Ignition System - BOSCH Hall Effect: Operation

The Hall Effect sending unit is mounted inside the distributor on a switch plate. A trigger wheel attached to the distributor shaft under the rotor, passes in and out of the air gap of the Hall Effect sending unit. There is 1 trigger wheel shutter for each cylinder of the engine. Shutter width determines dwell, which is not adjustable.

At speeds greater than 940 RPM, the Hall Effect sending unit signals the ignition control unit to make and break current flow in the primary circuit of the ignition coil.

As the ignition control unit breaks the primary circuit through the coil, secondary voltage is released through the high tension wiring, distributor cap and rotor to the spark plugs.