80 years have passed since then and I still ask myself the same question ( approx. - What is electricity?), but unable to answer it. © Nikola Tesla

Power Supply Power Calculators

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The importance of the power supply

Power supplies have traditionally received little attention, and their choice is very often made according to the residual principle, when compared with other PC components. At the same time, not only the smooth operation of the computer for several years depends on the quality and reliability of this node, but also such an important indicator as the amount of electricity consumed, and, accordingly, the electricity bill. In this article, we will try to answer why expensive power supplies are so good and what are the benefits of using them.

Component quality

The quality of the installed electronic components has a significant impact on the final price. An example here is the electrolytic capacitors used. The power supply is a node that heats up significantly during operation, especially if the PC has a ventilation scheme that creates a vacuum inside the case, in which part of the hot air moves through the PSU. The most common and inexpensive aluminum electrolytes have a maximum allowable temperature of 85 °C, but even slightly lower heating significantly reduces their MTBF. In reliable power supplies, conscientious manufacturers use more resistant types of capacitors, but the price of the product is higher. The choice of the manufacturer in favor of specialized diode assemblies or discrete elements has a corresponding effect on the final cost. In the first case, the bridge rectifier is guaranteed the identical performance of both arms and the maximum possible symmetry, and in the second case, a higher profitability of production.

circuit solutions

Modern power supplies can have several independent lines in +5 and +12 V circuits. The ideal, albeit expensive, circuit solution here is separate rectifiers (especially synchronous), and individual output filters are acceptable. In budget models, the most primitive options for obtaining “parallel” lines are often found, implemented by simply connecting wires to a common contact. The obvious disadvantage of such a simplification is the impossibility of effectively stabilizing the output voltage and the mutual influence of consumers.

Cheap PSUs may not have EMI input filters or are equipped with simplified single-loop solutions. In other words - with a high probability they will create problems for other electrical appliances in the course of their work.

If budget power supplies usually provide two types of protection: against short-term overvoltage in the external network and short circuit inside the unit, then high-quality devices support a more advanced security package. The best models are equipped with an intelligent circuit based on a special chip and are able to respond in a timely manner to excessive current consumption, overheating and undervoltage. In addition, inexpensive blocks do not have protection that prevents them from being turned on without a regular load, while such an operating mode is not terrible for expensive solutions.

Consequences of the choice

Spontaneous reboot of the computer can be caused not only by the unstable operation of the motherboard, memory problems or software reasons. Any power supply controls the output voltage level in all circuits and generates a control signal that allows the PC to be turned on. The latter is a logical unit that enters the input of the corresponding key element of the motherboard responsible for issuing the general reset command. The absence or short-term loss of the Power_OK signal automatically causes a reboot of the system, and the cause can be either the voltage going beyond the permissible limits or the incorrect operation of the control unit itself. For low-quality PSUs, the opposite manifestations are also possible, for example, the low speed of operation of this protection, tracking not all circuits, or giving a signal until the levels are completely stabilized (insufficient delay).

Another characteristic feature of budget power supplies is the use of the minimum allowable values ​​of electrolytic capacitors installed in the output filters. Their capacity directly affects the shutdown time during which the PSU is able to maintain the required voltage levels, allowing the computer to urgently complete critical operations. In the event of a short-term loss of mains power, it is even possible to continue the operation of the PC without rebooting. Simply put, some high-quality PSU models have a “built-in uninterruptible power supply”.