FAQs about PC power supply purchasing

As a computer's logistics support equipment, power sources have not been valued for a long time, but only need to be used. As the power consumption of the computer system continues to rise and the media and old gamers promote and promote power consumption, we gradually learn the importance of power supply and begin to face up to this indispensable accessory. However, due to the closeness of power supply products and the lack of Power Supply Knowledge of consumers, how to judge the quality of a power supply product is still in front of everyone.

As a result, a variety of "pseudo-knowledge" Play the role of "shopping tips" frequently appear, misleading everyone to choose power in their own smart. If you don't want to be fooled by the "pseudo knowledge" of those power supplies, read this article carefully.

Power Problems

Misunderstanding 1: the greater the power, the better the Power Supply

The task of power supply is to provide stable and sufficient power to the entire machine. Power only indicates the load that the power supply can carry, and it has nothing to do with the quality of the power supply. Some sellers often mislead people to say that the high power is better than the low power. This is the most simple "pseudo knowledge ".

Misunderstanding 2: confusion between rated power and maximum power

The rated power is the power that the power supply can run stably and safely. The maximum power is generally used to cope with sudden high power demands. If the power supply is output at the maximum power for a long time, even power supply security has a great impact. At present, the power of domestic power supply has a serious virtual mark, one of which is to use the maximum power for rated power, or simply do not distinguish, to confuse consumers.

Misunderstanding 3: The larger the power, the more expensive the electricity

This misunderstanding usually occurs in the absence of scientific thinking training or female users. The rated power only shows how much load the power supply can safely and stably drive, just like a car can carry up to 10 tons of goods, but it may not always carry 10 tons of goods, depending on whether there are so many goods. This is different from other household electrical appliances. other electrical appliances are loads. For example, if the power of the water heater is 1500 W, 1.5 kWh of electricity will be consumed in an hour.

Misunderstanding 4: The rated power is enough.

Most people are used to calculating the overall power consumption of the platform when purchasing power supplies, and then setting aside about 50 W of redundancy. This was possible in the early days when the power consumption of the computer was low, but it is not scientific now. Because the power supply redundancy is calculated in proportion, we usually leave 10-20%, but it is best to set aside about 50% redundancy. There are three reasons: the current market's power supply products have severe virtual standards; leave room for platform upgrades; the power supply has the highest conversion efficiency under 50% load, that is, the electricity cost is the least.

80 plus certification standards and conversion efficiency

Over the past two years, with the improvement of power products, a large number of 80 plus certified products have emerged on the market. This has led many people who do not know the truth to follow suit and believe that the 80 plus certified power supply is of guaranteed quality.

In fact, the 80 plus certification only targets the power supply conversion efficiency and does not involve other aspects. In fact, in addition to the 80 plus certification, there are also EMI electromagnetic conduction interference, EMI electromagnetic radiation interference, and voltage fluctuation, many performance and security-related metrics such as ripple size and cross-load capacity.

In general, manufacturers need to use better materials to improve the conversion efficiency. In a sense, the quality is improved, but in the fierce market competition, some irresponsible brands are not excluded. In order to reduce costs, materials that are not related to compression and conversion efficiency, such as eliminating EMI filter circuits, will not affect the conversion efficiency, however, it brings potential risks to power supply stability.

It is worth noting that the 80 plus certification organization is an energy-saving certification organization in the United States, so the certification standard is also based on the US power grid environment, that is, 115V @ 60Hz, china uses a V power grid. Under the same conditions, the conversion efficiency of the power supply under 230V is higher than that of 115V. Therefore, some sellers claim that their products comply with the 80 plus standard, but they do not spend thousands of dollars to apply for certification.

Power Factor and power factor correction PFC)

There are quite a few players who do not know the difference between conversion efficiency and power factor.

The conversion efficiency is the ratio of the power output power to the input power multiplied by 100%. This part of energy is consumed by the power supply during work and converted to heat. The 80 plus certification standard that everyone is familiar with is to authenticate the conversion efficiency. Generally, the power conversion rate is about 80%, while the high 80 plus gold medal is required to reach 90%. However, this value is also related to temperature, power grid environment, and load. If you are interested, you can query 80 plus standards.

The power factor is the ratio of the active power of the power supply to the apparent power, or the cosine of the phase difference between the voltage and the current in the AC circuit. Because there is a phase difference between the AC voltage and the current, the current cannot be used for all work, and some of the current is stored in the capacitor or back and forth in the power generation equipment and load. Ordinary electric energy meters in China cannot measure the current without doing work. Although we don't have to pay for this part of current, it is a burden for the overall power grid.

Power Factor Correction (PFCPower FactorCorrection) is a technology related to power factors ). It can be divided into passive PFC and active PFC. In the current market, passive PFC can only be seen on a few low-end power sources, which are generally divided into "inductance compensation" and "fill-in ". All are passive power factor correction. The former can only reach 0.7-0.8, and the latter can increase the power factor to about 0.9. The active PFC consists of inductance and capacitance and electronic components. It is used for Active Power Factor Correction. Generally, the power factor can be increased to more than 0.98. Active PFC is the trend of the times, so it is recommended that you choose an active PFC power supply when purchasing.

Stability issues

After using many computers for a period of time, there may be some inexplicable problems such as no response to the USB interface, blue screen crashes, long response time, and even a computer, when a nuclear bomb is fired, the power is cut off, and there are no other problems. At this time, we usually look for problems with the video card, motherboard and other accessories, but seldom focus on the power supply. In fact, many unstable problems are caused by the power supply problem, in this way, the lifetime of the motherboard and hard disk is greatly affected.

In fact, our power grid will be affected by many factors and cause instability, for example, the high-frequency clutter caused by electromagnetic radiation, the surge caused by lightning, and the low voltage caused by the large power consumption. However, a stable power supply environment is required inside the computer, in particular, the most "Delicate" hard disk, in the high-speed rotation work, any accident may cause irreparable damage, but "the hard disk price data is priceless ", hard drive failure is the most distressing. This task will undoubtedly require power supply.

To evaluate the quality of a power supply, we need to consider it comprehensively. The power supply purchasing method popular among the media and players has many "pseudo knowledge". We should not be biased towards it, but think more and question more, always remember to "pay for the goods ".

This article from the "Ghost King" blog, please be sure to keep this source http://ghostlan.blog.51cto.com/5413429/1298874