The initialism PSU often refers to a Power supply

Power supply

A power supply is a device that supplies electrical energy to one or more electric loads. The term is most commonly applied to devices that convert one form of electrical energy to another, though it may also refer to devices that convert another form of energy to electrical energy...

 unit, or specifically a computer's Power supply unit (computer)

Power supply unit (computer)

A power supply unit converts mains AC to low-voltage regulated DC power for the internal components of the computer. Modern personal computers universally use a switched-mode power supply...

.

The PSU powers all the computer's main components. There are many different PSUs that can come with anywhere up to 1500 watts for a standard desktop computer. The PSU is also sometimes referred to as the most important part of a computer. Without a good, reliable PSU a computer cannot function properly, or it could damage the rest of the computer.

PSU may also refer to:

Universities:

• Portland State University
  Portland State University
  Portland State University is a public state urban university located in downtown Portland, Oregon, United States. Founded in 1946, it has the largest overall enrollment of any university in the state of Oregon, including undergraduate and graduate students. It is also the only public university in...
  
  
• Pangasinan State University
  Pangasinan State University
  Pangasinan State University, commonly referred to as PSU, is a state university in the Philippines. The university was founded in its current form in 1979, although its origins trace back to the 1920s. PSU is notable for its many locations throughout the province of Pangasinan...
  
  
• Pennsylvania State University
  Pennsylvania State University
  The Pennsylvania State University, commonly referred to as Penn State or PSU, is a public research university with campuses and facilities throughout the state of Pennsylvania, United States. Founded in 1855, the university has a threefold mission of teaching, research, and public service...
  
  
• Plymouth State University
  Plymouth State University
  Plymouth State University, formerly Plymouth State College, is a regional comprehensive university located in Plymouth, New Hampshire and part of the University System of New Hampshire....
  
  
• Pittsburg State University
  Pittsburg State University
  Pittsburg State University, also called Pitt State or PSU, is a public university with approximately 7,100 students located in Pittsburg, Kansas, United States. A large percentage of the student population consists of residents within the Pittsburg region; the gender proportion is relatively equal...
  
  
• Plattsburgh State University
• Pembroke State University
• Prince of Songkla University
  Prince of Songkla University
  Prince of Songkla University was the first university in Southern Thailand, established in 1967. The name of the university was granted by His Majesty the King in honor of His Royal Highness Somdej Chao Fa Mahidol Adulyadej Kromma Luang Songkla Nakarin, the king's father.The university consists of...
  
  
• Prince Sultan University
  Prince Sultan University
  Prince Sultan University , located in Riyadh, Saudi Arabia is a private university funded by Riyadh Philanthropic Society for Sciences...
  
  
• Puntland State University
  Puntland State University
  Puntland State University is a university in Garowe, the capital of the Puntland region of Somalia.-History:The school traces its roots back to the Garowe School of Management, a women's school in Garowe offering courses in accounting, computer skills, business English and business management...
  
  
• Pacific States University
  Pacific States University
  Pacific States University is a private university in Harvard Heights , Los Angeles California, U.S. and member of ACICS . Founded in 1928 as an independent private institution, it has provided a comprehensive education in the fields of business, and computer science to more than 10,000 graduates...
  
  

In entertainment:

• Public Surveillance Unit
  Public Surveillance Unit
  The Public Surveillance Unit or PSU is a fictional institution in the Judge Dredd comic strip in 2000 AD. It was introduced in progs 954 and 959 . Notable PSU characters in the comic strip are Judge Niles, its chief, and Judge Roffman, who frequently assists Judge Dredd in surveillance, espionage...
  
  , a law enforcement organisation in the Judge Dredd comic strip
• Phantasy Star Universe
  Phantasy Star Universe
  is an action roleplaying game by Sega's Sonic Team for the PC, PlayStation 2 and Xbox 360. In Japan, it was released for the PC and PlayStation 2 on August 31, 2006, with the Xbox 360 version releasing on December 12, 2006. Its North American release was on October 24, 2006, available in all...
  
  , a persistent ORPG game by SEGA for PlayStation 2, Xbox 360 and PC
• Phantasy Star Universe: Ambition of the Illuminus
  Phantasy Star Universe: Ambition of the Illuminus
  is the first expansion of Sonic Team's internationally popular online RPG Phantasy Star Universe, available for the PC, PlayStation 2, and Xbox 360. Released initially in Japan on September 27, 2007, for PlayStation 2 and PC, subsequent territorial releases followed on November 20, 2007, when North...
  
  , a persistent ORPG game by SEGA for PlayStation 2, Xbox 360 and PC.
• PlayStation Universe, a popular PlayStation website

In mathematics:

• Projective Special Unitary group - a mathematics projective unitary group

Other Uses:

• Parti Socialiste Unifié
  Parti Socialiste Unifié
  Parti Socialiste Unifié can refer to:* Unified Socialist Party * Unified Socialist Party...
  
  
• Passenger service unit
  Passenger service unit
  PSU is an abbreviation in aviation for Passenger Service Unit. This aircraft component is situated above each seat row in the overhead panel above the passenger seats in the cabin of airliners. Amongst other things a PSU contains reading lights, loudspeakers, illuminated signs and automatically...
  
  
• Pilosebaceous unit
  Pilosebaceous unit
  The Pilosebaceous unit is an epidermal invagination found on most surfaces of the human body....
  
  
• Police Support Unit
• Polysulphone, plastic
• Port Security Unit
  Port Security Unit
  United States Coast Guard Port Security Units are deployable units organized for sustained force protection operations. They can deploy within 96 hours and establish operations within 24 hours. PSUs conduct OCONUS port security in support of requesting regional Combatant commander. They provide...
  
  , a U.S. Coast Guard expeditionary force protection unit.
• Power Supply Unit
• Power supply unit (computer)
  Power supply unit (computer)
  A power supply unit converts mains AC to low-voltage regulated DC power for the internal components of the computer. Modern personal computers universally use a switched-mode power supply...
  
  
• Practical salinity unit
• Prueba de Selección Universitaria
  Prueba de Selección Universitaria
  The University Selection Test or, as it is more commonly referred to, PSU, is a standardized university admissions examination used in Chile. It replaced in 2003 the Prueba de Aptitud Académica which had been working on since 1966....
  
  , public university admission test in Chile
• Public Sector Undertaking, a term for Indian companies that have a majority stake from the Government of India