---
title: "Build a proper R-2R DAC"
description: "R-2R DAC. What is a DAC? The letters stand for Digital to Analog Converter. An R-2R DAC is built using resistor ladders."
canonical: "https://www.baldengineer.com/build-a-proper-r-2r-dac.html"
author: "James Lewis"
date: "2015-11-06T16:10:58Z"
lastmod: "2015-11-06T16:10:58Z"
categories: ["blog","tutorials"]
tags: []
---

# Build a proper R-2R DAC


[![r-2r matrix illustration](/wp-content/uploads/2015/11/illustrative_matrix-1024x470.png)](/wp-content/uploads/2015/11/illustrative_matrix-1024x470.png)

Creating real analog outputs from a digital pin is possible when you use an R-2R DAC. What is a DAC? The letters stand for **D** igital to **A** nalog **C** onverter. This simple DAC is built using resistor. The principle works on voltage dividers. By enabling different combinations of resistors, it is possible to get various voltage levels.

Obviously, such a simple design will have some trade-offs.

The resolution depends on how many resistor steps you include. That is why discrete R-2R networks built on a breadboard have a staggered look. You could add more levels to smooth it out, or there are other options.

This [R-2R Logic Noise Post talks](http://hackaday.com/2015/11/05/logic-noise-digital-to-analog-with-an-r-2r-dac/) about how they work in detail and even includes a section on filtering the output to be less "stepped."