The primary function of a Bit Analog to Digital Converter (ADC) is to transform an analog signal into a digital format, allowing the system to interpret and process the information. The input to this converter is typically an electrical voltage or current that represents an analog value, such as sound or light. The ADC then samples this input at regular intervals, quantizes it into discrete levels, and finally assigns a binary code to each level. This digital output can be processed by digital circuits for various applications.