Power supplies

It may seem like a nondescript little box, buried in the depths of the chassis of your PC. In fact it is a vital component of the machine: without it, the PC will not turn on. Here’s what it does, how it is done, and how to choose it.
Sooner or later, happen to want to expand their The PC. Maybe we simply need more disk space, or we fell in love of a new ultra-powerful graphics card . Then we open the case, install the card I just received , and press richiudiamo all confident the ignition switch , but … does not happen nothing . The PC will not start . Us double-check everything and try Power supplyagain , nothing . Yet there is nothing wrong …

what has happened ? Well, in all probability, have put in the power supply crisis : the new board needs so enough energy to exceed the maximum permissible load, and the device automatically goes into protection not self-destruct. So to restart the PC , or give up the new card, or … change power supply. What does Computers (including laptops ) work with the current the electricity network at home, it is well known , but in reality the the internal circuitry is not able to take advantage of direct – Give charge mind the alternating current at 220 V For this reason it is converted into DC voltages low , of the order of 12 , 5 and 3.3 Volt .

Power supplies

The device that provides for this task is called PSU, acronym of power supply unit (literally ” drive for energy supply “) for us Italians , more concisely , is the power supply.
If this word your thoughts turn to big transformers in sheet metal , you’re out of the way : the totality of the power supply uses a technology called ” switching” , ie switching , which enables you to build devices more compact and efficient than older appliances induction . Aside from the “brutal” conversion operation of the voltage coming in, the power supply of the PC also has a series of functions ” ancillary ” : for example , deals stabilize the voltage so that it is the most possible “clean” , without peaks or ” ripple ” .
A series of filters is responsible to ensure that the high-frequency oscillator signal is propagated to the circuits of your PC or home network . Moreover, they are usually present protection systems that block surges and noise coming from the network ; another protection system is responsible for blocking the supply voltage in case of short circuits , to avoid the destruction of the motherboard or other components expensive . The last function is guaranteed feeder continuity of operation in case of power interruptions .


computer power supply

The interior of a modern power supply is busy circuits. are visible from the large left capacitors that stabilize the current in input, then the two groups power transistors oscillator (coupled to its heat sinks), in among whom is positioned transformer lowers the voltage. On the right there are output circuits with its coils and capacitors for noise reduction

The ATX standard explicitly requires that , if the input fails the electrical current , the power supply is able to maintain the output voltage stable for a maximum time of 16 ms ( milliseconds) , sufficient to overcome most of the interruptions of this type . Obviously, if our network has discontinuities of operation with greater duration , the power supply alone will not be able to maintain function in the PC , in this case , need to have a set of continuity, or of a power supply with backup battery integrated .

There is also another thing. The power supply contains power transistors that dissipate heat , and are then cooled typically by means of a fan . Most of the power supplies takes the cooling air from the inside of the computer chassis and then eject it from a grid on the rear side , in this way , the power supply ” cooperates ” to the PC cooling .

Factors choice How do you choose the ideal power supply for your PC? Taking into account various factors, of course, at least five to be exact. Are the power , size, connections , cooling and certifications. In most cases , the ideal is to take account of each factor in the order that we have just presented . In short, the selection process should follow about the flow described in the following paragraphs .

1 . power The key parameter , that for which often need to change a power supply fully functional, is the power delivered . If you add to your PC dual high-end 3D graphics card , most likely the power supply “base” not will be sufficient.

Difficult to say a priori what power you might need , since the variables involved are many . Typically, a desktop PC “normal” requires a power supply that says at least 500 Watts, but if you begin to install quad core , twin graphics cards and so on, you climb quickly toward 800-1000 watts. To make a calculation ” -Thumb ” , you should add the consumption (found in the leaves of technical specifications which are always available on the Internet) of the processor, graphics card , of any additional PCI card , and RAM ( 5 W for each DIMM) and all of the hard magnetic disks and optical ( for discs , always use the power consumed in conditions operations – for example, the recorder is in the etching step ) .

Then add 50 W to the board mother (100 W if the card is sophisticated, with many doors and built-in capabilities ) and another 50 for the fans . For a more precise calculation , you can use one of the ” Computers Consumer ” available on the web, for one example of ThermalTake ( www.thermaltake . outervision.com ) . At this point , still add 50 W to any card expansion and 20 W for each disk that you want to add the system in the future , and finally add the digit calculated a 20 % to compensate for the losses of the power supply . The end result will be the power of the device you’ll need to buy . Remember that most part of the power ( about 85% ) must be paid lines to +12 V.

Dimensions The vast majority of PCs on the market using standard power supplies that follow the specifications called ATX . The power of this type can be installed in all homes desktop and tower planned for motherboards with the same name. However, there are other form factors : in particular, the smaller cases may need to power microATX, ATX or flex Each power door label that provides more precise information on the actual power available than the simple fact of the total power the modern power connectors have a large number of cables and connectors out.

We find the cable to the motherboard (20 or 24 -pin), one per processor Pentium IV or higher ( 4-pin ATX12 ) or dual cards processor ( 8-pin EPS) , and the 6 or 8 -pin PCI -e (graphics cards in particular), and those for mass storage devices, IDE or SATA. Connector to the motherboard, from 20/24 poly ( separable to be used on motherboards of old type ) Connector 4-pin ATX12V to power a processor Pentium IV or higher 8-pin EPS connector for dual processor motherboard connector, 4 -pin hard drives, and mass storage to IDE connector for hard drives and mass storage devices to SATA connector for additional power to PCI cards 6 /8 pole (separable) December 9, 2009 65 BTX . Check the manual of the type of power supply chassis that can mount , and keep in mind that outside of the ATX standard choice collapse vertically .

