How does the ignition key in an car start the engine?
The ignition switch is like any other electrical switch but can only be switched using a key. Closing the switch sends power to the starter motor and the distributor coil and associated circuits. The starter motor engages temporarily to give the engine a kick start, whilst the coil gernerates a high tension supply to the spark plugs. The distributor cap sends that H.T. to each spark plug in turn which causes, as you may guess, a spark! This spark ignites the petrol which has been pumped up through the carburettor, which in turn causes small explosions which push each piston up or down according to which spark plug has been ‘sparked’! Once the engine is running, the starter motor disengages and the motion of the pistons take over. Get it?
