Transducer - wikipedia Transducer This article is about an engineering device. For the similarly named concept in computer science, see Finite state transducer. A transducer is a device that converts energy from one form to another. Usually a transducer converts a signal in one form of energy to a signal in another. Transducers are often employed at the boundaries of automation, measurement, and control systems, where electrical signals are converted to and from other physical quantities ( energy, force, torque, light, motion, position, etc. ). The process of converting one form of energy to another is known as transduction. Contents 1 Transducer types 1.1 Mechanical and electrical transducers 1.2 Sensors and actuators 1.3 Passive vs active sensors 2 Characteristics 3 Applications 4 See also 5 References 6 External links Transducer types Mechanical and electrical transducers Transducers that convert physical quantities into mechanical ones are called mechanical transducers ; Transducers that convert physical quantities into electrical are called electrical transducers. Examples are a thermocouple that changes temperature differences into a small voltage, or a Linear variable differential transformer ( LVDT ) used to measure displacement. Sensors and actuators Transducers can be categorized by which direction information passes through them : A sensor is a transducer that receives and responds to a signal or stimulus from a physical system. It produces a signal, which represents information about the system, which is used by some type of telemetry, information or control system. An actuator is a device that is responsible for moving or controlling a mechanism or system. It is controlled by a signal from a control system or manual control. It is operated by a source of energy, which can be mechanical force, electrical current, hydraulic fluid pressure, or pneumatic pressure, and converts that energy into motion. An actuator is the mechanism by which a control system acts upon an environment. The control system can be simple ( a fixed mechanical or electronic system ), software - based ( e.g. a printer driver, robot control system ), a human, or any other input. Bidirectional transducers convert physical phenomena to electrical signals and also convert electrical signals into physical phenomena. An example of an inherently bidirectional transducer is an antenna, which can convert radio waves ( electromagnetic waves ) into an electrical signal to be processed by a radio receiver, or translate an electrical signal from a transmitter into radio waves. Another example is voice coils, which are used in loudspeakers to translate an electrical audio signal into sound and in dynamic microphones to translate sound waves into an audio signal. Passive vs active sensors Passive sensors require an external power source to operate, which is called an excitation signal. The signal is modulated by the sensor to produce an output signal. For example, a thermistor does not generate any electrical signal, but by passing an electric current through it, its resistance can be measured by detecting variations in the current or voltage across the thermistor. Active sensors, in contrast, generate an electric current in response to an external stimulus which serves as the output signal without the need of an additional energy source. Such examples are a photodiode, and a piezoelectric sensor, thermocouple. Characteristics Some specifications that are used to rate transducers Dynamic range : This is the ratio between the largest amplitude signal and the smallest amplitude signal the transducer can effectively translate. Transducers with larger dynamic range are more `` sensitive '' and precise. Repeatability : This is the ability of the transducer to produce an identical output when stimulated by the same input. Noise : All transducers add some random noise to their output. In electrical transducers this may be electrical noise due to thermal motion of charges in circuits. Noise corrupts small signals more than large ones. Hysteresis : This is a property in which the output of the transducer depends on not only its current input but also its past input. For example, an actuator which uses a gear train may have some backlash, which means that if the direction of motion of the actuator reverses, there will be a dead zone before the output of the actuator reverses, caused by play between the gear teeth. Applications Transducers are used in electronic communications systems to convert signals of various physical forms to electronic signals, and vice versa. In this example, the first transducer could be a microphone, and the second transducer could be a speaker. Electromagnetic : Antennae -- converts propagating electromagnetic waves to and from conducted electrical signals magnetic cartridges -- converts relative physical motion to and from electrical signals Tape head, disk read - and - write heads -- converts magnetic fields on a magnetic medium to and from electrical signals Hall effect sensors -- converts a magnetic field level into an electrical signal Electrochemical : pH probes Electro - galvanic oxygen