Furthermore , especially in the segment of the power supplies and more powerful, there are various models that have a footprint greater in length than normal. To install one of these models is necessary to verify that the chassis is intended for use in power supplies of this type. If you need more detailed information on the various form factors used by the power supplies can take a look at the site www.formfactors.org (unfortunately only in English). 3 . Connections The output from a PC power supply are standard . Well, up to a certain point. Let’s say that lately the standards have multiplied.

At a minimum, there must be a 20-pin main connector to hook to the motherboard. But all newer motherboards require a 24 -pin connector . It is very likely that you will buy the power supply is therefore fitted with a connector piece, 20 + 4 pin, to be compatible with every motherboard. A wiring harness is responsible for providing energy to the disk storage . Check that the power supply has enough connectors for this purpose, and that they are of the right kind : those for IDE drives are not going well for the new SATA and vice versa , unlesspower supplies you obtain the appropriate adapters. So far feeders “classics .”

The newer ones , however, they also have some other connections : for example, a 4-pin said “+12 V” that feeds directly into the processor – the power supplies that have it are usually referred to as ATX12V ATX instead . other have an 8-pin connector to power up to 2 processors (usually is referred to as ” connector EPS “).

The connector is made ​​of EPS consists of 2 connectors “+12 V” side by side. Finally , many models Recent mountain also specific connectors to power directly PCI -e – typically cards graphic . It is a 6 or 8-pin connectors and power supplies who have it are often certified by the card manufacturers themselves ( see point 5) . 4 . cooling As mentioned above , the power transistor contains power , that produce heat .

To cool the circuitry is typically at least one fan , that sucks air from inside the PC and blows outside, helping the overall cooling of the the system. In some particularly powerful power supplies the fans are two, one inbound and one outbound . Are models with increased air flow , but of course are often also the noisiest . In contrast there are models ” fanless “, ie no fans , in which the cooling is achieved only through the use of Large heat sinks and chassis structure to the grid.

These models , generally more expensive , are totally silent and are particularly suitable to be used in areas such as home theater , where it is necessary that the PC does not produce hiss , hissing or buzzing . A third approach to the problem is to equip the power supply a large diameter fan ( for example 14 cm) that will be able to move a number flies high while maintaining a low number of revolutions , and thus being much more quiet than Models equipped with small fans . 5 . certifications The power supplies are provided with two types of certifications distinguished : those that attest to the electrical safety of operation , such as those issued internationally by TUV or Italy IMQ , or yet as the label “CE” that must appear on on products sold in Europe , and those computer properly , which indicate the compatibility connections with devices from various companies : in particular for Intel and AMD and the Ati and Nvidia graphics cards , including configuration Dual Card ( respectively called CrossFire and SLI) .

So if your PC is equipped with one of these configurations , check that there is marked for compatibility . Important for all, however, the presence the ” bolllino ” 80 plus in its various versions – see box of the same name . This attests to the efficiency of the device, ie the fact that it becomes the current usable by the PC most of the energy in input – an important indication for those who keep eco-sustainability of its computing experience .

answersIn the field of power supplies operate numerous marchi.Tuttavia, not all produce their own: many limited to “emphasize” power supplies rupower produced by thers. To find out who is the real producer of a power supply, is You can use a little trick: If the device port a certification mark on the label similar to the letters “HU” written in reverse, just below it  There is a numeric code that starts with an “E”. It identifies the true manufacturer. Here is a list of the principal.

Manufacturers of Power Supplies

E104405 Sea Sonic Electronics Co Ltd
E104407 Leadman Electronics Co Ltd
E119368 Samsung Electro-Mechanics Co Ltd
E126556 Taiwan Youngyear Electronics Co Ltd
E130843 Topower Computer Industrial Co Ltd
E131500 Pc Power & Cooling Inc
E131881 Delta Electronics Inc
E134014 Enermax Technology Corp
E134129 Powertech Systems Co Ltd
E138711 Moretec Electronics Industrial Co Ltd
E141182 Morex Information Enterprise Co Ltd
E141400 Seventeam Electronics Co Ltd
E142789 Nidec Potrans Corp
E143709 Hipro Electronics Co Ltd
E143756 Zippy Technology Corp
E144195 Sirtec International Co Ltd
E147055 Mapower Electronics Co Ltd
E156513 Power-Win Technology Corp
E161451 Channel Well Technology Co Ltd
E161557 Fortrex Electronic Co Ltd
E161936 Nipron Co Ltd
E164554 L & C Technology Inc
E166947 Enhance Electronics Co Ltd
E172499 Win-Tact Electronics Corp
E175472 Fore Point Industrial Ltd
E175856 Delta Electronics Inc
E176105 Antec Inc
E176239 Etasis Inc
E178102 Jou Jye Electronic Co Ltd
E178768 Wintech Electronics Corp
E181356 Shenzhen Chi Yuan Industrial Co Ltd
E185650 King Case Industrial Co Ltd
E186010 Atng Power Co Ltd
E190414 Fsp Group Inc
E191395 Delta Electronics (Thailand) Public Co Ltd
E193726 Ablecom Technology Inc
E193807 Powertech Systems Co Ltd
E199068 Delta Electronics Inc
E199442 Heroichi Electronic Co Ltd
E199529 Macron Power Technology Ltd
E203196 Deer Computer Co Ltd
E211481 Codegen Technology Co Ltd
E217431 Delta Electronics Inc
E242429 Super flower and TTGI
E243823 OCZ Technology
E313881 Delta Electronics Inc

External links

Power Supply Glossary file Pdf cui.com
Mouser is an authorized distributor for many power supply eu.mouser.com