How does a computer power supply work and what does it consist of? How to choose a power supply for a computer - tips for ordinary users.

Useful tips

Secondary power supplies are an integral part of the design of any radio-electronic device. They are designed to convert alternating or direct voltage from the mains or battery into the direct or alternating voltage required for the operation of the device; these are power supplies.

Power supplies can not only be included in the circuit of any device, but can also be made in the form of a separate unit and even occupy entire power supply workshops.

There are several requirements for power supplies. Among them: high efficiency, high quality output voltage, presence of protection, compatibility with the network, small size and weight, etc.

The tasks of the power supply may include:

Transfer of electrical power with a minimum of losses;
Transformation of one type of stress into another;
Formation of a frequency different from the frequency of the source current;
Change in voltage value;
Stabilization. The power supply must output stable current and voltage. These parameters should not exceed or fall below a certain limit;
Protection against short circuits and other faults in the power supply that could lead to breakdown of the device that supplies the power supply;
Galvanic isolation. Method of protection against the flow of equalizing and other currents. Such currents can damage equipment and injure people.

But often power supplies in household appliances have only two tasks - to convert alternating electrical voltage to DC and convert the frequency of the power supply.

Among power supplies, two types are most common. They differ in design. These are linear (transformer) and switching power supplies.

Linear power supplies

Initially, power supplies were manufactured only in this form. The voltage in them is converted by a power transformer. reduces the amplitude of the sinusoidal harmonic, which is then rectified by a diode bridge (there are circuits with one diode). convert the current to pulsating. And then the pulsating current is smoothed out using a filter on the capacitor. At the end, the current is stabilized using .

To simply understand what is happening, imagine a sine wave - this is exactly what the shape of the voltage entering our power supply looks like. The transformer seems to flatten this sine wave. The diode bridge horizontally cuts it in half and turns the lower part of the sine wave up. The result is a constant, but still pulsating voltage. The capacitor filter finishes the job and “presses” this sine wave to such an extent that an almost straight line is obtained, and this is D.C.. Something like this, perhaps too simply and crudely, can describe the operation of a linear power supply.

Pros and cons of linear power supplies

The advantages include the simplicity of the device, its reliability and the absence of high-frequency interference, unlike pulsed analogues.

Disadvantages include large weight and size, which increase in proportion to the power of the device. Also, triodes coming at the end of the circuit and stabilizing the voltage reduce the efficiency of the device. The more stable the voltage, the greater its losses will be at the output.

Switching power supplies

Switching power supplies of this design appeared in the 60s of the last century. They work on the inverter principle. That is, they not only convert direct voltage into alternating voltage, but also change its value. The voltage from the mains entering the device is rectified by the input rectifier. The amplitude is then smoothed by the input capacitors. High-frequency rectangular pulses with a certain repetition and pulse duration are obtained.

The further path of the pulses depends on the design of the power supply:

In units with galvanic isolation, the pulse enters the transformer.
In a power supply without decoupling, the pulse goes directly to the output filter, which cuts off the low frequencies.

Switching power supply with galvanic isolation

High-frequency pulses from capacitors enter a transformer, which separates one electrical circuit from another. This is the essence. Due to the high signal frequency, the efficiency of the transformer increases. This makes it possible to reduce the mass of the transformer and its dimensions in pulsed power supplies, and, consequently, the entire device. Ferromagnetic compounds are used as the core. This also makes it possible to reduce the size of the device.

This type of design involves converting current in three stages:

Pulse width modulator;
Transistor stage;
Pulse transformer.

What is a pulse width modulator

This converter is otherwise called a PWM controller. Its task is to change the time during which a rectangular pulse will be given. changes the time during which the pulse remains on. It changes the time at which the pulse is not given. But the feed frequency remains the same.

How is the voltage stabilized in switching power supplies?

All pulse power supplies implement a type of feedback in which, using part of the output voltage, the influence of the input voltage on the system is compensated. This allows random input and output voltage changes to be stabilized

In systems with galvanic isolation, they are used to create negative feedback. In a power supply without decoupling, feedback is implemented by a voltage divider.

Pros and cons of switching power supplies

The advantages include lower weight and size. High efficiency due to reduced losses associated with transition processes in electrical circuits. Lower price compared to linear power supplies. Possibility of using the same power supplies in different countries world where power grid parameters differ from each other. Availability of short circuit protection.

The disadvantages of switching power supplies are their inability to operate at too high or too low loads. Not suitable for certain types of precision devices as they create radio interference.

Application

Linear power supplies are actively being replaced by their switching counterparts. Now linear power supplies can be found in washing machines, microwave ovens, heating systems.

Switching power supplies are used almost everywhere: in computer equipment and televisions, in medical equipment, in most household appliances, in office equipment.

Hello again, dear readers! Let's talk about how to choose a power supply.

As you can see from the title of our next “ Sys.Admin» notes, today we will talk about the power supply (hereinafter - BP). You may ask: “why did we decide to devote an entire article to something like this? it would seem that, minor element personal computer(PC)?" We answer: - all because not all users (or rather, a minority) pay due attention to the healthy nutrition of their “pi-si”. But in vain!

I think you will agree with me if I say that power supplies are purchased from us on a “residual basis”, i.e. What haven't I bought yet? Oh yes - the power supply. Okay (how much do we have left?) - I’ll take this one on the left “ noname"(unknown manufacturer) on top shelf. Really, admit it?

