Temperature Sensor

Tuesday 20 September 2011 | posted in , | 0 comments



Temperature sensor is a sensor used to sense and measure the temperature of an object.

Principle:

The operation of the temperature sensor is based on the light absorption characteristics of silicon as a function of temperature.The absorption of light by the silicon layers varies with temperature and the variation modulates the intensity of the light received at the detector.


Construction:

The fiber is coated at one end with a thin silicon layer.This silicon layer is coated with a reflective coating at the back.The light source is connected into the fibre from one of its ends.The detector is used to receive the reflected signal from silicon layer.A simple thermometer can be built using LED as a light source and a photodetector to measures the intensity of light.


Working:

When the light is passed through the fiber from the source and the light after reflecting from the silicon layer returns to a detector.During this process,light is absorbed by the silicon layer.The absorption of light by silicon layer varies with temperature and this variation modulates the intensity of the light received at the detector. A Photodetector is used to measure the intensity of light and temperature is sensed.Temperature int the range from 80 degree to 700 degree celsius is measured using this technique.

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