Understand what types of protection components of PCB circuit boards are divided into?
PCB circuit board is mainly to provide interconnection between electronic components. It is very limited to improve the PCB protection ability only by the optimized design of the PCB board wiring. In order to ensure that the entire system has a better PCB protection ability, external PCB protection devices are essential. In fact, different PCB protection schemes can be selected according to specific needs. Typical PCB protection devices fall into the following categories:
1. Clamping diode. The transient voltage between the positive and negative polarity can be clamped within a certain range by two diodes, and the series resistance can be used to provide the power load, thereby protecting the PCB with positive and negative polarity.
2, transient voltage suppressor. Transient voltage suppressor, also known as TVS tube, is a solid-state diode specifically designed for PCB protection. The characteristics of TVS tube are short response time and small leakage current. It is an ideal protection device.
3. Resistive-capacitive components. By inserting resistance-capacitance components on each signal line, it can play a certain role in shielding the PCB. The series resistance can suppress the instantaneous peak current, and the capacitor connected to the ground in parallel can limit the instantaneous peak voltage.
4. Zener diode. Although the Zener diode is not specifically designed for PCB applications, its working characteristics determine that it has certain positive and negative PCB protection effects. Its disadvantage is. The N-junction is small, so it cannot bear a large peak current. In addition, the parasitic capacitance it generates is large, which may affect the normal operation of the circuit.
5. Gas discharge tube (GDT). The gas discharge tube uses glass or ceramics with a certain airtightness as the casing. The tube is filled with a stable gas such as neon or argon to maintain a certain insulation. The gas discharge tube has the advantages of large insulation resistance, small parasitic capacitance, and can recover by itself, but the disadvantages are that the response speed and life are not ideal, and the electrical performance will gradually decline with time.