A theoretical and experimental analysis of the E-t response corresponding to an electrolysis carried out using a combination of direct and alternating currents is presented. This study has been applied to a slow higher-order electrochemical reaction at standard electrodes (dropping mercury electrode (DME), static mercury drop electrode (SMDE) and plane electrode), without restrictions on the values of the amplitude and frequency of the alternating current. The use of current-time functions of this type allows the selective determination of the transition times of oxidized species for any cycle of the E-t response, as well as an i-E response for a complete a.c. cycle even when the reduced species is not initially present in the solution.