The cause of leakage of computer case and its solving method

Computer chassis is an indispensable part of the computer, it plays a fixed, protect the role of various parts of the computer, in addition, the computer chassis with electromagnetic radiation shielding important role. Because the computer chassis has CPU, graphics cards, motherboards and other accessories to develop fast, so in the assembly of computers has not been listed as the focus of attention. But the chassis is not useless, some users bought a kitchen chassis, because the motherboard and computer chassis to form a circuit, resulting in short circuit, so that the system becomes very unstable. There are some of the kitchen chassis, because the process technology is not in place, often the phenomenon of computer chassis leakage occurs. Today we analyze the computer chassis leakage.

Analysis on the causes of leakage of computer chassis

In the national 3C Certified Computer power supply, 220V AC input line are used three lines of power supply, respectively, the FireWire (L), 0 lines (N) and Ground (E). As a result of the 3C standard, the computer power through 3C must be added EMI filter circuit, in order to filter out the power grid high-frequency pulse interference, but also to filter the power itself to the external production. 220V AC, through the FireWire and 0-line input to the computer power of the EMI filter circuit, the connecting point between the capacitance is connected with the shell of the power supply, and the shell of the computer power supply is connected with the grounding wire, when there is no grounding wire (only second line power supply), the voltage is 110V because of the series partial pressure of the capacitor. (The theoretical value is half of the input voltage 220V), such a high voltage, because the computer chassis, motherboard and power supply shell are connected together, this will lead to computer chassis leakage, but due to small capacitance capacity (200W power is usually used 3300pF, 300W power supply usually uses 4700pF), so through the "leakage current" is very small, will not cause "electric shock" danger, but there will be "electric shock" feeling, "electric shock" the intensity of the feeling will be different from the power supply power, usually 300W power supply, because capacitance capacity is 4700pF, " Leakage current "than the 3300pF used by the 200W will be larger," electric shock "feeling will be stronger, which is why users will feel some power supply chassis leakage will be stronger, some power supply chassis leakage will be weaker reasons." From the above estimates visible, EMI filter capacitor produced by the "leakage current" in the A fraction a MA class, so the current is very small, no danger to the human body.

Computer power leakage solution.

We analyzed the above computer power leakage phenomenon. 3C power supply will have "leakage" phenomenon, accidentally encounter chassis metal parts, there will be "electric shock" feeling, many users are still not assured that the following 2 methods to eliminate the phenomenon of computer chassis failure.

① the best way is to use three-wire power, so that the first line has a good grounding, the computer power supply shell and ATX chassis will not bring "electricity". (This method is recommended for use)

② for a variety of reasons can not use the three-wire power users, users can make a ground, a one-foot-long iron wire into the more humid land, with wire to the wire and computer chassis metal plate connection.

If the previous two methods do not have the user, do not have to pay attention to this leakage flow, because it does not cause danger to the human body, some users with a wire to the computer chassis and the home of the pipe connection, this method can solve the leakage current problem, but more unsafe, because the grounding effect of the tap is unstable, If the computer really leakage, it will be very dangerous, do not recommend such a practice.

③ due to a computer in the case of a wire with the chassis together, this problem is very troublesome, probably to all the things in the chassis removed and then reinstall troubleshooting. or the chassis power cord quality issue.