Learn / Circuits / Pro / AND-gate door lock: two switches, one light
PRO
ADVANCED
Ages 10+
8:55
AND-gate door lock: two switches, one light
The light only comes on when BOTH switches are on. That's an AND gate — the first building block of every computer you own.
VIDEO · exercise walkthrough · chapters: parts · build · test · why
Blocks you need
Battery · LED · AND block · 2 Switches · 4 wires
You'll understand
Logic gatesAND conditionInputs and outputsHow computers decide
Steps
1Connect the battery to the AND block's power side.
2Wire each switch into one of the AND block's two inputs.
3Snap the LED onto the output.
4Try every combination: off/off, on/off, off/on, on/on. Only one lights it.