Redstone (a powdery substance mined from deeper levels of the Overworld in Minecraft ), when laid out in trails on a surface, conducts "redstone current" if it happens to be present. "Redstone current" may be generated by redstone torches (a constant source), switches (which may be turned on and off), or buttons (which supply a short "pulse" of redstone current when pressed). Other blocks can "do things" when they receive a redstone current. People have figured out how to arrange various blocks and layouts of redstone to create simple logic gates, from which you can assemble higher-level digital circuits. These circuits can actually occupy a fair amount of space in a Minecraft world, but the world in the PC version is so large as to be effectively unlimited.
Usually, in Survival mode, redstone and redstone current is used for much simpler purposes, such as creating doors that automatically open or close when someone walks on a pressure plate. One drawback is that water will "wash off" your redstone circuitry; one mod gets around this by introducing "red alloy wire" that conducts redstone current but can't be washed off.
>These circuits can actually occupy a fair amount of space in a Minecraft world, but the world in the PC version is so large as to be effectively unlimited.
Not exactly! Only a part of the world is loaded around the player at once, and redstone elsewhere is frozen, so you must construct redstone within these boundaries. Though, I think there might be a mod to "fix" this behavior.
Usually, in Survival mode, redstone and redstone current is used for much simpler purposes, such as creating doors that automatically open or close when someone walks on a pressure plate. One drawback is that water will "wash off" your redstone circuitry; one mod gets around this by introducing "red alloy wire" that conducts redstone current but can't be washed off.