An opto-isolator, also known as an optocoupler, is an electronic component that transfers electrical signals using light waves to provide electrical isolation between its input and output. It typically consists of a light-emitting diode (LED) and a photodetector, such as a photodiode or phototransistor, housed together. When an electrical signal activates the LED, it emits light that the photodetector receives, allowing the signal to pass without a direct electrical connection. This isolation is crucial in many applications, as it protects sensitive components from high voltages or noise in the circuit. Opto-isolators are commonly used in power supplies, signal processing, and communication systems, ensuring safe and reliable operation in various electronic devices.