But this is not the thing you should save on (because your entire sophisticated PC can turn into a pile of hardware in one second), and today I will tell you why.

By the way, this is a continuation of the cycle on selection criteria, that is, articles like “ ”, “ “, “ ” and all that different stuff from the “Selection Criteria” tag.

Go.

What is it and why is it needed - introductory

We will start with the “golden” rule for choosing/purchasing a power supply, which says: “Stingy, pays twice!” (and if he’s stingy, he’s also stupid, then three times :-)). Remember it, because a good power supply is the key to stable and long-lasting operation of a computer. Buying cheap model, You risk getting burned, please note, literally.

In order to make a conscious and right choice, let’s go over the theory (where would we be without it), and then “get into” practice and talk about the rules of choice.

So, the power supply, also known as the blocker, or the bepeshnik (and a bunch of other names) is responsible for ensuring stable and correct power supply (i.e. characteristics Not must be outside the permissible limits under different loads). In addition, the reliability and safety of information on the internal drives(in the event of a power failure, power surges, etc.) and how long the components of your “bosom” friend will work.

Everyone knows that a computer plugs into a standard electrical outlet, but (not everyone knows) that its components cannot receive power directly from the mains for two reasons.

Firstly, the network uses alternating current, and computer components require constant. Therefore, one of the tasks of the power supply is to “rectify” the current.

Secondly, different computer components require different supply voltages to operate, and some require several lines with different voltage. Thus, the power supply, among many other things, provides each device with current with the necessary parameters and for this it has several power lines (see image).

The main power circuits are voltage lines: + 3.3 B, + 5 B and + 12 B. Moreover, the higher the voltage, the greater the power transmitted through these circuits. Most powerful consumers energy such as video card, CPU and northbridge, use + lines 5 B and + 12 B. Voltage is supplied to the power connectors of hard drives and optical drives +5 B, for electronics and +12 B for motor. Negative supply voltages −5 In and −12 They allow small currents and are quite often not used by the motherboard.

What do we need from a power supply? Basic parameters to choose from

We have figured out that the power supply is the only source of electricity for all PC components; now we move on to the characteristics (of the current it produces), on which the stability of the entire system directly depends.

So, in general (from this), we don’t need so much, namely:

Provided stable and accurate voltage outputs 12 /5 /3.3 volt. The output voltage is not absolutely constant ( U), and constant/intermittent (ideal when U- can “walk” on 0.5 to the maximum);
Had a good line division system 220 In and your PC (it is bad systems that lead to soot on the boards)
Its elements were made of high-quality materials, because common cause The death of the power supply is cheap capacitors with a short service life, poor cooling (and excessive heating) of the power supply components, as well as the lack of fuses and other important things

If the above reasons and needs are not met, many cheap and medium-sized power supplies “fall out” beyond the standard values by 2 volts and this is with a total load 70 % nominal! This can lead to incomprehensible overloads of the computer “out of the blue,” freezes in the middle of important work, as well as, say, partial instability of devices (the monitor goes blank).

What do users say about this?
Naturally, they blame not their choice and savings, but the fact that “WindoZ Curve” or “Bill Gates Co. 3..” (c), although neither one nor the other is the reason for this.

However, we have digressed a little from the topic, but meanwhile we have already considered the main “electrical” parameters, although there are also many technical ones.

Let's deal with them.

Power supply characteristics - power

So, the main characteristic of a power supply is its power. It must be at least equal to total power consumed by components PC at maximum computing load, and with a normal choice, i.e. with an adequate buyer, it is good if it exceeds this indicator by 100 W or more. Otherwise, the computer may turn off at times of peak load, reboot, or, much worse, the power supply will burn out, and if, while burning, it supplies high voltage (to the motherboard, hard drives, DVD±RW), then it will not go to the “other world.” alone, and always in a friendly campaign of these devices (frequent practice).

You can independently make approximate calculations of the power required to power your computer. Each system component consumes some amount of power, adding up the power consumption values for all components inside the PC case and adding 20 % in reserve, you will receive the desired power of the power supply. In addition, on the Internet you can find special “calculator programs” for calculations of this kind.

One of these programs is free, Russian-language and quite adequate :-)

As already mentioned and you yourself understood, this calculator allows you to calculate the power of the power supply for a PC of any configuration. The program interface is simple and clear, so you can easily understand it and calculate the required power.

Efficiency Efficiency

High power in itself does not guarantee high-quality work. In addition to it, other parameters are also important, for example, efficiency. This indicator indicates what share of the energy consumed by the power supply from the electrical network goes to the computer components. The higher the efficiency, the less the power supply heats up (and there is no need for enhanced cooling using a noisy fan), i.e. more efficiently converts the energy from the electrical outlet into the stated watts and, of course, the less energy is wasted on heating. For example, if it is 60 %, That 40 % of energy is floating around your room (catch it :-)).

The “efficiency” of the power supply is assessed by its system of medals - standard “ 80 PLUS».

This standard implies several levels of effectiveness: Platinum, Gold, Silver And Bronze, and the specifications of each have their own set of requirements. Of course, power supplies " 80PLUS Platinum" or " 80PLUS Gold» will be more efficient (efficiency 90 % and higher) than their regular counterparts, but they are also more expensive. Therefore, it is better to use the rule here - choose a model with certification “ 80 PLUS", and select the level of the "medal" based on your budget (but not lower than bronze).

