Signal generation

A ferromagnetic sensor wheel with space for 60 teeth, with two teeth left out (gear notch) is mounted on the crankshaft. The speed sensor scans the tooth sequence of 58 teeth. When the sensor wheel teeth now pass the sensor, they alter the magnetic flux in the latter.

The amplitude of the alternating voltage diminishes as the gap between the sensor and the sensor wheel grows, and rises sharply as the speed increases.