- Issue Time
- Jun 24,2021
The main function of the printed circuit board is to connect various electronic components to a predetermined circuit. This article will specifically introduce six precautions for connecting printed circuit board components.
The printed circuit board realizes the electrical connection of pads and vias through the printed wires on the circuit board. At the same time, it also provides mechanical support for the fixed assembly of various electronic components such as integrated circuits. It can realize wiring and electrical connection or electrical insulation between various electronic components such as integrated circuits. When wiring and connecting components, we need to pay attention to the following items.
1. Cross circuits are not allowed in the printed circuit. For the lines that may cross, you can use "drilling" and "winding" to solve them. That is, let a lead "drill" through the gap under other resistors, capacitors, and triode pins, or "wind" from one end of a lead that may cross. In special circumstances, how complex the circuit is, it is also necessary to simplify the design. It is allowed to use wire to bridge to solve the problem of cross-circuit.
2. Components such as resistors, diodes, and tubular capacitors can be installed in "vertical" and "horizontal" installation methods. The vertical type refers to the installation and welding of the component body perpendicular to the circuit board, which has the advantage of saving space. The horizontal type refers to the installation and welding of the component body in parallel and close to the circuit board, and its advantage is that the mechanical strength of the component installation is better. For these two different mounting components, the component hole pitch on the printed circuit board is different.
3. The grounding point of the same level of the circuit should be as close as possible, and the power filter capacitor of this level of the circuit should also be connected to the grounding point of this level. In particular, the grounding points of the base and emitter of the transistor of this level should not be too far apart, otherwise, the copper foil between the two grounding points will be too long, which will cause interference and self-excitation. Using such a "one-point grounding method" circuit will work better. Stable and not easily self-excited.
4. The main ground wire must be arranged strictly according to the principle of high frequency-intermediate frequency-low frequency in the order of weak current too strong current. It must not be turned over and over randomly. The connection between the levels is rather long. Follow this rule. In particular, the grounding arrangement requirements of the frequency conversion head, regeneration head, and frequency modulation head are more stringent. If improperly, it will self-excite and make it unable to work. High-frequency circuits such as FM heads often use large-area surrounding ground wires to ensure a good shielding effect.
5. Strong current leads (common ground, power amplifier power leads, etc.) should be as wide as possible to reduce wiring resistance and voltage drop and reduce self-excitation caused by parasitic coupling.
6. The traces with high impedance should be as short as possible, and the traces with low impedance can be longer because the traces with high impedance are easy to whistle and absorb signals, which will cause the circuit to be unstable. The power cord, ground wire, base trace without feedback components, emitter lead, etc. are all low impedance traces. The base trace of the emitter follower and the ground wires of the two channels of the radio must be separated, each forming one path. , Until the end of the function is combined again if two ground wires are connected back and forth, it is easy to produce crosstalk and reduce the degree of separation.
If there is a problem in the connection part of the component, the printed circuit board cannot realize its own electronic function. So if you want to know more about printed circuit boards, you can get a more comprehensive solution by contacting us.
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