Ohmic drop effects on the voltammogram shape of the Prussian-blue reversible arrow Everitt＇s salt system have been studied by considering the electroactive film model. As the uncompensated resistance varies: the experimental characteristic curve parameters also varies. A dependence of the voltammograms with the graphite proportion was found related with the ohmic drop due to the composite electrodes. The optimal graphite proportion to obtain a good faradaic-to-charge current ratio was 62% in weight which coincides with the second percolation threshold. The ohmic overpotential, which relates the ohmic drop with the electrochemical magnitudes, is also minimum at this proportion.