Single Pick-Up Models
The distributor has a toothed wheel, called a reluctor, having one tooth for each of the engine's 8 cylinders. See Fig 1. As the reluctor rotates with the distributor shaft, its teeth approach, become aligned with, and pass the center pole piece of the pick-up coil. This interruption of the magnetic field around the pick-up coil creates an electronic signal.
This signal is transmitted to the control unit, which shuts off current flow to the primary circuit of the ignition coil as each signal is received.