A Redstone Comparator is a block in the game Minecraft that is used to compare and measure the strength of Redstone signals. It can take input from adjacent blocks and output a signal based on the strength of those inputs. This allows players to create more complex and efficient Redstone circuits. The comparator has two main functions: comparison and subtraction. In comparison mode, it checks the strength of two inputs and outputs the stronger signal. In subtraction mode, it subtracts the strength of one input from another, allowing for more intricate designs in Redstone contraptions, such as automatic farms or hidden doors.