Photoelectric sensor has basically 5 components, light source, light detector, lenses, logic circuit and output. However in this topic we are focusing on the light source and the light detector. Light source basically consists of a LED or a laser diode.
Table of Contents
Light source
Due to the cheap price and availability, most of the devices use LED as the light source. LED (Light emitting Diode) is a semiconductor that produces light when current is passed through them.
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Currently laser diodes are common in use due to its unique characteristics which include consistent wavelength of the emitted light, small beam diameter, and long range.
Light detector
The light detector is the component used to detect the light produced by the light source. They are commonly known as photodiode or phototransistor. Due to its capability of sensing the different pulses of light they are known as receiver. There best application is in the receiver end of the optical fiber data transmission. The transponder connected with it converts the light sensed by these detectors to electrical pulses.
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The spectral response of the light detector determines its sensitivity to different wavelengths in light spectrum. Thus, to increase the sensitivity, the spectral of source and the detector are matched.
References
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- Encyclopedia: Definition of:laser, Accessed:27.3.2014
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