sensors Hydrogen sensors Electromechanical ( electromechanical output devices are generically called actuators ) : Accelerometers Air flow sensors Electroactive polymers Rotary motors, linear motors Galvanometers Linear variable differential transformers or rotary variably differential transformers Load cells -- converts force to mV / V electrical signal using strain gauges Microelectromechanical systems Potentiometers ( when used for measuring position ) Pressure sensors String potentiometers Tactile sensors Vibration powered generators Electroacoustic : Loudspeakers, earphones -- converts electrical signals into sound ( amplified signal → magnetic field → motion → air pressure ) Microphones -- converts sound into an electrical signal ( air pressure → motion of conductor / coil → magnetic field → electrical signal ) Pickup ( music technology ) -- converts motion of metal strings into an electrical signal ( magnetism → electrical signal ) Tactile transducers -- converts electrical signal into vibration ( electrical signal → vibration ) Piezoelectric crystals -- converts deformations of solid - state crystals ( vibrations ) to and from electrical signals Geophones -- converts a ground movement ( displacement ) into voltage ( vibrations → motion of conductor / coil → magnetic field → signal ) Gramophone pickups -- ( air pressure → motion → magnetic field → electrical signal ) Hydrophones -- converts changes in water pressure into an electrical signal Sonar transponders ( water pressure → motion of conductor / coil → magnetic field → electrical signal ) Ultrasonic transceivers, transmitting ultrasound ( transduced from electricity ) as well as receiving it after sound reflection from target objects, availing for imaging of those objects. Electro - optical ( Photoelectric ) : Fluorescent lamps -- converts electrical power into incoherent light Incandescent lamps -- converts electrical power into incoherent light Light - emitting diodes -- converts electrical power into incoherent light Laser diodes -- converts electrical power into coherent light Photodiodes, photoresistors, phototransistors, photomultipliers -- converts changing light levels into electrical signals Photodetector or photoresistor or light dependent resistor ( LDR ) -- converts changes in light levels into changes in electrical resistance Cathode - ray tubes ( CRT ) -- converts electrical signals into visual signals Electrostatic : Electrometers Thermoelectric : Resistance temperature detectors ( RTD ) -- converts temperature into an electrical resistance signal Thermocouples -- converts relative temperatures of metallic junctions to electrical voltage Thermistors ( includes PTC resistor and NTC resistor ) Radioacoustic : Geiger - Müller tubes -- converts incident ionizing radiation to an electrical impulse signal Radio receivers converts electromagnetic transmissions to electrical signals. Radio transmitters converts electrical signals to electromagnetic transmissions. See also Horn analyzer List of sensors Tactile sensor References Agarwal, Anant. Foundations of Analog and Digital Electronic Circuits. Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, 2005, p. 43. Jump up ^ Agarwal, Anant. Foundations of Analog and Digital Electronic Circuits. Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, 2005, p. 43 ^ Jump up to : To cite a book with a credited author Winer, Ethan ( 2013 ). `` Part 3 ''. The Audio Expert. New York and London : Focal Press. ISBN 978 - 0 - 240 - 82100 - 9. Jump up ^ Fraden J. ( 2016 ). Handbook of Modern Sensors : Physics, Designs, and Applications 5th ed. Springer. p. 1 Jump up ^ Kalantar - zadeh, K. ( 2013 ). Sensors : An Introductory Course 2013th Edition. Springer. p. 1 Jump up ^ Fraden J. ( 2016 ). Handbook of Modern Sensors : Physics, Designs, and Applications 5th ed. Springer. p. 7 Jump up ^ Fraden J. ( 2016 ). Handbook of Modern Sensors : Physics, Designs, and Applications 5th ed. Springer. p. 7 External links Introduction to Closed Loop Hall Effect Current Transducers Federal Standard 1037C, August 7, 1996 : transducer A sound transducer with a flat flexible diaphragm working with bending waves Sensors Acoustic, sound, vibration Geophone Hydrophone Microphone Seismometer Automotive, transportation Air -- fuel ratio meter Blind spot monitor Crankshaft position sensor Curb feeler Defect detector Engine coolant temperature sensor Hall effect sensor MAP sensor Mass flow sensor Omniview technology Oxygen sensor Parking sensors Radar gun Speed sensor Speedometer Throttle position sensor Tire - pressure monitoring system Torque sensor Transmission fluid temperature sensor Turbine speed sensor Variable reluctance sensor Vehicle speed sensor Water sensor Wheel speed sensor Chemical Breathalyzer Carbon dioxide sensor Carbon monoxide detector Catalytic bead sensor Chemical field - effect transistor Electrochemical gas sensor Electrolyte -- insulator -- semiconductor sensor Electronic nose Fluorescent chloride sensors Holographic sensor Hydrocarbon dew point analyzer Hydrogen sensor Hydrogen sulfide sensor Infrared point sensor Ion selective electrode Microwave chemistry sensor Nitrogen