What is the difference between sensor and transducer?

Question

plz tell me the diffrence between these two....

Answer 1

Sensor Lowest level of assembly. It only offers mV output and can be used up to 10 feet away from electronics
Transducer Sensor with high-level voltage output with a drive capability up to 30 feet with minimum output signal loss.
Transmitter Sensor with current output, such as 4-20mA; ideal for long transmissions and offers good immunity in noisy environment.


Most sensors are electrical or electronic, although other types exist. A sensor is a type of transducer. Direct indicating sensors, for example, a mercury thermometer, are human readable. Other sensors must be paired with an indicator or display, for instance a thermocouple.

Sensors are used in everyday life. Applications include automobiles, machines, aerospace, medicine, industry and robotics.

Technical progress allows more and more sensors to be manufactured with MEMS technology. In most cases this offers the potential to reach a much higher sensitivity.

A transducer is a device, usually electrical, electronic, or electro-mechanical, that converts one type of energy to another for various purposes including measurement or information transfer. In a broader sense, a transducer is sometimes defined as any device that converts a signal from one form to another.

http://en.wikipedia.org/wiki/Sensor

Answer 2

A sensor DETECTS particular variations in different things - such as sound, light, force, etc. It converts this information into a form of energy (usually electricity) that records the variations.
A transducer CONVERTS one form of energy (light, electricity, etc.) into another form... So in effect a Sensor USUALLY is a transducer, but does not have to be - as example, as simple mechanical counter detects the items it counts - which in themselves are NOT a form of energy.

Answer 3

A transducer is a device that converts input energy of one form into output energy of another form.
A sensor is a type of transducer that converts the physical phenomena of interest into a signal for use by the system.
For example, a microphone is a sensor that converts sound energy (in the form of pressure) into electrical energy, while a loudspeaker is an actuator that converts electrical energy into sound energy.
In the case of the mechanical counter, it converts the kinetic energy of the object in motion into kinetic energy (the counter movement). Nobody said a trasducer cannot give the same kind of energy as its output as its input energy.

Answer 4

a transducer is defined as any device that converts a signal from one form to another whereas a sensor is one which identifies the intensity of the measured variable and trigger an event

Answer 5

the basic difference is sensor is which detects a signal where as transducer converts the non electrical to electrical signal example LVDT

Answer 6

A transducer is a device, usually electrical, electronic, or electro-mechanical, that converts one type of energy to another for various purposes including measurement or information transfer. In a broader sense, a transducer is sometimes defined as any device that converts a signal from one form to another.

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

Electrochemical:
pH probe
electro-galvanic fuel cell
Electromechanical:
(electromechanical output devices are generically called actuators)
electroactive polymers
galvanometer
MEMS
motor, linear motor
potentiometer when used for measuring position
Accelerometer
strain gauge
switch
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
Tactile transducer
Photoelectric:
Laser diode, light-emitting diode - convert electrical power into forms of light
photodiode, phototransistor, photomultiplier tube - converts changing light levels into electrical form
Electromagnetic:
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
tape head - converts changing magnetic fields into electrical form
Hall effect sensor - converts a magnetic field level into electrical form
Electrostatic:
electrometer
liquid crystal display (LCD)
Thermoelectric:
RTD Resistance Temperature Detector
thermocouple
Peltier cooler
thermistor (includes PTC resistor and NTC resistor)
Other:
Geiger-Müller tube used for measuring radioactivity.


Most sensors are electrical or electronic, although other types exist. A sensor is a type of transducer. Direct indicating sensors, for example, a mercury thermometer, are human readable. Other sensors must be paired with an indicator or display, for instance a thermocouple.

Sensors are used in everyday life. Applications include automobiles, machines, aerospace, medicine, industry and robotics.

Technical progress allows more and more sensors to be manufactured with MEMS technology. In most cases this offers the potential to reach a much higher sensitivity. See also MEMS sensor generations.


[edit] Types
Since a significant change involves an exchange of energy, sensors can be classified according to the type of energy transfer that they detect.


