The Redstone Comparator (pronounced kəmˈparətər) is a block for use with redstone circuitry. It has two inputs: one from the back ('signal A') and one from the side ('signal B'). If signal B is stronger than signal A, there will be no output. Otherwise, it can be set to either repeat signal A at its current strength, or output the difference between both inputs in subtraction mode.
It provides a "subtraction" feature which results in the output being the strength of the back ('signal A') minus the strength of the side ('signal B'), however for this to work the player must make sure that the front redstone torch is lit. Signal B has to be less powerful than signal A for it to work. An example is if the back has a strength of 15, and the side has a strength of 1 the output is 14. Right-clicking the comparator will toggle the torch.
The comparator also provides a feature which is activated when the rear of the comparator (the side with two redstone torches) is placed against a storage block. Doing this causes the comparator to emit a signal that is equal to the percentage the storage block is full. Some people call this fill-checking.
The comparator looks similar to a repeater, except with an additional redstone torch.
Crafting
| Ingredients | Input » Output |
|---|---|
| Redstone Torches, | Template:Grid/Crafting Table |
Uses
As a low-delay wire/diode
Like a repeater, the comparator acts as a diode. On its own, a comparator can be used as a diode (with 1 redstone tick delay), providing output of the same strength as its input, but not allowing current to flow against the direction of its arrow.
As a comparator
The comparator's side inputs may be used to set a threshold for the input signal. The input, signal A, will only be output if it is greater than or equal to signal B. Otherwise, there is no output. Signal A is the signal input to the back of the comparator. Signal B is considered the greater of the two side inputs; the weaker side input is ignored. This is similar to a real-life op-amp without a feedback circuit, with signal A to its non-inverting input and signal B to its inverting input.
As a diminisher
If a comparator is right-clicked, its third redstone torch becomes active. In this state, the output will be signal A minus signal B: the input signal will be reduced by the comparison signal. If signal B is greater than or equal to signal A, of course, there will be no output. This is similar to a real-life op-amp with a feedback wire from its output directly to its negative input (hence no amplifying effect but subtracts inputs), with signal A to its non-inverting input and signal B to its inverting input.
As a clock
If a Redstone Torch or a Lever is connected directly to signal A and the output is forwarded to signal B and the comparator toggle is set to on, the device will act as a clock.
As an inventory contents checker
If a comparator is placed next to a container, it will provide an output based on the percentage of used space in the container. This includes: regular/large/trapped Chest, Furnace, Dispenser, Hopper, Brewing Stand, Dropper, Jukebox, or a Detector Rail with a Minecart with Chest / Hopper on it. The comparator may be separated from the input by one solid block if the 3 blocks form a line, however redstone current from below the separator may interfere. See below for more info.
Inventory checking output
When a container is empty, the output is off.
When it is not empty, the output signal strength is calculated as follows:
signal strength = truncate(1 + ((sum of all slots' fullnesses) / number of slots in container) * 14)
fullness of a slot = (amount of items in slot) / (max stack size for this type of item)
Example: 300 blocks in a dispenser (which has 9 slots), where each block stacks to a maximum of 64, produces output with a signal strength of 8:
1 + ((300 items / 64 items per slot) / 9 slots) * 14 = 8.292, truncated is 8
Note that a non-stackable item is counted as a full slot (1 item in a slot, with a max stack size of 1: 1 / 1 = 1.0), and items which stack up to 16 (such as ender pearls and snowballs) are similarly considered a full slot at 16.
Specific output signal strength creation
It can be useful in redstone circuits to use containers with comparators to create signals of a specific strength. The number of items required in a container to produce a signal of desired strength is calculated as follows:
items required = max(desired signal strength, roundup((total slots in container * 64 / 14) * (desired signal strength - 1) ) )
Example: To use a furnace (which has 3 slots) to create a strength 9 signal, you need 110 items:
max(8, (3*64/14)*(9-1)) = 109.714, rounded up is 110
Power listings of a chest
This chart shows the redstone output of a regular chest, with a items of stack size 64. (Note this does not include Large Chests.)
