The primary winding of an ignition coil is connected in series with an ignition switch that can be switched by a control circuit. A circuit including a capacitor, a resistor, and a diode is configured between the control terminal and the collector of the ignition switch. When the primary current is switched on, the capacitor discharge brings about a voltage reduction at the base of the ignition switch resulting in slowing down the trailing voltage edge at the collector of the ignition switch.