Dielectric spectroscopy of colloidal suspensions : I. The dielectric spectrometer
Four-electrode signal-processing techniques have a number of advantages over conventional bridge techniques in dielectric spectroscopy, but are not widely used because complex electronic circuits are required. A new design for a dielectric spectrometer of this type which circumvents these problems is described here. The device has been tested using electrical networks, pure electrolytes, and dilute colloidal suspensions. In experiments with a dilute, amphoteric latex, large suspension dielectric constants are found.
Myers, D., & Saville, DA. (1989). Dielectric spectroscopy of colloidal suspensions : I. The dielectric spectrometer. Journal of Colloid and Interface Science, 131(2), 448-460. https://doi.org/10.1016/0021-9797(89)90187-2