[edit] Thermal
temperature sensors: thermometers, thermocouples, temperature sensitive resistors (thermistors and resistance temperature detectors), bi-metal thermometers and thermostats
heat sensors: bolometer, calorimeter

[edit] Electromagnetic
electrical resistance sensors: ohmmeter, multimeter
electrical current sensors: galvanometer, ammeter
electrical voltage sensors: leaf electroscope, voltmeter
electrical power sensors: watt-hour meters
magnetism sensors: magnetic compass, fluxgate compass, magnetometer, Hall effect device,
metal detectors

[edit] Mechanical
pressure sensors: altimeter, barometer, barograph, pressure gauge, air speed indicator, rate of climb indicator, variometer
gas and liquid flow sensors: flow sensor, anemometer, flow meter, gas meter, water meter, mass flow sensor
mechanical sensors: acceleration sensor, position sensor, selsyn, switch, strain gauge

[edit] Chemical
Chemical sensors detect the presence of specific chemicals or classes of chemicals. Examples include oxygen sensors, also known as lambda sensors, ion-selective electrodes, pH glass electrodes, and redox electrodes.


[edit] Optical and radiation
electromagnetic time-of-flight. Generate an electromagnetic impulse, broadcast it, then measure the time a reflected pulse takes to return. Commonly known as - RADAR (Radio Detection And Ranging) are now accompanied by the analogous LIDAR (Light Detection And Ranging. See following line), all being electromagnetic waves. Acoustic sensors are a special case in that a pressure transducer is used to generate a compression wave in a fluid medium (air or water)
light time-of-flight. Used in modern surveying equipment, a short pulse of light is emitted and returned by a retroreflector. The return time of the pulse is proportional to the distance and is related to atmospheric density in a predictable way.

[edit] Ionising radiation
radiation sensors: Geiger counter, dosimeter, Scintillation counter, Neutron detection
subatomic particle sensors: Particle detector, scintillator, Wire chamber, cloud chamber, bubble chamber. See Category:Particle_detectors

[edit] Non-ionising radiation
light sensors, or photodetectors, including semiconductor devices such as photocells, photodiodes, phototransistors, CCDs, and Image sensors; vacuum tube devices like photo-electric tubes, photomultiplier tubes; and mechanical instruments such as the Nichols radiometer.
infra-red sensor, especially used as occupancy sensor for lighting and environmental controls.
proximity sensor- A type of distance sensor but less sophisticated. Only detects a specific proximity. May be optical - combination of a photocell and LED or laser. Applications in cell phones, paper detector in photocopiers, auto power standby/shutdown mode in notebooks and other devices. May employ a magnet and a Hall effect device.
scanning laser- A narrow beam of laser light is scanned over the scene by a mirror. A photocell sensor located at an offset responds when the beam is reflected from an object to the sensor, whence the distance is calculated by triangulation.
focus. A large aperture lens may be focused by a servo system. The distance to an in-focus scene element may be determined by the lens setting.
binocular. Two images gathered on a known baseline are brought into coincidence by a system of mirrors and prisms. The adjustment is used to determine distance. Used in some cameras (called range-finder cameras) and on a larger scale in early battleship range-finder
interferometry. Interference fringes between transmitted and reflected lightwaves produced by a coherent source such as a laser are counted and the distance is calculated. Capable of extremely high precision.
Scintillometers measure atmospheric optical disturbances.

[edit] Acoustic
sound sensors: microphones, hydrophones, seismometers.
acoustic: uses ultrasound time-of-flight echo return. Used in mid 20th century polaroid cameras and applied also to robotics. Even older systems like Fathometers (and fish finders) and other 'Tactical Active' Sonar (Sound Navigation And Ranging) systems in naval applications which mostly use audible sound frequencies.


[edit] Other types
motion sensors: radar gun, speedometer, tachometer, odometer, occupancy sensor, turn coordinator
orientation sensors: gyroscope, artificial horizon, ring laser gyroscope
distance sensor (noncontacting) Several technologies can be applied to sense distance: magnetostriction

[edit] Non Initialized systems
Gray code strip or wheel- a number of photodetectors can sense a pattern, creating a binary number. The gray code is a mutated pattern that ensures that only one bit of information changes with each measured step, thus avoiding ambiguities.

[edit] Initialized systems
These require starting from a known distance and accumulate incremental changes in measurements.

Quadrature wheel- An disk-shaped optical mask is driven by a gear train. Two photocells detecting light passing through the mask can determine a partial revolution of the mask and the direction of that rotation.
whisker sensor- A type of touch sensor and proximity sensor.


[edit] Resolution
The resolution of a sensor is the smallest change it can detect in the quantity that it is measuring. Often in a digital display, the least significant digit will fluctuate, indicating that changes of that magnitude are only just resolved. The resolution is related to the precision with which the measurement is made. For example, a scanning probe (a fine tip near a surface collects an electron tunnelling current) can resolve atoms and molecules.