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Transducer

A transducer is a device that converts one type ofenergy to another. The conversion canbe to/from electrical,electro-mechanical,electromagnetic,photonic,photovoltaic, or any

other form of energy. While the termtransducer

commonly implies use as asensor/detector, any device which converts energy can be considered a transducer.

Types

Transducers may be categorized by application:sensor,actuator, or combination.

A sensor is used to detect a parameter in one form and report it in another form of energy

(usually an electrical and/or digital signal). For example, apressure sensormight detect

pressure (a mechanical form of energy) and convert it to electricity for display at aremote gauge.

An actuator accepts energy and produces movement (action). The energy supplied to an

actuator might be electrical or mechanical (pneumatic,hydraulic, etc.). Anelectric motor

and a loudspeakerare both transducers, converting electrical energy into motion fordifferent purposes.

Combination transducers have both functions; they both detect and create action. For

example, a typicalultrasonic transducerswitches back and forth many times a second

between acting as an actuator to produce ultrasonic waves, and acting as a sensor todetect ultrasonic waves.

Applications

Electromagnetic:

o Antenna - converts electromagnetic waves into electric current and vice

versa

o Cathode ray tube (CRT) - converts electrical signals into visual form

o Fluorescent lamp, light bulb - converts electrical power into visible light

o Magnetic cartridge - converts motion into electrical form

o Photodetectororphotoresistoror light dependent resistor (LDR) - converts

changes in light levels into resistance changes

o Tape head - converts changing magnetic fields into electrical formo Hall effect sensor- converts a magnetic field level into electrical form

only

Electrochemical:

o pH probes

o Electro-galvanic fuel cell

o Hydrogen sensor

http://en.wikipedia.org/wiki/Energyhttp://en.wikipedia.org/wiki/Electricityhttp://en.wikipedia.org/wiki/Electricityhttp://en.wikipedia.org/wiki/Electro-mechanicalhttp://en.wikipedia.org/wiki/Electromagnetismhttp://en.wikipedia.org/wiki/Electromagnetismhttp://en.wikipedia.org/wiki/Electromagnetismhttp://en.wikipedia.org/wiki/Photonichttp://en.wikipedia.org/wiki/Photonichttp://en.wikipedia.org/wiki/Photovoltaichttp://en.wikipedia.org/wiki/Photovoltaichttp://en.wikipedia.org/wiki/Sensorhttp://en.wikipedia.org/wiki/Sensorhttp://en.wikipedia.org/wiki/Sensorhttp://en.wikipedia.org/wiki/Actuatorhttp://en.wikipedia.org/wiki/Pressure_sensorhttp://en.wikipedia.org/wiki/Pressure_sensorhttp://en.wikipedia.org/wiki/Pressure_sensorhttp://en.wikipedia.org/wiki/Pressurehttp://en.wikipedia.org/wiki/Gaugehttp://en.wikipedia.org/wiki/Pneumatichttp://en.wikipedia.org/wiki/Hydraulichttp://en.wikipedia.org/wiki/Hydraulichttp://en.wikipedia.org/wiki/Electric_motorhttp://en.wikipedia.org/wiki/Electric_motorhttp://en.wikipedia.org/wiki/Loudspeakerhttp://en.wikipedia.org/wiki/Ultrasonic_transducerhttp://en.wikipedia.org/wiki/Ultrasonic_transducerhttp://en.wikipedia.org/wiki/Antenna_(radio)http://en.wikipedia.org/wiki/Cathode_ray_tubehttp://en.wikipedia.org/wiki/Fluorescent_lamphttp://en.wikipedia.org/wiki/Light_bulbhttp://en.wikipedia.org/wiki/Magnetic_cartridgehttp://en.wikipedia.org/wiki/Photodetectorhttp://en.wikipedia.org/wiki/Photoresistorhttp://en.wikipedia.org/wiki/Photoresistorhttp://en.wikipedia.org/wiki/Tape_headhttp://en.wikipedia.org/wiki/Hall_effect_sensorhttp://en.wikipedia.org/wiki/PH_meterhttp://en.wikipedia.org/wiki/Electro-galvanic_fuel_cellhttp://en.wikipedia.org/wiki/Hydrogen_sensorhttp://en.wikipedia.org/wiki/Energyhttp://en.wikipedia.org/wiki/Electricityhttp://en.wikipedia.org/wiki/Electro-mechanicalhttp://en.wikipedia.org/wiki/Electromagnetismhttp://en.wikipedia.org/wiki/Photonichttp://en.wikipedia.org/wiki/Photovoltaichttp://en.wikipedia.org/wiki/Sensorhttp://en.wikipedia.org/wiki/Actuatorhttp://en.wikipedia.org/wiki/Pressure_sensorhttp://en.wikipedia.org/wiki/Pressurehttp://en.wikipedia.org/wiki/Gaugehttp://en.wikipedia.org/wiki/Pneumatichttp://en.wikipedia.org/wiki/Hydraulichttp://en.wikipedia.org/wiki/Electric_motorhttp://en.wikipedia.org/wiki/Loudspeakerhttp://en.wikipedia.org/wiki/Ultrasonic_transducerhttp://en.wikipedia.org/wiki/Antenna_(radio)http://en.wikipedia.org/wiki/Cathode_ray_tubehttp://en.wikipedia.org/wiki/Fluorescent_lamphttp://en.wikipedia.org/wiki/Light_bulbhttp://en.wikipedia.org/wiki/Magnetic_cartridgehttp://en.wikipedia.org/wiki/Photodetectorhttp://en.wikipedia.org/wiki/Photoresistorhttp://en.wikipedia.org/wiki/Tape_headhttp://en.wikipedia.org/wiki/Hall_effect_sensorhttp://en.wikipedia.org/wiki/PH_meterhttp://en.wikipedia.org/wiki/Electro-galvanic_fuel_cellhttp://en.wikipedia.org/wiki/Hydrogen_sensor

