Common question that comes up about pull-up resistors: what value do you pick and why not just use a piece of wire? In this follow-up electronics tutorial, the bald engineer looks at how to pick a pull-up resistor value. Note that while focused on pull-up everything said in this video would apply to pull-down as well.

If you’re new to pull-up resistors, check out this longer Pull-Up Resistor Tutorial.

Watch the full video

Fan of making things beep, blink and fly. Created AddOhms. Stream on Twitch. Video Host on element14 Presents and writing for Hackster.IO. Call sign KN6FGY.


  1. Hi James, as always very informative video. I have one question; Why or when should the internal pull-up resister in the arduino uno be used or should we always add in a pull up resister? for example (pinMode(2,INPUT_PULLUP);)
    Thanks Richard

    • No, you should not always use them. Push buttons are the most common use. You also use them when devices use “open collector” outputs. A PIR motion sensor, for example. I2C devices use pull-up resistors since SDA and SCL are open-collector drivers.

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