The power cables supply electrical power from the power supply to the drives and other devices. The power cables are red, yellow, and black. The yellow wire furnishes 12 volts of power. The red wire furnishes 5 volts of power. The two black wires are the ground wires for the yellow and red wires. Some drives, like the 1.44MB floppy drive, use a smaller cable and connector, but the wires still have the same voltage.
