Pick-Up Coil: Description and Operation

Distributor Assembly:

As the signal rotor turns with the distributor shaft, protrusions on the rotor (one for each cylinder) pass close to the pick-up coil, causing a disruption in the coil's magnetic field. This disruption is the signal used by the igniter to disconnect the primary coil circuit ground connection and induce high voltage from the coil secondary windings. To control ignition timing advance, the relationship between signal rotor and pick-up coil varies with engine load (vacuum advance mechanism) and engine speed (centrifugal advance mechanism).