Among other things, information on all modules of the standard " 80 PLUS", available on the organization's website. Manufacturers certify models that are known to be of high quality using it, since power supplies with cheap circuitry simply will not pass the criteria. It is for this reason that this certificate is additional guarantee quality, that is, look for a power supply with it.

Power Factor Correction

The module allows you to significantly increase the efficiency (“bepeshnik”) PFC, which in Russian means “power factor correction.” Module PFC- a special element designed for power factor correction and aimed at protecting the network. PFC conditionally divided into active (Active) and passive (Passive).

We recommend purchasing power supplies with PFC(they allow you to achieve high level Efficiency - up to 95 %), and active (Active), because APFC, additionally equalizes the input voltage, which in turn allows all devices that output analog signal from the computer.

Note that models with APFC a little more expensive than their passive counterparts, but the difference in efficiency will later be reflected in your energy bills.

Maximum current on individual lines

The total power of the power supply is the sum of the powers that it can provide on individual power lines. If the load on one of them exceeds the permissible limit, the system will lose stability, even if the total power consumption is far from the nominal value. In total (as you already know) there are three lines 12V; 5V And 3.3V; a little more about them.

12 -volt is supplied primarily to powerful consumers of electricity - the video card and the central processor. The power supply must provide as much as possible on this line more power. To power high-performance video cards, two 12 -volt lines. Lines with voltage 5 B supplies power to the motherboard, hard drives and optical drives PC. Lines on 3.3 B, go only to the motherboard and provide power to the RAM.

It is also worth saying that the line load is modern systems, as a rule, is uneven and here it is worth considering that it is “heaviest” of all 12 -voltage channel, especially in configurations with powerful video cards, but about the lines 5V/3.3V You should also not forget that their total current should not exceed 30 % of the total power supply current.

Dimensions

When specifying the dimensions of a power supply, manufacturers, as a rule, limit themselves to designating the form factor, which must meet the standard ATX 2.X. See this on the power supply itself (arrow 1 in the image) or on the documentation that came with it. Also, when purchasing, we advise you to compare its dimensions with the dimensions of “ seat". Please note that if the case bears the inscription “ noise killer"(arrow 2 in the image), then the fan rotates as slowly as possible, which reduces the sound level. The rotation speed is regulated by a special temperature sensor.

Old power supply (standard AT), which turns the computer on and off using a regular power switch, is far from the most the best option. Nowadays, its purchase can only be justified by the fact that you have an “ancient” machine at home, into which it is physically impossible to insert a more modern module.

It's better to choose ATX- a device that works only after a command from the motherboard. This technology makes it possible to remove the high-voltage wire from the unit and improve safety. Even if the block ATX burns out, the likelihood that something else will be damaged is much lower. In its turn ATX the standard has several different modifications. Version ATX 2.03 , produced for powerful computers with high energy consumption.

Cable management system. All about "wires"

This name combines the way cables are connected to the power supply. The essence of the technology is that only required cables included in the delivery set.

For example, the unit has many cables that allow you to connect, say, from 3 before 5 hard drives, before 2 -3 video cards, etc. But usually a computer has a maximum of three hard drives and one video card. In this case, it turns out that all these unused cables are simply hanging in the system unit and only interfere with cooling, because... obstruct air circulation.

Modular cable connection technology allows you to connect only the ones you need as needed. this moment cables, and leave unnecessary ones “out”. For such modules, only the main cables are non-removable, for example, for power supply motherboard, processor and one cable for additional food video cards.

The power supply must not only provide the necessary power, but also correctly supply voltage to all components, and for this you need the appropriate connectors.

For example, there should be at least six pieces (although you can expand it with a special splitter, but you have to buy it). A computer with two hard drives and a pair of optical drives already uses four of these connectors, and Molex Other devices can also be connected - for example, case fans and “ancient” video cards with an interface AGP. The power cables must be long enough to reach all required connectors. Another important additional option, the presence of which is highly desirable, is the cable braid.

Firstly, it greatly simplifies the installation of a computer and connecting new devices, and secondly, it allows you to avoid cable clamps and breaks due to tangling.

Cooling and noise

During operation, the components of the power supply become very hot and require increased cooling. For this purpose, fans (built into its case) and radiators are used. Most use one size fan 80 or 120 mm (which are quite noisy), and the higher the power of the power supply, the more intense the air flow is required in order to cool it. To reduce noise levels in quality systems circuits are used to control the fan rotation speed in accordance with the temperature inside the block module.

Some models allow the user to determine the fan speed using a regulator on the back wall; there are also models that continue to “pump” air some time after the computer is turned off. Thanks to this, computer components cool down faster after work.

Safety

High-quality power supplies are equipped with various systems to protect against power surges, overloads, overheating and short circuits. These features protect not only the power supply, but also other components of the computer.

Note that the presence of such systems in the power supply does not eliminate the need to use sources uninterruptible power supply and network filters.

MTBF

As a rule, the guarantee is N The number of hours of work is one of the signs of a quality product. Yes, such models are somewhat more expensive, but the manufacturer determines the guaranteed operating time of the device. The best option here is the deadline 3 -5 years. Information about this is contained in the instruction manual and is also duplicated on the packaging.

Manufacturer and weight

When buying any good thing, we always look at the brand/manufacturer - BP is no exception. In my eyes, the company has proven itself best Chieftech(model Chieftec or its older version Chieftec- divine, I know from my own experience and the experience of hundreds of friends). It might be worth paying attention to: InWin, Seasonic, FSP, Zalman etc., so take a closer look at them. Buy noname It is strongly and irrevocably not recommended.

