An optocoupler integrates a light-emitting diode (LED) and a photodetector within a single package. Unlike other optical devices, its light does not emit outside the package. Its appearance is similar to that of non-isolator solid-state relays. Although optocouplers are optical devices, they process electrical signals rather than light. The isolation provided by optocouplers is essential in scenarios where preventing electrical interference or ensuring safety is critical.

  One of the primary functions of optocouplers is signal isolation. By eliminating direct electrical connections between input and output, these devices protect sensitive components from voltage spikes, noise, and other potential interference. This isolation is particularly important in high-voltage and noisy environments.

  Microcontroller-based systems frequently use optocouplers to isolate input and output signals. This enhances the safety of microcontrollers and protects them from damage caused by voltage spikes or ground loops.