Sensor device and method for its operation

摘要

The sensor device (10) has a sensor surface (22) exposed to fluid (14), and a permanent magnet (24) that produces a magnetic field in an area of the sensor surface. A detector detects ferromagnetic particles (12) in the area of the sensor surface. An induction coil (30) induces magnetic fields aligned against a magnetic field of the magnet. A condenser i.e. double-layered condenser, is discharged over the coil, where maximum magnetic field induced by the discharge of the condenser over the coil is stronger than the magnetic field of the magnet. The detector is selected from a group consisting of a ferrous-resonance detector, an interdigital condenser, a hall detector, resistive detector and an optical detector. An independent claim is also included for a method for operating a sensor device.