It is also worth knowing that a high-quality power supply should weigh on average from 2 before 2.5 kg (so you can safely take a scale with you and measure its weight). Don’t take one as light as a feather, because there is a chance that the manufacturer saved on the filling (transformers, radiator, etc.).

In order to at least somehow encourage you for the fact that you yourself wanted to understand all the intricacies of such a complex device and have already passed a good half of the article, I’ll tell you about one more useful feature(which is worth paying attention to), which few people know about.

All models sold overseas and Russian market must be certified Underwriters Laboratories), as a number UL. Power supplies are certified in laboratories UL, after which they are assigned a number. The most interesting thing is that this number always indicates the real manufacturer, regardless of what brand the latter is sold under. And in the online database UL You can always search by manufacturer number and see the parameters of the power supply. To find a number UL, you do not need to open the module itself. Typically, this number is located under the logo UL and starts with a letter E.

When you find the number UL on the label, it’s just a matter of small things: you need to contact and enter the number in the “ UL File Number" Then you need to press the " Search" and that's it.

You will receive information about the manufacturer, as well as a link to a document that outlines the main characteristics of the power supply, including maximum load along the lines. No number UL indicates the dubious quality of the product. Such power supplies should not be taken.

Practice choosing a power supply. We read the label.

In general, the theory is over (:-)), now a few words about practice..

So you came to the store and want to choose a high-quality power supply yourself. What should I pay attention to and what should I do?

Well, the most important thing you have to do is turn on my head and remember everything you already know. Also, you should not ask for advice from a sales consultant (as a rule, who only took office yesterday), but it is better to pick up the device, turn it around and find its “technical passport” (which, by the way, is present on every power supply) in the form here such stickers.

So, let's deal with it (the sticker).

How to choose a power supply - nuances according to the label - steps

The main parameter on it is the so-called Combined Power/Combined Wattage. This is the maximum total power for all existing power lines. In addition, the maximum power for individual lines also matters. If there is not enough power on a line to “feed” the devices connected to it, then these components may operate unstably, even if the total power is sufficient.

As a rule, not all power supplies indicate the maximum power for individual lines, but all of them indicate the current strength. Using this parameter, it is easy to calculate the power: to do this, you need to multiply the current by the voltage in the corresponding line.

The power of a power supply can be calculated by adding up the powers on its individual lines (arrow 1, in the image). They, in turn, are determined by multiplying the voltage on the corresponding line by the maximum current strength on it (arrow 2, in the image).

Step two.
Let's remember the number UL(on the sticker) and are looking for reliable information about the manufacturer.

Step three.
We are looking for the inscription of compliance with the standard “ 80 PLUS"and determine the efficiency.

Step four.
We estimate the weight using an experienced (scales) or “manual”(:-)) method.

Actually, on this visual inspection finished (the label has been studied), the necessary parameters have been identified - we can safely take our future power supply.

So, buy - bought, but now you also need to connect it correctly. There is nothing complicated about this and you can do it yourself just fine, having previously become familiar with the “topology” of the connectors (i.e. what/where to connect). To make it easier to understand this, the following will help you: conditional diagrams.

A cable with this connector is connected to the motherboard. Depending on the board type, it is equipped 20 or 24 contacts;
Modern processors usually require additional power. A separate cable from the power supply is intended for this;
Powerful video cards also require additional power. To do this, use one or two connectors with 6 or 8 contacts;
Disk devices with interface IDE and case fans are connected to the power supply 4 - type connectors Molex;
Hard drives and optical drives with interface SATA connectors of a different type are used to receive power

That's all, we figured out the connection.
You see, it’s not so difficult if you know the topology of the connectors and the basic connection rules, and you now know them.

So, cross your fingers, now you can not only choose the “right” power supply, but also connect it, and therefore breathe life into your “hardware” (:-)).

Thus, you have moved from the level of “who should I ask and should I call a specialist?” to a qualitatively new level of “why! I’ll do everything myself.” Congratulations!

And in the end, I will summarize everything that was said here (and a lot was said here, believe me), so that everything is finally placed on the shelves for you. So, when buying a power supply, you should always remember that:

Sufficient power. Choose a power supply with power reserve (for 10 -30 % more than the total consumption of all components);
Efficiency no less 80-85 %;
Sufficient line power 12 B, for powerful consumers;
Line power ratio +5 B + 3.3 The total power should not be greater than 3 To 10 (30% );
Certification" 80 PLUS", preferably higher Bronze;
Active module PFC(Power Factor Correction);
Compliance with standard ATX 2.X.;
System Cable management- modular cable connection;
Surge protection system;
Well-known manufacturer ( Cooler Master, Enermax, Chieftec, FSP, OCZ, Zalman);
Heavy weight;
Good cooling.

Follow these simple tips and you won't need a fire extinguisher :-)

Where is the best place to buy a power supply?

, - for those who are not afraid to buy abroad and save money. There are many, several popular brands, and in general a nice store where they stock regulars and so on;
, - perhaps the best choice in terms of price-quality ratio SSD(and not only). The prices are quite reasonable, although the range is not always ideal in terms of variety. The key advantage is the guarantee that really allows for 14 days to change the product without any questions, and in case of warranty problems, the store will take your side and help solve any problems. The author of the site has been using it for years 10 at least (since the days when they were part of Ultra Electoronics), which is what he advises you to do;
, - one of the oldest stores on the market, as the company exists somewhere around 20 years. Decent selection, average prices and one of the most convenient sites. Overall a pleasure to work with.

