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Sensors and Transducers

·124 words·1 min·
Stefano
Author
Stefano

Sensors and Transducers
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Sensors detect physical quantities. Transducers convert one energy form to another (typically physical quantity → electrical signal).

By Measured Quantity
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Quantity Common Sensors
Temperature Thermocouple, RTD (PT100), Thermistor (NTC/PTC)
Pressure Strain gauge, piezoelectric
Position Potentiometer, encoder, LVDT
Light LDR, photodiode, phototransistor
Proximity Inductive, capacitive, ultrasonic, infrared

Key Characteristics
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Sensitivity, linearity, accuracy, precision, response time, range.

Temperature Sensors
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  • Thermocouple: two metals, wide range (-200 to +2000°C), cheap but less precise
  • RTD (PT100): platinum resistance, very precise (-200 to +850°C)
  • NTC thermistor: resistance decreases with temperature, high sensitivity

Proximity Sensors
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  • Inductive: detects metals only (electromagnetic field)
  • Capacitive: detects any material (electric field)
  • Ultrasonic: emits sound waves, measures echo time

Applications
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Industrial automation, automotive, smart homes, smartphones, medicine.