capable of measuring dielectric properties down to the very low frequency of 0.01 cps. The paper, which I am privileged to present today, summarizes the effort made in the Dielectrics Section of the National Bureau of Standards to improve and test this apparatus to the point that it can be used to make precise measurements of dielectric properties at these low frequencies. Complete details related to the analysis of the bridge circuit, the operational procedure, etc., will be published in the near future². The present bridge operates at frequencies between 0.01 and 200 cps, measuring capacitances up to 100 pf and conductances between 10^-9 to 10^-15 mhos. It is possible to expand these measureable ranges.