The optocoupler is an electrical-optical-electrical conversion device that transmits electrical signals through light. Due to the long service life and wide operating temperature range of the device, it is widely used in process control, industrial communication, household appliances, medical equipment, communication equipment, computers, and precision instruments. In the process of continuous development and improvement of current technology, its operating speed, operating current, and integration level will be greatly improved. In order to further expand the function of the optocoupler, on the basis of ordinary optocoupler devices, the modulation signal can be loaded through the LED, through the exclusive signal in the form of light, the extraction of the photodiode and the way of receiving the optical signal, and at the same time restore the relevant data. Data can be transmitted during the electrical-optical-electrical conversion process to realize the communication function.

Photocouplers are used as terminal isolation components in long-line information transmission, which can greatly improve the signal-to-noise ratio. Therefore, it is widely used in various circuits.