The system in an internal combustion engine that initiates the chemical reaction between fuel and air in the cylinder charge by producing a spark. An ignition system for a multicylinder internal combustion engine has three basic functions: (1) to provide a sufficiently energetic spark to initiate the burning of the fuel-air mixture within each cylinder; (2) to control spark timing for optimum efficiency so that cylinder pressure reaches its maximum value shortly after the piston reaches the top of its compression stroke; and (3) to select the correct cylinder fired.