Short for Printed Circuit Board, a PCB was invented by Paul Eisler while working on a radio in 1936 and is a board made of plastic or fiberglass that holds ICs and other components. A good example of a PCB found in all computers today is the computer motherboard. The circuit board is most often green from the solder mask that coats the board, however, can be any other color, including red, blue, and even black. The picture is an up-close example of a printed circuit board. In the picture below, is an example of a circuit board from a Wacom tablet, in the bottom right portion of this board are some ICs that give the board its brains.