---
title: "Discussion on \"What Does a Pull-Up Resistor Do? (And Why Your Button Reads Random Values Without One)\" | Hashnode"
description: "Discussion on \"What Does a Pull-Up Resistor Do? (And Why Your Button Reads Random Values Without One)\". A pull-up resistor gives an input pin a definite voltage when nothing drives it. Why a floating pin reads garbage, what value to use, pull-up vs pull-down."
url: "https://hashnode.com/posts/what-does-a-pull-up-resistor-do-and-why-your-button-reads-random-values-without-one/6af40e3b3c58d14c01ea3cee"
---

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# [What Does a Pull-Up Resistor Do? (And Why Your Button Reads Random Values Without One)](https://digicirq.hashnode.dev/what-does-a-pull-up-resistor-do-and-why-your-button-reads-random-values-without-one?utm_source=hashnode&utm_medium=feed)

A pull-up resistor gives an input pin a definite voltage when nothing drives it. Why a floating pin reads garbage, what value to use, pull-up vs pull-down.

15h ago · 4 min read · digicirq.hashnode.dev  
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## Written by

[DigiCirq](https://hashnode.com/@digicirq)

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Electronics, explained one circuit at a time. Written guides to every DigiCirq video.

DigiCirq is a faceless, diagram-only channel: short animated explainers on how electronics, Arduino, microcontrollers and the apps on your phone really work. Each post here is the written guide to one video, with the numbers worked out and something to try on your own bench. Videos: youtube.com/@digicirq

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