PC Hardware A Beginner’s Guide

Chapter 14: Power Supply and Electrical Issues^327

The features of these form factors are compared in the following table:

Form Factor Dimensions (WxDxH) in inches Case Style

PC XT 8.8 x 5.7 x 4.8 Desktop PC XT

AT 8.5 x 6 x 6 Desktop or Tower

Baby AT 6.6 x 6 x 6 Desktop or Tower

LPX 6 x 5.6 x 3.4 Desktop

ATX/NLX 6 x 5.6 x 3.4 Desktop or Tower

SFX 4 x 5 x 2.5 Desktop or Tower

WTX 6 x 9.2 x 3.4 (single fan)

9 x 9.2 x 3.4 (double fan)

Tower

The voltages supported by each of the form factors are listed here:

Form Factor Output Voltage

PC XT +/–12V, +/–5V

AT +/–12V, +/–5V

Baby AT +/–12V, +/–5V

LPX +/–12V, +/–5V

ATX/NLX +/–12V, +/–5V, +3.3V

SFX +/–12V, +5V, +3.3V

WTX +12V, +5V, +3.3V

Figure 14-10. WTX power supply