In this paper we study the behavior of frequency characteristic of electrode currents of the four-electrode electrochemical cell. Navier-Stokes and Nernst-Planck equations was solved numerically with parameters appropriate experimental cell and electrolyte. Obtained results are compared with the results predicted by the convection-diffusion equation (with the most frequently used constant active component concentration on anodes) and with experimental data. These data agree well in the considered range of frequencies. (C) 2011 Elsevier B.V. All rights reserved.