A Redstone Comparator is a Redstone device that compares the strengths of two different Redstone power sources to figure out whether a third Redstone connection needs to be powered or not. The Redstone comparator consists of a short Redstone flashlight on the “head”, two vertical Redstone flashlights on the “tail” and two additional ports on the sides for taking in other Redstone power sources. While relatively simple to make, the proper use of a Redstone comparator requires some understanding of the underlying mechanisms.
Creation of a Redstone comparator
Using a crafting table, a redstone comparator requires three redstone torches, three stone blocks along the bottom, and a piece of wispy quartz in the center. Stone blocks cannot be pebbles, stone bricks, andesite, or any other stone-like blocks. Only stone that has been worked through a furnace or mined with a Silk Touch pickaxe will work in this crafting recipe.
Using a Redstone Comparator in Compare Mode
When the short head redstone flashlight is not powered and dims, the redstone comparator is in compare mode. Comparators will automatically be in Compare mode when positioned down, although right clicking on it will change the current mode.
Related: How to make a redstone clock in Minecraft
When in Compare mode, the comparator, as the name suggests, will compare the strength of Redstone’s power source towards its tail with the strength of the stronger Redstone source on either side. Redstone’s power is considered stronger the closer his power source is to the Comparator. This means that, in theory, a Redstone flashlight placed directly next to the comparator is much stronger than a Redstone flashlight separated by several blocks of Redstone wire.
If a redstone source on either side is stronger than the source wired to the tail, the redstone comparator will stop the power transfer to the head. However, if the source to the tail is closer than one of the side sources, or if there are no other energy sources to the sides, the head will still receive energy.
Using a Redstone Comparator in Subtraction Mode
After placing a Redstone comparator down, right clicking on it will switch from Compare mode to Subtract mode. This will light up the short Redstone flashlight on the comparator head. Subtract mode works slightly opposite to how Compare mode works.
Instead of checking if a side source is stronger than the tail source and, if this is true, by cutting off the power to the head, the Subtract mode instead subtracts the stronger of the two side sources from the force of the tail source. If the response to this subtraction is positive and the side source is stronger than the tail source, the power will flow through the head. If the forces in the head and side are equal, or if the head is stronger than the side, the power will not flow through.
Are you looking to take your Redstone systems to the next level? Try using some Redstone repeaters to adjust the timing.