Detector for determining rotation speed and direction, e.g. in water meters

摘要

The detector has a rotor with at least three sectors with different magnetic properties and a circuit for detecting the rotor motion with a sensor adjacent to the rotor and containing a resonant circuit. The resonant circuit is stimulated by time controlled pulses and differently damped by the sectors so that the decay duration of the stimulated oscillations depends on the magnetic properties of the adjacent sector. The resonant circuit signal is evaluated