PRINTED
CIRCUIT BOARDS
In electronics,
PRINTED circuit boards, or PCBs, are used to mechanically support and electrically connect electronic components using
conductive pathways, or traces, etched from copper sheets laminated onto a non-conductive substrate. Alternative names are printed wiring board or PWB or etched wiring board
PCBs are rugged, inexpensive, and can be highly reliable. They require much more layout effort and higher initial cost than either wire-wrapped or point-to-point constructed circuits, but are much cheaper, faster, and consistent in high volume production.
Most PCBs are composed of between one and sixteen conductive
layers separated and supported by layers of insulating material (substrates) laminated (glued) together.Layers may be connected together through drilled
holes called
vias. Either the holes are electroplated or small rivets are inserted. High-density PCBs may have blind vias, which are
visible only on one surface, or buried vias, which are visible on neither.