Logic Gates: AND, OR, NOT
Logic gates combine on/off inputs into a decision. NOT inverts a signal, AND fires only when every input is on, and OR fires when any input is on. They are the alphabet of redstone computing.
What are logic gates?
A logic gate takes one or more on/off inputs and produces a single on/off output according to a fixed rule. String gates together and you can make a circuit “decide” things — open a door only when two levers are both on, sound an alarm if any sensor trips, and so on. Every redstone contraption, from a simple trap to a working calculator, is built from these few gates.
The three foundational gates are NOT, AND, and OR.
The NOT gate (inverter)
A NOT gate flips its input: on becomes off, off becomes on. In redstone the natural NOT gate is a redstone torch on a block — power the block and the torch goes dark; leave it unpowered and the torch glows. It's the single most important gate because AND and OR are built from inverters.
The AND gate
An AND gate outputs on only when every input is on. With two levers, the output lights only when both are flipped; turn either off and the output dies. A common redstone AND uses two torches to invert each input, feeding a third torch so that only the all-on case lets power through.
The OR gate
An OR gate outputs on when any input is on. In redstone this is delightfully simple: just merge the input wires into one output line. If any branch carries power, the output is on. It's the easiest gate to build — often just dust joining together.
Key facts
- NOT: output is the opposite of the input (a redstone torch).
- AND: output on only when all inputs are on.
- OR: output on when any input is on (merge the wires).
- AND and OR are commonly built by combining NOT gates (torches).
- Combine these three and you can build every other gate, including XOR and memory.
Bedrock note
Because Bedrock torches only switch off under strong power and solid blocks absorb weak power from dust, torch-based AND/NOT gates must be wired so each input strongly powers the relevant block. If a gate seems stuck, check that the driving signal isn't just weak dust touching a block. This simulator enforces the Bedrock strong/weak power rule.