LightMySky

Logic Gates and Truth Tables

The and, or and not circuits that everything else is built from, and the table that fixes what each one outputs for every possible input.

No account needed. Progress saves in this browser.

What a learner can do afterwards

  • Complete the truth table for AND, OR and NOT
  • Work out the output of two gates wired together
  • Match a written condition to the gates that would compute it

1 · Read

Gates are tiny circuits that decide with 1s and 0s. NOT takes one wire and flips it. AND needs both inputs true, while OR needs just one. Three gates, endless decisions.

Try it together

A truth table lists every input pair with its output. AND shows true only once, for true and true. OR shows false only once, for false and false.

Gates chain into circuits when one output feeds the next input. Take A and B through AND, then OR that answer with C. To read any circuit, trace one gate at a time with pencil and paper.

Good to know

Your code mirrors this hardware: and, or and not behave the same in both. If rain or hiking means boots, that or is the same OR as the gate.

NOT flips, AND wants both, OR wants one, and truth tables with wired chains turn those rules into real decisions.

2 · Watch

Take it off screen

Print a worksheetA4 with an answer key page for grown-ups. No screen, no internet.

Where it sits

Then practise

8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.

Spotted a problem on this page? Tell us
Logic Gates and Truth Tables · Computing, ages 15 to 16 · LightMySky