Basic knowledge of PCB board

1. Via-connection channel of double-layer board
This is the part that I couldn't figure out before. Get a PCB will find that there are many small holes with large needle tips. This is the via hole. Its structure is as follows.

Figure 1.1
The function of the via hole is mainly to connect the copper wires on the positive and negative plates, and most of the vias are the red areas in the figure. When the front wires are not well arranged due to staggering, vias can be used. Like the "overpass", the two-dimensional plane of the wiring into three-dimensional space. The vias in the blue area mainly connect the copper plates on both sides to achieve the effect of "common ground.

The following figure clearly shows the structure of the via hole. The copper in the hole part is generally obtained by electrolytic reduction.

2. Pad-Can be used to identify positive and negative poles
Pads are used for soldering of component pins. Its size is larger than the. Interestingly, pads have not only round shapes, but also square shapes. Generally, square pads represent high-voltage pins (I haven't paid attention to this detail before, haha)

Figure 2.1 Square and round pads
Another small detail in the above figure is that some round pads are cross-shaped, which grounds the pins directly. The grounding on the PCB board is actually connected to the negative pole, and the large area of copper plates are connected to the negative pole of the power supply. This ensures that all GND pins are common ground.

3. Commonly used electronic components
The commonly used resistors are not shown in the figure. Now, chip resistors are mainly used, and there are few in-line resistors.
Crystal-the heart of the circuit board, the number above represents the frequency

Fig. 3.1 Crystal Oscillator
Capacitor, there are black cylindrical, there are flat shape

Digital tube, of course, now many directly use the display screen

Buzzer

Four-pin switch-connect the pins of the same color in the figure.

4.PCB package
The so-called PCB packaging is to show the actual electronic components, chips and other parameters (such as component size, length and width, pin spacing, etc.) in the form of pictures so that they can be called when drawing PCB diagrams.

PCB sub-assembly is divided according to the installation method, and can be divided into SMD devices, plug-in devices, and special devices (sink devices)

5. Silk screen-let's engrave the name
After designing a PCB, with its own name and studio logo on the finished product, the satisfaction is full of wood. Of course, the main function of screen printing is to indicate the corresponding component label. PCB design, you can use a piece of A4 paper to print down on the components to see if there is shelter, font size is appropriate. Among the common signs are:

R(resistance)电阻
U(unit) unit module/integrated circuit
C(capacitance)电容
Q three-stage tube
X crystal oscillator
6. Concluding remarks
Personally, all people who use PCB should learn how to make PCB, including circuit design, AltiumDesign/Protel, soldering circuit boards, etc. Maybe you never need to make a circuit board, but with this knowledge can make you more familiar with the circuit board, ready to write programs.