ADD：
1. Power
Power of course is the most important indicators of power, but also many people know that the only target. Now Prescott core: Pentium 4 computer power has reached the 103 ~ 120W, high-end graphics cards to be outdone, GeForce 6800 power consumption has more than 100W. Therefore, the rated power supply from the previous 200 ~ 250W up to 300W or more, or even do some high-power 550 ~ 600W, really frightening. However, the general level of greater than 2.0G "old" CPU plus low-end graphics cards, the whole power consumption is generally around 100W. The following is typical of the host common power table.
See generally cases Sui power will not work at full capacity, there is no small margin. This is to ensure long-term reliable power supply to provide a guarantee, but it is a result, many poor power to sneak it in, they dare to label with the large power, but in fact it has failed.
Many people are accustomed to long periods of time off the computer power supply, power supply on standby, not only to long-term consumption of more than 10 watts of power, but also easy to Shi standby circuit caused by long-term continuous working and failure (in which case there is no exhaust fan, heat easily focus) , is also prone to lightning strikes and other unexpected damage. Therefore, we must cultivate the habit of power off the main valve.
2. Power Factor
The so-called power factor, is the AC power to promote the load if the load was capacitive or inductive, will make the current waveform and phase shift between the voltage waveform, the result is less than the power to promote the useful load current waveform in the total power consumption under the system , their ratio is the power factor. When the power factor may reach a small less than 0.6, which means that more than 40% loss of power are online on the road, while the power is not recorded on the meter in general, international standards, national standards are more strictly to the electrical power factor restrictions, generally require more than 0.8.
Power factor can be corrected by appropriate compensation increase, that is, PFC (Power Fac-tol'Correction) c When a notebook simply because of its first class was rectified on the filter, so the load was capacitive, so that you can in string into the appropriate circuit inductor current waveform adjustment, bringing the total close to purely resistive load characteristics. This is the "passive PFC" principle.
Now the State to enforce CCC, set forth requirements on power factor, most power supplies are used as a passive PFC inductor core components. Select here to remind you that the best-known brand of quality products, do not get petty face a significant loss.
High-end power supply with active PFC for power factor correction circuit can get better results.
3. Efficiency
Efficiency refers to the power supply output power and input power ratio, which reflects the switch, transformer, rectifier filter circuit components lose heat loss of the power (of course, including electromagnetic radiation and noise emission of energy, but relatively small). Clearly, if the power efficiency is low, not only the output power is low, and severe fever, easy to fail, the fan noise will be evident.
4. Voltage range of adaptation
United States, Japan and other countries using 110V AC power standard, while China and Europe compared to 220V. The traditional method is to use to adapt to a toggle switch to change the rectifier means to adapt to two voltage purposes, and new high-end products with wide range of voltage adaptation is designed to meet the voltage input 90 ~ 240V, the power supply particularly useful in areas in poor condition.
5. Noise
All common computer power fan forced exhaust heat is used, the main sources of fan noise. Many power supplies use a small fan noise is very annoying, and now many high-quality power supply with 12cm fan and even tapped the 9cm, and the use of temperature control are designed to take into account the requirements of cooling and quiet.
Some old-fashioned bad power supply just over 20 kHz frequency, sometimes down to the audio range, resulting in an extremely annoying high-frequency noise, sensitive ears will hear this, especially hearing sensitive Children are especially harmful. Typical power output level of quality before the wave rectifier shown as 3.
Instructions as the numerical oscilloscope 66.811kHz, scanning speed 5μs block. Conducive to such a high frequency core loss reduction and power small, but the parameters of the switch more demanding. In any case it is certainly far beyond the range of human hearing.
6. EMC characteristics
EMC is Elect ro M agnetiCCompatibility, electromagnetic compatibility. This is EMI (electromagnetic interference) characteristics of accompanying indicators produced, now have national mandatory standard. Good EMC design requires not only the degree of tolerance to EMI compliance, also called the degree of EMI to produce low enough. Computer power supply tolerance. EMI generally no problem, the problem is that it is a serious source of EMI interference, whether radiation or feedback on the grid disturbance, are very serious and must take appropriate measures to resolve. The manufacturers of various power products quite different. Quality products generally contain two or more EMI filter circuit. This two-way filtering measures to make the internal power supply and power grid, "interfere with each other", are to maintain a good environment.
