diodes as a result shunts due to impurities cannot take effect before the ignition voltage corresponding to the sum of breakdown voltages of all diodes is achieved as soon as the ignition voltage is reached the state changing diode cascade switches through suddenly so that the ignition voltage is applied to the spark plug and a spark flashes over in principle the state changing diode cascade can be arranged at any desired location on the secondary side of the ignition coil due to the self capacitance of the lines to the spark plugs however the steepening effect lessens as the line length increases therefore the cascade is preferably provided directly in the spark plug connector rise times of over 20 to several hundred ns e g 50 ns can be achieved for the voltage applied to the spark plug with the aid of this steepening effect the spark plugs accordingly become insensitive with respect to shunts which particularly improves the cold starting characteristics of the internal combustion engine moreover it has been shown that the heat value dimensioning of spark plugs is uncritical due to this state changing diode cascade it is known that 34 cold spark plugs 34 that is plugs with excessive heat values tend to become carbon fouled which leads to shunts this results in misfiring and cold starting problems these problems are eliminated due to the improved voltage vs time curve at the spark plug the voltage controlled electronic high voltage switch according to the.