Pick-Up Coil: Description and Operation

Construction and Operation
The pick-up consists of a winding around a pole-piece attached to a permanent magnet. When the reluctor tooth passes across the pick-up limb, the magnetic field around the pick-up winding is intensified, creating a voltage in the winding. The rise and fall of this voltage is sensed by the amplifier and is used to trigger the output stage of the amplifier, which in turn switches on and off the current flowing in the primary winding of the coil. The amplifier controls the maximum current flowing in the primary circuit.