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Electromechanical (electromechanical output devices are generically called

actuators):

o Electroactive polymers

o Galvanometer

o Microelectromechanical systems

o Rotary motor,linear motoro Vibration powered generator

o Potentiometerwhen used for measuring position

o Load cell - converts force to mV/V electrical signal using strain gauge

o Accelerometer

o Strain gauge

o String potentiometer

o Air flow sensor

o Tactile sensor

Electroacoustic:

o Loudspeaker, earphone - converts electrical signals into sound (amplifiedsignal magnetic field motion air pressure)

o Microphone - converts sound into an electrical signal (air pressure

motion of conductor/coil magnetic field signal)

o Pickup (music technology) - converts motion of metal strings into an

electrical signal (magnetism electricity (signal))o Tactile transducer- converts solid-state vibrations into electrical signal

(vibration ? signal)

o Piezoelectric crystal - converts solid-state electrical modulations into an

electrical signal (vibration electrical current signal)

o Geophone - converts a ground movement (displacement) into voltage

(vibrations motion of conductor/coil magnetic field signal)o Gramophone pickup - (air pressure motion magnetic field signal)

o Hydrophone - converts changes in water pressure into an electrical form

o Sonar transponder(water pressure motionof conductor/coil

magnetic field signal)

Photoelectric:

o Laser diode,light-emitting diode - converts electrical power into forms of

light

o Photodiode,photoresistor,phototransistor,photomultipliertube - converts

changing light levels into electrical form

Electrostatic:o Electrometer

Thermoelectric:

o Resistance temperature detector(RTD)

o Thermocouple

o Thermistor(includes PTC resistor and NTC resistor)

