Vias are generally divided into three categories: blind vias, buried vias, and through vias. A blind hole refers to the top and bottom surfaces of a printed circuit board. It has a certain depth and is used for the connection between the surface layer circuit and the inner layer circuit. Buried hole refers to the [...]
The fundamental effects of circuit board chip inductors: filtering, oscillation, delay, notch, etc. Image saying of circuit board chip inductor: "through DC, blocking communication" Passing DC to circuit board chip inductor: The so-called passing DC means that in a DC circuit, the effect of the inductor is equivalent to a wire, and it has no [...]
There are four main quality characteristics of circuit board prepregs: Resin content (RC), fluidity (RF), gel time (also called geltime, GT)), volatile content (also called volatile content, VC) . In the military standard MIL-P-13949, there is also a control index for dicyandiamide crystallization. In recent years, FR-4 and its prepreg production factories have also begun [...]
When the circuit board has been designed and laid out, and the connectivity and other issues did not go wrong during the test, is the PCB circuit board done? Either there is no error or no problem with the circuit board. Many engineers with little experience and overconfidence end the PCB testing process. In mass [...]
The common etching solution used to make circuit boards is ferric chloride solution. This article introduces the use of a mixed solution of hydrochloric acid and hydrogen peroxide to make circuit boards. "Copyright Statement: This article is provided by finishing, part of the content comes from the Internet, if you violate your rights, please contact [...]
The circuit board miniaturizes and visualizes the circuit, and plays an important role in the mass production of fixed circuits and the optimization of the layout of electrical appliances. So how much do you know about circuit boards? The following is organized by learning friends about what is a circuit board, I hope everyone likes [...]
2FeCl3 + Cu = 2FeCl2 + CuCl2, using the oxidizing copper oxide element of ferric ions, because the surface of the printed circuit board is copper-plated
I. Detection before power on When a circuit board is soldered, it is usually not to directly supply power to the circuit board when checking whether the circuit board can work normally, but instead to follow the steps below to ensure that there is no problem at each step and then power on is not [...]
The inspection after PCBA cleaning is mostly performed by visual inspection. For high-reliability products, special inspection equipment and standard methods are required to measure cleanliness. The standards for measuring cleanliness mainly include ion pollution and surface insulation resistance. First, cleanliness standards (1) Ionic pollution At present, there is no clear standard for ionic contamination in [...]
Prevent the deformation of the film inside the fence. 4. Design the alignment accuracy marks on the four corners of the board. 29. Why should the board be pre-baked before registration exposure? And is it baked at low temperature (75 ± 5 ℃)? Answer: Pre-baking of the board before the registration exposure: it is to [...]