Magnetic sensors detect changes and disturbances in a magnetic field like flux, strength and direction. Other types of detection sensors work with characteristics like temperature, pressure, light. From established knowledge about the existing magnetic field and the data collected from sensors regarding changes and alterations, many things can be known. Rotation, angles, direction, presence and electrical current can all be monitored. Magnetic sensors are divided into two groups, those that measure the complete magnetic field and those that measure vector components of the field. The vector components are the individual points of the magnetic field. The techniques used to create these sensors involve various combinations of physics and electronics. ref
Different Types of Sensors
Passive Speed Sensors
Analog Variable ReIuctance (VR) Geartooth Sensors Passive Sensors generate a sine; wave output with; no external power source. Voltage is determined by target speed and air gap.