Understanding Power Supplies

Table of contents:

  • 1.Understanding power supplies: What they do
  • 2.Understanding power supplies: ATX power supplies
  • 3.Single or multiple 12V rails
  • 4.Understanding power supplies: modular power supplies
  • 5.Power supply Connectors


Check out the video below to help in your understanding of power supplies, and help you realize how important they are to your setup.



1.Understanding power supplies: What they do

The power supply or PSU is without doubt one of the most important parts of your setup. As with all electrical devices a computer requires a stable current to be able to function.

Computers components can be very sensitive things. Any kind of surge in power and they can be damaged. Therefore the PSU has to do its job exceptionally well in order for the computer to remain functioning.

If you watched the video above you now know that a Power supply has to do a number of things before the power is usable by the components it is feeding. It has to lower the voltage and then turn it into a DC current rather than an AC current which comes from your wall socket. Not only does it do this but it also has to filter the current in order to remove any spikes or surges. This kind of technology is really what separates the top brands from the more cheap and cheerful PSU’s thrown in with a gaming case. It requires a sophisticated and well designed PSU to be able to provide a high end computer which a usable source of power.

check out: http://en.wikipedia.org/wiki/Power_supply_unit_%28computer%29


2.Understanding power supplies: ATX power supplies

An ATX power supply is the modern standard of power supply and was first brought in way back in 1995 by Intel.

ATX became the standard Power supply format and is still used today. However the ATX has had to transform over the years to keep up with the power needs of components such as the CPU and the graphics card.

ATX power supplies work on three kinds of voltage rails, +3.3 V, +5 V, and +12 V.  More detail on rails can be found later in the article.

CPU’s have come to dictate the design direction of power supplies.  As processors increased in their power needs but powered by a low voltage (typically around 1.5V, 2V)

This saw the introduction of the Voltage regulator module and the update to ATX12V 1.0.

The Voltage regulator module is specifically designed to take a the +12V supplied by the Power supply and convert it into a lower voltage to be used by the CPU.

The 12V has become the most important rail in the Power supply as it feeds both the graphics card and the CPU, most power supplies concentrate most of its output to be 12V.


3.Single or multiple 12V rails

This is a very grey area when it comes to power supplies. This can be blamed largely on the manufactures themselves who tend to use multiple rails as a marketing technique to make their power supplies sound better than they are.

It is essential to understanding power supplies so we found a great post for you to read through so you can understand the differences between single or multiple 12V rails. We feel it necessary to pass on this article as it gives you a great in depth knowledge, so when it comes to buying your own Power supply you won’t be fooled by various marketing ploys: http://www.jonnyguru.com/forums/showthread.php?t=3990


4.Understanding power supplies: modular power supplies

Notice in the picture the power supply on the left is modular.

A modular power supply is quite simply a power supply that has detachable connector leads.

Connector leads are the connectors from the power supply to the various components it powers.

A standard Power supply has a selection of leads that are not detachable and are connected inside the power supply. This setup is perfectly acceptable for most setups.

The reason modular supplies were brought in was to cater for people who wanted complete control over the internal power supply cables. They wanted the choice of being able to take various leads out if they were not being used.

Modular power supplies allow for this because the leads plug into allocated slots on the power supply. This means that for those looking to save space inside their computer, or for those who like to have a more organized internal layout inside they have the choice to remove unwanted cables.


5.Power supply Connectors







Picture Acknowledgement:

By User Smial on de.wikipedia (Own work) [FAL, GFDL 1.2 (http://www.gnu.org/licenses/old-licenses/fdl-1.2.html) or CC-BY-SA-2.0-de (http://creativecommons.org/licenses/by-sa/2.0/de/deed.en)], via Wikimedia Commons

By Ni-sama (Own work) [CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0) or GFDL (http://www.gnu.org/copyleft/fdl.html)], via Wikimedia Commons

By Victor Korniyenko (Own work) [CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons

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