 Analog-to-digital converter

An analog-to-digital converter produces a discrete numerical code from an input voltage. Its specifications include input range, resolution, conversion rate, input impedance, offset, gain error and nonlinearity. A uniform $b$-bit converter covering voltage span $V_{\mathrm{span}}$ has nominal spacing $q\simeq V_{\mathrm{span}}/2^b$. The uniform-quantization error bound applies to rounding inside the range, while clipping is a different error. Sampling and quantization are separate operations: neither sufficient sampling rate nor a large bit count alone guarantees accurate reconstruction.

An analog-to-digital converter (ADC) is an electronic device that converts analog signals—continuous signals that can vary over time—into digital signals, which are represented in discrete numerical values. This process allows analog inputs, such as sound, light, temperature, and other physical phenomena, to be processed, stored, and manipulated by digital systems, such as computers and microcontrollers.

Many/most microcontroller boards have analog-to-digital converters built into them, it is very convenient. E.g. it is the case for the Raspberry Pi Pico.