Charlie Harvey

Pulley Logic Gates

What, you might wonder, is a logic gate and why, you might further wonder, should I care? Logic gates in their various forms make up a fair amount of the circuitry that enables modern computers to work. Like your phone or your computer.

Logic gates work a bit like one of those truth tables you might have encountered if you ever studied boolean logic. They take one or more inputs in and emit a single output. The output differs depending on the inputs and the type of gate. Combine gates together and you can make everything from a multiplexer to computer memory and microprocessors.

I came across this video of how to build the common logic gates with pulleys the other day and thought it showed the operations of the gates really nicely. It makes my brain spin a bit when I think about the hundreds of thousands of these gates that are flicking on and off as I type this sentence and the millions that will have done so to enable you to read it!


  • Be respectful. You may want to read the comment guidelines before posting.
  • You can use Markdown syntax to format your comments. You can only use level 5 and 6 headings.
  • You can add class="your language" to code blocks to help highlight.js highlight them correctly.

Privacy note: This form will forward your IP address, user agent and referrer to the Akismet, StopForumSpam and Botscout spam filtering services. I don’t log these details. Those services will. I do log everything you type into the form. Full privacy statement.