Redstonery
Redstonery › Circuits › Comparator clock
Clock circuit

Comparator clock

Use feedback to alternate a comparison result.

5 × 3 footprint1 layer9 blocksTested in 4 rotationsJava Edition 26.2
Open in the simulatorBuild it in the game

Layout

Layer 0 (on the floor)
lever [face=floor, facing=north, powered=true] at x 0, z 0comparator [facing=west, mode=subtract] at x 1, z 0redstone dust at x 2, z 0redstone dust at x 2, z 1redstone dust at x 2, z 2redstone dust at x 1, z 2repeater [facing=south, delay=1] at x 1, z 1repeater [facing=west, delay=1] at x 3, z 0redstone lamp at x 4, z 0
redstone dustrepeater or comparatorinputlamparrows point where a device sends its output; north is up

How it works

A subtract comparator cancels its own output. A repeater restores the feedback to 15 so this is a digital high/low clock, not merely changing analog strength. The lamp averages short pulses; inspect the output wire.

  1. The comparator subtracts a returning side signal from its main input.
  2. The feedback path must let the useful output fall low again; a value changing between two positive strengths is not automatically an on/off clock.

Timing

Measured at the output: a period of 8 game ticks (0.40 s), 4 ticks high and 4 low, repeating for the 600 ticks the test watches.

Inputs and outputs

  • Inputenable (x 0, y 0, z 0)
  • Outputclock wire (x 2, y 0, z 0)
  • Indicatordicator: short pulses overlap the lamp delay (x 4, y 0, z 0)

Blocks you need

4 × redstone dust, 2 × repeater, 1 × lever, 1 × comparator, 1 × redstone lamp.

Build it in the game: 9 commands

Relative to where you stand, with x running east and z running south. Paste one line at a time into chat, or into a chain of command blocks. The block art is the game's own; the layout is what the page above shows.

setblock ~0 ~0 ~0 minecraft:lever[face=floor,facing=north,powered=true]
setblock ~1 ~0 ~0 minecraft:comparator[facing=west,mode=subtract]
setblock ~2 ~0 ~0 minecraft:redstone_wire
setblock ~2 ~0 ~1 minecraft:redstone_wire
setblock ~2 ~0 ~2 minecraft:redstone_wire
setblock ~1 ~0 ~2 minecraft:redstone_wire
setblock ~1 ~0 ~1 minecraft:repeater[facing=south,delay=1]
setblock ~3 ~0 ~0 minecraft:repeater[facing=west,delay=1]
setblock ~4 ~0 ~0 minecraft:redstone_lamp