A generator including a source of electric energy connected to means for generating sparks between the electrodes of an ignition spark plug, is characterized in that it comprises a first power portion including first means forming a capacitor for storing energy in series with first means forming a diode, wherein the first means forming a capacitor are also connected to the ignition spark plug through a gas spark gap and at least one second triggering portion including second means forming an energy storage capacitor in series with second means forming a diode, wherein the second means forming a capacitor are connected through at least one controlled semiconductor switching unit, to a primary winding of a voltage step-up transformer for which one secondary winding is connected in series with the gas spark gap between the first means forming a capacitor and the ignition spark plug.