1. Power

Of course, the primary power is the power index, but also many people know the only indicators. Now Prescott core: Pentium 4 computer power has reached the 103 ~ 120W, high-end graphics cards to be outdone, GeForce 6800 has exceeded the power consumption 100W. Therefore, the rated power supply from the previous 200 ~ 250W up to 300W or more, or even do some high-power 550 ~ 600W, is really astounding. However, the general level of greater than 2.0G "old" CPU plus low-end graphics card, the machine consumes about 100W in general. The following is typical of the host common power table.

Under normal conditions the power can be seen Sui will not work at full capacity, there is not a small margin. This is to ensure the long-term reliable power supply to provide a guarantee, but it is a result, many poor-quality power to deceive, they dare to mark the big power, but in fact impossible to achieve.

Many people used to turn off the computer for long periods of power, the power on standby, not only to long-term consumption of more than ten watts of power, but also easy to make stand-circuit caused by continuous long-term failure (when there is no exhaust fan, heat easy to focus) also prone to lightning strikes and other unexpected damage. Therefore, we must cultivate the habit of total gate turn off the power.

2. Power Factor

The so-called power factor, refers to 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 results useful to promote the power of the load current waveform is less than the system in the total power consumption , their ratio is the power factor. When the power factor may reach 0.6 small following, which means that more than 40% loss of power are on the line, while the power is not recorded on the meter in general, international standards, national standards are more strictly to the electrical power factor restrictions, the general requirements to reach more than 0.8.

Power factor is corrected by appropriate compensation increase, and this is PFC (Power Fac-tol'Correction) c in the computer power on the conduct of its first stage rectifier filter, so the load was capacitive, so that you can circuit inductance in series to adjust the appropriate current waveform, making the total nearly pure resistive load characteristics. This is the "passive PFC" principle.

Now the state to enforce CCC, set forth requirements for power factor, so most of the power have used iron-core inductor as a passive PFC components. Select here to remind you that the best-known brand of quality products, do not get petty suffer a great deal.

High-end power supply with active PFC for power factor correction circuit can be more effective.

3. Efficiency

Efficiency refers to the power output power to input power ratio, which reflects the switch, transformer, rectifier filter circuit components, such as loss of heat for the loss of power (of course, including electromagnetic radiation and noise emission of energy, but relatively insignificant.) Obviously, if the power efficiency is low, not only the output power is low, and severe fever, susceptible to failure, fan noise will be very obvious.

4. Voltage adjust range

United States, Japan and other countries using 110V AC power standard, while China and Europe compared to 220V. Traditional adaptation is to use a toggle switch to change the way rectifier filter, to adapt to the purpose of the two voltages, while the new high-end products with wide voltage range to adapt the design to adapt to the voltage input 90 ~ 240V, the power supply particularly useful in areas in poor condition.

5. Noise

All is the use of common computer power exhaust fan forced cooling, the main source of noise is the fan. Many power supplies use a small fan noise is very annoying, and now many high-quality power supply with 12cm fan and even the tap of 9cm, and the use of temperature control designed to take into account the requirements of cooling and quiet.

The poor quality of some of the old power supply is only twenty kHz operating frequency, sometimes down to the audio range, have an extremely annoying high-frequency noise, sensitive ears will hear this, especially the sensitive hearing children, is particularly harmful. Typical power output stage of high-quality rectifier waveform before filtering is shown as 3.

Value indicates the oscilloscope 66.811kHz, scanning speed in the 5μs block. Conducive to such a high frequency and power reduction in core losses small, but the parameters of the switch more demanding. In any case it is certainly far beyond the human hearing range.

6. EMC characteristics

EMC is Elect ro M agnetiCCompatibility, electromagnetic compatibility. This is EMI (electromagnetic interference) characteristics accompanying indicators have now have national mandatory standards. EMC design requires not only a good degree of tolerance to EMI standards, 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 the back of the grid disturbance, are quite serious and must take appropriate measures to resolve. The manufacturers of the various power products quite different. Excellent product generally includes more than two EMI filter circuit. This two-way filtering measures to make the internal power supply and power grid, "interfere with each other," and they maintain a good environment.