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Della Zhang

Email:zx@pcb-smt.net 

Tel:+8675526978081

Fax:+8675526978080

Mobile:+8613510199155

Web:www.pcb-smt.net/www.pcbapcb.com 

Factory address: 3/F. 1/B, 18-2 Yuquan East Rd. Yulv Village. Guangming New district. Shenzhen. China.

Bus Subway Card System Pcb Board

Testing Service:Test fixture/AOI/X-ray Hole Wall Copper Thickness:0.025mm 1mil OEM/ODM:T-SOAR One-stotp Service

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Bus Subway Card System Pcb Board

Bus subway card system pcb board

应用行业 

The general inspection in the circuit board means the final inspection of the circuit board. In English, the FQC indicates the general inspection of the circuit board. The general inspection of the circuit board has a professional department in the department of circuit board production to carry out the line to be issued. The board performs a full-scale systematic inspection to prevent the circuit board from malfunctioning due to mistakes in the production process. In the inspection process, it is necessary to carefully check each process of the circuit board, such as: whether the plating is good, the shape is good, the characters are clear, etc. Some conditions need to be checked, and the circuit board is also needed. Carry out testing work to ensure that the circuit board is a product that can work normally when it is shipped, so as to ensure that the product quality meets the needs of users. Intuitive inspection method: This method refers to the kind of intuition-visual, olfactory, auditory and tactile sensation to check the fault of the board to be repaired without using any equipment and equipment, without welding any circuit components. method. The intuitive inspection method is the simplest method of equipment failure. The law can be divided into a power-on inspection method and a non-power-on inspection method. The circuit board professional inspection instrument is used to carefully check the on-off condition of various circuits of the circuit board, and the voltage value and current value in each circuit are compared and compared under normal conditions to find out whether the circuit board is qualified.

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In the case where the board is not powered, there may be a problem with the resistance of the board, or some other component may cause this to happen. The board is not powered, and the components in the board may be soldered or soldered, resulting in no power. In the case that the board is not powered, we can first use a multimeter to detect the circuit in the board, see if the circuit is disconnected, and then test. When replacing the circuit board, do not directly replace the good circuit board. Before replacing it, make sure that the circuit board test board body has a short circuit condition. If there is a short circuit, it cannot be replaced directly, otherwise the replaced circuit board will be burned out immediately. Shenzhen Honglijie Electronics can provide PCBA functional test of circuit board to ensure the normal operation of PCBA products.

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 In the production process, the circuit board must undergo the process of making copper, electroplating tin, soldering of the connector, etc., and the materials used in these links must ensure low resistivity, in order to ensure that the overall impedance of the circuit board is low and meet the product quality requirements. run. Tin plating of the circuit board is the most prone to problems in the entire circuit board production, and is the key link affecting the impedance. The biggest defects of the electroless tin plating layer are easy discoloration (both easy to oxidize or deliquesce) and poor brazability, which may cause the circuit board to be difficult to solder, and the impedance is too high, resulting in poor conductivity or instability of the entire board. There are various signal transmissions in the circuit board conductor. When the transmission frequency is increased, the frequency must be increased. 

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 If the line itself is different due to etching, laminate thickness, wire width, etc., the impedance value will be changed to make the signal Distortion, resulting in reduced performance of the board, so you need to control the impedance value within a certain range. In the production process of the circuit board, we must consider the installation components after the plug-in, to consider the electrical performance and signal transmission problems, so the lower the impedance, the better. The reason for the circuit board resistance process is more, the high resistance is also divided into the inner layer is too high, or the outer layer is too high, in the general case, the reason why the circuit board is too high resistance. The lines are relatively thin, resulting in high resistance of the circuit board. The copper thickness of the circuit board is relatively thin, resulting in high resistance of the circuit board. The line spacing of the circuit board, the thickness of the dielectric layer is thick, and the thickness of the outer layer of the ink is thick, which causes the resistance of the circuit board to become high.

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Such as input / output, AC / DC, strong / weak signals, high / low frequency, high pressure / low voltage, etc., their direction should be linear (or separated), must not blend together. Its purpose is to prevent mutual interference. The best direction is in a straight line, but it is generally difficult to achieve. The most unfavorable trend is the ring. Fortunately, isolation can be improved. For DC, small signal, low voltage PCB design requirements can be lower. So "reasonable" is relative. Little grounding point I don't know how many engineers and technicians have discussed it, which shows its importance. In general, it is required to share a common ground. For example, multiple ground wires of the forward amplifier should be connected and then connected to the trunk line. In reality, it is difficult to do it completely because of various restrictions, but you should try to follow it. This problem is quite flexible in practice. Everyone has their own set of solutions. It can be easily understood if it can be explained for a specific board. In general, only a few power supply filtering/decoupling capacitors are drawn in the schematic, but they are not indicated where they should be connected. In fact, these capacitors are set for switching devices (gates) or other components that require filtering/decoupling. These capacitors should be placed as close as possible to these components, and it would be ineffective if they are too far apart. Interestingly, the grounding point problem is less noticeable when the power supply filtering/decoupling capacitors are properly arranged. 

认证1

The lines are exquisite: the conditions are wide and the lines are never made fine; the high-voltage and high-frequency lines should be smooth, no sharp chamfers, and corners should not be used. The ground wire should be as wide as possible. It is best to use a large area of copper, which has a considerable improvement on the grounding point problem. Some problems occur in post-production, but they are brought about by PCB design. They are: too many hole holes, and the copper sinking process will cause hidden dangers. Therefore, the design should minimize the number of holes. Straight lines in the same direction are too dense, and it is easy to form a piece when welding. Therefore, the line density should be determined by the level of the welding process. The distance between the solder joints is too small, which is not conducive to manual soldering, and can only solve the welding quality by reducing the work efficiency. Otherwise it will leave hidden dangers. Therefore, the determination of the minimum distance of the solder joint should take into account the quality and work efficiency of the welding personnel. The pad or via hole size is too small, or the pad size is not properly matched to the hole size. The former is not good for manual drilling, and the latter is not good for CNC drilling. It is easy to drill the pad into a "c" shape and drill the pad again. The wire is too thin, and the large area of the unwiring area is not provided with copper, which is likely to cause uneven corrosion. That is, when the unwiring area is corroded, the thin wire is likely to corrode too much, or it may be broken or completely broken.

FASTPCBA Technology Co.,Ltd is a competitive China bus subway card system pcb board OEM manufacturer, supplier and vendor, you can get quick turn bus subway card system pcb board production prototypes and samples from our factory.
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