电脑电源功率计算City power into power after the first passes through the choke coil and capacitance filter high frequency noise and interference signal, then rectified and filtered high voltage DC and then enter the core part of the power supply switch circuit. The switch circuit is mainly responsible for the conversion of DC current into high frequency pulsating DC sending high-frequency switch transformer step-down, then filter the high frequency AC part, so as to get the computer needs more "pure" low voltage DC power. Because the core part of the computer power supply is the switching circuit, the computer power supply is usually called the Supply Power (Switching).Power outputParts of a computer system are used in low voltage DC power, but the specific requirements of different parts of the voltage and current are different, such as speed to meet the requirements of thousands per second RPM hard drive spindle motor and drive control circuit for power supply must not be the same, so the power supply has a corresponding output satisfy the power supply demand of different. As you can see from Figure 1, the power supply of the hard disk is divided into two parts, DC +5V and +12V.As far as the most common ATX power supplies are concerned, there are several kinds of power output:+3.3V: mainly through the motherboard conversion, drive chipset, memory and other circuits.+5V: at present, the main drive and CD-ROM drive control circuit (except the motor), motherboards and floppy drive, etc..+12V: used to drive the hard disk and optical drive motor, cooling fan, or expand the slot through the motherboard to drive other boards. In the latestPentium 4, Pentium 4 processor due to increased power consumption, the power supply requirements are higher, therefore specifically increased plug a 4Pin +12V voltage is supplied to the motherboard, the motherboard supply transform CPU and other circuit. Therefore, configure the Pentium 4 system to use +12V, 4Pin plug power supply.-12V: mainly used for some serial circuit, its amplifier circuit needs to use +12V and -12V, but the current requirements are not high, so the -12V output current is generally less than 1A.-5V: mainly used to drive certain ISA card circuit, the output current is usually less than 1A.+5VSB:+5VSB stands for "+5V Standby", which means that a +5V wait voltage is used to wake up the system after the system is closed. The 5VSB is a single power circuit, where the +5VSB is present whenever there is an input voltage. In this way, the computer can implement remote MODEM wakeup or network wake-up function. The earliest of the 1 edition of ATX only requires +5VSB supply current to 0.1A, but with the power of CPU and motherboard increased, 0.1A has been unable to meet therequirements of the system, so the output of the power supply +5VSB ATX now generally can reach more than 1A, or even 2A.Generally speaking, the normal power supply products should be marked nameplate on the supply current of each output (Figure 3), understand more clearly is not a bad thing for the index of the product, so please try to buy the power to choose this kind of products.Power of a power supplyAs we all know, the power is calculated by the voltage multiplied by the current, for the power supply in Figure 3, whether the DC output voltage multiplied by the current, and then add together, that is, the rated power output power? According to figure 3,We can get the data in Table 1, they will add up to get the output power of 360.9W, and according to its actual nameplate can see the rated output power of the power is 250W (the maximum output power of 320W).Table 1: output voltage / current and powerOutput voltage; output current; output power+12V 13A 156W+5V 26A 130W+3.3V 16A 52.8W-5V 0.5A 2.5W-12V 0.8A 9.6W+5VSB 2A 10WIn fact, ATX power output can not reach the maximum output current nominal, so we can see such as "+5V&+3.3V:145W in power on the nameplate, the indexes of 5V, +3.3V&+12V:240W + +5V and +3.3V said," the maximum combined output of 145W, +5V, 3.3V and +12V + 240W combined with maximum output. If the data is calculated by Table 1, the value is 338W, greatly exceeding the 240W limit. Obviously, it is totally wrong to calculate the power rating of a power supply by simple accumulation.Usually, we often refer to the power supply generally refers to the rated power output power, but can be seen from Figure 3, in addition to mark the rated power, and maximum power, so here we first look at several power supply.Rated powerThere is no specific formula for the power rating of the power supply. The calibration of power rating is usually carried out by cross load test, and the maximum current of each output voltage is obtained by detecting the load voltage drop and ripple factor of the main voltage of the power supply. The specific method is that: in the premise of not exceeding the maximum current output by gradually reducing the load resistance, and measuring the load pressure and the ripplecoefficient, when the load voltage