What is PCB? Printed circuit board or abbreviated as PCB is a passive component designed to mechanically support electronic components and provide inter-connectivity between components and other PCB.
Raw PCB - a pre-fabricated board with copper tracks and drilled holes ready to take the components.
Circuit assembly - a PCB populated with electronic components, ready to install into the machinery.
Single sided - a board with one layer of conductive material. Electronic components are installed on the top side while the connector traces are on the bottom side.
Double sided - a printed board with connecting traces on both sides and components either on top side only or both sides.
Multilayer PCB - both top and bottom sides have components but there is a number of internal layers providing interconnection among layers. The maximum number of layers in a myltilayer PCB is practically limited to 16 by certain EDA software programs or to 24 by majority of the main-stream PCB manufacturer requirements.
Flex PCB - flexible boards are used in limited spaces and in gadgets with moving parts such as printers, scanners and robots. Flex boards ar fabricated on transparent and semi-transparent ribbons. Multilayer flex PCB are possible.
FR-4 or Flame Retardant 4 is an epoxy resin based material used for making a printed circuit board substrate. It is a self-extinguishing fire retardant material with insulative characteristics. FR-4 is limited to signal frequencies of 2 GHz. The main manufacturers of FR-4 is Germany and China.
Gerber File - a file format used by EDA or Electronic Design Automation software to produce complicated single and multilayer PCB designs. Gerber is supported by EDA programs like FreePCB, OrCAD, CadSoft Eagle, Zuken CadStar and others.