1 Blocks/items = 1 SignalStr
124 Blocks/items = 2 SignalStr
247 Blocks/items = 3 SignalStr
371 Blocks/items = 4 SignalStr
494 Blocks/items = 5 SignalStr
618 Blocks/items = 6 SignalStr
741 Blocks/items = 7 SignalStr
864 Blocks/items = 8 SignalStr
988 Blocks/items = 9 SignalStr
1111 Blocks/items = 10 SignalStr
1235 Blocks/items = 11 SignalStr
1358 Blocks/items = 12 SignalStr
1482 Blocks/items = 13 SignalStr
1605 Blocks/items = 14 SignalStr
1728 Blocks/items = 15 SignalStr
Jukebox record identification
Unlike most containers, the signal output by a jukebox represents the record it contains. It outputs:
| Signal | Record |
|---|---|
| 0 | none |
| 1 | 13 |
| 2 | cat |
| 3 | blocks |
| 4 | chirp |
| 5 | far |
| 6 | mall |
| 7 | mellohi |
| 8 | stal |
| 9 | strad |
| 10 | ward |
| 11 | 11 |
| 12 | wait |
| 13 | unused |
| 14 | unused |
| 15 | unused |
Other Unique Container Outputs
End Portal Frame blocks output a full signal of 15 if they contain an Eye of Ender and zero otherwise.
Cauldrons output different signal strengths depending on how much water is inside. From completely empty to completely full, the output values are 0, 2, 3, and 4.
Video
Redstone Comparator/video
History
| r |
|---|
| u | |||||
|---|---|---|---|---|---|
1.6{{Extension DPL}}<ul><li>[[Glowstone Dust|Glowstone Dust]]<br/>{{Item
| image = Glowstone Dust.png
|type=
| renewable = Yes
| stackable = Yes (64)
}}
'''Glowstone dust''' is an [[item]] obtained from mining [[glowstone]], and is mainly used to create [[potion]]s with increased strength and decreased duration.
== Obtaining ==
=== Mining ===
When broken using anything other than a [[Silk Touch]]-enchanted [[tool]], a [[glowstone]] block drops 2-4 glowstone dust. A [[Fortune]] enchantment increases the chances of higher drops, with Fortune III allowing an average yield of 3.5 glowstone dust per block.
=== Mob loot ===
[[Witch]]es have a chance of dropping 0–6 glowstone dust upon death. This is increased by 3 per level of [[Looting]], for a maximum of 0-15 glowstone dust. <!-- Do not add the blaze as it is in violation of MCW:UPTODATE due to the Legacy Console Edition being discontinued. Any edit that adds the blaze to this section will be immediately reverted. -->
=== Trading ===
{{IN|bedrock}}, journeyman-level cleric [[villager]]s sell one glowstone dust for 4 [[emerald]]s as part of their trades.
== Usage ==
=== Crafting ingredient ===
{{crafting usage}}
=== Brewing ingredient ===
{{brewing
|showname=1
|head=1
|Glowstone Dust
|Thick Potion
|base=Water Bottle
}}
{{brewing
|name=Increased Potency
|showbase=1
|Glowstone Dust
|base=[Potion of Healing II]Potion of Healing;[Potion of Regeneration II]Potion of Regeneration;[Potion of Strength II]Potion of Strength;[Potion of Swiftness II]Potion of Swiftness;[Potion of Harming II]Potion of Harming;[Potion of Poison II]Potion of Poison;[Potion of Leaping II]Potion of Leaping
|foot=1
}}
== Data values ==
=== ID ===
{{edition|java}}:
{{ID table
|edition=java
|showforms=y
|generatetranslationkeys=y
|displayname=Glowstone Dust
|spritetype=item
|nameid=glowstone_dust
|form=item
|foot=1}}
{{edition|bedrock}}:
{{ID table
|edition=bedrock
|shownumericids=y
|showforms=y
|notshowbeitemforms=y
|generatetranslationkeys=y
|displayname=Glowstone Dust
|spritetype=item
|nameid=glowstone_dust
|id=394
|form=item
|foot=1}}
== History ==
{{History|java alpha}}
{{History||v1.2.0|snap=preview|[[File:Glowstone Dust JE1 BE1.png|32px]] Added glowstone dust.
|Glowstone dust currently uses nine dust to [[crafting|craft]] 1 [[glowstone]] block.
