label: printed circuit board,Printed circuit board
The pcb substrate most commonly used in printed circuit boards is a glass fiber reinforced (fiberglass) epoxy resin with a copper foil bonded on to one or both sides. PCB made from paper reinforced phenolic resin with a bonded copper foil are less expensive and are often used in household electrical devices. The printed circuits are made of copper, which is either plated or etched away on the surface of the substrate to leave the pattern desired. (See "additive" and "subtractive" processes described in step 3 under The Manufacturing Process).
The copper circuits are coated with a layer of tin-lead to prevent oxidation. Contact fingers are plated with tin-lead, then nickel, and finally gold for excellent conductivity. Purchased components include resistors pcb, capacitors, transistors, diodes, integrated circuit chips pcb, and others pcb.
