opto-coupler

 An opto-coupler, also known as an optocoupler, opto-isolator, or photocoupler, is an electronic device that uses a light-emitting diode (LED) to transmit a signal from one circuit to another. It is used to electrically isolate two circuits, allowing them to communicate without a direct electrical connection. This isolation is important in applications where electrical noise or voltage spikes could potentially damage sensitive electronic components.

Opto-couplers consist of an LED on one side and a photodetector on the other side. When the LED is turned on, it emits light that is detected by the photodetector, which converts the light into an electrical signal. The electrical signal is then transmitted to the second circuit, allowing the two circuits to communicate.

Opto-couplers are commonly used in a variety of applications, such as data transmission, motor control, and voltage regulation. They are particularly useful in situations where it is necessary to isolate a high-voltage circuit from a low-voltage circuit, or where electrical noise or interference could cause problems.