|Also, each glowstone block drops only one glowstone dust.}}
{{History|java beta}}
{{History||1.6.6|The crafting recipe for glowstone blocks has been changed from 9 glowstone dust to 4.
|Each glowstone block now drops 2-4 glowstone dust when broken.}}
{{History|java}}
{{History||1.0.0|snap=Beta 1.9 Prerelease 3|Glowstone dust can now be [[brewing|brewed]] in a [[water bottle]] to create a [[thick potion]].
|Glowstone dust now strengthens the [[potion]]s of [[Swiftness]], [[Healing]], [[Harming]], [[Poison]], [[Regeneration]] and [[Strength]].}}
{{History|||snap=Beta 1.9 Prerelease 4|Glowstone dust now strengthens the new potion of [[Regeneration]].}}
{{History||1.3.1|snap=12w21a|Glowstone dust has become a renewable resource, as priest [[villager]]s now sell glowstone blocks.}}
{{History||1.4.2|snap=12w38b|[[Witch]]es now have a chance of [[drops|dropping]] glowstone dust.}}
{{History||1.4.6|snap=12w49a|Glowstone dust can now be used to [[crafting|craft]] a [[firework star]] with a twinkle effect.}}
{{History||1.8|snap=14w27a|Glowstone dust now strengthens the new [[potion of Leaping]].}}
{{History||1.9|snap=15w31a|Glowstone dust is now used to craft [[spectral arrow]]s.
|Glowstone dust can no longer be added to extended [[potion]]s.}}
{{History||1.13|snap=17w47a|Prior to [[1.13/Flattening|''The Flattening'']], this [[item]]'s numeral ID was 348.}}
{{History|||snap=18w07a|Glowstone dust now strengthens the new [[potion of the Turtle Master]].}}
{{History||1.14|snap=18w43a|[[File:Glowstone Dust JE2 BE2.png|32px]] The texture of glowstone dust has been changed.}}
{{History||1.16|snap=20w07a|Glowstone dust has a {{frac|2|109}} (~1.83%) chance of being offered by [[piglin]]s when [[bartering]], in a stack size of 2–4.}}
{{History|||snap=20w09a|Glowstone dust now has a {{frac|10|226}} (~4.42%) chance of being offered by piglins when bartering, in a stack size of 1–5.}}
{{History||1.16.2|snap=20w28a|Glowstone dust can no longer be obtained from bartering with piglins.}}
{{History|pocket alpha}}
{{History||v0.2.0|[[File:Glowstone Dust JE1 BE1.png|32px]] Added glowstone dust. It is currently unobtainable and serves no purpose.}}
{{History||v0.5.0|Glowstone dust is now obtainable through the [[nether reactor]].
|Glowstone dust can be used to craft [[glowstone]] blocks.}}
{{History||v0.12.1|snap=build 1|Glowstone dust can now be obtained through [[the Nether]] instead of the nether reactor.
|Glowstone dust is now available in the [[creative]] [[inventory]].|Glowstone dust can now be used to [[brewing|brew]] thick [[potion]]s and to strengthen potions.}}
{{History||v0.14.0|snap=build 1|Added [[witch]]es, which have a chance of [[drops|dropping]] glowstone dust upon [[death]].}}
{{History|bedrock}}
{{History||1.2.0|snap=beta 1.2.0.2|Glowstone dust can now be used to [[crafting|craft]] a [[firework star]] with a twinkle effect.}}
{{History||1.10.0|snap=beta 1.10.0.3|[[File:Glowstone Dust JE2 BE2.png|32px]] The texture of glowstone dust has been changed.}}
{{History||1.11.0|snap=beta 1.11.0.4|Glowstone dust can now be [[trading|bought]] from cleric [[villager]]s.}}
{{History||1.16.0|snap=beta 1.16.0.57|Glowstone dust can now be obtained from [[bartering]] with [[piglin]]s.}}
