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What is a Power Supply Unit and its features

Should you be constructing or enhancing your personal computer, you may be curious about the definition of a power supply unit (PSU), its features and necessity. A PSU is a piece of hardware that gives your computer and its accessories electricity. It changes the wall outlet’s alternating current (AC) to direct current (DC), which the computer’s components may use. Your computer would not be able to operate at all without a PSU.

How Does a PSU Work?

A PSU is often found behind the computer chassis, where it is attached to the motherboard and power supply. A fan on the PSU removes hot air from the case and cools the device. Additionally, the PSU features a number of connectors that link to the CPU, RAM, hard drive, optical drive, graphics card, and fans, among other parts of the computer.

The PSU transforms the wall outlet’s AC power into the various DC voltages needed by the computer’s components. Three voltages are most commonly used: 3.3V, 5V, and 12V. In addition, the PSU supplies a 5V standby voltage, which enables remote or keyboard-and-mouse-activated computer turning. When the power is stable and ready for use, the PSU also signals the motherboard.

What are the types of PSU?

PSUs come in a variety of forms, sizes, powers, levels of efficiency, and features. The ATX PSU, which complies with the ATX specification defining the form factor and voltage tolerances of the PSU, is the most popular kind of PSU for desktop computers. The ATX PSU’s standard dimensions are 150 x 86 x 140 mm, and it connects to the motherboard via a 20- or 24-pin main connector.

An additional PSU type is the ATX12V PSU, which is an expansion of the ATX PSU and adds a 4- or 8-pin connector to supply the CPU with more power. More powerful processors and graphics cards that need more power than the ATX PSU can offer are supported by the ATX12V PSU.

Additional PSU varieties include the TFX PSU, a slim version of the ATX PSU designed for slim cases; the EPS PSU, a server-grade ATX12V PSU that offers greater power and stability; the Flex ATX PSU, a flexible ATX PSU that can be used in a variety of cases; and the SFX PSU, a smaller version of the ATX PSU designed for compact cases.

What are the features of a PSU?

  • Wattage: The maximum power a PSU can supply to the parts of a computer is measured in watts. A PSU’s wattage should be equal to or more than the total power consumed by the parts of the computer. To determine how much power your computer uses, you can utilize a power supply calculator and select a PSU appropriately. A gaming computer needs a PSU of 500W to 800W or more, but a standard desktop computer needs a PSU of 300W to 500W.
  • Efficiency: The power output to input ratio indicates a power supply unit’s efficiency. Efficiency determines how much power is wasted as heat and how much the electricity bill is. The 80 Plus certification, which goes from 80 Plus to 80 Plus Titanium, rates a PSU’s efficiency. The PSU is guaranteed to have an efficiency of at least 80% at different load levels by the 80 Plus certification. A PSU with a greater efficiency rating is of higher quality and costs more.
  • Modular: A PSU with detachable cables that may be plugged in or taken out as needed is called a modular PSU. By using a modular PSU, you may keep the case free of unnecessary cords by using just the ones that you actually need. Additionally, a modular PSU enhances the case’s cooling and ventilation. A PSU with fixed cables that are affixed to the unit permanently is called a non-modular PSU. Although less versatile and neat, a non-modular PSU is less expensive and easier to install.
  • Protection: In the event of power surges, short circuits, overloads, overheating, or other problems, a PSU should include a number of protection circuits to shield the computer’s internal components. Over-voltage protection (OVP), under-voltage protection (UVP), over-current protection (OCP), over-power protection (OPP), over-temperature protection (OTP), and short-circuit protection (SCP) are a few of the frequently found protective characteristics.


A computer’s power supply unit, or PSU, is an essential part that gives the machine and its accessories electricity. A PSU transforms the wall outlet’s AC power into the various DC voltages needed by the computer’s parts. In addition, a PSU has a number of attributes that impact its compatibility, quality, and performance. The wattage, efficiency, modularity, protection, and type of PSU that fits your motherboard and casing should all be taken into account when selecting one for your computer.