Three models used in electrochemical literature to fit experimental data for insertion/extraction processes investigated by the potential step chronoamperometry (PSCA) technique are examined and compared in this article. The first model (MI) gives a theoretical expression of Faradaic current transient taking reaction kinetics at the electrode surface, diffusion process in the host material and Ohmic drop effects into consideration. The 'cell-impedance controlled diffusion' constraint is used in the second model (M-n) together with the diffusion equations and boundary conditions. Finally, the third model (M-III) applies when the diffusion flux of injected/extracted species at the electrode surface is limited by interfacial charge transfer kinetics represented by the Butler-Volmer equation. The use of a finite-difference method is required to numerically solve models MII and MIII. First, the theoretical predictions from models M-I, M-II and M-III are compared when a small potential step is applied on the electrode. It is stated that the theoretical expression of current transient derived from model M, is the analytical solution of both models M-II and M-III under small-signal (linearization) conditions. Next, the three models are numerically compared under Langmuir isotherm conditions, assuming a constant diffusion coefficient of guest species in the host material. It is shown that the 'cell-impedance controlled diffusion' constraint used in model M-II does not work very well when a large potential step is applied on the electrode. Finally, an alternative formulation of the boundary condition at the host material I electrolyte interface (model M-III) is used to study the influence of Ohmic drop, together with the use of large potential steps. (c) 2005 Elsevier Ltd. All rights reserved.