Ignition magneto

[1] A simple magneto (an electrical generator using permanent magnets) is able to produce relatively low voltage electricity, however it is unable to produce the high voltages required by a spark plug as used in most modern engines (aside from diesel engines).

[3] A second coil, with many more turns than the primary, is wound on the same iron core to form an electrical transformer.

[5] The hub of the magneto rotates while the drive shaft is held stationary, and the spring tension builds up.

When the magneto is supposed to fire, the flyweights are released by the action of the body contacting the trigger ramp.

[8] Ignition magnetos were soon used on most cars, for both low voltage systems (which used secondary coils to fire the spark plugs) and high voltage magnetos (which fired the spark plug directly, similar to induction coil ignition).