http://en.wikipedia.org/wiki/Actuatorhttp://en.wikipedia.org/wiki/Electroactive_polymershttp://en.wikipedia.org/wiki/Galvanometerhttp://en.wikipedia.org/wiki/Microelectromechanical_systemshttp://en.wikipedia.org/wiki/Electric_motorhttp://en.wikipedia.org/wiki/Linear_motorhttp://en.wikipedia.org/wiki/Linear_motorhttp://en.wikipedia.org/wiki/Vibration_powered_generatorhttp://en.wikipedia.org/wiki/Potentiometerhttp://en.wikipedia.org/wiki/Load_cellhttp://en.wikipedia.org/wiki/Strain_gaugehttp://en.wikipedia.org/wiki/Accelerometerhttp://en.wikipedia.org/wiki/Strain_gaugehttp://en.wikipedia.org/wiki/String_potentiometerhttp://en.wikipedia.org/wiki/Mass_flow_sensorhttp://en.wikipedia.org/wiki/Tactile_sensorhttp://en.wikipedia.org/wiki/Loudspeakerhttp://en.wikipedia.org/wiki/Earphonehttp://en.wikipedia.org/wiki/Amplifierhttp://en.wikipedia.org/wiki/Magnetic_fieldhttp://en.wikipedia.org/wiki/Motion_(physics)http://en.wikipedia.org/wiki/Motion_(physics)http://en.wikipedia.org/wiki/Microphonehttp://en.wikipedia.org/wiki/Motion_(physics)http://en.wikipedia.org/wiki/Magnetic_fieldhttp://en.wikipedia.org/wiki/Magnetic_fieldhttp://en.wikipedia.org/wiki/Pickup_(music_technology)http://en.wikipedia.org/wiki/Magnetismhttp://en.wikipedia.org/wiki/Magnetismhttp://en.wikipedia.org/wiki/Tactile_transducerhttp://en.wikipedia.org/wiki/Piezoelectricityhttp://en.wikipedia.org/wiki/Geophonehttp://en.wikipedia.org/wiki/Magnetic_fieldhttp://en.wikipedia.org/wiki/Magnetic_fieldhttp://en.wikipedia.org/wiki/Phonographhttp://en.wikipedia.org/wiki/Motion_(physics)http://en.wikipedia.org/wiki/Magnetic_fieldhttp://en.wikipedia.org/wiki/Hydrophonehttp://en.wikipedia.org/wiki/Sonar#Transponderhttp://en.wikipedia.org/wiki/Motion_(physics)http://en.wikipedia.org/wiki/Motion_(physics)http://en.wikipedia.org/wiki/Magnetic_fieldhttp://en.wikipedia.org/wiki/Photoelectric_effecthttp://en.wikipedia.org/wiki/Laser_diodehttp://en.wikipedia.org/wiki/Laser_diodehttp://en.wikipedia.org/wiki/Light-emitting_diodehttp://en.wikipedia.org/wiki/Photodiodehttp://en.wikipedia.org/wiki/Photoresistorhttp://en.wikipedia.org/wiki/Photoresistorhttp://en.wikipedia.org/wiki/Phototransistorhttp://en.wikipedia.org/wiki/Phototransistorhttp://en.wikipedia.org/wiki/Photomultiplierhttp://en.wikipedia.org/wiki/Electrometerhttp://en.wikipedia.org/wiki/Resistance_temperature_detectorhttp://en.wikipedia.org/wiki/Thermocouplehttp://en.wikipedia.org/wiki/Thermistorhttp://en.wikipedia.org/wiki/Actuatorhttp://en.wikipedia.org/wiki/Electroactive_polymershttp://en.wikipedia.org/wiki/Galvanometerhttp://en.wikipedia.org/wiki/Microelectromechanical_systemshttp://en.wikipedia.org/wiki/Electric_motorhttp://en.wikipedia.org/wiki/Linear_motorhttp://en.wikipedia.org/wiki/Vibration_powered_generatorhttp://en.wikipedia.org/wiki/Potentiometerhttp://en.wikipedia.org/wiki/Load_cellhttp://en.wikipedia.org/wiki/Strain_gaugehttp://en.wikipedia.org/wiki/Accelerometerhttp://en.wikipedia.org/wiki/Strain_gaugehttp://en.wikipedia.org/wiki/String_potentiometerhttp://en.wikipedia.org/wiki/Mass_flow_sensorhttp://en.wikipedia.org/wiki/Tactile_sensorhttp://en.wikipedia.org/wiki/Loudspeakerhttp://en.wikipedia.org/wiki/Earphonehttp://en.wikipedia.org/wiki/Amplifierhttp://en.wikipedia.org/wiki/Magnetic_fieldhttp://en.wikipedia.org/wiki/Motion_(physics)http://en.wikipedia.org/wiki/Microphonehttp://en.wikipedia.org/wiki/Motion_(physics)http://en.wikipedia.org/wiki/Magnetic_fieldhttp://en.wikipedia.org/wiki/Pickup_(music_technology)http://en.wikipedia.org/wiki/Magnetismhttp://en.wikipedia.org/wiki/Tactile_transducerhttp://en.wikipedia.org/wiki/Piezoelectricityhttp://en.wikipedia.org/wiki/Geophonehttp://en.wikipedia.org/wiki/Magnetic_fieldhttp://en.wikipedia.org/wiki/Phonographhttp://en.wikipedia.org/wiki/Motion_(physics)http://en.wikipedia.org/wiki/Magnetic_fieldhttp://en.wikipedia.org/wiki/Hydrophonehttp://en.wikipedia.org/wiki/Sonar#Transponderhttp://en.wikipedia.org/wiki/Motion_(physics)http://en.wikipedia.org/wiki/Magnetic_fieldhttp://en.wikipedia.org/wiki/Photoelectric_effecthttp://en.wikipedia.org/wiki/Laser_diodehttp://en.wikipedia.org/wiki/Light-emitting_diodehttp://en.wikipedia.org/wiki/Photodiodehttp://en.wikipedia.org/wiki/Photoresistorhttp://en.wikipedia.org/wiki/Phototransistorhttp://en.wikipedia.org/wiki/Photomultiplierhttp://en.wikipedia.org/wiki/Electrometerhttp://en.wikipedia.org/wiki/Resistance_temperature_detectorhttp://en.wikipedia.org/wiki/Thermocouplehttp://en.wikipedia.org/wiki/Thermistor

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