The choice, traditionally, is yours. Of course, there are all kinds Yandex Market"no one canceled it, but from good shops I would recommend these, and not some others large networks(which are often not only expensive, but also detrimental in terms of quality of service, warranty, etc.).

Afterword

That's all! I hope you have learned a lot (and whoever knew, remembered) from this material and now choosing and purchasing the “right” power supply will not cause you the slightest difficulty, moreover, now you will become a “guru” on these issues, for most of your hardware brethren :-).

Until next time, stay on the IT wave " Notes.Sysadmin", don't switch! ;)

If you have questions, additions, or other differences, then comments are at your service.

PS: Thanks to team member 25 KADR for the existence of this article

If you buy a computer, it may already come with standard block nutrition. But, given the most important function of this unit for stable, long-term operation, it is worth familiarizing yourself with its characteristics, and, if necessary, replacing it with one more suitable for you, taking into account all the requirements for this element. You can select a powerful and reliable power supply for your computer by reading the general requirements for it, choosing the type, power and manufacturer, taking into account the specific features of the equipment installed in your system unit.

What is a computer power supply

Most computers are connected directly to a public electrical outlet without the use of additional stabilizers that smooth out surges, voltage drops and frequency of the supply network. A modern power supply device must provide all computer components with a stable voltage of the required power, taking into account peak loads when performing complex tasks. graphic tasks. All expensive components of the computer - video cards, HDD, motherboard, processor, and others.

What does it consist of?

Modern computer power supply devices have several main components, many of which are mounted on cooling radiators:

Input filter to which mains voltage is supplied. Its task is to smooth the input voltage, suppress ripple and noise.
The mains voltage inverter increases the mains frequency from 50 Hz to hundreds of kilohertz, making it possible to reduce the size of the main transformer while maintaining its useful power.
The pulse transformer converts the input voltage to low voltage. Expensive models contain several transformers.
Standby voltage transformer and controller that controls the inclusion of the main power supply in automatic mode.
An AC signal rectifier based on a diode assembly, with chokes and capacitors that smooth out ripples. Many models are equipped with an active power factor correction.
Stabilization of the output voltage is carried out in high-quality devices independently for each power line. Inexpensive models use one group stabilizer.
An important element in reducing energy costs and reducing noise is a fan speed thermostat, the operating principle of which is based on the use of a temperature sensor.
Signal units include a voltage and current consumption control circuit, a system for preventing short circuits, overloads of current consumption, and overvoltage protection.
The case must accommodate all of the listed components, including a 120 mm fan. A high-quality power supply will provide the ability to disconnect unused harnesses.

Types of power supplies

The power supply devices for desktop PC systems differ from those used in laptops. There are several types of these devices based on their design:

Modular devices provide the ability to disconnect unused wiring harnesses.
Fanless, passively cooled devices are quiet and expensive.
Semi-passive power devices are equipped with a cooling fan with a control controller.

To standardize the size and physical layout of computer modules, the concept of form factor is used. Nodes that have the same form factor are completely interchangeable. One of the first international standards in this area was the AT (Advanced Technology) form factor, which appeared simultaneously with the first IBM-compatible computers and was used until 1995. Majority modern devices Power supplies use the ATX (Advanced Technology Extended) standard.

Intel in December 1997 introduced a motherboard of a new microATX family, for which a smaller power supply device was proposed - Small Form Factor (SFX). Since that time, the SFX standard has been used in many computer systems. Its advantage is the ability to use five physical forms and modified connectors for connecting to the motherboard.

The best power supplies for computers

When choosing power supplies for your computer, you should not save money. Many manufacturers of such economy class systems exclude important anti-interference elements to reduce prices. This is noticeable by the jumpers installed on the circuit board. To standardize the quality level of these devices, the 80 PLUS Certificate was created, indicating an efficiency factor of 80%. Improvements in the characteristics and components of computer power supplies have led to the updating of varieties of this standard to:

Bronze – efficiency 82%;
Silver – 85%;
Gold – 87%;
Platinum – 90%;
Titanium – 96%.

You can buy a power supply for your computer in computer stores or supermarkets in Moscow, St. Petersburg, and other Russian cities where big choice components. For active Internet users, find out how much it costs, make a selection from large quantity models, you can buy a power supply for a PC in online stores, where you can easily select them from photos, order them based on promotions, sales, discounts, and make a purchase. All goods are delivered by courier services or, cheaper, by mail.

AeroCool Kcas 500W

For most home desktop computers, 500W will do. Suggested option made in China combines good performance quality and reasonable price:

Model name: AEROCOOL KCAS-500W;
price: 2,690 rubles;
characteristics: form factor ATX12V B2.3, power – 500 W, active PFC, efficiency – 85%, standard 80 PLUS BRONZE, color – black, MP connectors 24+4+4 pin, length 550 mm, video cards 2x(6+ 2) pin, Molex – 4 pcs, SATA – 7 pcs, connectors for FDD – 1 pc, 120 mm fan, dimensions (WxHxD) 150x86x140 mm, power cord included;
pros: active power factor correction function;
cons: efficiency is only 85%.

