Sensors

Only available on StudyMode
  • Topic: Sensors, Sensor, Pressure
  • Pages : 7 (1320 words )
  • Download(s) : 54
  • Published : May 20, 2013
Open Document
Text Preview
Sensors

Content: 1. Introduction……………………………………..3 2. Sensor types………………………………….....4 3. Temperature sensors…………………………....6 4. Thermistors…………………………………..…6 5. Thermocouple…………………………………..7 6. Pressure sensors………………………………...8 7. Level sensors………………………………..…..9 8. Electromagnetic sensor……………………..…..9 9. Differential pressure sensors…………………..10 10. Classification of measurement errors………….11 11. List of used literature…………………………..12

2

Introduction

A sensor (also called detector) is a converter that measures a physical quantity and converts it into a signal which can be read by an observer or by an (today mostly electronic) instrument. For example, a mercury-in-glass thermometer converts the measured temperature into expansion and contraction of a liquid which can be read on a calibrated glass tube. A thermocouple converts temperature to an output voltage which can be read by a voltmeter. For accuracy, most sensors are calibrated against known standards. Sensors are used in everyday objects such as touch-sensitive elevator buttons (tactile sensor) and lamps which dim or brighten by touching the base. There are also innumerable applications for sensors of which most people are never aware. Applications include cars, machines, aerospace, medicine, manufacturing and robotics. There are many different designs of sensors that are commercially available for monitoring and controlling industrial processes. Technological advances have enabled the development of sensors with microscopic precision. They use MEMS technology and are called Micro sensors.

3

Sensor Types
The sensors are a of type converters (transducers). They convert one physical quantity into another. Therefore, they can be classified according to the type of energy that is transferred.    -

Thermal Temperature sensors: thermometer, thermostat, bimetal thermometer Thermal sensors: calorimeter, flow sensor

Electromagnet Resistance sensors: ohmmeter, multimeter Electrical sensors: galvanometer, ammeter Power sensors: voltmeter, electroscope Electricity sensors: kWh meters, Magnetic sensors: magnetic compass, magnetometer Metal detectors Radar

Mechanical Pressure sensors: barometer, barograph, manometer, gauge pressure, wind speed indicator

-

Fluid flow sensors: flow sensor, gas sensor, pressure switch Sensors for density and viscosity of the fluid: viscometer, hydrometer Mechanical sensors: proximity sensor, acceleration sensor, displacement sensor, interruption sensor



Moisture sensor: Humidistat Liquid level measurement sensor: Level stat

Chemical 4

-

Chemical sensors: oxygen sensor, ion-selective electrode, pH glass electrode, carbon monoxide detectors

 -

Smell sensors: QCM sensor, tin oxide gas sensor

Optical Light sensors or photo detectors, including semiconductors such as photo cells, photo-diodes, photo-transistors, CCD image sensor and other

-

Infrared sensors use infrared rays to detect objects in the environment and sources of heat

-

Proximity sensors are similar to distance sensors, but they are much finer and complex. These sensors can detect only certain distances. They can be optical (combination of photo-cells, LED’s or lasers).They can be used in cell phones, in photocopying machines as detector for paper and other devices

-

Focus - Large industrial lenses can be focused on the servo system. Distance of the focused element is determined by adjusting the lens.

-

Binocular - Two images obtained from the same starting point overlap according to the system of mirrors and prisms. Their setup is used to determine distance.

 -

Acoustic Acoustic: they use timeout delay of the propagation of the ultrasonic UV rays Sound sensors: microphone, hydrophone, seismometer

5

Temperature sensors
Temperature is a basic measure used in many processes. Many U.S. factories still use Fahrenheit temperature scale, but Celsius is the standard unit of measure. The temperature can...
tracking img