The stator, which is under the flywheel does two things... <br />First it generates voltage which is sent to the switchbox... The triggers also under the flywheel is what "triggers" the switchbox to release the charge to the coils and eventually the spark plugs....<br /><br />Second, the stator also sends current to the rectifier... The rectifier converts the current from AC to DC, which in turn charges the battery... It sends somewhere around 14.5 volts of charge to the battery when the engine is running...<br /><br />You can hook up a Tach wire to the top of the rectifier if you are interested in using a Tachometer...(thought you might want to know that )