One: Interpretation of power supply parameters
For each power supply, there is a nameplate on the power supply housing. The nameplate is full of many parameters, so which parameters should be paid attention to? Pay attention to the following parameters when purchasing power supply.
1: power supply
We need to pay attention to the power of power supply: rated power and maximum output power.
Rated power: There is no specific formula for calculating the rated power of power supply. Rated power generally refers to the effective power that can be continuously output; That is, the stable output power of the power supply under normal working environment. Rated power is the most important parameter specification of power supply. If the rated power of the power supply can't meet the needs of your computer, then all kinds of unpredictable problems are likely to follow.
By analyzing the standards formulated by intel, we can see that +5V is one of the most important outputs of power supply, and there is a general rule that the current value of +5V is 10 times, which is close to the rated power value of power supply. Therefore, in general, consumers can estimate the rated power of a power supply by this method-that is, the maximum output current of +5V times 10. Of course, the current output capacity of the+12VDC terminal is enhanced after the ATX2.03 standard, so when the rated power is not indicated on the nameplate of the power supply, the estimation of the power supply needs to be comprehensively considered in combination with the output current of+12V.
Maximum output power: the maximum power that can be output when the power supply works stably. Generally speaking, the maximum output power of the power supply is higher than the rated power. Generally, the maximum output power of a power supply is 1.3~ 1.6 times of its rated power. Because the actual output power of the power supply has a great relationship with the temperature of the environment. If the heat dissipation of the power supply is not ideal, the long-term power output of the power supply will also decrease; In addition, when the ambient temperature is lower than -5 degrees or higher than 50 degrees, the output power of the power supply will be greatly reduced, usually only reaching 50~60% of the normal temperature. Therefore, when the power supply works, it often cannot reach the maximum output power, and usually only works at the rated power.
Tip: At present, the rated power and maximum output power are generally indicated on the nameplate of the power supply on the market, but many power supplies do not indicate the rated power and maximum output power. At this time, consumers need to know what their rated power and maximum output power are.
2. Various certifications
It is an important step to read the authentication information clearly when purchasing power supply. To evaluate the quality of a power supply, we can first look at whether it has passed the necessary safety certification. Generally speaking, the more certification items, the more reliable the power quality. Although many certifications are not necessary, one certification is necessary, that is, the power supply currently on the market must pass the national compulsory 3C certification before it can be sold. Whenever the power supply market is rectified, many shops will close their doors and take shelter from the wind. One of the reasons may be that some of the power supplies they sell have not passed 3C certification.
3c: "CCC", the full name is "China National Compulsory Product Certification". The existing 3C certificate has four versions * * *: CCC(S) safety certification and CCC(S & E) safety and electromagnetic compatibility certification, CCC(EMC) electromagnetic compatibility certification and CCC(F) fire protection certification. CCC(S) only stands for passing safety standards. CCC (S&; E) Certification standard, which puts forward two requirements for the safety and electromagnetic compatibility of power supply. CCC(S & amp； E) logo can be understood as having passed 3C certification, which is also the standard that any power supply product must meet. Some famous brand power supplies may use forged signs to deceive consumers when they fail to pass 3C certification. Everyone needs to pay attention.
80 Plus is a new certification, which is formulated to accelerate the development of energy-saving technology and is a symbol of high power conversion efficiency. The certification requirement is to integrate the internal power supply of the system, so that the power supply can achieve more than 80% power efficiency at 20%, 50% and 100% load points. At present, the conversion efficiency of most power supplies on the market is only 70%-75%, and there are not many power supplies that can obtain 80 Plus certification temporarily, and these power supplies are quite high-end products. However, with the development of power technology, we have reason to believe that more and more power supplies will be certified by 80 Plus in the future.
In addition to 3C certification, some high-quality power supplies will pass FCC certification, which is a certification on electromagnetic interference. A power supply certified by FCC will shield the electromagnetic interference generated during its work and eliminate the harm to human body. In addition, some advanced power supplies will also see the UL certification mark, which is one of the most stringent certifications in the world at present, and there are related restrictions on the structure, materials, testing instruments and methods of power supplies.
