

They are particularly useful where long data cables that could be susceptible to induced voltage transients or ground plane surges enter an electronic device containing sensitive semiconductor components. There are many different types of optoisolator circuits that are widely used in communications, control, and monitoring systems where data signals could provide a point of ingress for harmful voltages to damage a device. The components are sealed in an opaque package to prevent interference from external light. This provides a barrier to any voltage transients or overvoltage levels that appear at the input from affecting the electrical circuit at the output of the optoisolator. Then, within the same device, a light-sensitive device such as a photodiode, phototransistor, or photodarlington transistor converts the light signal back into an electrical signal. In simplest terms, an optoisolator works by taking an input electrical signal and converting it into a light signal using a light-emitting diode, generally operating in the near-infrared spectrum. Opto-isolators act as a protection mechanism, ensuring that harmful electrical currents cannot flow across the device. Because there is no need to directly pass voltage or current between the inputs and outputs in an optoisolator circuit, these components can be used to provide electrical isolation in two regions in a PCB.


An optoisolator is an electronic device that can be used to pass information between a diode without passing an electrical current.