AeroCool VX-750 750W

The 750 W VX line of power supplies are assembled from high-quality components and provide stable and reliable power to entry-level systems. Such a device from Aerocool Advanced Technologies (China) is protected from voltage surges in the network:

Model name: AeroCool VX-750;
price: 2,700 rub.;
characteristics: ATX 12V 2.3 standard, active PFC, power – 750 W, current along the lines +5 V – 18A, +3.3 V – 22 A, +12 V – 58 A, -12 V – 0.3 A, +5 V – 2.5 A, 120 mm fan, connectors 1 pc 20+4-pin ATX, 1 pc Floppy, 1 pc 4+4-pin CPU, 2 pcs 8-pin PCI-e (6+2), 3 pcs Molex, 6 pcs, dimensions – 86x150x140 mm, weight – 1.2 kg;
pros: fan speed control;
cons: no certificate.

FSP Group ATX-500PNR 500W

The Chinese company FSP produces a wide range of high-quality components for computer equipment. The option offered by this manufacturer has low price, but equipped with a network overload protection module common use:

Model name: FSP Group ATX-500PNR;
price: 2,500 rub.;
characteristics: ATX 2V.2 standard, active PFC, power – 500 W, line load +3.3 V – 24A, +5V – 20A, +12V – 18 A, +12 V – 18A, +5V – 2.5A, - 12 V – 0.3A, 120 mm fan, 1 pc 20+4-pin ATX connectors, 1 pc 8-pin PCI-e (6+2), 1 pc Floppy, 1 pc 4+4-pin CPU, 2 pcs Molex , 3 pcs SATA, dimensions – 86x150x140 mm, weight – 1.32 kg;
pros: there is short circuit protection;
cons: no certification.

Corsair RM750x 750W

Corsair products provide reliable voltage control and operate quietly. The presented version of the power supply device has an 80 PLUS Gold Certificate, low noise level and a modular cabling system:

Model name: Corsair RM750x;
price: RUB 9,320;
characteristics: ATX 12V 2.4 standard, active PFC, power – 750 W, line load +5 V – 25 A, +3.3 V – 25 A, +12 V – 62.5 A, -12 V – 0.8 A, +5 V – 1 A, 135 mm fan, connectors 1 pc 20+4-pin ATX, 1 pc Floppy, 1 pc 4+4-pin CPU, 4 pcs 8-in CI-e (6+2), 8 pcs Molex, 9 pcs SATA, 80 PLUS GOLD certificate, short circuit and overload protection, dimensions – 86x150x180 mm, weight – 1.93 kg;
pros: temperature-controlled fan;
cons: high cost.

Thermaltake power supply devices are distinguished by high functionality and stability of all characteristics. The proposed version of such a device is suitable for most system units:

model name: Thermaltake TR2 S 600W;
price: RUR 3,360;
characteristics: ATX standard, power – 600 W, active PFC, maximum current 3.3 V – 22 A, +5 V – 17 A, + 12 V – 42 A, +12 V – 10 A, 120 mm fan, motherboard connector – 20+4 pin;
pros: can be used in new and old computers;
Cons: no network cable included.

Corsair CX750 750W

The purchase of a high-quality and expensive power supply device is justified when using expensive other components. The use of Corsair products will make it unlikely that this equipment will fail due to the fault of the power supply device:

Model name: Corsair CX 750W RTL CP-9020123-EU;
price: RUR 7,246;
characteristics: ATX standard, power – 750 W, load +3.3 V – 25 A, +5 V – 25 A, +12V – 62.5A, +5 V – 3 A, -12V – 0.8 A, dimensions – 150x86x160 mm, 120 mm fan, efficiency – 80%, dimensions – 30x21x13 cm;
pros: fan speed controller;
cons: expensive.

Deepcool DA500 500W

All Deepcool products are certified to the 80 PLUS standard. The proposed model of the power supply device has a Bronze degree certificate, has protection against overload and short circuit:

Model name: Deepcool DA500 500W;
price: RUR 3,350;
characteristics: form factor Standard-ATX 12V 2.31 and EPS12V, active PFC, Main connector – (20+4)-pin, 5 15-pin SATA interfaces, 4 molex connectors, for video card – 2 interfaces (6+2)- pin, power – 500 W, 120 mm fan, currents +3.3 V – 18 A, +5 V – 16 A, +12 V – 38 A, -12 V – 0.3 A, +5 V – 2.5 A ;
pros: 80 PLUS Bronze certificate;
cons: not noted.

Zalman ZM700-LX 700 W

For modern models For processors and expensive video cards, it is advisable to buy certified power supplies of at least Platinum standard. The presented computer power supply from Zalman has an efficiency of 90% and high reliability:

model name: Zalman ZM700-LX 700W;
price: RUR 4,605;
characteristics: ATX standard, power - 700 W, active PFC, +3.3 V - 20 A, current +5 V - 20 A, + 12V - 0.3 A, 140 mm fan, dimensions 150x86x157 mm, weight 2.2 kg;
advantages: short circuit protection;
cons: not noted.

How to choose a power supply for your computer

Trust your valuables computer equipment little-known manufacturers should not. Some dishonest manufacturers disguise the low quality of their equipment under “fake” quality certificates. Chieftec has a high rating among manufacturers of power supply devices for computers, Cooler Master, Hiper, SeaSonic, Corsair. It is desirable to have protection against overload, overvoltage and short circuit. It can say a lot appearance, case material, fan mounts, quality of connectors and harnesses.

