What it is
A drawing board for digital logic. Switches are inputs, lamps are outputs, and nine kinds of part sit in between.
Build: add parts from the toolbar, drag them into place, and drag from an output dot to an input dot to connect them. Click a switch to flip it.
See: wires that carry a 1 turn blue, lamps light up.
Read: the truth table lists every combination of the switches and marks the one that is set right now.
Solve: five challenges, from "AND from NAND" to an alarm system, check the whole truth table and say which input combination is still wrong.
Gates use the rectangular IEC symbols (&, ≥1, =1, 1) taught in many European schools, with the English name under each.
Safe for school use
Everything happens in the page: no account, nothing uploaded, nothing stored. "Share" puts the circuit into the link itself, after the #, which never reaches a server. Opening a shared link only draws the circuit it describes.
Ideas for class
Discover: start with the AND circuit that opens by default. Learners flip both switches and write down when the lamp lights. Then swap the gate for OR, XOR and NAND.
Half adder: load the example, then ask why the second lamp is called the carry.
Challenge race: pairs solve "XOR without XOR" and share their link with the class; compare how many gates each solution needs.