Information About optical sensor

What is an optical sensor?

A optical current sensor is used to measure current, In CT there is a use of iron core but as the rating of current to be measured increseS the CT saturation occurs this will leads to inaccurate representation of The current, but this does not ocur in OCS ,It uses light to measure the current,Current flowing in a conductor induces a magnetic field, which, through the Faraday effect, rotates the plane of polarization of thelight traveling in a sensing path encircling the conductor.thus by measurin this rotation the current is measured.(by GAURAV GAUR LNT, INDIA) For decades, optical sensors have been finding their way into an increasing number of applications. The development of semiconductors in the 1940s and '50s led to lower-cost, compact and efficient light-sensing devices. Photodetectors were used in camera light meters, street lights and traffic counters. Fiber optics allowed sensitive equipment to work in electrically noisy environments. Sensors packaged with tiny integrated circuits yielded detectors that were simpler to use. Optical sensors have improved efficiency and reliability of control systems at a reasonable cost.

Types of Optical Sensors

1.Photodetector

  • Light-sensitive semiconductor materials have been used in a variety of electronic components. Photodetectors range from simple resistive photocells to photodiodes and transistors. The detector must be part of a switching or amplification circuit; by themselves, they can carry only small amounts of current. They're used to control elevator-door closers, assembly-line part counters and safety systems.
  • Fiber optics have advantages over standard electrical cabling for some environments. The fibers carry no current, so they're immune to electrical interference. They pose no sparking or shock hazard if the cable is damaged. Depending on the design, the light in the fiber may be used as a sensor itself, or it may serve as a signal path for a separate sensor package.
  • Objects radiate light according to their temperature and produce the same colors at the same temperatures. A pyrometer estimates the temperature of an object by sensing the color of the light it gives off. An optical pyrometer is an older device; the operator compares a glowing filament in a viewfinder to a hot object to determine its temperature. Electronic pyrometers use a light-sensitive semiconductor to measure temperature automaticallys. Pyrometers are used when direct contact is inconvenient, unsafe or impossible. Applications include monitoring smelting furnaces and determining the temperature of stars.
  • Miniature proximity detectors use light to sense when objects are nearby. They contain an LED source and a detector to measure reflected light. Measuring a few millimeters on a side, they're small enough to be used in small electronic appliances and cell phones. They have a range of a few inches, useful for determining the alignment of paper in a copier, for example, the presence of your hand, or if a laptop case is open or closed.
  • Infrared sensors are used in situations where visible light would be inconvenient or counterproductive. They can be used to tell if someone's in a room, by the heat given off by a person's body. Infrared is also useful for signaling, forming the basis of remote controls for video and audio.

Fiber Optics

Fiber optics have advantages over standard electrical cabling for some environments. The fibers carry no current, so they're immune to electrical interference. They pose no sparking or shock hazard if the cable is damaged. Depending on the design, the light in the fiber may be used as a sensor itself, or it may serve as a signal path for a separate sensor package.

Pyrometer

Objects radiate light according to their temperature and produce the same colors at the same temperatures. A pyrometer estimates the temperature of an object by sensing the color of the light it gives off. An optical pyrometer is an older device; the operator compares a glowing filament in a viewfinder to a hot object to determine its temperature. Electronic pyrometers use a light-sensitive semiconductor to measure temperature automaticallys. Pyrometers are used when direct contact is inconvenient, unsafe or impossible. Applications include monitoring smelting furnaces and determining the temperature of stars.

Proximity Detector

Miniature proximity detectors use light to sense when objects are nearby. They contain an LED source and a detector to measure reflected light. Measuring a few millimeters on a side, they're small enough to be used in small electronic appliances and cell phones. They have a range of a few inches, useful for determining the alignment of paper in a copier, for example, the presence of your hand, or if a laptop case is open or closed.

Infrared

Infrared sensors are used in situations where visible light would be inconvenient or counterproductive. They can be used to tell if someone's in a room, by the heat given off by a person's body. Infrared is also useful for signaling, forming the basis of remote controls for video and audio.

Other models …..

Need More Information:  

1-What is the application ?  

2-Submit more information ?  

3-wich brand you use or like to use ?

Power By How It Work

20th Jan 2015

Recent Posts