{{History||1.16.100|snap=beta 1.16.100.54|Glowstone dust can no longer be obtained from [[barter]]ing with [[piglin]]s.}}
{{History|console}}
{{History||xbox=TU1|xbone=CU1|ps=1.0|wiiu=Patch 1|switch=1.0.1|[[File:Glowstone Dust JE1 BE1.png|32px]] Added glowstone dust.}}
{{History||xbox=TU8|0–2 glowstone dust is now [[drops|dropped]] when a [[blaze]] is killed.}}
{{History|Ps4}}
{{History||1.90|[[File:Glowstone Dust JE2 BE2.png|32px]] The texture of glowstone dust has been changed.}}
{{History|New 3DS}}
{{History||0.1.0|[[File:Glowstone Dust JE1 BE1.png|32px]] Added glowstone dust.}}
{{History|foot}}
== Issues ==
{{issue list}}
{{Items}}
[[Category:Renewable resources]]
[[Category:Brewing recipe]]
[[de:Glowstonestaub]]
[[es:Polvo de piedra luminosa]]
[[fr:Poudre lumineuse]]
[[hu:Izzókő-por]]
[[ja:グロウストーンダスト]]
[[ko:발광석 가루]]
[[nl:Gloeisteenstof]]
[[pl:Jasnopył]]
[[pt:Pó de pedra luminosa]]
[[ru:Светокаменная пыль]]
[[tr:Işık Taşı Tozu]]
[[uk:Пил світлокаменю]]
[[zh:荧石粉]]</li><li>[[Water Bucket|Water Bucket]]<br/>{{Item
| title = Water Bucket
| renewable = Yes
| image = Water Bucket.png
| stackable = No
}}
A '''water bucket''' is a [[bucket]] filled with [[water]].
== Obtaining ==
=== Interacting ===
To fill an empty [[bucket]] with water, {{control|use}} it on a [[water]] source block. The water is consumed in the process. Flowing water does not fill a bucket.
{{control|Using}} an empty bucket on a [[cauldron]] filled with water (water level 3) empties the cauldron and fills the bucket.
Water buckets can also be filled by placing an empty one in the fuel slot of a [[furnace]], and a wet [[sponge]] into the oven slot. The bucket is filled when the [[smelting]] process completes, which also leaves the sponge dry and ready to be reused.
=== Chest Loot ===
{{LootChestItem|water-bucket}}
== Usage ==
{{Control|Using}} a water bucket on a solid block places a water source block against that block, emptying the bucket; using a water bucket on a [[waterlogging|waterloggable]] block waterlogs the block. In [[the Nether]], however, the water evaporates, making a fire extinguishing sound and displays smoke particles while nothing gets placed.
=== Dispensers ===
A [[dispenser]] can be loaded with a water bucket, and when activated it places a water block directly before it, emptying the bucket. A dispenser loaded with an empty bucket and a water source right in front of it draws the source into the bucket when activated.
=== Cauldrons ===
A single water bucket can fill a [[cauldron]], and using an empty bucket on a water-filled cauldron fills the bucket. Empty buckets cannot be filled from partly-filled cauldrons.
=== Filling bucket with mobs ===
Water buckets can be used on a [[fish]], [[axolotl]] or [[tadpole]] to create a [[bucket of aquatic mob]].
=== Transportation ===
{{main|Tutorials/Elevators#Water elevators}}
Water buckets can be used as a means of quickly descending great heights in the [[Overworld]] and [[the End]], either by creating a waterfall or using the water bucket while falling to create a safe water landing.
Water buckets can also be used to climb vertical surfaces anywhere but [[the Nether]] by repeatedly creating higher waterfalls from the bottom and swimming up them.
