A redstone repeater is a block used in redstone circuits to "repeat" redstone signals back to full strength, delay signals by 1-4 redstone ticks, prevent signals moving backwards, or to "lock" signals in one state.
A single redstone repeater is generated naturally in each jungle temple.
A redstone repeater has a front and back – the arrow on the top points to the repeater's front. A repeater also has two small redstone torches on its top – the color of the torches indicates whether its output is on (dark red when off, bright red when on) and the distance between them indicates the delay the repeater adds to the signal transmission.
A repeater can only be placed on opaque blocks (dirt, stone, etc., but not glass, leaves, etc.), or upside-down slabs or stairs. If the support block is moved or removed, the repeater will turn back into an item as if "mined".
A repeater is 0.125 blocks high (1/8 of a block).
A repeater only transmits signals from its back to its front, but its behavior can be modified from the side (see signal locking, below).
A redstone repeater can be powered by any of the following components at its back:
- an active power component (redstone torch, lever, block of redstone, etc.)
- powered redstone dust
- a powered redstone comparator or another powered redstone repeater facing the repeater
- a powered opaque block (including any opaque mechanism component such as a dispenser, redstone lamp, etc.)
A redstone repeater can power any of the following components at its front:
- redstone dust
- a redstone comparator or another redstone repeater facing away from the repeater
- a mechanism component (such as pistons, doors, etc.)
- an opaque block
An opaque block powered by a redstone repeater is called "strongly-powered" (as opposed to an opaque block "weakly-powered" by redstone dust). A strongly-powered opaque block can power adjacent redstone dust, as well as other redstone components.
A redstone repeater can "repeat" a redstone signal, boosting it back up to power level 15.
Redstone signals have a maximum power level of 15 and that level drops by 1 for every block of redstone dust the signal travels through. If a signal must travel through more than 15 blocks of redstone dust, a redstone repeater can be used to boost the signal back up to full strength. An extra two blocks of distance can be achieved by placing solid opaque blocks before and after the repeater.
While redstone repeaters can allow signals to travel great distances, each adds some delay to the transmission. An alternative is an instant repeater circuit (aka Instawire) which allows distance transmission with no delay.
When initially placed, a redstone repeater has a delay of 1 redstone tick (equivalent to 2 game ticks, or 0.1 seconds).
By right-clicking on the repeater once, a repeater's delay can be set from 1 to 2 ticks (indicated by the distance between the two small redstone torches on the top of the repeater) right-clicking again makes a three-tick delay, right-clicking again makes a four-tick delay, and right clicking again resets back to one. Longer delays can be made with multiple repeaters – for example, a repeater set to '4' and another to '1' will give a half second delay (0.4s + 0.1s = 0.5s).
A repeater set to a delay of 2-4 ticks will increase the length of any shorter pulse to match the length of the repeater's delay. For example, a repeater set to a 4-tick delay will change any shorter pulse into a 4-tick pulse.
A redstone repeater acts as a "diode" – it will only allow redstone signals through in one direction (unlike redstone dust or opaque blocks which can transmit redstone signals in any direction).
A diode can be used to protect a redstone circuit from redstone signals feeding back into the circuit from its output, or can be used to isolate one part of a circuit from another.
Alternative diodes include redstone comparators and transparent diodes.
A redstone repeater can be "locked" by another powered redstone repeater facing its side. When locked, the repeater will not change its output (whether powered or unpowered), no matter what the input does. When the side repeater turns back off, the repeater will go back to its normal behavior.
A repeater can also be locked by a powered redstone comparator facing its side. This offers additional possibilities for locking signals because a comparator's output can be affected from 3 sides as well as by containers.
While a repeater is locked by another repeater (but not by a comparator), the small movable redstone torch on top will change into a bedrock bar, indicating its locked status.
A redstone repeater is defined by its ID and block data. A redstone repeater also has a block state which is expected to replace the functionality of block data in a future version.
A redstone repeater's ID specifies whether it is currently powered.
|Name||ID Name||Block ID|
|Redstone Repeater (inactive)||
|Redstone Repeater (active)||
A redstone repeater's block data specifies its orientation and delay.
|A two-bit field storing a value from 0 to 3 specifying the direction the redstone repeater is facing:
|A two-bit field storing a value from 0 to 3 specifying the redstone repeater's delay:
Effectively, add the repeater's facing value (0 to 3) to 4×(delay-1). For example, a repeater facing west with a delay of 3 redstone ticks would have a block data value of 3 + 4×(3-1) = 11.
- See also: Block states
||Specifies the redstone repeater's delay in redstone ticks.|
||The direction of the input side of a redstone repeater;
the output goes in the opposite direction.
||True if the repeater is currently locked.|
|1.3||Repeaters added, implemented by Jeb. Originally the 4 possible settings were "1, 2, 5 and 7", but this was changed to "1, 2, 3, and 4" for simplicity's sake.|
|A device placed directly in front of a repeater exhibits some strange behavior in its initial release. If the input to the repeater is a redstone wire or torch then the effect on the device seems to be inverted, and if the input is anything else then the device isn't affected by the repeater at all. When the repeater and device are connected by wire, everything works as expected.|
|Another bug is that repeaters fail to update their state when their input is a block being charged by a redstone wire and the piece of wire right next to the block is destroyed. If the wire is powering the repeater when it is destroyed then the repeater will stay on until some other event triggers an update for it, like placing a block next to it.|
|1.6||Previously, the particles generated when the block was destroyed looked like those of a Pumpkin. This bug was fixed in Beta 1.6.|
|1.7||Redstone will now automatically face towards and connect to redstone repeaters like any other redstone mechanism.|
|1.0.0||Repeaters will now remember their state and pass power when the save is reloaded. Previously, when the save was reloaded they would not pass on power. This meant that clocks had to be restarted every time you played the game. Several reboot systems were developed for this purpose.|
|1.3.1||Redstone repeaters can be found inside jungle temples, which is a part of a puzzle mechanism. This is the first time a repeater can be found generated in the world.|
|1.4.2||12w42a||Jeb planned to add latches as a block. Instead, the functionality was added to the redstone repeater itself. The redstone repeater texture was also slightly changed for the lock feature.|
|1.8||Repeaters no longer produce block light when powered.|
|TU1||Added redstone repeaters.|
|TU3||Redstone will now automatically face towards and connect to redstone repeaters like any other redstone mechanism.|
Issues relating to "Redstone Repeater" are maintained on the issue tracker. Report issues there.
- In the coding, the redstone repeater is referenced as "diode".
- If the player shoots an arrow onto a repeater, every time the repeater changes state it will make the sound that arrows make as they make contact with a block.
- Snow tiles are exactly the same height as repeaters.