oxide sensor Nondispersive infrared sensor Olfactometer Optode Oxygen sensor Pellistor pH glass electrode Potentiometric sensor Redox electrode Smoke detector Zinc oxide nanorod sensor Electric, magnetic, radio Current sensor Electroscope Galvanometer Hall effect sensor Hall probe Magnetic anomaly detector Magnetometer MEMS magnetic field sensor Metal detector Planar Hall sensor Radio direction finder Test light Environment, weather, moisture Actinometer Bedwetting alarm Ceilometer Dew warning Electrochemical gas sensor Fish counter Frequency domain sensor Gas detector Hook gauge evaporimeter Humistor Hygrometer Leaf sensor Psychrometer Pyranometer Pyrgeometer Rain gauge Rain sensor SNOTEL Snow gauge Soil moisture sensor Stream gauge Tide gauge Weather radar Flow, fluid velocity Air flow meter Anemometer Flow sensor Gas meter Mass flow sensor Water metering Ionising radiation, subatomic particles Bubble chamber Cloud chamber Geiger -- Müller tube Geiger counter Ionization chamber Neutron detection Particle detector Proportional counter Scintillation counter Semiconductor detector Scintillator Thermoluminescent dosimeter Wire chamber Navigation instruments Airspeed indicator Machmeter Altimeter Attitude indicator Depth gauge Fluxgate compass Gyroscope Inertial navigation system Inertial reference unit Magnetic compass MHD sensor Ring laser gyroscope Turn coordinator Variometer Vibrating structure gyroscope Yaw - rate sensor Position, angle, displacement Accelerometer Angular rate sensor Auxanometer Capacitive displacement sensor Capacitive sensing Gravimeter Inclinometer Integrated circuit piezoelectric sensor Laser rangefinder Laser surface velocimeter Lidar Linear encoder Linear variable differential transformer Liquid capacitive inclinometers Odometer Photoelectric sensor Piezoelectric accelerometer Position sensor Rotary encoder Rotary variable differential transformer Selsyn Sudden Motion Sensor Tachometer Tilt sensor Ultrasonic thickness gauge Variable reluctance sensor Velocity receiver Optical, light, imaging Active pixel sensor Angle -- sensitive pixel Back - illuminated sensor Charge - coupled device Contact image sensor Electro - optical sensor Flame detector Infrared Kinetic inductance detector LED as light sensor Light - addressable potentiometric sensor Nichols radiometer Optical fiber Photodetector Photodiode Photoelectric sensor Photoionization detector Photomultiplier Photoresistor Photoswitch Phototransistor Phototube Position sensitive device Scintillometer Shack -- Hartmann wavefront sensor Single - photon avalanche diode Superconducting nanowire single - photon detector Transition edge sensor Tristimulus colorimeter Visible - light photon counter Wavefront sensor Pressure Barograph Barometer Boost gauge Bourdon gauge Hot - filament ionization gauge Ionization gauge McLeod gauge Oscillating U-tube Permanent Downhole Gauge Piezometer Pirani gauge Pressure gauge Pressure sensor Tactile sensor Time pressure gauge Force, density, level Bhangmeter Force gauge Hydrometer Level sensor Load cell Magnetic level gauge Nuclear density gauge Piezoelectric sensor Strain gauge Torque sensor Viscometer Thermal, heat, temperature Bimetallic strip Bolometer Calorimeter Exhaust gas temperature gauge Flame detection Gardon gauge Golay cell Heat flux sensor Infrared thermometer Microbolometer Microwave radiometer Net radiometer Quartz thermometer Resistance thermometer Silicon bandgap temperature sensor Special sensor microwave / imager Thermistor Thermocouple Thermometer Proximity, presence Alarm sensor Doppler radar Motion detector Occupancy sensor Passive infrared sensor Proximity sensor Reed switch Stud finder Touch switch Triangulation sensor Wired glove Sensor technology Active pixel sensor Back - illuminated sensor Biochip Biosensor Capacitance probe Carbon paste electrode Catadioptric sensor Digital sensors Displacement receiver Electromechanical film Electro - optical sensor Fabry -- Pérot interferometer Fisheries acoustics Image sensor Image sensor format Inductive sensor Intelligent sensor Lab - on - a-chip Leaf sensor Machine vision Microelectromechanical systems Photoelasticity Quantum sensor Radar Ground - penetrating radar Synthetic aperture radar Radar tracker Sensor array Sensor fusion Sensor grid Sensor node Soft sensor Sonar Staring array Transducer Ultrasonic sensor Video sensor technology Visual sensor network Wheatstone bridge Wireless sensor network Related List of sensors NDL : 00573298 Retrieved from `` https://en.wikipedia.org/w/index.php?title=Transducer&oldid=838711819 '' Categories : Transducers Talk Contents About Wikipedia বাংলা Català Dansk Deutsch Eesti Ελληνικά Español Euskara فارسی Français Gaeilge Galego हिन्दी Bahasa Indonesia Italiano עברית Kurdî Bahasa Melayu Nederlands 日本 語 Norsk nynorsk Polski Português Română Русский Српски / srpski Srpskohrvatski / српскохрватски Basa Sunda Svenska தமிழ் ไทย Türkçe Українська اردو 中文 27 more Edit links This page was last edited on 28 April 2018, at 20 : 45. 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Question: non electric signal is converted into electrical signal by
Answer: transduction