General analytical and fully explicit equations for the transient charge-potential-time (Q(p)-E-p-t) and current-potential-time (I-p-E-p-t) responses of quasi-reversible electroactive diffusionless systems valid for any multipotential pulse technique are presented. The expressions for the non faradaic contributions to both responses are also deduced and simple and effective methods to quantify and eliminate them are proposed. The use of a discrete potential pulse sequence leads to stepped or continuous sigmoidal Q(p)-E-p-t curves depending on the reversible or non reversible nature of the electrode process, a behaviour which cannot be obtained when a continuous time dependent potential is applied, as in Cyclic Voltammetry. Easy methods for estimating thermodynamic and kinetic parameters of the electroactive film are proposed and experimentally tested. (c) 2006 Elsevier B.V. All rights reserved.