PCB is made of different components and a variety of complex technological processing, and the structure of PCB circuit board has single-layer, double-layer and multi-layer structures. Different hierarchical structures have different ways of making.
This article will introduce in detail :PCB circuit board components name and the corresponding use, and PCB circuit board single-layer, double-layer, multi-layer structure production and various types of work layer main functions.
First, the printed circuit board is mainly composed of solder pads, through holes, installation holes, wires, components, connectors, filling, electrical boundaries, etc. The main functions of each component are as follows:
Pad: A metal hole used to weld the pins of a component.
Pass hole: a metal hole used to connect the pins of a component between layers.
Mounting hole: Used to fix the printed circuit board.
Conductor: Copper film used to connect the pins of the component to the electrical network.
Connector: A component used to connect circuit boards.
Filling: Apply copper to ground wire network to reduce impedance.
Electrical boundary: used to determine the size of the board. All components on the board must not exceed this boundary.
Second, there are three common laminate structures of printed circuit board, including Single Layer PCB, Double Layer PCB and Multi Layer PCB. The brief description of these three laminate structures is as follows:
(1) single-layer board: that is, only one side of copper and the other side of the circuit board without copper. Components are usually placed on an uncoppered side, which is primarily used for wiring and welding.
(2) Double Layer board: that is, two sides are coated with copper circuit board, usually called one side as the Top Layer, the other side as the Bottom Layer. Generally, the top layer is used as the surface for placing components, and the bottom layer is used as the welding surface for components.
(3) multilayer board: that is, a circuit board containing multiple working layers, in addition to the top and bottom layer also contains a number of intermediate layer, usually the intermediate layer can be used as a wire layer, signal layer, power layer, ground, etc. The layers are insulated from each other and the connection between the layers is usually achieved through holes.
Third, printed circuit board includes many types of work layer, such as signal layer, protection layer, screen printing layer, internal layer, etc., the role of each layer is briefly introduced as follows:
(1) Signal layer: mainly used for placing components or wiring. Protel DXP usually contains 30 intermediate layers, i.e. Mid Layer1~Mid Layer30. The middle layer is used to arrange signal lines, while the top and bottom layer are used to place components or copper coating.
(2) protective layer: mainly used to ensure that the place on the circuit board does not need tin plating is not tinned, so as to ensure the reliability of the circuit board operation. Top Paste and Bottom Paste are the Top layer and Bottom layer respectively. Top Solder and Bottom Solder are Solder paste protection layers and Bottom Solder paste protection layers respectively.
(3) Screen printing layer: mainly used to print the serial number, production number and company name of the components on the printed circuit board.
(4) Internal layer: mainly used as signal wiring layer, Protel DXP contains a total of 16 internal layers.
(5) Other layers: mainly include 4 types of layers.
Drill Guide: Mainly used for the location of holes on printed circuit boards.