An analog-to-digital converter (ADC) is a device that transforms continuous signals, like sound or light, into a digital format that computers can process. This conversion allows for the representation of real-world data in binary code, which consists of zeros and ones. ADCs are essential in various applications, including audio recording, digital cameras, and telecommunications. They enable devices to capture and manipulate analog signals, making it possible to store, transmit, and analyze information in a digital environment.