Motherboard power connector

The number and type of connectors installed on the motherboard depend on its type. The main ones are connectors:

4 pin – for power supply to the processor, HDD drives;
6 pin – for powering video cards;
8 pin – for powerful video cards;
15 pin SATA – for connecting the SATA interface with hard drives, CD-ROM.

Power supply power

All requirements for stable operation can be met by power supplies for computers, the power of which is selected with a reserve and exceeds the rated consumption of all computer components by 30-50%. The power reserve guarantees that the cooling properties of radiators are exceeded, the purpose of which is to remove excessive overheating of its elements. It is difficult to determine the device you need based on a review of their offer on the Internet. For this purpose, there are websites where, by entering the parameters of your components, you can calculate the required characteristics of power supply devices.

Power consumption ratings for home computers range from 350 to 450 W. It is better to buy power supplies for commercial purposes from a nominal value of 500 W. Gaming computers and servers must be run with power supplies of 750 W or higher. An important component of a power supply device is PFC or power factor correction, which can be either active or passive. Active PFC increases the power factor value up to 95%. This parameter is always indicated in the passport and instructions for the product.

Video

Secondary power supply- a device that converts the electrical parameters of the main power supply source (for example, industrial network) into electricity with the parameters necessary for the operation of auxiliary devices.

The power supply can be integrated into the overall circuit (usually in simple devices; or when even a slight voltage drop on the supply wires is unacceptable - for example, a computer motherboard has built-in voltage converters to power the processor), made in the form of a module (power supply, power rack, etc. further), or even located in a separate room (power supply workshop).

Secondary power supply tasks

Ensuring power transmission- the power source must ensure the transmission of the given power with minimal losses and compliance given characteristics at the exit without harm to yourself. Usually the power of the power source is taken with some reserve.
Voltage waveform conversion- conversion of alternating voltage into direct voltage, and vice versa, as well as frequency conversion, formation of voltage pulses, etc. Most often, it is necessary to convert alternating voltage of industrial frequency into direct voltage.
Voltage value conversion- both increase and decrease. Often a set of several voltages of different values is needed to power different circuits.
Stabilization- voltage, current and other parameters at the output of the power source must lie within certain limits, depending on its purpose under the influence of a large number of destabilizing factors: changes in input voltage, load current, and so on. Most often it is necessary to stabilize the voltage at the load, but sometimes (for example, to charge batteries) current stabilization is necessary.
Protection- the voltage or load current in the event of a malfunction (for example, a short circuit) of any circuits may exceed permissible limits and damage the electrical appliance or the power source itself. Also, in many cases, protection is required against the passage of current along the wrong path: for example, the passage of current through the ground when a person or foreign object touches live parts.
Galvanic isolation of circuits- one of the measures to protect against current flow along the wrong path.
Adjustment- during operation, it may be necessary to change any parameters to ensure proper operation of the electrical appliance.
Control- may include adjustment, turning on/off any circuits, or the power source as a whole. It can be either direct (using controls on the device body), or remote, as well as programmatic (ensuring on/off, adjustment at a given time or with the occurrence of any events).
Control- display of parameters at the input and output of the power source, switching circuits on/off, protection activation. It can also be direct or remote.

Most often, secondary power supplies are faced with the task of converting electricity from an alternating current network of industrial frequency (for example, in Russia - 240 V 50 Hz, in the USA - 120 V 60 Hz).

The two most typical designs are transformer and switching mode power supplies.

Transformer

Linear power supply

The classic power supply is a transformer power supply. In general, it consists of a step-down transformer or autotransformer, whose primary winding is designed for mains voltage. Then a rectifier is installed that converts the alternating voltage into direct voltage (pulsating unidirectional). In most cases, the rectifier consists of one diode (half-wave rectifier) or four diodes forming a diode bridge (full-wave rectifier). Other circuits are sometimes used, such as in voltage-doubling rectifiers. After the rectifier, a filter is installed to smooth out oscillations (pulsations). Usually it is simply a large capacitor.

Also, filters for high-frequency interference, surges (varistors), short-circuit protection (short circuit), voltage and current stabilizers can be installed in the circuit.

Transformer dimensions

E e f f 1 = S 33...70 , (\displaystyle E_(eff1)=(\frac (S)(33...70)),)

Here S (\displaystyle S) expressed in cm 2, E e f f 1 (\displaystyle E_(eff1))- in volts. Smaller denominator values are chosen for low-power transformers, larger ones for high-power ones.

Another way to increase the power of a transformer is to increase the operating frequency. Approximately, we can assume that for a given transformer size, its power is directly proportional operating frequency. Therefore, an increase in frequency in k (\displaystyle k) times with constant power allows you to reduce the size of the transformer by ∼ k (\displaystyle \sim (\sqrt (k))) times (the cross-sectional area of the magnetic circuit decreases by ∼ k (\displaystyle \sim k) times), or, accordingly, its mass in ∼ k 3 / 2 (\displaystyle \sim (\sqrt[(3/2)](k))) once.

In particular, including these considerations, a frequency of 400 Hz with a voltage of 115 V is usually used in on-board power networks of aircraft and ships.

But an increase in frequency worsens the magnetic properties of magnetic cores, mainly due to an increase in hysteresis losses, therefore, at operating frequencies above a few kHz, ferrodielectric magnetic cores of transformers are used, for example, ferrite or made of carbonyl iron.

