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The PC Power Supply Guide for the Masses

  1. Introduction
  2. PSU Abbreviations and Glossary
  3. Connectors used in a PC Power Supply
  4. PSU cables: Non-Modular, Modular and the middle-ground!
  5. Power Supply Labels
  6. Power Supply Form-Factor- ATX12V
  7. Power Supply Form-Factor- SFX12V
  8. Basic requirements of a power supply
  9. Facts about 80 Plus Certification
  10. Protection Circuits and Features
  11. List of Power Supplies, OEM and Review Links
  12. Common PC Power Supply Myths
  13. Resource Links and References
  14. View All

Power supplies also provide protection circuits. This helps in many situations, usually by cutting off the power to the system and therefore shutting it down before something happens. Some companies that provide AC power cord with the power supply have a small blow fuse on the socket, but that’s not the only fail-safe. The internal safety features are as follows:

Over Voltage Protection (OVP):

As the heading is self-explanatory, this shuts the power off if the output crosses its preset current value.

Under Voltage Protection (UVP):

Like OVP, but shuts off it goes below a particular minimum current.

Over Current Protection (OCP):

If any of the rails pulls more power than it should from the power supply, the OCP switches the power supply off.

Over Temperature Protection (OTP):

If the internals of the power supply crosses a certain temperature threshold set by the manufacturer, it switches itself off.

Short Circuit Protection (SCP):

If anything on the power supply is shorted, it will turn off and even not allow you to start the system.

Surge & Inrush Protection (SIP):

This protection prevents the system from turning on if it detects an influx of inrush current at the time of switching the system on which will ultimately degrade the components.

Brown Out Protection (BOP):

BOP works by protecting the system from low voltages, either by stopping the system from turning on or turning it off.

No Load Protection:

This is a preventive measure in case if there is no load via its output rails. This design is avoided since its interferes with Intel C6 power state feature.

Some of these are deemed essential by known power supply manufacturers, even for the lower wattage/load type power supplies.

There are two issues: usually, the users do not know the value that the power supply manufacturers have set it to. Second- manufacturers don’t really disclose this information. We would not know if a manufacturer have kept these presets in ‘ideal’ values- or if its too close or too far off from ideal values. There is no real standard for this.

There are certain features that PSU brands and/or manufacturers implement. They are as follows:

Temperature Controlled fans: With the hopes to keep the noise from the system as minimal as possible, some manufacturers have temperature controlled fans which turns on once it reaches a certain temperature.

The better solution in my opinion would be manufacturers having better fans for their power supply or having a PWM controls where minimum load would mean lesser RPM mode.


  1. Koolest ripper guide to What is and what is not on SMPS!
    Thanks for adding those SMPS suggestions! 🙂

  2. Much appreciated!

    I plan on putting more guides per component so that many people from newbies to regular users can understand “what is” and “what is not” for many components to help them make better purchase decisions! This way, we can guide even the newest of end users to understand whenever they read our reviews!

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