What is Computer Power Supply?

What makes your computer a power box of metallic elements, ports, and wires, a practically operating machine? The most indispensable component, without which every device is just a useless item, is known as a power supply. It furnishes a system with electrical power to come into action. Being PC enthusiasts, we are highly impatient to know what is computer power supply and how crucial it is for our PC. The power element in a computer that supplies every PC component with the required sum is called the Power Supplying Unit (PSU) with the acronym P/S or PS.

This unit comes in metallic packing and is located in one corner of the PC case. Power supply to all elements is not an exclusive function of the PSU; one of the dedicated actions is to convert the electric current and set it according to the system requirements. The alternating current (AC) that comes from the primary circuit of your home power supply is transformed to direct current (DC).

Then the PSU allows it to enter the PC’s internal network and power up all elements. In many systems, you may have observed that the power-supplying unit is fitted on the back of the device. This alignment is because of its mandatory power connection to the external circuit.

To send power to the system storage, processing unit, GPU, and motherboard, a power-supplying unit consists of a fair number of integrated connectors. A standard computer’s power supply is intrinsic to its structural composition. However, some PCs and laptops have independent power supplies not included in their casing. A PSU comes in solid metallic packing, which you must secure in the case. Opening the packing can result in an electric shock as its internal capacitors can hold a charge even if the main power supply is off.

Where is the power supply located in a computer?

Typically, a computer tower lodges a power-supplying unit on its back interface. If your device is a bit older, the PSU would be present on the top end of the tower. However, modern desktop computers have changed their location. You can spot a power unit on the bottom of the case that could be on the left or right side.

Parts found on the back of a power supply

The back interface of a power supply unit comprises cable connectors, switches, and openings for venting the internal environment to the outside. To link your computer to the power source, the back connector on the PSU helps establish a connection using a cord. As a power unit has a fan inside its packed case for cooling, it is permitted to communicate to the external air using an opening. Two switches are also fitted on the back panel; the red one enables users to change the voltage of the current they want to feed to their PC.

The other rocket switch is the main button which turns the power supply on and off. The forepart of the PSU, though named front side, is hidden inside the PC case and is visible only if you open it. This side is crowded with cables and connectors that make their way to the motherboard, storage, and other elements. The connector which binds a power unit to the motherboard is called ATX Style Connector. However, many such connectors are specified to connect a particular division to the power supply. Examples include EPS connector, Molex connector, Auxiliary connector, PCI-E connector, and Berg connector.

Parts found inside a power supply

The inner working apparatus of a power supply unit consists of qualified components which perform specific tasks. Below we have enlisted this setup in a sequence that all units follow to act cooperatively.

  1. Transformer: A transformer helps to keep a stable voltage level by stepping it up or down whenever it deviates from the usual need.

  2. Rectifier: A PSU obtains the alternating current (AC) from your home’s primary circuit. But the AC is of no use to your system; therefore, the rectifier is the first component to capture all the electric waves and transform them to direct current (DC) waves.

  3. Filter: Rectifier sends DC waves to the filter, whose responsibility is to make them smooth for an easy flow in the PC circuit.

  4. Voltage Regulator: It controls the nature of DC output, such as power and watts, and ensures only the correct amount and strength of DC is further issued to the PC hardware.

What items are powered by the computer PSU?

A stable supply of power is mandatory for each component lodged inside your personal computer. Even a few seconds of power deprivation will shut down everything inside the PC case, like the disc drives, hard drives, processor, RAM, graphics card, and motherboard. All these units capture a constant wave of current from the PSU and pass it on to the peripheral devices such as printers, USB elements, and keyboards.

Does the fan always run on a power supply?

With a continuous power supply, a fan is supposed to perform typically. However, you could examine many problem-generating areas if a fan stops running despite the current flow. For example, your computer might not work correctly, or the fan has failed to spin. You can also consider replacing the power supply with a new one. Some power supply units come with a variance in controlling features. They may cause fans to over or underspin due to temperature fluctuations. However, a typical fan or power supply will never push a fan to stop spinning.


Today’s guide highlights different aspects of a computer’s power supply unit. This unit ensures a sustainable power circulation for all the PC components and certifies the supply meets a set of standards the machine can accept and process. Otherwise, operating on an AC supply, shuffling voltage, and unfiltered current waves is unreliable for any device. To pass on such hectic duties, a power-supplying unit consists of genius elements in its case, which perform in an orderly manner to supplement each other tasks.

However, any surges or drops in current voltages can compel you to pay a high cost. A staggering voltage can damage your power supply and your computer’s entire power circuit. So to prevent such shortages and shocks, use a surge protector or a UPS ( Uninterruptable Power Supply). If you find a UPS pricey, try the other affordable option and plug your computer in a surge protector.