In this paper, the key is to introduce PCB phosphorus copper ball in detail, the first detailed introduction of PCB electroplating copper need to use phosphorus containing copper ball, followed by the discussion of the use of phosphorus copper ball in PCB
the control of hydrochloric acid concentration value need not be slightly lower, the current intensity is slightly higher, not only the amount of the area and hemp sand can be defeated.
in the design of PCB board, PCB anti-ESD design can be realized by layering, proper layout and wiring and installation. The PCB layout and wiring can be adjusted to prevent ESD.
PCBA machining circuit board debugging steps and methods: 1. Board surface observation and resistance check, 2. Install components, 3. Detect power supply output voltage, 4. Preset overcurrent protection current, 5. Install and test other modules
Circuit board PCBA processing process can be roughly divided into: empty plate loading - printed solder paste - mounting devices - reflow welding -AOI testing - receiving plate - finished product inspection - parts after welding - circuit board open/short
Pay attention to the wiring of signal lines under the magnetic beads, between the pads and those that may come into contact with the magnetic beads. Some magnetic beads conduct electricity quite well and may produce unexpected conductive paths.
Ensure the machining accuracy and assembly accuracy of guide column and guide sleeve; Reduce the fit gap between the shape of pusher plate and the die, and make the shape of pusher plate consistent with the concave and convex shape.
Only under certain conditions can the 20H principle have obvious effects. 1. The power plane shall be located inside the PCB, and the upper and lower layers adjacent to it shall be 0V planes, and the distance between the two 0V planes shall be at least 20
Common bad reasons for PCBA welding resistance film processing :1. Welding pad and through hole connection. 2. Solder resistance design between pad and pad, solder resistance graphic specifications should conform to the design of welding end distribution
The difference between them is that the core is thinner, the pp sheets of one or two layers and five or six layers are thinner, and there is a core board between the core board and the core board without copper foil on both sides, so generally this kind o
The characteristics of the gold process: the copper on the circuit board is mainly copper, copper solder in the air is easy to be oxidized, which will cause the electrical conductivity is to eat tin bad or bad contact, reduce the performance of the circui
The function of PCB design discharge teeth: in surge testing or ESD testing, the two ends of the common-mode inductor will produce high voltage, there will be a flying arc, if the distance is close to the surrounding devices, it may cause damage to the su
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