(Redirected from Transducers)
A 'transducer' is a device, usually
electrical,
electronic,
electro-mechanical,
electromagnetic,
photonic, or
photovoltaic that converts one type of
energy to another for various purposes including measurement or information transfer (for example,
pressure sensors). In a broader sense (for example in the
Viable System Model) a transducer is sometimes defined as any device that converts a signal from one form to another. A very common device is an audio speaker, which converts electrical voltage variations representing music or speech, to mechanical cone vibration. The speaker cone in turn vibrates air molecules creating acoustical energy.
Types of transducers
This list is confined to the narrower definition of the term.
★ Electromagnetic:
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Antenna - converts electromagnetic waves into electric current and vice versa.
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Cathode ray tube (CRT) - converts electrical signals into visual form
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Fluorescent lamp,
light bulb - converts electrical power into visible light
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Magnetic cartridge - converts motion into electrical form
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Photocell or
light-dependent resistor (LDR) - converts changes in light levels into resistance changes
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Tape head - converts changing magnetic fields into electrical form
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Hall effect sensor - converts a magnetic field level into electrical form
★ Electrochemical:
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pH probe
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Electro-galvanic fuel cell
★ Electromechanical (electromechanical output devices are generically called
actuators):
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Electroactive polymers
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Galvanometer
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MEMS
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Rotary motor,
linear motor
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Vibration powered generator
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Potentiometer when used for measuring position
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Load cell converts force to mV/V electrical signal using
strain gauges
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Accelerometer
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Strain gauge
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Switch
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String Potentiometer
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Air flow sensor
★ Electroacoustic:
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Geophone - converts ground movement (displacement) into voltage
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Gramophone pick-up
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Hydrophone - converts changes in water pressure into an electrical form
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Loudspeaker,
earphone - converts changes in electrical signals into acoustic form
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Microphone - converts changes in air pressure into an electrical signal
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Piezoelectric crystal - converts pressure changes into electrical form
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Tactile transducer
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Photoelectric:
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Laser diode,
light-emitting diode - convert electrical power into forms of light
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Photodiode,
photoresistor,
phototransistor,
photomultiplier tube - converts changing light levels into electrical form
★ Electrostatic:
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Electrometer
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Liquid crystal display (LCD)
★ Thermoelectric:
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RTD Resistance Temperature Detector
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Thermocouple
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Peltier cooler
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Thermistor (includes PTC resistor and NTC resistor)
★ Radioacoustic:
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Geiger-Müller tube used for measuring radioactivity.
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Receiver (radio)
See also
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Finite state transducer
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Ultrasonic transducer
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Signal transduction
Reference
★ J. Allocca and A. Stuart, ''Transducers: Theory and Application'', Reston 1984.
External links
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What are Transducers?
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whatis: transducer
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Federal Standard 1037C, August 7, 1996: transducer
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American National Standard for Telecommunications - Telecom Glossary 2000: transducer