A general analytical solution for the chronopotentiometric response of a charge transfer reaction when the reactant and product are adsorbed following a linear adsorption isotherm has been derived for the expanding sphere with any power law electrode model using a perturbation function of the form I(t) = I0t(q). The expressions corresponding to a stationary plane electrode, to a stationary sphere electrode, and to the two models of the dropping mercury electrode (DME), expanding plane and expanding sphere, can be deduced as particular cases of the equations obtained here. The influence exerted by the sphericity of the electrode on the potential-time (E-t) curves and the characteristics of these curves are discussed.