Transducer - Definition and Overview

A transducer is a device that converts one type of energy to another, or responds to a physical parameter. A transducer is in its fundamental form a passive component. If the component is electrical then it generally has two electrical terminals.

See also electronics, gear, sensor

List of transducers

• Electrochemical:
  • battery
  • fuel cell
  • pH probe
  • Rechargeable battery
• Electromechanical:
  • actuator
  • circuit breaker
  • dynamo
  • galvanometer
  • MEMS
  • motor, linear motor
  • servomechanism
  • switch
  • piezoelectric
  • quartz
  • relay
  • strain gauge used in weight/force measuring.
• Electroacoustic:
  • gramophone pick-up
  • hydrophone - converts changes in water pressure into an electrical form
  • loudspeaker, earphone - converts changes in electrical signals into acoustic form
  • microphone - converts changes in air pressure into an electrical signal
  • piezoelectric crystal - converts pressure changes into electrical form
• Photoelectric:
  • Laser diode, light-emitting diode - convert electrical power into forms of light
  • photodiode, phototransistor - converts changing light levels into electrical form
  • solar cell - converts light energy into electrical energy
• Electromagnetic:
  • antenna (electronics) - converts airborne RF signals into electrical form
  • cathode ray tube (CRT) - converts electrical signals into visual form
  • fluorescent lamp, light bulb - converts electrical power into visible light
  • magnetic cartridge - converts motion into electrical form
  • photocell or light-dependent resistor (LDR) - converts changes in light levels into resistance changes
  • reed switch - converts a strong magnetic field into a switch activation
  • tape head - converts changing magnetic fields into electrical form
• Magnetic:
  • Hall effect sensor - converts a magnetic field level into electrical form
• Electrostatic:
  • electrometer
  • liquid crystal display (LCD)
• Thermoelectric:
  • thermocouple
  • Peltier cooler
  • thermistor (includes PTC resistor and NTC resistor)
• Other:
  • Geiger-Müller tube used for measuring radioactivity.
• Electronic. These components change one electrical parameter in response to another. By some definitions these are electronic components, not transducers.
  • diode
  • gyrator
  • varicap diode, varactor diode, tuning diode
  • negative impedance converter, NIC
  • Schottky diode
  • transistor, Field effect transistor (FET)
  • Transorb
  • tunneling diode
  • varistor
  • voltage-dependent resistor
  • Zener diode
• Electrical. These components change one electrical parameter in response to another. By some definitions these are passive electronic components, not transducers.
  • capacitor
  • inductor
  • transformer
  • resistor
• Mechanical.
  • gear

Sources/references

The Danish Wikipedia (http://da.wikipedia.org/wiki/Transducer)

External links

• whatis: transducer (http://whatis.techtarget.com/definition/0,,sid9_gci213215,00.html)
• Federal Standard 1037C, August 7, 1996: transducer (http://www.its.bldrdoc.gov/fs-1037/dir-037/_5539.htm)
• American National Standard for Telecommunications - Telecom Glossary 2000: transducer (http://www.atis.org/tg2k/_transducer.html)