Computer Science - Computer Hardware - Discussion

The 20-pin main power connector is standard for all power supplies conforming to the ATX and ATX12V 1.x power supply form factors and consists of a Molex Mini-Fit Jr. Connector housing with female terminals. For reference, the connector is Molex part number 39-01-2200 (or equivalent) , and the standard terminals are part number 5556 (see the following figure). This is a 20-pin keyed connector with pins configured as shown in the next table. The colors for the wires listed are those the ATX standard recommends; however, to enable them to vary from manufacturer to manufacturer, they are not required for compliance to the specification. I like to show these connector pinouts in a wire end view, which shows how the pins are arranged looking at the back of the connector (from the wire and not the terminal end). This way, you can see how they would be oriented if you were back-probing the connector with the connector plugged in.

ATX 20-pin motherboard main power connector, perspective view. ATX 20-pin motherboard main power connector, perspective view.

ATX 20-pin main power connector, side and terminal end view. ATX 20-pin main power connector, side and terminal end view.

ATX (Advanced Technology eXtended) is a motherboard form factor specification developed by Intel in 1995 to improve on previous de facto standards like the AT form factor. It was the first major change in desktop computer enclosure, motherboard, and power supply design in many years, improving standardization and interchangeability of parts. The specification defines the key mechanical dimensions, mounting point, I/O panel, power and connector interfaces between a computer case, a motherboard, and a power supply. With the improvements it offered, including lower costs, ATX overtook AT completely as the default form factor for new systems within a few years. ATX addressed many of the AT form factors annoyances that had frustrated system builders. Other standards for smaller boards usually keep the basic rear layout but reduce the size of the board and the number of expansion slots. In 2003, Intel announced the BTX standard, intended as a replacement for ATX. As of 2009 the ATX form factor remains a standard for do-it-yourselfers; BTX has however made inroads into pre-made systems. This was designed to solve the problems in BAT and LPX motherboards.

ATX-Advance Technology Extended as 20pins, 20+4pins and 24+4pins

AT connector is 20 pins connector and ATX is 24 pins connector.

Is form factor is ratio of any two values?

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What is the difference between AT and ATX Motherboard?

What is the difference between ATX, AT & Baby AT?

This is nice questions to learn more thing. Thanks.

FORM FACTOR: Shape and layout of the Motherboard.

Advance technology extended 20/24 pin
AT-12 pin