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Circuits with different types and functions of grounding require various grounding methods. The common grounding methods used in electronic and electrical equipment include the following: 1. Safety grounding: Safety grounding involves connecting the casing of high-voltage equipment to the ground. Firstly, it is to prevent charge buildup on the casing, which could lead to electrostatic discharge and pose a risk to equipment and human safety. For example, the grounding of computer cases, as well as the tail section of tank trucks that is dragged along the ground, serve to release any accumulated charge and prevent accidents ； Secondly, when the insulation of the cable components in a device is damaged and causes the casing to become charged, it triggers the protection mechanism of the power supply, which then cuts off the power supply in order to protect the safety of the workers, such as in the casings of refrigerators and rice cookers. Thirdly, it can shield against the strong electric fields generated by devices, providing protection; for example, in the case of protective fences around civil transformers. 2. Lightning protection grounding: When power electronic equipment is struck by lightning, whether it is a direct strike or an induced strike, without appropriate protection, the equipment can suffer severe damage or even become unusable. To prevent lightning strikes, we generally install lightning rods at high locations (such as rooftops or the tops of chimneys) and connect them to the ground, so as to protect equipment and people from harm in the event of a lightning strike. Both safety grounding and lightning protection grounding serve to provide safe protection for electronic and electrical equipment as well as personnel, thereby safeguarding the safety of such equipment and people. 3. Working ground: The working ground provides a reference potential for the proper operation of the circuit. This reference potential is generally set to zero. This reference potential can be set at a certain point, section, or component within the circuit system. When this reference potential is not connected to ground, it is considered a relative zero potential. However, this relative zero potential is unstable; it changes with variations in external electromagnetic fields, which in turn alters the parameters of the system and leads to unstable operation of the circuit system. When this reference potential is connected to the ground, it is considered to be the zero potential of the ground and does not change with variations in external electromagnetic fields. However, an unreasonable working ground can instead increase circuit interference. For example, interference caused by an incorrect ground point, or interference resulting from improper connection of the common terminals of electronic devices. To effectively control various interferences generated by the circuit during operation, so that it complies with electromagnetic compatibility principles. When designing circuits, depending on the nature of the circuit, the working ground can be classified into different types, such as DC ground, AC ground, digital ground, analog ground, signal ground, power ground, and supply ground. Different grounds should be set up separately. Do not mix them together in the same circuit; for example, digital ground and analog ground cannot share the same ground wire, otherwise the two types of circuits will generate very strong interference that can damage the circuit! 4. Signal: The signal ground is the common reference ground wire for the zero potential of various physical quantity signal sources. Since signals are generally weak and prone to interference, an improper grounding can cause interference in the circuit; therefore, high requirements are placed on the signal ground. 5. Simulated ground: The simulated ground is the common reference ground for the zero potential in analog circuits. In analog circuits, there are small-signal amplifiers, multi-stage amplifiers, rectifier circuits, voltage regulator circuits, and so on. Improper grounding can cause interference and affect the proper operation of the circuits. Grounding in analog circuits is of great significance for the entire circuit; it is one of the foundations for its proper operation. Therefore, proper grounding in analog circuits cannot be ignored as it has an impact on the entire circuit. 6. Digital ground: The digital ground is the common reference ground for zero potential in digital circuits. Since digital circuits operate in a pulsed state, especially when the edges of the pulses are steep or the frequency is high, a large amount of electromagnetic interference is generated, which disturbs the circuit. If grounding is not done properly, it can exacerbate interference; therefore, careful consideration must be given to the selection of the digital ground point as well as the layout of the grounding wires. 7. Power ground: The power ground is the common reference ground wire at zero potential of the power supply. Since the power supply typically supplies power to various units within a system, and the requirements regarding the nature and parameters of the power supply can vary greatly among these units, it is necessary to ensure both the stable and reliable operation of the power supply itself as well as that of the other units. The power ground is generally the negative pole of the power supply. 8. Ground for power: The ground for power is the common reference ground at zero potential for the load circuit or the power drive circuit. Due to the high current and voltage in the load circuit or power drive circuit, if the resistance of the ground wire is high, a significant voltage drop occurs, leading to substantial interference; therefore, there is considerable interference on the power ground wire. Therefore, the power supply must be installed separately from other low-voltage systems to ensure the stable and reliable operation of the entire system.