Redstone circuits/Logic/AND

A device where the output is on when all inputs are on. A 3-input AND gate is shown, but, like OR gates, AND gates can be freely "ganged", combining groups of inputs and then combining the results.

A typical use for an AND gate would be to build a locking mechanism for a door, requiring both the activating button and the lock (typically a lever) to be on.

AND gates act similarly to a "tri-state buffer", where input B acts like a switch, so that if it is off, input A is disconnected from the rest of the circuit. The difference from real-life tri-state buffers is that one cannot drive a low current in Minecraft. (See the Wikipedia article for details.) However, many of the designs reflect this similarity, by having one input representing a circuit, which is opened or closed by a sticky piston driven by the other input.