Optocoupler (Optical coupler
) is a new type of semiconductor "electric-optical-electric" conversion device which takes light as the medium and the input signal is coupled to the output end. In other words, it has the power to transform the electronic signal into the corresponding change law of the optical signal, and then converted to the same change law of the same electrical signal transmission. It can effectively isolate the noise and suppress interference to achieve the electrical insulation between the input and output. This signal transmission is not comparable to the general solution which uses the isolation of the transformer and the electromagnetic relay for signal transmission.