Why does a computer need a power supply?
In short: How a computer's power supply turns alternating mains electricity into the steady, low-voltage direct current its chips need, through rectification, switch-mode conversion and multiple output rails.
A 2:03 short film in the series “How Things Work”, narrated by intellect_voice_01.
Sources used in this film: Hackatronic, “Switched Mode Power Supply SMPS Block Diagram & Working”; NASA Goddard Space Flight Center (archival educational page "From Stargazers to Starships" / "All Things Electric and Magnetic" by Dr. David P. Stern, last updated 13 March 2010), “The Reason for Using Alternating Current”; Stanford University (Physics 240 coursework by Ryan Hamerly, 2010), “Direct Current Transmission Lines”; International Electrotechnical Commission (IEC), World Plugs page (archived copy via the Internet Archive Wayback Machine, captured 28 Nov 2025), “World plugs”; Colorado State University, Department of Electrical and Computer Engineering (ECE562 course lecture notes, Lecture 35: Transformer Design), “l35.PDF”; Intel Corporation (ATX12V Power Supply Design Guide, Version 2.2, March 2005), reproduced as Samsung Electronics Co., Ltd. Exhibit 1085 on the USPTO PTAB public documents site, “download-documents”; Intel Corporation (Power Supply Design Guide for Desktop Platform Form Factors, Document 336521-002, June 2018), “Power Supply Design Guide for Desktop Platform Form Factors”; IEEE Transactions on Power Electronics (paper by Princeton University and pSemi Corporation researchers, hosted on a Princeton University site), “chen-vib-2021.pdf”; Princeton University (conference paper by Baek, Wang, Elasser, Chen, Jiang (Google) and Chen; file name indicates APEC 2020), “jaeil_apec20_paper.pdf”; CLEAResult (operator of the 80 PLUS® power supply certification programme), “What do the different PSU (power supply units) ratings mean? | CLEAResult”; Intel Corporation, “ATX12VO (12V Only) Desktop Power Supply Design Guide”.
Sources used in this film
- Hackatronic — Switched Mode Power Supply SMPS Block Diagram & Working · View →
- NASA Goddard Space Flight Center (archival educational page "From Stargazers to Starships" / "All Things Electric and Magnetic" by Dr. David P. Stern, last updated 13 March 2010) — The Reason for Using Alternating Current · View →
- Stanford University (Physics 240 coursework by Ryan Hamerly, 2010) — Direct Current Transmission Lines · View →
- International Electrotechnical Commission (IEC), World Plugs page (archived copy via the Internet Archive Wayback Machine, captured 28 Nov 2025) — World plugs · View →
- Colorado State University, Department of Electrical and Computer Engineering (ECE562 course lecture notes, Lecture 35: Transformer Design) — l35.PDF · View →
- Intel Corporation (ATX12V Power Supply Design Guide, Version 2.2, March 2005), reproduced as Samsung Electronics Co., Ltd. Exhibit 1085 on the USPTO PTAB public documents site — download-documents · View →
- Intel Corporation (Power Supply Design Guide for Desktop Platform Form Factors, Document 336521-002, June 2018) — Power Supply Design Guide for Desktop Platform Form Factors · View →
- IEEE Transactions on Power Electronics (paper by Princeton University and pSemi Corporation researchers, hosted on a Princeton University site) — chen-vib-2021.pdf · View →
- Princeton University (conference paper by Baek, Wang, Elasser, Chen, Jiang (Google) and Chen; file name indicates APEC 2020) — jaeil_apec20_paper.pdf · View →
- CLEAResult (operator of the 80 PLUS® power supply certification programme) — What do the different PSU (power supply units) ratings mean? | CLEAResult · View →
- Intel Corporation — ATX12VO (12V Only) Desktop Power Supply Design Guide · View →
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Sources
- Summary by Intellect · source: Hackatronic: Switched Mode Power Supply SMPS Block Diagram & Working
- Also: NASA Goddard Space Flight Center (archival educational page "From Stargazers to Starships" / "All Things Electric and Ma: The Reason for Using Alternating Current
- Also: Stanford University (Physics 240 coursework by Ryan Hamerly, 2010): Direct Current Transmission Lines
- Also: International Electrotechnical Commission (IEC), World Plugs page (archived copy via the Internet Archive Wayback Machin: World plugs
- Also: Colorado State University, Department of Electrical and Computer Engineering (ECE562 course lecture notes, Lecture 35: T: l35.PDF
- Also: Intel Corporation (ATX12V Power Supply Design Guide, Version 2.2, March 2005), reproduced as Samsung Electronics Co., Lt: download-documents
- Also: Intel Corporation (Power Supply Design Guide for Desktop Platform Form Factors, Document 336521-002, June 2018): Power Supply Design Guide for Desktop Platform Form Factors
- Also: IEEE Transactions on Power Electronics (paper by Princeton University and pSemi Corporation researchers, hosted on a Pri: chen-vib-2021.pdf
- Also: Princeton University (conference paper by Baek, Wang, Elasser, Chen, Jiang (Google) and Chen; file name indicates APEC 2: jaeil_apec20_paper.pdf
- Also: CLEAResult (operator of the 80 PLUS® power supply certification programme): What do the different PSU (power supply units) ratings mean? | CLEAResult
- Also: Intel Corporation: ATX12VO (12V Only) Desktop Power Supply Design Guide
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