A new method of a graphical representation of the electrode impedance is proposed. The method allows one to construct the impedance of a complicated circuit by summing up impedance plots for series and parallel branches. Rules for constructing complex representations are presented. New shapes of impedance plots for some of the most typical circuits are analyzed. The method opens additional possibilities for analyzing how the experiment accuracy impacts the limits of discovery of individual elements of complicated circuits. The method gives grounds to introduce the notion of the information potential of an experimental setup. Conditions for a complete decidability of equivalent circuits are shown by the example of a system that comprises several parallel branches consisting of the Frumkin-Melik-Gaikazyan impedances.