Application of High‐Frequency Reflectometry for Measurement of Minute Changes in Electrolytic Conductance

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Abstract
The paper presents a method of measuring small variations in electrolytic conductance applicable also to dynamic measurements. By means of a probe immersed in the solution a high‐frequency field is applied, variations in the absorption of which are detected by a special instrument, the H‐F reflectometer, and indicated on separate meters as changes in resistive and capacitive components of the combined impedance, of probe and electrolyte. At the frequency used, 1085 kc/s, absorption maximum occurs at conductivities around 10–4 ohm‐1 cm‐1, at which a change in conductivity of 10‐1 ohm‐1 cm‐1 can be measured with reasonable accuracy in long‐term experiments and transient changes of 10–8 ohm‐1 cm‐1 can be detected using variations in the capacitive component as index. By means of a graphical method an analysis is made of an equivalent circuit simulating the electrical properties of an electrolyte. It is shown that a series circuit of a varying resistance and a fixed‐value capacitance approximates several of the characteristics of a solution.