A conceptually simple and computationally efficient implicit approach to the simulation of current/time transients at the channel electrode is presented. The generality of the method is illustrated with reference to the simple case of a step between potentials corresponding to zero and transport-limited currents for a simple redox reaction (where good agreement with existing analytical theory is found), to ECE and to DISP1 processes, and finally to the case of double-potential steps. The latter are confirmed to be a possible means of distinguishing between ECE and DISP1 reactions.