A transducer is a device, usually electrical, electronic, electro-mechanical, electromagnetic, photonic, or photovoltaic that converts one type of energy or physical attribute to another for various purposes including measurement or information transfer (for example, pressure sensors). Electronics refers to the flow of charge (moving Electrons through Nonmetal conductors (mainly Semiconductors, whereas electrical In Engineering, electromechanics combines the Sciences of Electromagnetism of Electrical engineering and mechanics. Electromagnetism is the Physics of the Electromagnetic field: a field which exerts a Force on particles that possess the property of Photonics is the science of generating controlling and detecting Photons particularly in the visible and near Infra-red spectrum, but Photovoltaics ( PV) is the field of technology and research related to the application of Solar cells for Energy by converting Sunlight directly In Physics and other Sciences energy (from the Greek grc ἐνέργεια - Energeia, "activity operation" from grc ἐνεργός A pressure sensor measures the Pressure, typically of Gases or Liquids.

The term transducer is commonly used in two senses; the sensor, used to detect a parameter in one form and report it in another (usually an electrical or digital signal), and the audio loudspeaker, which converts electrical voltage variations representing music or speech, to mechanical cone vibration and hence vibrates air molecules creating acoustical energy. A sensor is a device that measures a physical quantity and converts it into a signal which can be read by an observer or by an instrument

Types of transducers

This list is confined to the narrower definition of the term.

• Electromagnetic:
  • Antenna - converts electromagnetic waves into electric current and vice versa. An antenna is a Transducer designed to transmit or Receive electromagnetic waves In other words antennas convert electromagnetic waves into
  • 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
  • Photodetector or Photoresistor (LDR) - converts changes in light levels into resistance changes
  • Tape head - converts changing magnetic fields into electrical form
  • Hall effect sensor - converts a magnetic field level into electrical form only. The cathode ray tube (CRT is a Vacuum tube containing an Electron gun (a source of electrons and a Fluorescent screen with internal or A fluorescent lamp or fluorescent tube is a Gas-discharge lamp that uses Electricity to excite mercury Vapor. The incandescent light bulb, incandescent lamp or incandescent light globe is a source of electric Light that works by Incandescence, (a general A magnetic cartridge is a Transducer used for the playback of Gramophone records on a turntable or phonograph. Photosensors or photodetectors are Sensors of Light or other Electromagnetic energy A photoresistor or Light Dependent Resistor or CdS Cell is a Resistor whose resistance decreases with increasing incident light intensity A tape head is a type of Transducer used in Tape recorders to convert electrical signals to magnetic fluctuations and vice versa A Hall effect sensor is a Transducer that varies its output Voltage in response to changes in Magnetic field.
• Electrochemical:
  • pH probes
  • Electro-galvanic fuel cell
• Electromechanical (electromechanical output devices are generically called actuators):
  • Electroactive polymers
  • Galvanometer
  • MEMS
  • Rotary motor, linear motor
  • Vibration powered generator
  • Potentiometer when used for measuring position
  • Load cell converts force to mV/V electrical signal using strain gauge
  • Accelerometer
  • Strain gauge
  • String Potentiometer
  • Air flow sensor
• Electroacoustic:
  • Geophone - convert a ground movement (displacement) into voltage
  • 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
  • Tactile transducer
• Photoelectric:
  • Laser diode, light-emitting diode - convert electrical power into forms of light
  • Photodiode, photoresistor, phototransistor, photomultiplier tube - converts changing light levels into electrical form
• Electrostatic:
  • Electrometer
• Thermoelectric:
  • RTD Resistance Temperature Detector
  • Thermocouple
  • Peltier cooler
  • Thermistor (includes PTC resistor and NTC resistor)
• Radioacoustic:
  • Geiger-Müller tube used for measuring radioactivity. A pH meter is an electronic instrument used to measure the PH ( Acidity or alkalinity) of a liquid (though special probes are sometimes used to measure An electro-galvanic fuel cell is an electrical device used to measure the concentration of Oxygen gas in Scuba diving and Medical equipment An actuator is a mechanical device for moving or controlling a mechanism or system Electroactive Polymers or EAPs are Polymers whose shape is modified when a Voltage is applied to them A galvanometer is a type of Ammeter; an instrument for detecting and measuring Electric current. Microelectromechanical systems ( MEMS) is the technology of the very small and merges at the nano-scale into Nanoelectromechanical systems (NEMS and Nanotechnology An electric motor uses Electrical energy to produce Mechanical energy. A linear motor or linear induction motor is essentially a multi-phase Alternating current (AC Electric motor that has had its Stator "unrolled" Vibration powered generator s are mechanisms for converting kinetic energy derived from ambient vibration to electrical energy A potentiometer is a three-terminal Resistor with a sliding contact that forms an adjustable Voltage divider. A load cell is an electronic device ( Transducer) that is used to convert a force into an electrical signal A strain gauge (alternatively strain gage) is a device used to measure the strain of an object An accelerometer is a device for measuring Acceleration and gravity induced reaction forces A strain gauge (alternatively strain gage) is a device used to measure the strain of an object A string potentiometer is a Transducer used to detect and measure linear position and velocity using a flexible cable and spring-loaded spool The term geophone derives from the Greek word "geo" meaning " earth " and "phone" meaning "sound" The phonograph, or gramophone, was the most common device for playing recorded Sound from the 1870s through the 1980s A hydrophone (Greek "hydro" = "water" and "phone" = "sound" is a Microphone designed to be used underwater for recording or listening For the Marty Friedman album see Loudspeaker (album A loudspeaker, speaker, or speaker system is an electroacoustical Headphones (also known as earphones, earbuds, stereophones, headsets) are a pair of small Loudspeakers or less commonly a single Piezoelectricity is the ability of some materials (notably Crystals and certain Ceramics including bone to generate an Electric potential in response to A tactile transducer or "bass shaker" is a device which is made on the principle that low bass frequencies can be felt as well as heard Introduction When a Metallic surface is exposed to Electromagnetic radiation above a certain threshold Frequency, the light is absorbed and Electrons A laser diode is a Laser where the active medium is a Semiconductor similar to that found in a Light-emitting diode. A photodiode is a type of Photodetector capable of converting Light into either current or Voltage, depending upon the mode of operation A photoresistor or Light Dependent Resistor or CdS Cell is a Resistor whose resistance decreases with increasing incident light intensity A photodiode is a type of Photodetector capable of converting Light into either current or Voltage, depending upon the mode of operation Photomultiplier tubes ( photomultipliers or PMT s for short members of the class of Vacuum tubes and more specifically Phototubes are extremely An electrometer is an electrical instrument for measuring Electric charge or electrical Potential difference. Resistance thermometers, also called resistance temperature detectors ( RTD s are Temperature Sensors that exploit the predictable change in In Electrical engineering and industry thermocouples are a widely used type of temperature sensor and can also be used as a means to convert thermal Potential Thermoelectric cooling uses the Peltier effect to create a Heat flux between the junction of two different types of materials A thermistor is a type of Resistor with resistance varying according to its Temperature. A Geiger-Müller tube (or GM tube) is the sensing element of a Geiger counter instrument that can detect a single particle of Ionizing radiation, and typically
  • Receiver (radio)

References

• J. This article is about a radio receiver for other uses see Radio (disambiguation. Allocca and A. Stuart, Transducers: Theory and Application, Reston 1984.

External links

• What are Transducers?
• whatis: transducer
• Federal Standard 1037C, August 7, 1996: transducer
• American National Standard for Telecommunications - Telecom Glossary 2000: transducer