An optocoupler is an electronic component that transfers electrical signals between two isolated circuits using light. It typically consists of a light-emitting diode (LED) and a photodetector, such as a photodiode or phototransistor. When an electrical signal activates the LED, it emits light that the photodetector receives, allowing the signal to pass without direct electrical connection. Optocouplers are commonly used in various applications, including power supplies, signal isolation, and data communication. They help protect sensitive components from high voltages and noise, ensuring reliable operation in electronic systems.