Logic Gates

In A

In B

Gate 0

This row wants: ON (1)

Instructions

Level 1: The AND gate. The output must be ON only when A and B are both ON.

Truth table

The board shows one row. Test checks all four.

A	B	Wanted	Yours
0	0	0	?
0	1	0	?
1	0	0	?
1	1	1	?

About Logic Gates

Logic Gates is a puzzle about boolean logic. That is the on and off maths inside every processor. Each level gives you a truth table, which lists the output wanted for every input. You pick the gates that make the circuit give exactly that output.

How to play

Read the level. It tells you when the output must be ON.
Look at the truth table. It has four rows, for inputs A and B.
Choose a gate for each slot from the drop-down list.
Press Test. It checks all four rows, not just the one shown.
Fix any row that is wrong, and test again.

What it practises

You meet AND, OR, NOT, XOR, NAND, NOR and XNOR one by one. Early levels use one gate, and some later ones chain two. This practises reading a truth table and working out which gate fits. Each of the 10 levels has exactly one right choice of gates.

Questions

How do logic gates work?: A gate takes ON or OFF inputs and gives one output. AND gives ON only if both inputs are ON. OR gives ON if either one is ON.
What is a truth table?: It's a list of every input mix and the output for each. With inputs A and B there are four rows.
Can teachers use Logic Gates for a lesson on boolean logic?: Yes. It is free, runs in the browser, and needs no sign-up. Students can play on a phone or laptop with nothing to install.