What is a PCB circuit board
Printed circuit board {PCB circuit board}, also known as printed circuit board, is a provider of electrical connections for electronic components. Its development has a history of more than 100 years; its design is mainly layout design; the main advantages of using circuit boards are greatly reducing errors in wiring and assembly, and improving automation and production labor rates.
的 PCB circuit board composition
1. Circuit and Pattern: The circuit is used as a tool for the conduction between the originals. In design, a large copper surface will be designed as the ground and power layer. The lines and drawings are made at the same time.
2. Dielectric layer: used to maintain the insulation between the circuit and the layers, commonly known as the substrate.
3. Through hole (via): A via can make more than two levels of circuits communicate with each other, a larger via is used as a component plug-in, and a non-via (nPTH) is usually used as Surface mount positioning for fixing screws during assembly.
4, Solder resistant ink (Solder resistant / Solder Mask): Not all copper surfaces need to eat tin on the parts, so non-tin-eating areas, a layer of material that is isolated from the copper surface (usually epoxy resin) will be printed. To avoid short circuit between non-tin-eating lines. According to different processes, it is divided into green oil, red oil, and blue oil.
5. Silk screen (Legend / Marking / Silk screen): This is an unnecessary structure. Its main function is to mark the name and location frame of each part on the circuit board, which is convenient for maintenance and identification after assembly.
6. Surface Finish: As the copper surface is easily oxidized in the general environment, it can not be tinned (poor solderability), so it will be protected on the copper surface to eat tin. The protection methods are HASL, ENIG, Immersion Silver, Immersion TIn, and Organic Solder Flux (OSP). Each method has advantages and disadvantages, which are collectively referred to as surface treatment.
PCB circuit board design steps
The basic design process of the circuit board can be divided into the following four steps:
(1) Design of circuit schematic diagram: The design of circuit schematic diagram is mainly to draw the schematic diagram by using the schematic editor of Protel DXP.
(2) Generate a network report: A network report is a report showing the relationship between the circuit principle and the various components in the circuit. It is a bridge and link between the circuit schematic design and the circuit board design. Ground to find the connection between components, so as to facilitate the subsequent PCB design.
(3) Printed circuit board design: Printed circuit board design is what we usually call PCB design. It is the final form into which the circuit schematic diagram is converted. The related design in this part is more difficult than the circuit schematic diagram design. , We can use the powerful design features of Protel DXP to complete this part of the design.
(4) Generate printed circuit board reports: After the printed circuit board design is completed, various reports must be generated, such as generating pin reports, circuit board information reports, network status reports, etc., and finally printed out printed circuit diagrams.