How to choose a power supply and not bite your elbows later

Most (if not all) of the computer power supply units being sold are assembled in China. Of course, the statement that "China is China is different" has not been canceled, but the quality of the bulk of these devices, to put it mildly, is at a low level. This fact is not hidden by anyone, so often the question is raised, how to choose a power supply. Moreover, even well-known manufacturers often indicate overestimated percentages for 20 values of rated currents. In principle, they can be understood, because in a tough market competition for survival all means are good, well, the user ... he has to carefully study the passport data of the equipment and understand how to choose a power supply for the computer. We'll talk about this today.

The power supply unit is located in the computer case and supplies all components with electricity. In general, the task assigned to it is quite simple and has long been successfully solved in electrical engineering: standard 220 V AC is applied to the input, and a bunch of constant voltages - 3, 5, 12 V, with both polarities appearing at the output. If the consultant at the computer store asked the question "How to choose a power supply?", He, of course, will advise the optimal solution, but he adds that it is recommended to change the blocks every 1-2 years. This is an important addition, which is rarely followed, but in vain. The internal elements of the pulsed power supply do not correspond to the declared characteristics with time (for example, the capacitors dry up), therefore it needs to be changed.

So, how to choose a power supply? The first indirect sign of a good block is its weight. It sounds funny, but it really is. The switching power supply unit is a rather complex product, requiring careful follow-up of the circuit during assembly. If you open a cheap Chinese block, then the PCB will surprise with its emptiness: in place of the marked elements soldered jumper, and the radiator can not be called massive. Therefore, when choosing not to be ashamed to evaluate the weight of the block.

The second recommendation is known to everyone who has read at least a little how to choose a power supply. Nevertheless, if possible, it makes sense to collect a little extra money and buy a product of well-known companies - GlacialPower, Zalman, FSP, etc. Such a unit will ensure reliable operation of the computer, since its parameters are more or less adequate. Let's give an example from life: there are two power supply units - GlacialPower with a capacity of 450 W and Codegen with 250 W. Compare the passport data and ... we understand that everyone has his own math. The total claimed power Codegen on plus lines 3 and 5 V is equal to the same parameter for GlacialPower! The conclusion is obvious - cheap Chinese blocks can be bought, but with a two-fold power reserve and use them for not more than a year. In addition, branded products support different "goodies", for example, intelligent fan control, which means so valuable silence in the work.

In modern systems, the main load falls on the line +5 and +3.3 V, so the unit should be selected based on the maximum current of these lines (the more, the better). On the sticker with the passport data, these values are always given. If the power of these lines is less than that of the processor, then we are looking for a more efficient model.

Before going to the store it is recommended to calculate the power of the power unit. For this, there are special programs or websites. It is necessary to specify the type of processor, video card, memory, etc. Remember that the obtained value will be indicative, and the model should be chosen as "calculated value + 20%".

Summarize:

- calculate the required power;

- choose a heavy brand power supply;

- we are convinced that the power of +3.3 and +5 V is enough.

In addition, you can pay attention to the number of power connectors: sometimes connectors for SATA hard drives are not enough and you have to use adapters with Molex, which is not too convenient.