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Monthly Archives: September 2017
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September 28, 2017
1. The overlap of the welding plates. a. The overlap of welding plates means the holes are overlapped, when multiple drilling happens to one position, it would result in the damage of hole. b. Overlap of two holes in a multi-layer board will cause it scrapped. 2. The abuse of graphics layer. a. Doing some useless connection in the graphics layer is easily misunderstood, for example, a design for 4 layer PCB uses the circuit of 5 layer PCB or even above. b. In violation of conventional design, such as, the side of electronic parts is designed at the Bottom layer, and the welding side is designed at the Top layer, these all will cause troubles. 3. The characters are in a mess.
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September 26, 2017
The basic principle for the whole process of PCB design is: make the whole design beautiful as much as possible on the basis of following the requirements of product electrical and mechanical structure, keep the layout of electronic parts uniform and orderly in the printed circuit board. Here are the items and tips you should check:
- PCB size must be consistent with the size of processing drawings and follow the PCB manufacturing requirements.
- Check if the electronic components are conflicting in the two-dimensional and three-dimensional spaces.
- Is the distribution of electronic components in a well-organized, neat manner?
- Is it easy to replace the components that are frequently replaced? Is the plug-in
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September 20, 2017
1. Avoid the input end getting too close to the output end, especially in the case of high gain. For the following reasons: 1) When it is a positive amplifier, being too close would generate the parasitic capacitance - positive feedback loop – then cause the shock; this shock is independent of the input signal, that is, it could happen without input. The frequency of this shock depends on the circuit structure and parasitic capacitance and other factors, most of the time it’s over 1MHz. However, with the changes of parasitic capacitance, what would be caused is not only the circuit shock, sometimes the situation of work instability and deterioration would happen. 2) When it’s the opposite amplifier, the Miller effect is generated, which would cause the deterioration
