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. This isolation helps protect sensitive components from high voltages or noise in a circuit, making them essential in various applications, such as power supplies and signal processing. Typically, an opto-isolator consists of a light-emitting diode (LED) and a photodetector, like 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 through while maintaining isolation between the two sides of the circuit.