== Sounds ==
{{el|je}}:
{{Sound table
|sound=Fill water bucket1.ogg
|sound2=Fill water bucket2.ogg
|sound3=Fill water bucket3.ogg
|subtitle=Bucket fills
|source=player
|description=When a bucket is filled with water
|id=item.bucket.fill
|translationkey=subtitles.item.bucket.fill
|volume=1.0
|pitch=1.0
|distance=16}}
{{Sound table
|sound=Empty water bucket1.ogg
|sound2=Empty water bucket2.ogg
|sound3=Empty water bucket3.ogg
|subtitle=Bucket empties
|source=block
|description=When the bucket is placed
|id=item.bucket.empty
|translationkey=subtitles.item.bucket.empty
|volume=1.0 <ref group=sound>Except for the second copy of {{cd|empty1}}, which is 0.9</ref>
|pitch=1.0
|distance=16
|foot=1}}
{{el|je}}:
{{Sound table
|type=bedrock
|sound=Fill water bucket1.ogg
|sound2=Fill water bucket2.ogg
|sound3=Fill water bucket3.ogg
|source=block
|description=When a bucket is filled with water
|id=bucket.fill_water
|volume=1.0
|pitch=1.0}}
{{Sound table
|sound=Empty water bucket1.ogg
|sound2=Empty water bucket2.ogg
|sound3=Empty water bucket3.ogg
|source=block
|description=When a water bucket is emptied
|id=bucket.empty_water
|volume=1.0
|pitch=1.0}}
{{Sound table
|rowspan=2
|sound=Water Splash Old.ogg
|source=block
|description=When a water bucket is placed in a cauldron<wbr><ref group=sound name=bucketsplash>{{Bug|MCPE-135919}}</ref>
|id=cauldron.fillwater
|volume=0.1
|pitch=1.0}}
{{Sound table
|source=block
|description=When a water bucket is removed from a cauldron<wbr><ref group=sound name=bucketsplash/>
|id=cauldron.takewater
|volume=0.1
|pitch=1.0
|foot=1}}
==Data values==
=== ID ===
{{edition|java}}:
{{ID table
|edition=java
|showforms=y
|generatetranslationkeys=y
|displayname=Water Bucket
|spritetype=item
|nameid=water_bucket
|form=item
|foot=1}}
{{edition|bedrock}}:
{{ID table
|edition=bedrock
|showaliasids=y
|shownumericids=y
|showforms=y
|notshowbeitemforms=y
|generatetranslationkeys=y
|displayname=Water Bucket
|spritetype=item
|nameid=water_bucket
|aliasid=bucket / 8
|id=362
|form=item
|translationkey=item.bucketWater.name
|foot=1}}
== Advancements ==
{{load advancements|Tactical fishing;The Cutest Predator;Bukkit bukkit}}
==History==
{{History|java infdev}}
{{History||20100615|[[File:Water Bucket JE1 BE1.png|32px]] Added water buckets.}}
{{History|java alpha}}
{{History||v1.2.6|{{control|use|text=Using}} a water bucket on [[block]]s with GUIs ([[chest]]s, [[furnace]]s, etc.) no longer places the water.}}
{{History|java}}
{{History||1.0.0|snap=Beta 1.9 Prerelease 2|Water buckets can now be used to fill [[cauldron]]s.}}
{{History||1.3.1|snap=12w15a|[[Dispenser]]s have now been given the ability to dispense water buckets. They can also collect if activated again.}}
{{History||1.8|snap=14w25a|A water bucket is now shown as the icon when [[water]] is used as a layer in [[Superflat]].}}
{{History|||snap=14w25b|[[Smelting]] a wet [[sponge]] while an empty bucket is in the fuel slot fills the bucket with water.}}
{{History||1.9|snap=15w44a|A full [[cauldron]] can now be emptied with a bucket, yielding a water bucket.}}
{{History|||snap=15w50a|Added sounds for collecting and pouring water using a bucket.}}
{{History||1.13|snap=17w47a|Prior to the ''[[Flattening]]'' this item's numerical ID was 326.}}
{{History|||snap=18w08b|Water buckets can now be used to pick up [[fish]] mobs.}}
{{History||1.14|snap=18w43a|[[File:Water Bucket JE2 BE2.png|32px]] The texture of water buckets has now been changed.
|Water buckets can now suck up liquids directly adjacent to the side they are facing. How this works is unknown, given the water bucket clearly already contains a liquid.}}
{{History|||snap=18w48a|Water buckets can now be found in [[chest]]s in [[village]] fishing cottages.}}
{{History|||snap=19w02a|Water buckets can now be used to put out [[campfire]]s.}}
{{History||1.17|snap=20w51a|Water buckets can now be used to collect [[axolotl]]s.}}
{{History||1.19|snap=22w11a|Water buckets can now be used to collect [[tadpole]]s.}}
{{History||1.19.3|snap=22w45a|Water buckets can now be emptied into [[waterlogging|waterlogged]] blocks, instead of placing water against them.<ref>{{bug|MC-127110|||Fixed}}</ref>}}
{{History|upcoming java}}
{{History||Villager Trade Rebalance<br>(Experimental)|link=Java Edition 1.20.2|snap=23w31a|[[Wandering trader]]s now have a chance to [[trading|buy]] a water bucket from the player.}}
{{History|pocket alpha}}
{{History||v0.7.0|[[File:Water Bucket JE1 BE1.png|32px]] Added water buckets.
