Therefore, careful consideration should be given to the placement of ground wires in the layout. Mixing all kinds of ground will cause unstable power supply. The following points should be noted in the design of ground wire:
The parameters of PCB board layer, the distance between signal wires, the electrical characteristics of the driver and receiver end, and the connection mode of signal wires all have a certain influence on the crosstalk.
Now the production of gold plate is rarely, in the actual trial process, 90% of the gold plate can be replaced by gold plate sinking gold plate, gold plate welding poor is his fatal shortage, is also the direct cause of Princecircuit to give up gold plate
it is easy to drill solder from the end of the covering layer to under the covering layer, especially when the bonding strength of the covering layer and copper foil surface is low, this phenomenon is more likely to occur frequently.
When a constant current is obtained from the power source, the transmission line looks like an impedance and has a constant impedance value, which can be called the "surge impedance" of the transmission line.
In principle, the smaller the test point, the better (of course, to meet the requirements of the test machine), the shorter the branch, the better.
The success of a product, one is to pay attention to the internal quality, two is to take into account the overall beauty, both are more perfect in order to consider the product is a success.
The basic knowledge of each device on the circuit board is repaired and tested until the bad parts are found and replaced, so a circuit board is repaired.
With the introduction of surface mount technology, automatic detection technology of circuit board is applied, and the packaging density of circuit board increases rapidly.
The circuit board makes the circuit miniaturized and intuitive, which plays an important role in the mass production of fixed circuit and the optimization of electrical appliance layout.
depending on the thickness of the gold layer, if the thickness is thin, the nickel layer may appear in the gold layer due to diffusion and oxidation, affecting the reliability, not inadvertently.
This process can ensure that the oil cover through the hole is good, the plug hole is smooth, the wet film color is consistent, the hot air leveling can ensure that the through hole is not tin, no tin beads in the hole, but it is easy to cause the ink pad
