Optocouplers, also known as opto-isolators, are components that transfer electrical signals between two isolated circuits by using infrared light. The core component is an opto-coupler, which consists of an LED (light-emitting diode) on the input side and a photodetector (phototransistor, photodiode, or photo-triac) on the output side. To work well, they need to be correctly connected and used in the feedback loop. Transferring signals over a light. There are many different applications for optocoupler circuits, so there are many different design requirements, but a basic design for an optocoupler providing isolation for example between two circuits, simply involves the choice of appropriate resistor values for the two resistors R1 and R2.
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