|Water buckets were simply called "Bucket".}}
{{History||v0.7.4|Water buckets no longer stack to 64.}}
{{History||v0.14.0|snap=build 1|Dispensers can now shoot out water from water buckets.}}
{{History|bedrock}}
{{History||1.4.0|snap=beta 1.2.14.2|Water buckets can now be used to pick up [[fish mob]]s.
|Moved all bucket items, including water buckets, from the Equipment tab to the Items tab in the [[Creative inventory]].{{verify|type=update}}{{info needed}}<!---please check snapshots, only 1 major release version was checked each--->}}
{{History||1.10.0|snap=beta 1.10.0.3|[[File:Water Bucket JE2 BE2.png|32px]] The texture of water buckets has now been changed.}}
{{History||1.16.100|snap=beta 1.16.100.56|The ID of water buckets has been changed from <code>bucket/8</code> to <code>water_bucket</code>.}}
{{History||1.17.0|snap=beta 1.16.230.52|Water buckets can now be used to collect [[axolotl]]s.}}
{{History||1.18.10|snap=beta 1.18.10.24|Water buckets can now be used to collect [[tadpole]]s behind the "Wild Update" experimental toggle.}}
{{History|console}}
{{History||xbox=TU1|xbone=CU1|ps=1.0|wiiu=Patch 1|switch=1.0.1|[[File:Water Bucket JE1 BE1.png|32px]] Added water buckets.}}
{{History||xbox=TU9|[[Dispenser]]s have now been given the ability to shoot out the [[liquids]] inside water buckets. They can also suck up the liquids if activated again, but a bug prevents the empty [[bucket]] from being filled. Whether this was ever fixed is unknown.}}
{{History||xbox=none|xbone=none|ps=1.90|wiiu=none|switch=none|[[File:Water Bucket JE2 BE2.png|32px]] The texture of water buckets has now been changed.}}
{{History|New Nintendo 3DS Edition}}
{{History||0.1.0|[[File:Water Bucket JE1 BE1.png|32px]] Added water buckets.}}
{{History|foot}}
==Issues==
{{issue list}}
==Gallery==
<gallery>
Water Bucket SDGP.png|Water bucket in the [[Super Duper Graphics Pack]].
</gallery>
==References==
{{Reflist}}
{{Items}}
[[Category:Renewable resources]]
[[Category:Tools]]
[[de:Wassereimer]]
[[ja:水入りバケツ]]
[[pt:Balde de água]]
[[th:ถังน้ำ]]
[[uk:Відро води]]
[[zh:水桶]]</li></ul> | 13w18a | Comparators now give out a signal for Cauldrons and End Portal frames depending on their state. | |||
Issues
Issues relating to "Redstone Comparator" are maintained on the bug tracker. Report issues there.
Trivia
- The comparator does not re-strengthen a redstone signal. This means it can not be used for super-long instant circuits.
- If placed every second block between redstone, they can endlessly carry a signal, at same speed than repeaters on first setting, without it losing power strength. Placing a non-transparent block at every corner allows it to bend without losing power. It is also possible to reduce the needed amount of comparators further (and thus improve the signal speed) by facing the comparators into solid blocks behind which redstone is placed
- A redstone comparator outputs a strong signal. This does not mean it resets the signal strength like repeaters, but it means the signal can be picked up through a block without using a repeater (Like a repeater)
- If you join up the redstone torches, an arrow is created which points to the redstone output. This arrow can also be seen as a red triangle on the Comparator, if one looks hard enough.
Gallery
- ComparatorsExplained.PNG
An image depicting two comparators and their inputs and outputs.
- Comporatorssubtract.png
This image explains the way comparator subtraction works.
- Inverteddaylightsensor.png
Using subtraction mode to make a night sensor, i.e., 1 charge = 14 charge
- TrappedChestJingle.png
A jingle that uses comparators. Is connected to a trapped chest.
- JukeboxLock.png
A comparator used with a jukebox to serve as a lock.
