Resistance based electrical transducers



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

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

Resistance Thermometer (RTD), types, materials and characteristics and calibration