# Resistance based electrical transducers

**URL:** <https://forumautomation.com/t/resistance-based-electrical-transducers/4932>\
**Category:** Field Instrumentation\
**Tags:** displacement, force, gas-flow, resistance, pressure\
**Created:** [October 15, 2018, 12:24am UTC](https://forumautomation.com/t/resistance-based-electrical-transducers/4932 "2018-10-15T00:24:58Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![divyasree](https://forumautomation.com/letter_avatar_proxy/v4/letter/d/edb3f5/32.png) [@divyasree](https://forumautomation.com/u/divyasree)\
**Post date:** [October 15, 2018, 12:24am UTC](https://forumautomation.com/t/resistance-based-electrical-transducers/4932/1 "2018-10-15T00:24:58Z")

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**Potentiometer device**

Principle of operation - Movement of a slider ( by external force acting on it) causes the resistance to change in the potentiometer and subsequently the bridge circuit Application - Pressure, Displacement

**Resistance Strain gauge** Principle of operation - Expansion or compression of the wire alters the resistance of the element, Application - Force, torque, displacement

**Pirani gauge or hot wire meter** Principle of operation - Temperature changes have effect on the resistance of the material, So when a cool gas passes through a normally heated wire, the resistance changes. Application - Gas flow, Gas pressure

**Resistance Thermometer** Principle of operation - Temperature coefficient is the phenomenon where a change in temperature effects the resistance, metals have positive temperature co efficient where in the rise in temperature leads to rise in resistance Application - Temperature,Radiant heat

**Thermistor** Principle of operation - Working with the temperature coefficient phenomenon, metal oxides have negative temperature coefficient, where temperature increase leads to decrease in resistance Application - Temperature, flow

**Resistance hygrometer** Principle of operation - Moisture content alters the resistance of the conductive strip Application - Relative humidity

**Photoconductive cell** Principle of operation - The resistance of the element changes with incident light. Application - Photosensitive relay