The interaction that occurs between a supporting electrolyte and electrode-immobilized gold nanoclusters (GNCs) in voltammetric experiments is modeled with equivalent circuits. Several new versions of the Randles circuit are developed that are shown to better represent the electrical behavior of the clusters including their rectification effect. When combined with the orthodox theory of Coulomb blockade, these circuits also allow the quantized charging seen in cluster CVs to be simulated. From such modeling, the ratio of the ionic charging time to the electronic charging time is identified as the crucial factor determining whether or not quantized charging is observed. (C) 2003 Elsevier Ltd. All rights reserved.