Abstract: Ignition system for internal combustion engines, including a transformer having a primary side with a primary winding and a secondary side with at least one secondary winding, a chopper connected to the primary winding for addressing the primary winding, a d-c or rectified a-c voltage source connected to the chopper, the at least one secondary winding being selectively coupled to spark plugs of the internal combustion engine, and electronic control means connected to the chopper for driving the chopper with pulse sequences having individual width-modulated pulses and for supplying the spark plugs with igintion pulse sequences having corresponding individual ignition pulses with modulated energy.