Position sensor
Encyclopedia
A position sensor
Sensor
A sensor is a device that measures a physical quantity and converts it into a signal which can be read by an observer or by an instrument. For example, a mercury-in-glass thermometer converts the measured temperature into expansion and contraction of a liquid which can be read on a calibrated...

 is any device that permits position measurement. It can either be an absolute position sensor or a relative one (displacement sensor). Position sensors can be either linear or angular.

Some position sensors available today:-
  • Inductive Non-Contact Position Sensors
    Inductive sensor
    An inductive sensor is an electronic proximity sensor, which detects metallic objects without touching them.The sensor consists of an induction loop. Electric current generates a magnetic field, which collapses generating a current that falls asymptotically toward zero from its initial level when...

  • String Potentiometer
    String potentiometer
    A string potentiometer is a transducer used to detect and measure linear position and velocity using a flexible cable and spring-loaded spool. Other common names include "string pot", "cable-extension transducer", "draw wire sensor", and "yo-yo sensor"....

     (aka String Pot)
  • Linear variable differential transformer
    Linear variable differential transformer
    The Linear Variable Differential Transformer is a type of electrical transformer used for measuring linear displacement. A counterpart to this device that is used for measuring rotary displacement is called a Rotary Variable Differential Transformer...

     (LVDT)
  • Potentiometer
    Potentiometer
    A potentiometer , informally, a pot, is a three-terminal resistor with a sliding contact that forms an adjustable voltage divider. If only two terminals are used , it acts as a variable resistor or rheostat. Potentiometers are commonly used to control electrical devices such as volume controls on...

  • Capacitive transducer
  • Eddy-current sensor
  • Hall effect sensor
    Hall effect sensor
    A Hall effect sensor is a transducer that varies its output voltage in response to a magnetic field. Hall effect sensors are used for proximity switching, positioning, speed detection, and current sensing applications....

  • Proximity sensor
    Proximity sensor
    A proximity sensor is a sensor able to detect the presence of nearby objects without any physical contact.A proximity sensor often emits an electromagnetic or a beam of electromagnetic radiation , and looks for changes in the field or return signal. The object being sensed is often referred to as...

     (optical)
  • Grating sensor
  • Rotary encoder
    Rotary encoder
    A rotary encoder, also called a shaft encoder, is an electro-mechanical device that converts the angular position or motion of a shaft or axle to an analog or digital code. The output of incremental encoders provides information about the motion of the shaft which is typically further processed...

     (angular)
  • Seismic displacement pick-up
  • Piezo-electric transducer(Piezo-electric)
  • Photodiode array

Literature

  • David S. Nyce: Linear Position Sensors: Theory and Application, New Jersey, John Wiley & Sons Inc. (2003)

Lion Precision: Capacitive Sensor Operation
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