In this chapter, we shall study the current response as a function of time of a redox system when the electrode potential is varied by a sequence of potential steps or potential pulses. These methods should more generally be called chronoamperometry or transient amperometry, but are usually referred to as pulse voltammetry. We shall restrict the present study to reversible electrode reactions, i.e. those that are limited by the diffusion of the reactants and products. We will therefore make the hypothesis of infinitely rapid electrochemical reactions. Thus, the interfacial concentration of the oxidised and reduced species are imposed by the Nernst equation, whilst the concentrations in solution will depend on the distance from the electrode and on the time; they will thus be notated c(x,t).