Electronic ignition system

An electronic ignition system comprising:

• an ignition coil having a primary winding and a secondary winding;
• means defining a spark gap in series with said secondary winding;
• a primary transistor and a current limiting circuit in the circuit of said primary winding;
• a further transistor connected to be controlled by a control signal and connected in front of said primary transistor for controlling said primary transistor, said further transistor presenting a current path;
• a resistor network in the current path of said further transistor;
• and means connected to said further transistor and said resistor network for deriving pulses whose width represents the residence time of maximum current through said primary winding from the voltage curve at said resistor network and wherein said further transistor and said resistor network constitute means for causing said further transistor to operate in its saturation region when there is a rise in current in said primary winding and for producing a jump in voltage to a constant maximum value at said resistor network when the current in said primary winding is limited to its maximum value by said current limiting circuit.