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Basic principle of photoelectric coupler
- Mar 17, 2017 -

Optocoupler input and signal light source light, light intensity depends on the size of the excitation current, this light to the package with the light and then, light current is produced by the photoelectric effect, by a light output of lead, which achieved power and light electric conversion.

Photo-coupler consists of three parts: the light emission and light receiving and signal amplification. Light emission part composed mainly of organic Electroluminescent device, organic light emitting devices are generally light-emitting diodes, light emitting diode with forward voltage, the electrical energy into light and glow, LEDs using DC, AC and pulse power-driven, but light emitting diode must be added when using forward voltage. Light receiving part composed mainly of photosensitive devices, photosensitive devices are generally photosensitive transistor, photo-transistor PN junction is used in a reverse voltage is applied, reverse resistance from large to small in the light of principles to work.

Optical signal amplification, which consists of an electronic circuit, and so on. Light emitting device pins as input, and photosensitive device PIN as an output port. When added to the input signal, light up core organic Electroluminescent devices, photosensitive device the light after light current and amplified by electronic circuits the output, electric → light → electricity conversion, in order to achieve electrical isolation of the input and output circuits. Because Photo-coupler isolation between input and output circuits, and signal transmission with unidirectional advantages of Photocoupler has good resistance to electromagnetic interference and electrical insulation capabilities.