The computer case is an indispensable accessory for the computer. It plays a role in fixing and protecting various parts of the computer. In addition, the computer case plays an important role in shielding electromagnetic radiation. Due to the rapid development of CPU, graphics card, motherboard and other accessories in the computer chassis, it has not been listed as a key consideration in the assembly of computers. However, the chassis is not useless. Some users buy a brand-name chassis, because the motherboard and the computer chassis form a loop, resulting in a short circuit, making the system very unstable. There are also some brand-name chassis. Because the process technology is not in place, the leakage of the computer case often occurs. Today, we analyze the cause of the leakage of the computer case. Analysis of the causes of computer chassis leakage In the national 3C-certified computer power supply, the 220V AC input lines are powered by three wires, which are FireWire (L), Neutral (N) and Ground (E). Due to the 3C standard, the EMI filter circuit must be added to the 3C computer power supply to filter out the interference of the high-frequency pulse in the power grid to the power supply, and also to filter out the power supply itself. 220V AC, input into the EMI filter circuit of the computer power supply through the live and neutral lines, the connection point between the capacitors is connected with the outer casing of the power supply through the screw, and the outer casing of the computer power supply is connected with the grounding wire when there is no grounding. When the line is used (only when the two-wire power supply is used), the voltage is 110V (the theoretical value is half of the input voltage of 220V) due to the series voltage division of the capacitor. This high voltage is due to the computer chassis, the ground wire of the motherboard, and the power supply casing. It is connected together, which will cause leakage of the computer case, but because the capacitance is very small (200W power supply usually uses 3300pF, 300W power supply usually uses 4700pF), so the "leakage current" is small, no Will cause "human shock" danger to the human body, but there will be a feeling of "electric shock", "electric shock", the intensity of the feeling will vary depending on the power supply, usually 300W power supply, because the capacitance capacity is 4700pF, <;leakage current> will be larger than the 3300pF used by 200W, “shocks”sense will be stronger, which is why users It will be felt that some power supply chassis leakage will be stronger, and some power supply chassis leakage will be weaker. It can be seen from the above estimation that the leakage current generated by the EMI filter capacitor is a few milliamperes at zero, so the current is small and does not pose a danger to the human body. Solution to computer power leakage We analyzed the leakage of the computer power supply above. 3C power supply will have "leakage" phenomenon, when accidentally hit the metal part of the chassis, there will be a feeling of "electric shock", many users are still not assured, the following two methods are introduced to eliminate this computer chassis failure phenomenon . 1 The best way is to use three-wire power supply, so that the first line has a good grounding, the computer power supply shell and the ATX chassis will not bring "Electric". (Recommended for this method) 2 For users who cannot use the three-wire power supply for various reasons, the user can make a ground wire, insert a one-foot long iron wire into the damp land, and use the wire to connect the iron wire to the computer. The metal plates of the chassis are connected. If the user can't do it in the previous two methods, there is no need to pay attention to the leakage current, because it is not dangerous to the human body. Some users use a wire to connect the computer case with the water pipe in the home. It can solve the leakage current problem, but it is even more unsafe because the grounding effect of the water pipe is unstable. If the computer really leaks, it will be very dangerous. This is not recommended. 3 Because a certain cable in the computer case is placed together with the chassis, this problem is very troublesome. It is very necessary to completely remove the contents of the chassis and reinstall it to solve the problem. Or the quality of the chassis power cord. The above is the analysis and solution of the leakage of the computer case, I hope to help everyone. This article comes from [System Home] www.xp85.com