PCB. Stands for Printed Circuit Board.. A PCB is a thin board made of fiberglass, composite epoxy, or other laminate material.Conductive pathways are etched or printed onto board, connecting different components on the PCB, such as transistors, resistors, and integrated circuits.PCBs are used in both desktop and laptop computers.onductive pathways are etched or printed onto board, connecting different components on the PCB, such as transistors, resistors, and integrated circuits. PCBs are used in both desktop and laptop computers.