COMPUTER-AIDED ANALYSES OF ELECTRIC-FIELDS USED IN ELECTROROTATION STUDIES

The spatial variations of the magnitude and phase of the electric fiel d produced by electrodes used in electrorotation studies have been com puted, using the charge density method, at 10-degrees intervals for on e complete AC cycle of the applied voltages. These results, together w ith the development of a more general theoretical treatment than has h itherto been applied to this problem, enable the time-averaged rotatio nal torque and dielectrophoretic force acting on a particle to be dete rmined as a function of its location within the inter-electrode space. Correction factors that can be applied to electrorotation spectra to take account of the relative position, or change in position, of the t est particle are provided for electrodes of polynomial and circular ge ometry.