First, the definition of PCB circuit board PCB (
Printed Circuit Board)
The Chinese name is printed circuit board, also known as printed circuit board. It is an important electronic component, a supporting body for electronic components, and a carrier for electrical connection of electronic components.
Because it is made by electronic printing, it is called a printed circuit board.
II. Composition of PCB the PCB is mainly composed of pads, Vias, mounting holes, wires, components, connectors, filling, electrical boundaries, etc. The main functions of each component are as follows: Pads: metal holes for soldering component pins.
Vias: metal holes used to connect component pins between layers.
Mounting hole: used to fix the printed circuit board.
Wire: Electrical network copper film used to connect component pins.
Connector: components used for connection between circuit boards.
Filling: copper coating for ground wire network can effectively reduce impedance.
Electrical boundary: used to determine the size of the circuit board. All components on the circuit board cannot exceed this boundary.
Three, common circuit board layer structure, printed circuit board common layer structure includes single-layer board (
Single Layer PCB), Double board (
Double Layer PCB)And multilayer board (Multi Layer PCB)
Three, the brief description of these three slab structures is as follows :(1)
Single-layer board: a circuit board with only one side coated with copper and the other side not coated with copper.
Usually components are placed on the side without copper application, and the side with copper application is mainly used for wiring and welding. (2)
Double-layer board: that is, a circuit board with copper on both sides, usually called one side as the top layer (Top Layer), The other side is the bottom layer (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: a circuit board that contains multiple working levels. In addition to the top layer and the bottom layer, it also contains several intermediate layers. Usually, the intermediate layer can be used as a wire layer, a signal layer, a power layer, a ground layer, etc.
Layers are insulated from each other, and the connection between layers is usually realized through vias.
Four, common circuit board layer structure constitutes a printed circuit board (Jie with PCB proofing production)
Including many types of working layers, such as signal layer, protective layer, silk screen layer, internal layer, etc. The functions of various layers are briefly introduced as follows :(1)
Signal layer: mainly used to place components or wiring.
Protel DXP usually contains 30 intermediate layers, namely Mid Layer1 ~ Mid Layer30, the middle layer is used to arrange signal lines, and the top and bottom layers are used to place components or copper. (2)
Protective layer: it is mainly used to ensure that the places on the circuit board that do not need to be tinned are not tinned, thus ensuring the reliability of the circuit board operation.
Among them, Top Paste and Bottom Paste are the Top solder resist layer and the Bottom solder resist layer respectively;
Top Solder and Bottom Solder are Solder paste protective layer and Bottom Solder paste protective layer respectively. (3)
Screen printing layer: mainly used to print the serial number, production number, company name, etc. of components on the printed circuit board. (4)
Internal layer: mainly used as signal wiring layer, Protel DXP contains 16 internal layers. (5)Other layers: mainly includes 4 types of layers. Drill Guide (Drilling azimuth layer)
: Mainly used for drilling positions on printed circuit boards.
The above is the introduction of PCB composition and some main functions. For more details, please click hope to help everyone.