Angular and Linear Position Sensors
Angular and linear position sensors are electronic devices used to simultaneously measure both angular and linear position changes relative to a reference position. The most common technologies used are Hall effect, inductive, magneto-resistive and resistive. Other technologies exist to measure either angle or linear position. Rotation position can be sensed using devices like: mechanical encoders, optical encoders, synchros and resolvers. Linear position can be measured using devices like: linear variable differential transformers (LVDT) and linear potentiometers.
Magneto resistive sensors are devices that detect linear, angular or rotational displacement in a saturated magnetic field. They comprise of one or more saturated mode four element Wheatstone bridge sense elements that output a voltage related to the direction of magnetic flux that is passing over the sensor. Multiple bridge elements provide extended range for angular measurement. They are highly accurate, able to resolve position better than fractions of mms and degrees, handle large variations in the distance between magnet to sensor and insensitive to vibration and shock. Devices may only work over a partial unit circle.
Hall effect sensors used in angular and position sensing are also designed to operate in relation to a magnetic field. They are sensitive to flux density applied parallel and orthogonal to the surface of the device. This makes them able to sense three components of flux density (Bx, By, Bz) and also allows them to sense the position and orientation of any moving magnet. They can detect a full 360o rotation or linear displacement in a single dimension. They usually have an inbuilt microprocessor to calculate these based upon the Hall sensor outputs. Read more Read less