Classification of Transducers

  

1. Passive Transducer:  No generation of voltage

Eg. , Strain Gauge, RTD  (Resistance Temperature Detector),  Resistance Hygrometer, Thermistor,  Piezoelectric Transducer, etc. 

2. Active Transducer: Generation of voltage/current

E.g.  Thermocouple, Piezoelectric Transducer, Photo-volatile Cell, Tachogenerator 

3. Analog Transducer 

E.g., Strain Gauge, LVDT, Thermocouple, Thermistor

4. Digital Transducer

E.g., Turbine meter used in for flow measurement


5. Transducer (converts a non-electrical quantity into an electrical quantity)

Eg. LVDT (mechanical displacement to electrical), Thermocouple (Temp to voltage)

6. Inverse Transducer (an electrical quantity into a non-electrical quantity)

E.g., Piezoelectric crystals 

7. Primary and secondary Transducer 

E.g. For pressure measurement, a bourden tube is used, which is used to convert pressure to displacement. After, LVDT is used to convert displacement to electrical energy. Here, bourden tube is primary transducer and LVDT is a secondary transducer. 

8. Resistance Transducer (Change in resistance as some quanity changes)

E.g., Potentiometer device, Strain Gauge, Pirani Gauge, RTD, Thermistor, Resistance Hydrometer

9. Inductive Transducer 

E.g., LVDT, Touchpad, Proximity sensor 

10. Capacitance Transducer 

E.g. Microphone (Not all types), Touchpad