Circuitry
essentials:circuit_wrench
<item>Circuits/$ are redstone devices like Repeaters or Comparators that are low-lag and can do advanced logic.
Crossroads relies heavily on <item>Circuits/$ to automate several machines, but they are also very useful for vanilla redstone.
Place <item>Wire Plate/$, and use a <item>Circuit Wrench/$ to convert the wire into the selected circuit (this consumes Nether Quartz). Shift-right-clicking with the <item>Circuit Wrench/$ opens a menu to choose which circuit to place, and which describes each circuit type. Example circuits are <item>AND/$, <item>XOR/$, and <item>Multiplication/$, which do what the names suggest.
<item>Circuits/$ that are either adjacent or connected with <item>Wire Plate/$ can transfer redstone values other than the vanilla 0-15 integers, including values up to 1 billion and decimals.
<item>Circuits/$ themselves can connect directly to vanilla redstone, and a <item>Wire Splice Plate/$ can connect <item>Wire Plate/$ with vanilla redstone. Each <item>Circuit/$ other than <item>Wire Plate/$ and <item>Wire Splice Plate/$ has a two tick delay (1 redstone tick).
<item>Circuits/$ allow compactly and easily making advanced redstone circuitry, and make doing actual math calculations with redstone easy.
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A very important circuit is the <item>Reader Circuit/$, which is like a comparator, except it can measure larger values or with decimal points. A lot of Crossroads machines use this, so it's worth remembering!