A major feature of photocouplers is electrical insulation between the output and the input. As illustrated in Figure 1, the absence of an electrical connection between the input and the output has the advantage of allowing linking between circuits with different GND potentials, and preventing the effect of GND noise (which could occur in the case of a shared design) due to separation of the both GNDs.
Using these merits, photocouplers can be applied to air conditioners and switching power supplies.
For specific application examples, refer to the following URL.
|Photocouplers / Optocouplers|