Computer power supply types, functions, and components

 Computer power supply  types, functions, and components

computer power supply unit (PSU) showing cables and connectors

The Computer power supply units (PSUs) provide electrical power to all computer components. A power connector distributes the energy from the power unit to other components via power connectors. It connects the computer system unit to the power wall socket. ATX12V, LFX12V, CFX12V, EPS12V, TFX12V, and WTX12V are the main types of power supplies. It is the responsibility of the PSU to convert alternating current (AC) into a direct current (DC) which the computer can use. Connectors, transformers, rectifiers, switches, and cooling fans make up a power unit. These components, along with others, enable the PSU to work efficiently.

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Types of computer power supply

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Power supplies are classified depending on the form factor. This factor should not be confused with the motherboard form factor which is specific to the motherboard. Some of the most common types of power supply units are:

ATX12V: In addition, it has a +12 V power connector and a higher +12 V DC output power capability than standard ATX.

LFX12V (low profile): Low-profile form factor with 12V connector used most commonly on picoBTX/nanoBTX motherboards. They are designed for low power consumption of 180W to 260W.


 These 8-pin connectors were originally developed for servers. They connect the processor to the motherboard.

CFX12V: With a 12-volt connector, these systems have a power rating of 220W to 300W and are designed for systems with Balanced Technology Extended (BTX) motherboards.

SFX12V: MicroATX and FlexATX systems can be powered by these small form factor power supplies. They have an output power of 160W to 300W.

TFX12V: With a power range between 180W and 300W, they are suited for small and low-profile microATX and FlexATX systems.

Workstations and select servers are designed with WTX12V form factors.

Components of PSU

Computer power supply  types, functions, and components
Computer power supply  types, functions, and components

There are a number of components that make up a computer. In addition to the power supply, a computer also needs a converter to convert AC power to DC. Below is a list of the main components that make up the computer.

A connector is a device that connects different components including a computer motherboard, disc drive, expansion card, etc. 

Plugs into a wall socket to connect to a power source externally.

Power supply fan: cools the unit down

One switch turns on the PSU; the other changes the power voltage intake. There are two kinds of switches.

Incoming power can be stepped up or down using a transformer

Power is converted from AC to DC by a rectifier.

Power is regulated by voltage regulators.

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Types of power supply connectors

From the PSU, motherboard, and other components get power supply using a cable connector that links the component to the power unit. The main components that get power directly from PSU are the motherboard, DVD drive, Hard disk, processor, and expansion card among others. The 4 main connectors used are:

The 24-pin connector on the motherboard is used to supply power to the motherboard. It supplies all the required power; however, most other components draw their power from the mainboard.

Motherboard connector for 24-pin computer power supplies

To reduce the number of cables, many SATA points are placed on the same wire in order to power the SATA storage device and disc drive.

Molex connectors: They were used to connect hard drives and front panel monitors in the old days

In the past, floppy disk drives (FDDs) were connected with Berg connectors with four pins.

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When choosing a power supply (PSU), consider these factors

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It should also physically fit within the casing of the computer. It should be compatible with the motherboard form factor.

The standard calculation for computing power is watts. A computer’s power consumption depends on how much power is needed to function at its optimum level. You can check the wattage of the power supply by calculating the product of the voltage in (volts) and the current in (amperes).

 In comparison to a standard personal computer, gaming or high-performance computers require more watts.

Connectors: make sure the power connectors for motherboards, CPUs, hard drives, and other components are compatible and supply the correct voltage.

Noise from the cooling fan on the power supply: Ensure the power supply has a quieter fan.

Power efficiency (80 plus rating): A power supply should be rated according to its efficiency. An 80 plus rating certifies a power supply’s efficiency. A high rating indicates that the computer uses power efficiently. Thus, the power supply saves energy, reduces overheating, and increases its lifespan.

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Functions of computer power supply

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Power supplies are essential components of any computer. Without power, the machine cannot function. PSUs are primarily responsible for powering the machine.

For computer use, convert AC to DC from the wall socket.

Using a fan installed within, they serve as a cooling system.

The motherboard and other components are powered by this power supply.

Different motherboard components can be connected to the power unit via its connectors.

Maintenance of power supply units

To ensure your power supply operates properly without any problems, we recommend the following maintenance checklist routine. The power supply is a critical component of a computer that needs to be in good working condition in order for it to function efficiently.

Protect the power supply from surges by using a power surge protector.

Regularly remove dust using the recommended form cleaner.

Power supply overheating is caused by a failed cooling fan.

Make sure your computer’s power casing is properly attached.

Don’t overpower your computer by using the wrong power wattage.

What is a Power Supply Unit?

 On a desktop computer, the power supply unit is the place where the power cord plugs in and typically contains an I/O power switch. The power supply unit converts AC electricity into DC electricity and distributes it to the rest of the computer. 

Connecting the Dots: PSU Cables and Power Distribution

There are numerous power cables connecting the PSU to the rest of the computer if you open a standard computer case. The cables supply power to the motherboard, hard drives, and case electronics. Most PSUs also have extra cables to connect peripherals that require a great deal of power, such as graphics cards. Modular power supplies are becoming increasingly common in recent years, allowing for the installation of multiple power cables.

Also, the motherboard distributes power to the CPU and RAM slots as well as the connectors for the CPU and case fans. In addition to providing power directly from the PSU, the motherboard can also help distribute power. Unlike other PSUs, the motherboard can distribute power so that the PSU doesn’t have to be connected directly to every component. In addition to the clutter of wires, many system components, such as integrated graphics chips and CPUs, are too small or delicate for direct PSU connection. Your computer will be able to handle all the power it needs with the help of a solid PSU and a compatible motherboard. 

Power Ratings and Voltage Rails 

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PSUs have a power rating that is one of the most important features to consider. Generally expressed as Watts (W), the power rating represents how much power the unit can draw from the system before overloading. PSUs typically have a power rating between 300W and over 1000W. Computers with multiple graphics cards installed, such as those for gaming or graphics processing, typically have PSUs with higher power ratings. These units usually contain an associated power unit or brick that converts AC to DC, just like a desktop power supply. Laptop power supplies typically range from 50W to over 200W. 

Depending on the voltage requirements of different system components, voltage rails are used as supplies of voltage, which vary in amount. A PSU’s voltage is another key feature. A PCI network card, for example, is likely to draw power from a +5 V rail, while the CPU fans will draw power from a +12 V rail. In a nutshell, voltage rails are the levels of voltage that are available to every component in a system. A power supply’s power rating determines its maximum power capacity, but its voltage rails determine how that power is distributed. 

Importance of Using the Correct PSU

While most PSUs are based around standardized designs to allow for easy installation, there are a few variants that exist for different applications. 

PSU Lifespan

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PSUs are more likely to wear and tear than other system components because they handle large amounts of electricity on a regular basis. Therefore, the PSU lifespan plays an important role in determining a power supply’s reliability. This lifespan is usually referred to as the mean time between failures (MTBF). When a PSU has a higher MTBF value, it is more reliable and will last longer than a PSU with a lower MTBF value. 

In general, PSUs with higher quality materials and better cooling have longer lifespans due to the reduced amount of heat-related stress. With standard temperature variations, they can operate for around 100,000 hours on average. Modern servers are sometimes equipped with hot-swappable power supplies that can be quickly replaced in the event of failure because of their relatively short lifespans. Your server can benefit from a high-quality, reliable power supply unit if you want to prevent unexpected downtime. 

Your understanding of computer power supply units has improved, and now you can choose the right one for your needs more easily. In order to ensure that your computer never runs out of power, you need to consider the wattage, voltage, form-factor, and lifespan of your PSU.