Computer power supply guide

Multinational certification mark: the quality of power supply has certified FCC, American UR and China the Great Wall sign, the certification is the certification bodies within the industry according to the technical specification of the power to develop professional standards, including production flow, electromagnetic interference and safety protection, those who meet certain indicators of products in order to use the certification mark in the packaging and product surface in the declaration of the certification. It should be said that there is a certain degree of authority.
Noise and filtering: this index needs through professional equipment to quantify judgment, mainly by filtering and 220V AC converter switching power supply DC low voltage, DC output noise smoothing degree mark, filtering the level of quality is directly related to the AC component of DC output level is called the ripple coefficient, the coefficient is as small as possible. At the same time, the capacity and quality of the filter capacitor is also related to the stability of the voltage when the current changes greatly.
Transient response capability: when the input voltage changes in a wide range of time (within the allowable range), the output of the steady voltage value to restore the normal time, but also the power of the abnormal response.
Voltage holding time: in PC system backup UPS occupies a large proportion of the grid when a sudden power failure, the backup of UPS switching power supply, but it generally requires the 2-10ms switching time (according to the specific properties of UPS and, so in the meantime) needs the power by the storage device can store electricity maintenance short supply power, the general quality of the holding time can be up to 12-18ms, to ensure the normal power supply of UPS during handover.
Electromagnetic interference: due to the working principle of switching power supply is determined with strong electromagnetic shock, with external radiation characteristics similar to radio waves, if not shielding may affect other devices, if the mobile phone or wireless communication device in the computer near, if the decline occurred on the description of the quality of communication by electromagnetic interference. So the amount of radiation of the domestic harmful is strictly limited by the outside power supply general tin and chassis is shielded, but the leakage of just how much weight problems can hardly be avoided. Because this kind of interference can not be seen and touched, and anti electromagnetic interference to spend a larger cost, so the poor power supply are ignored this indicator. In the international standards of FCCA and FCC, in the country also has the national standard A (industrial grade) and the national standard B B (household electrical appliances) standard, the quality of the power supply can be passed B level standard.
Start delay: This is a new concept, to provide a stable power supply stable periodic output must take some time on the beginning of this cycle in voltage stability is very difficult to guarantee, so the power supply designers to delay 100ms-500ms, such as power and stability after the computer to provide high quality power supply.
Overvoltage protection: ATX power supply is much more than the traditional AT 3.3V voltage regulator module group, some motherboards without the direct use of 3.3V as part of the motherboard power equipment, even with a voltage stabilizing device line, there are limits to the input voltage, when the voltage is increased to the power supply equipment may cause serious irreversible physical damage. So the overvoltage protection of power supply is very important.
Power efficiency: power efficiency and power supply design is closely related to the high efficiency of the power supply can improve the efficiency of the use of electricity, to a certain extent, can reduce the power consumption and heat.
Power supply life: general power life in accordance with 3-5 calculation of the possible failure of the cycle, the average working time between 80000-100000 hours.
Given the current popular configuration, 200W power has been stretched, in order to be able to operate more secure system, leaving a very important margin. So, how to choose a good power supply? In fact, the real price or choose a good power supply, mainly to consider the following factors:
1, security specifications: industry at home and abroad in the power supply element selection, material insulation, flame retardant and other aspects have strict safety standards provisions, such as the famous UL, CSA, TUV, CCIB and so on, while the domestic famous is CCEE (China electronic product quality certification). If you have these signs on the power supply, which means that it passed the certification. Due to the long period of application of Safety specifications, there are strict restrictions and requirements, the cost is very large, and to accept regular and irregular supervision and inspection. Once the application is filed, it is not allowed to change, replace or modify the components and types of the products. Therefore, there are safety specifications of the starting point of the product will be much higher than the non safety specifications.
2, electromagnetic interference specification: from the perspective of electromagnetic security, the computer to meet the electromagnetic interference standard. Electromagnetic interference on the grid will have adverse effects on electronic equipment, but also on human health hazards. Most countries in the world and the international organization for standardization has set some standards for electromagnetic interference and radio frequency interference, the standard requirements of electronic equipment manufacturers of radiation and conduction interference of their products is reduced to an acceptable level, the most famous is "FCCCLASSB". It is the electromagnetic interference standards developed by the United States on the residential environment, the current domestic market through the test certification of the power supply only a few, such as licensing, licensing, Parkson Huntkey Great Wall.
3, load change rate: computer power output is a multi output, each output has a certain range and specifications. Users in the use of different requirements or configuration, there will be a variety of deviations. The power supply shall be guaranteed not to produce output due to the use of different loads