In practical EMI shielding, the electromagnetic shielding efficiency depends largely on the physical structure of the chassis, namely, the continuity of conduction. The seams and openings in the chassis are leakage sources of electromagnetic waves.
Here, it is temporarily classified into two categories: one is electrical related safety spacing, one is non-electrical related safety spacing.
After the circuit is completed, solder resistance ink is coated on the circuit as protection of the circuit. There are liquid photosensitive, heat curing and UV hardening.
Our electronic products are often more than 60% - reliability problems are in the PCB design of the electronic circuit board; Relevant theoretical and practical experience is required for working and performing PCBS;
In the high-speed era, the ideal wiring on any section of schematic diagram has become an unsatisfactory wiring on PCB, bringing a variety of unexpected high-speed problems. Therefore, PCB engineers also need to accumulate experience and theoretical knowl
For circuits with large redundancy of power pins, the number of matched capacitors can also be calculated according to the number of output pins, and every 5 outputs is matched with a 100nf filter capacitor.
In the manufacture of high density packaging structure such as BGA for PCB raw materials technical requirements, special analysis should be carried out carefully, the selection of substrate and copper foil thermal expansion coefficient basically to match.
The above conclusions are similar when the power source ground distance is less than 10mil. However, when the power source is located at 20mil or even 50mil, the situation changes slightly. As shown in Figure 3, when the ground distance of the power suppl
PCB proofing is the basis of the mass production of circuit board products. It is important to save cost, improve design and break through innovation, so PCB proofing is an indispensable part of PCB batch processing.
The small circuit material on the surface of PCB board is copper foil. Originally, copper foil is covered on the whole board, but in the manufacturing process, the middle part is etched away, and the remaining part becomes a network of small lines.
In the typical radiation case of EMC testing and rectification, common-mode voltage parasitic between analog circuit and digital circuit is the main reason for the formation of common-mode radiation.
If the design rules do not meet the requirements of PCB manufacturing process, it will not only affect the function of the product so simple, even can not process can not realize the design intention of the engineer.
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