and ripple coefficient exceeds the allowable range, record the current value as the maximum working current. The maximum operating current of each output is recorded, and then compared with the power standard set by Intel to determine the rated output power of the power supply.Maximum output powerThe maximum output power refers to the maximum power output when the power supply is stable. A power rating of 200W, the actual output is not necessarily lower than 200W, may be higher, after all, the calibration of rated power and the actual use of the environment is a certain difference.peak powerPeak power is the power that can be supplied in a short time (usually 30 seconds), but the power does not work long enough in this extreme state. Usually the power peak can exceed the maximum output power of about 50%, because the circuit hard disk in the start state of the draw is far greater than the normal work of the value, so the system often use this buffer provides the current required to start for the hard disk, start to full speed will be restored to normal levels.How to judge the power of the power supply?There are many brands of power that do not mark actual output power, but provide a "300XX" and the like model to play to the dealer. Since the voltage and current data on the powernameplate can not be relied solely on, the power rating of the power supply can be accurately calculated,How to determine the power rating of the power output? Of course, the most accurate way is to load tests, but only manufacturers can do it. As an ordinary consumer, we can judge the approximate power of the power according to the ATX power design standard.Notice the difference between ATX 2.03 and ATX 12VBefore judging the power supply, we should first understand the power version, and Figure 4 and figure 5 represent the two most common power standards on the market: the ATX 2.03 and the ATX 12V. For different versions, the standard requirements for power supply are not the same, but the current market power of the two versions of the distinction is not very strict.The so-called Pentium 4 power refers to ATX 12V, not ATX 2.03. The difference between ATX 12V and ATX 2.03 is as follows:The current output capability of +12V is enhanced, and the new regulation of current output, surge current peak, capacity of filter capacitor and protection of +12V are made;New 4Pin +12V power connector has been added;+5VSB's current output capability is enhanced.Standard ATX 2.03 and ATX 12V power specificationsHow much power does the computer burn?When purchasing power supplies or upgrading computers, it is important to ensure that the power supply is able to provide sufficient current to drive the internal equipment of the system. The method is to calculate the power consumed by each part of the system. In order to accurately calculate the power consumption of different parts is difficult, some devices will be clearly marked out of power consumption (Figure 1), such as a variety of storage devices, but manufacturers usually do not provide power consumption card products, so we can estimate according to table 6. The equipment with different power consumption is CPU and video card. For the same manufacturing process of CPU, the higher the frequency, the higher the power consumed, and the increase of voltage overclocking will also increase the power consumption of CPU. According to the graphics display chip and different collocation memory, the power difference is relatively large, some high performance graphics (such as GeForce FX and Radeon 9700) have begun to use additional power supplies.Table 6: typical power consumption of equipment (derived from AMD company technical data)+3.3V, +5.0V, +12.0V, maximum powerMotherboard 3.00A 2.00A 0.30A 1 23.50WAthlon XP 2100+ / 7.49A 1 89.91W256MB DDR / 3.00A / 2 15.00WAGP video card 6.00A 2.00A / 1 29.80WIDE hard disk / 0.80A 2.00A 1 56.00WDVD-ROM / 1.20A 1.10A 1 19.20WCD-RW / 1.20A 0.80A 1 15.60WFloppy / 0.80A / 1 4.00WPCI sound card 0.50A 0.50A / 1 4.15WPCI NIC 0.40A 0.40A / 1 3.32WChassis fan / / 0.25A 1 3.00WProcessor fan / / 0.25A 1 3.00WKeyboard / 0.25A / 1 1.25WMouse / 0.25A / 1 1.25WTotal 283.98WTable 6 shows the maximum power consumption of each component. When you estimate the overall maximum power according to the actual situation of the system, you can buy the power supply that meets the requirements of the power supply according to this data.For example, the configuration in Table 6 calculates that themaximum power consumption is about 284W, so it is possible to select a power source with a maximum output power of 300W. But note that the computer will not be ready to achieve this power when in use, so some users to use inferior power is not the power shortage problem immediately, but the performance of the hard disk boot failure, automatic restart, crashes and other some faults occur in a random, in which case we often pay attention to the motherboard, memory CPU, the key component, just ignore the power of seemingly simple.。