NOT GATE (INVERTER)

Truth Table

Overview: what the NOT Gate (Inverter) is and does

The simplest logic gate. Inverts the input signal, when input is ON, output is OFF, and vice versa. Built with a single redstone torch. The foundation for all other gates.

In plain terms, the output is simply the opposite of the single input. The NOT gate, or inverter, is the seed every other gate grows from — a single redstone torch on a block is a complete NOT gate, and combinations of inverted signals build AND, NAND, and the rest.

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

Reading its truth table, the output is on when the input is off, and off otherwise.

Expressed as boolean algebra that is output = NOT A.

A torch-on-block NOT gate adds 1 redstone tick (0.1s) of delay as the torch flips state.

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 a solid block (e.g., cobblestone).
2. 2Place a redstone torch on the output side of the block.
3. 3Run redstone dust into the input side of the block.
4. 4When the input is powered, the block becomes powered, turning the torch OFF.
5. 5When the input is unpowered, the torch stays ON and outputs signal 15.
6. 6Verify it against the truth table: leaving the input unpowered should drive the output ON. Walk through every input combination once to confirm the gate matches the table above.

Uses & applications

• ▸The NOT gate, or inverter, is the seed every other gate grows from — a single redstone torch on a block is a complete NOT gate, and combinations of inverted signals build AND, NAND, and the rest.
• ▸Torch on block (classic, 1 torch, 1 block) — a practical build choice for this gate.
• ▸Torch on wall (attached to side of block) — a practical build choice for this gate.
• ▸Comparator-based inverter (subtract mode with side input of 15) — 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-on-block NOT gate adds 1 redstone tick (0.1s) of delay as the torch flips state. 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.

NOT Gate (Inverter) FAQ