What Is a PC Power Supply?

A power supply unit is a device used in computers to take the main Alternating current (AC) and convert it into Direct Current (DC) that the computer can use. If the central processor of a computer could be called the brain, the power supply is the frequently underestimated stomach that processes food to provide energy for use. Without a power supply, a pc would just be a complicated and expensive paperweight. All parts that need to function need to be powered through this unit.

The power supply's function is to convert volatile AC to DC that can be used by the computer. Computer power supplies are the part that is plugged into an outlet to receive input voltage to process for the computer. This power is transferred to components in the computer via a series of power cables, porting the power to the motherboard, CPU, graphics card, hard drives, and such. These cables are formatted most frequently in two ways, either modular, with cables being free from the PSU, allowing the builder to use only the cables that they need, and non-modular, having all cables irremovably attached to the power supply. The latter is cheaper but less convenient, as all of the cables are attached and run through a hole in the supply. A power supply provides a 5-volt standby to power the computer's standby functions, and the psu and motherboard talk back and forth when turning on or off or giving status on the parts. The motherboard regulates the power transfer and distribution.

1981 - IBM PC power supply units supply two main voltages: +5 V and +12 V. It supplied two other voltages, −5 V and −12 V, but with limited amounts of power. Included the line-voltage switch. The +12 V supply was used primarily to operate motors such as in disk drives and cooling fans. The 5 V rail still delivered most of the power for other functions.

1995 - ATX power supplies were of a standard developed by intel that quickly became the norm and has three positive voltage rails, 3.3 V, 5 V, and 12 V. The ATX power supply distinctly has several cables and far more power and capability, forcing the IBM supplies into obscurity. ATX added the 5 V standby rail to the design, allowing the unit to cover the PC's standby functions.

2011 - 12V-only power supplies are a custom design for specific motherboards, made with the idea of having only 12v rails from the PSU to the motherboard, and 5v and 3.3v conversion on the board. This device would only work with a specific motherboard and power supply set. Much less popular than the ATX iteration and was eventually introduced into the ATX iteration as ATX12VO.

Step 1: A designated area for the power supply will usually be obvious on any PC case, usually on the back, and either on the top or bottom, sometimes covered by a shroud.

Step 2: Mounting the power supply into the designated spot is as simple as lining it up in the hole, making sure that the fan, indicated by the fan grill, is in a position where it can pull air from somewhere, and then screwing it into the hole with provided screws either with the power supply or with the case.

Step 3: Plugging in all of the proper cables will require some education. There are many tutorials on the internet that can help with plugging each cable into their designated spot. It is important also to know your hardware so you know what needs to be plugged in.

PC power supplies are a very tightly packed little mess of components. They consist of a mass of components packed onto a circuit board, all with the function of converting the Alternating Current from an electrical outlet to the Direct Current that the PC parts can use.

Different power supplies have different designs, but they all consist of a transformer, to convert the current, and a series of capacitors, transistors, and diodes that work to split the power to the voltage rails.

ATX - introduced in 1995, ATX covers the standard array of all PC power supplies in the world today, ATX power supplies are a standard 150mm by 86mm by 180mm box.

SFX12V - a small form factor power supply with a 12 volt connector, optimized for systems that are specifically of a SFF or Small Form Factor layout.

TFX12V - a Thin Form Factor power supply with a 12 V connector for microATX system layouts with a low profile, being thin and smaller.

First off, there are two primary measures that PSUs have for fault tolerance. The first involves backing up data to a data center or a database of some sort. Any data backed up in the cloud will survive power supply failure, and depending on the type of failure, the hard drives will still be intact, with data stored in them. A second is the Uninterruptable power supply, a device that can keep running in the case of a power failure, keeping the important devices alive until issues can be quickly resolved.

Power supplies will show when they are not properly functioning. If a power supply is not working properly, it may make noise, perhaps running too hot or fast. Another issue can involve overloading of the power that the system tries to draw, resulting in computer crashes.

A few devices that can be used for repairing a power supply include an anti-static wrist strap or mat, because it can never hurt to be safe and not shock your components with static electricity, a screwdriver with an array of heads, and a crimp tool, which can be used to make cold weld joints between wires. All are helpful if not necessary when working with a power supply.

Sources include:

- https://en.wikipedia.org/wiki/Power_supply_unit_(computer)

- https://www.nytimes.com/wirecutter/reviews/best-uninterruptible-power-supply-ups/

- https://temcoindustrial.com/product-guides/tools/crimping-tool-selection-guide#:~:text=Crimpers%20are%20tools%20used%20to,Wire%20Gauge)%20they%20can%20accept.

- Personal Experience