ATX Power Supplies Switch

ATX Power Supplies Switch

First introduced by the Intel Corporation in 1995, the ATX form factor is a specification defining the critical characteristics of interconnectedness between a power supply unit (or PSU), a processor or motherboard, and a computer chassis.

The specification accounts for a number of different dimensions of connectivity between these components, including the physical specifications of the computer (length, width and depth), the power source and current used the input and output panel, the mounting points for the computer case and the pin connectors.

Replacing or updating power supplies for the ATX form factor, which is currently the industry standard specification for personal computers, can involve a number of different components ranging from the pin-out connectors, power switches, cooling fans or fuses.

Most of these components are commercially available either from online retailers or from local computer hardware stores. A simple internet search or browse through the phonebook can help identify companies that retail some of these different supplies.

Evolution of ATX

Advanced Technology eXtended or ATX has actual gone through a number of different versions since its introduction in 1995. Newer versions typically offer improvements in organization of components such as power switches and fans while also improving power efficiency.

For example, under the original specification, cooling fans drew air from outside the machine case and expelled it directly onto the power supply unit. However, later iterations had cooling fans which drew hot air from within the chassis and expelled it outside the case, which allowed the processor to run more efficiently. The most up to date version of the ATX form factor specification is ATX 12V 2.3, standard since approximately March 2007.

Power switch improvements under the ATX specification

Under earlier form factors which preceded the ATX specification (such as the AT or Advanced Technology specification), computer cases typically made use of a power switch that was directly connected to the computer’s power supply unit.

  • Electrical mains were connected to the power supply unit via a cable with the wires typically soldered directly to the switch, making it very difficult to replace if any of the components of the power supply unit failed.
  • One of the major improvements offered by the ATX specification is that the power supply unit is not connected directly or exclusively to an on or off switch. This provides two important benefits—first, the computer can typically be shut off via software (i.e. giving a command to stand by or shut down through the operating system), rather than just by pressing the power button.
  • Additionally, not soldering the wires from the power switch directly to the power supply unit allows individual components to be replaced more easily and less expensively.

Self-repair and instalment

While it is possible to replace components of the power supplies yourself, such as the switch or fuses, it is important to remember always to disconnect the PSU from the mains before any work takes place.

Additionally, PSUs may carry a residual charge even after being unplugged, which can give a nasty shock if not grounded properly first.