Ignition Primary Circuit

The low voltage portion of motorcycle ignition system. As current flows through the primary winding of the ignition coil, it produces an electro-magnetic field. We can either make that magnetic field grow in strength very rapidly (rising field ignition coil) or we can establish a magnetic field and cause it to collapse very rapidly (collapsing field ignition coil). It is the motion of the magnetic field either rising or collapsing very rapidly that induces the secondary winding in the ignition coil to provide the extremely high voltage required to spark the sparkplug under a load.