What Is A Power Supply?

Date First Published: 2nd July 2022

Topic: Computer Systems

Subtopic: Computer Hardware

Article Type: Computer Terms & Definitions

Difficulty Level: 5/10

Learn more about what a power supply is in this article.

A power supply, also known as a P/S, a PSU, or a power supply unit, is a hardware component used to provide electric power to a computer. A power supply works by receiving power from an electrical outlet and converting the electrical current from alternating current to direct current, which is the correct format that is useable by the computer. Additionally, it regulates the voltage passed through the computer in order to prevent overheating.

Power supplies are vulnerable to power surges and voltage spikes, since they are the first place an electronic device receives electricity. It is recommended to protect a power supply with a surge protector, preventing them from being damaged by electrical surges. A UPS (Uninterruptible Power Supply) that makes use of battery backup to maintain power during power outages can also be used. Some power supplies may include a fuse that will blow if the surge is too great.

Warning:

Since power supplies contain capacitors that can store electricity for long periods of time and cause an electrical shock even if the computer is turned off and unplugged, never open the casing of a power supply.

Location

The power supply is usually located at the top back of the computer case and secured by screws, although in newer computer cases, it is located at the bottom back. For an all-in-one computer, the power supply can be found at either the back left or the back right.

The location of the power supply can be determined by finding where the power cord is plugged in. The power cord directly connects to the power supply. When removing the computer case cover, the power supply will look like a metal box with a fan inside and attached cables.

Does A Laptop Have A Power Supply?

Because laptop computers run on a battery, they don’t have a power supply. Instead, they have an AC adapter that provides power to the laptop and charges the battery.

Power Supply Components

The four components of a power supply include:

• Transformer – Increases or decreases the incoming voltage with little loss of power to match the requirements of a computer.
• Rectifier – Converts AC (alternating current) to DC (direct current).
• Filter – Smooths out the ripple contained in the pulses of DC coming from the rectifier circuit.
• Voltage regulator – Maintains the voltage of a power source within acceptable limits. It also reduces any leftover ripples in the voltage that could cause overheating or drops in power.