Tip: It is very important to see whether the power supply has passed 3C certification and whether there is 3C certification label on the nameplate.
Second: power supply design
1: power supply housing and weight:
Whether the power supply shell material is excellent or not is also an important indicator of power supply performance.
Considering that the casing affects the electromagnetic shielding and heat dissipation of the power supply, at present, the casing of ATX power supply mostly adopts galvanized steel plate, and some products adopt all-aluminum products to improve heat dissipation. Now there are some so-called "gold edition" products on the market, and the shell is plated with gold or nickel, which is not only beautiful, but also plays a role in rust prevention.
And some inferior power supplies will naturally not use high-grade materials, usually with thin shells or simply galvanized iron sheets. This kind of power supply shell has poor strength, and a little force will cause great deformation, let alone radiation protection and heat dissipation.
It is often possible to observe whether the power supply meets the specifications by weight. Generally speaking, the weight of materials and internal components used in a good power supply shell will be heavier than that of an inferior power supply. So when shopping, if you feel that the power supply is very light, everyone should pay attention.
Tip: When buying a power supply, remember to try it yourself to see if it is too light.
2: Fan, cooling hole
Consumers can directly observe the fan through the power housing. During the operation of the power supply, the fan plays a very important role in the heat dissipation of the computer. Loose sheets just radiate heat into the air. If the hot air cannot be discharged in time, the heat dissipation effect will be greatly reduced.
At present, more and more power sources begin to use the design of super-large air volume 12cm fan. The exhaust air volume is about 30% higher than that of the 8cm fan of ordinary power supply, and the 8cm fan can achieve heat dissipation effect at half speed when running at full speed, effectively reducing noise. Some high-end power supplies are designed with double fans, and 8cm fans are installed at the air inlet to speed up the flow of hot air in the cabinet. Because it is located directly above the CPU, it can effectively reduce the internal temperature of the chassis.
In addition, there are more or less cooling holes on the power supply shell, and the temperature of the power supply will continue to rise during operation. In addition to cooling by a fan connected to the power supply, cooling holes are also an important facility to increase air convection. In principle, the larger the cooling hole area of the power supply, the better, but pay attention to the position of the cooling hole, so that the air inside the power supply can form a good convection effect and the hot air inside the power supply can be discharged in time.
Tip: For the choice of power supply fan, it is generally better to choose a cooling fan with large size and faster rotation speed.
3: Wires and interfaces
With more and more advanced hardware, the power consumed by computers is also increasing. If the quality of the power output line is poor, it is likely to cause overload, overheating or even burning. However, because of the low cost of wire rod, the power wire rod on the market is still relatively qualified.
In terms of power interface, in addition to the general interface, we should also pay attention to whether the power supply is equipped with the 6Pin power interface that many graphics cards need now. Considering that hard disks and optical drives with SATA interfaces have gradually become popular at this stage, it is also necessary to pay attention to whether the power supply is equipped with two or more SATA interfaces. In addition, some high-end power supplies will also have their own 2-minute fan speed diagnosis interface, which is connected with the corresponding "PowerFanConnector" speed diagnosis interface of the motherboard, so that users can conveniently enter the BIOS of the motherboard to check the fan speed of the power supply and understand the working condition of the power supply more intuitively. In short, we need to focus on the interface, which must be rich in order to expand its use in the future.
Tip: the power interface must be rich, otherwise it will be very troublesome to upgrade the computer in the future.
Three: Other information you must know when buying power supply.
We can't get much information about power supply through appearance, only through product introduction or consultation. For example, whether the power supply has PFC design and whether the circuit has complete primary and secondary EMI circuits is very important.
Tip: Some power supply nameplates will have instructions on using PFC design, but many power supplies do not. If you care about the PFC design of power supply, it is recommended to ask clearly when purchasing power supply.