AND GATE

Truth Table

Overview: what the AND Gate is and does

Outputs ON only when ALL inputs are ON. Built by combining two NOT gates into a NOR configuration on the inverted inputs, or by using redstone torches. Essential for requiring multiple conditions to be true simultaneously.

In plain terms, the output is on only when both inputs are on at the same time. AND is the gate of preconditions: it is how a circuit demands that two separate switches, sensors, or states all agree before anything happens, which is why secure doors and safety interlocks lean on it.

This page describes the gate as it behaves in Java Edition 1.21; the truth table and timings below match vanilla redstone exactly.

How it works: the redstone mechanics

Across its four input combinations the output is on in 1 case — A on with B on — and off in the remaining 3.

Expressed as boolean algebra that is output = A AND B.

A torch-based AND (two inverters into a NOR) adds about 2 redstone ticks because the signal passes through two torch stages.

Because redstone signals are just on or off, "on" here means a powered line (signal 1-15) and "off" means an unpowered line (signal 0); the gate cares only about presence or absence of power, not its exact strength.

How to build it

1. 1Place two input lines (A and B) leading into separate blocks.
2. 2Place a redstone torch on top of each input block (these are NOT gates, inverting A and B).
3. 3Run both inverted signals into a single block.
4. 4Place a redstone torch on the output side of that block (a NOR of the inverted inputs).
5. 5The output torch is ON only when both input torches are OFF (both inputs ON).
6. 6Verify it against the truth table: setting the inputs to ON and ON should drive the output ON. Walk through every input combination once to confirm the gate matches the table above.

Uses & applications

• ▸AND is the gate of preconditions: it is how a circuit demands that two separate switches, sensors, or states all agree before anything happens, which is why secure doors and safety interlocks lean on it.
• ▸3-torch AND gate (compact, uses 3 torches) — a practical build choice for this gate.
• ▸Repeater-based AND (uses two repeaters into one block with torch) — a practical build choice for this gate.
• ▸Comparator AND (compare mode, output only if both sides have signal) — a practical build choice for this gate.

Tips & common mistakes

• !Keep your inputs isolated with repeaters if signals are flowing back into each other; uncontrolled backflow between dust lines is the most common reason a gate reads the wrong value.
• !Remember the propagation cost: A torch-based AND (two inverters into a NOR) adds about 2 redstone ticks because the signal passes through two torch stages. If you chain several gates, those ticks add up and can desynchronise a fast circuit.
• !When a multi-gate circuit misbehaves, test each gate in isolation against its own truth table before assuming the wiring between them is at fault.

AND Gate FAQ