Accurate Dielectric Measurements Research Articles

Hysteresis phenomena in the incommensurate phase of (TMA)2ZnCl4, and at the lock-in transition

Abstract We performed accurate dielectric measurements in the region close to the lock-in transition of (TMA)2ZnCl4, at 10 kHz. Partial and complete hysteresis cycles are presented, and sample dependences and influence of thermal history are found. The observations are compared to results on solitons, obtained by other methods.

Complex dielectric properties of macroemulsions using a calibrated microwave resonance dielectrometer

A microwave cavity resonance dielectrometer has been employed in a study of the complex dielectric properties of macroemulsions consisting of oil, water, and stabilizing surfactant. A method for the simultaneous determination of emulsion type and water content from complex dielectric measurements is described. Also presented is a reference calibration technique for the microwave dielectrometer, which permits a convenient experimental routine and quite accurate dielectric measurements if referenced to exact standards. A voltage ratio technique is described which allows accurate measurement of both low- and high-loss samples in the same cavity.

A Capacitor for Accurate Wide Range Dielectric Constant Measurements on Compressed Fluids

A capacitor is described which has been used to make accurate measurements of the dielectric constant of liquid and gaseous oxygen over a wide temperature (55–300 K) and pressure (0.2–34 MN/m2) range. The capacitor is simple to construct and its stability is unaffected by large hydrostatic pressure variations. The temperature variation of the vacuum capacitance is small and remains reproducible even after repeated temperature and pressure cycling.

Non-polarizing electrodes for dielectric measurements on glasses

Sodium and sodium amalgam have been found to act as non-polarizing electrodes for soda glasses, and an electrode assembly is described which is suitable for accurate dielectric measurements. The elimination of edge relaxation effects by means of a guard ring was found to be essential. Comparative measurements with silver electrodes suggest that these do not act as simple blocking electrodes but that a diffusion layer arises of much greater thickness than the Debye length.

Application of Guard Electrodes in Dielectric Measurements

Guard electrodes are useful devices which enable accurate dielectric measurements to be made on small samples of insulating material. They are generally applied to the electrode system of the material for the measurements of: (1) insulation resistance; (2) dielectric constant; (3) power factor. The following is a brief survey of the technique and application of guard electrodes derived from a background of considerable experience in the dielectric laboratories of the writer's company.