Modern sources of secondary power supply of various household appliances, computers, printers, etc. are now almost entirely carried out according to circuits and have almost completely replaced classical transformers. In such sources, the galvanic separation of the powered circuit and the supply network, obtaining a set of the necessary secondary voltages, is carried out using high-frequency transformers with ferrite cores. The source of high-frequency voltage is pulsed switching circuits with semiconductor switches, usually transistor ones. The use of such devices, often called inverters, makes it possible to significantly reduce the weight and dimensions of the device, and also, additionally, to improve the quality and reliability of the power supply, since pulsed sources are less critical to the quality of the power supply in the primary network - they are less sensitive to surges and dips in the mains voltage, changes in its frequency.

Advantages and disadvantages

Advantages of transformer power supplies. Disadvantages of transformer power supplies.

Large weight and dimensions, proportional to power.
Metal consumption.
The trade-off between reduced efficiency and output voltage stability: to ensure stable voltage, a stabilizer is required, which introduces additional losses.

Switching power supply

The most common version of the power supply involves converting 220 Volts of alternating voltage (U) into a reduced direct voltage. In addition, power supplies can provide galvanic isolation between input and output circuits. In this case, the transformation ratio (the ratio of input and output voltages) can be equal to unity.

An example of such use would be the energy supply of premises with high degree danger of defeat electric shock, for example, bathrooms.

In addition, quite often household power supplies can be equipped with built-in additional devices: stabilizers, regulators. indicators, etc.

TYPES AND TYPES OF POWER UNITS

First of all, the classification of power supplies is carried out according to the principle of operation. There are two main options here:

transformer (linear);
pulse (inverter).

Transformer block consists of a step-down transformer and a rectifier that converts alternating current into direct current. Next, a filter (capacitor) is installed that smooths out ripples and other elements (output parameter stabilizer, short-circuit protection, high-frequency (RF) interference filter).

Advantages of a transformer power supply:

high reliability;
maintainability;
simplicity of design;
minimum level interference or lack thereof;
low price.

Disadvantages - heavy weight, large dimensions and low efficiency.

Impulse power block- an inverter system in which alternating voltage is converted into direct voltage, after which high-frequency pulses are generated, which undergo a series of further transformations (). In a device with galvanic isolation, pulses are transmitted to a transformer, and in the absence of one, directly to the low-pass filter at the output of the device.

Thanks to the formation of RF signals, small-sized transformers are used in switching power supplies, which allows reducing the size and weight of the device. To stabilize the voltage, negative feedback is used, thanks to which a constant voltage level is maintained at the output, independent of the load.

Advantages of a switching power supply:

compactness;
light weight;
affordable price and high efficiency (up to 98%).

In addition, it should be noted that there are additional protections that ensure the safety of using the device. Such power supplies often provide protection against short circuits (short circuits) and failure when there is no load.

Disadvantages - operation of a larger component of the circuit without galvanic isolation, which complicates repairs. In addition, the device may cause interference high frequency and has a lower load limit. If the power of the latter is less than the permissible parameter, the unit will not start.

PARAMETERS AND CHARACTERISTICS OF THE POWER SUPPLY

When choosing a power supply, you should take into account a number of characteristics, including:

power;
output voltage and current;
as well as the availability additional options and opportunities.

Power.

A parameter that is measured in W or V*A. When choosing a device, you should take into account the presence of inrush currents in many electrical receivers (pumps, irrigation systems, refrigerators, and others). At the moment of start-up, power consumption increases by 5-7 times.

As for other cases, the power supply is selected taking into account the total power of the powered devices with a recommended margin of 20-30%.

Input voltage.

In Russia this parameter is 220 Volts. If you use a power supply in Japan or the USA, you will need a device with an input voltage of 110 Volts. In addition, for inverter power supplies this value can be 12/24 Volts.

Output voltage.

When choosing a device, you should focus on the rated voltage of the consumer used (indicated on the device body). It could be 12 Volts, 15.6 Volts and so on. When choosing, you should buy a product that is as close as possible to the required parameter. For example, to power a 12.1 V device, a 12 V unit is suitable.

Output voltage type.

Most devices are powered by stabilized direct voltage, but there are also those that are suitable for unstabilized or alternating voltage. Taking this criterion into account, the design is also selected. If an unstabilized constant U at the input is enough for the consumer, a power supply with a stabilized voltage at the output is also suitable.

Output current.

This parameter may not be indicated, but if you know the power, it can be calculated. Power (P) is equal to voltage (U) times current (I). Therefore, to calculate the current, it is necessary to divide the power by the voltage. This parameter is useful for selecting a suitable power supply for a specific load.

As a rule, the operating current should exceed the maximum current consumption of the device by 10-20%.

Efficiency.

High power supply power is not a guarantee of good performance. No less important parameter is the efficiency factor, which reflects the efficiency of energy conversion and its transmission to the device. The higher the efficiency, the more efficiently the unit is used, and the less energy is spent on heating.

Overload protection.

Many sources are equipped with overload protection, which ensures that the power supply is turned off if the level of current consumed from the network is exceeded.

Deep discharge protection.

Its task is to break the power circuit when the battery is completely discharged (typical for uninterruptible power supplies). After power is restored, the device's functionality is restored.

In addition to the options listed above, the power supply may provide protection against short circuits, overheating, overcurrent, overvoltage and undervoltage.

All materials presented on this site are for informational purposes only and cannot be used as guidelines or regulatory documents.