Summary form only given. Most of the experimental data available in the literature on electrical discharges is referred to the breakdown characteristics of discharge gaps for different geometries in air. However, in order to understand the physical processes associated with the electrical discharges, it is necessary to obtain experimental data on the temporal variation of current- voltage during the pre-breakdown and the spark stage. This information is necessary to understand how the resistance of the discharge channel varies as a function of time and the energy dissipation during the discharge. The aim of this work present a study performed on a self- breakdown pressured gap, where voltage and current were measured when a fast electrostatic discharge (ESD) occurred between two electrodes. This fast ESD was produced by a floating electrode charged with corona currents, obtaining some hundreds of amperes of peak-current amplitude and a few nanoseconds of risetime and pulse width. The internal gas was dry air at different pressures.