The means of gold immersion process is being PCB board printed route nominal stacking colour stability, good finish, flat plating, excellent solderability nickel-gold plating, the difference between immersion gold and gold fingers,
Total Impedance (TI) is the sum of the impedance of all components to the current in the entire circuit or system. It is an important parameter in AC circuits and is used to describe the degree to which the circuit impedes the alternating current.The significance of the total impedance calculation is that it is an important parameter of the current in the circuit and helps to determine the magnitu
how to calculate impedance, it depends on trace width, trace space, soldermask thick, dielectric thickness and dielectric constants factors.
The reason of circuit board getting hairy, the phenomenon of half a month's service under the conformal coating, that picture is all creep corrosion, only the other one has been tampered with, silver PCB, electron microscope magnification, conformal coating after the dendrites indicate that the degree of cleanliness is not enough, there is ionic contamination
The reasons for component false soldering Insufficient soldering temperature, The soldering surface is not clean, Poor solder quality, The soldering iron tip is oxidized, Improper treatment of the component pins, Improper soldering operation, Improper use of flux, Poor solderability of the circuit board or components
bga rework, next to the resistor on the growth of this tin bead, it is because tin changes from solid to liquid, the volume expands, heat segregation,BGA bottom filler, desoldering peak temperature is too high, or the rate of heating is too large, the solder ball melting volume expansion will be spattered tin phenomenon occurs, the original filler glue before repair to be removed, otherwise the fl
Analysis of the cause of the black powder found between PCB and the component, Tin oxide is a black semiconductor, it is oxidation of dynamic molten solder, component of oxide slag is SnO2
The reason of copper on the chip pins is exposed after soldering, the coating is not plated, If it is the upper and lower surfaces of the parts, the plating is not done well. If it is the side, it is acceptable to have different positions
