This document describes an R-2R ladder digital-to-analog converter (DAC). It explains that an R-2R ladder DAC uses only two resistor values, R and 2R, to convert a binary input signal into an analog output voltage. The circuit diagram and working of the R-2R ladder is provided. A 4-bit R-2R ladder DAC is simulated showing the output combinations. Advantages like only needing two resistor values and ability to expand bits are discussed. Applications like audio amplifiers and motor control are also listed.