Influence of AC field distribution on impedance of the conductivity cell

The АС impedance model of a liquid conductivity has been developed to assess the influence of electromagnetic vector potential. It has been proved that the field in a liquid conductor is quasi-static. Approximation error, even taken for very concentrated solutions (e.g. sea water), does not exceed 0.01 ppm. The calculation of resistance of the four-electrode cell is given with the account of Ampere's circuit law. Two types of errors are defined: DC error due to finite thickness of electrodes, and AC error due to presence of displacement currents when using an impedance model.