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.

Fig 1: Exploded View Of Distributor Used On Dual Pick-Up System For V8 Engines

Courtesy of CHRYSLER GROUP, LLC

Reluctor has one though for each cylinder 

This interruption of the magnetic field around the pick-up coil(s) creates an electronic signal. This signal is transmitted to the control until, which shuts off current flow to the primary circuit of the ignition coil as each signal is received.