Different grounding methods in circuits

YouTube：https://youtube.com/shorts/M-wmtXuxF_8

There are various grounding methods in circuits, and each grounding method has its specific uses and characteristics:

1. **Single-point grounding** - **Definition**: All circuit parts that need to be grounded are connected to a common grounding point. This grounding method can effectively avoid mutual interference between different circuits.

- **Application scenarios**: It is applicable to low-frequency analog circuits, such as audio amplification circuits. In audio amplification circuits, tiny signals are easily interfered with. Through single-point grounding, the grounding terminals of the pre-amplification stage, power amplification stage, etc. can all be connected to a common point, so that the ground currents between different stages will not interfere with each other, thus reducing noise and ensuring the purity of the audio signal.

- **Advantages**: It can effectively prevent the generation of ground loop currents and reduce electromagnetic interference between circuits. It is especially effective for low-frequency circuits that are sensitive to interference.

- **Disadvantages**: In high-frequency situations, due to the inductance existing in the grounding wire, as the frequency increases, the inductive reactance of the inductance increases, which may lead to a deterioration of the grounding effect.

2. **Multi-point grounding**

- **Definition**: Each grounding point in the circuit is directly connected to a large conductive plane (such as the metal shell of the equipment or the grounding busbar), and this conductive plane can be regarded as the common ground.

- **Application scenarios**: It is often used in high-frequency circuits, such as the motherboard circuits of computers. In high-frequency circuits, the wavelength of signals is short and the signal change speed is fast. The multi-point grounding method can provide a lower impedance path for high-frequency signals, reducing electromagnetic radiation and signal reflection. Because high-frequency currents can flow into the earth through the shortest path, excessive potential differences on the grounding wire can be avoided.

- **Advantages**: In a high-frequency environment, it can provide a lower grounding impedance, reduce the radiation and reflection of high-frequency signals, and ensure the normal operation of the circuit.

- **Disadvantages**: It is easy to form ground loops, resulting in ground loop currents. When there is a potential difference between different grounding points, the ground loop current will generate interference signals in the circuit, especially in low-frequency cases, and this interference may be more obvious.

3. **Hybrid grounding** - **Definition**: It combines the characteristics of single-point grounding and multi-point grounding. In the circuit, according to the frequency characteristics of the signal, the circuit is divided into different parts. Single-point grounding is adopted for the low-frequency part, and multi-point grounding is adopted for the high-frequency part.

- **Application scenarios**: In some complex electronic equipment, such as communication base station equipment. There are both low-frequency control circuits and high-frequency radio frequency transmitting and receiving circuits in the equipment. For the control circuit part, single-point grounding is adopted to ensure its stability and anti-interference ability; for the radio frequency circuit part, multi-point grounding is adopted to meet the transmission requirements of high-frequency signals.

- **Advantages**: It combines the advantages of single-point grounding and multi-point grounding, can obtain a good grounding effect in different frequency ranges, effectively reduce electromagnetic interference, and improve the overall performance of the circuit.

- **Disadvantages**: The circuit design is relatively complex, and it is necessary to carefully consider the division and connection methods of different grounding parts to ensure the effectiveness of the grounding system.

4. **Floating ground** - **Definition**: The ground of the circuit has no direct electrical connection with the earth, but is isolated by components such as capacitors and transformers.

- **Application scenarios**: It is applied in some circuits with high requirements for electrical safety or those that need to isolate external interference. For example, some high-precision measurement circuits in medical equipment. These circuits may be affected by interference from the power grid or leakage current. Adopting the floating ground method can isolate the circuit from the earth, avoid the risk of electric shock to the human body, and at the same time reduce the impact of external interference on the measurement accuracy.

- **Advantages**: It can effectively isolate interference from the earth, improve the anti-interference ability of the circuit, and to a certain extent ensure electrical safety and prevent electric shock accidents.

- **Disadvantages**: Since the circuit ground has no direct connection with the earth, if static electricity accumulates inside the circuit, it may lead to electrostatic discharge and damage electronic components; moreover, the isolation components such as capacitors in the floating ground system may introduce additional capacitive reactance and have an impact on high-frequency signals.