Description : Most modern desktop computer power supplies conform to the ATX form factor. ATX power supplies are turned on and off by a signal from the motherboard. They also provide a signal to the motherbord to indicate when the DC power lines are correct so that the computer is able to boot-up. While an ATX power supply is connected to the mains supply it provides a 5V stand-by (5VSB) line so that the standby functions on the computer and certain peripherals are powered. The most recent ATX PSU standard is version 2.31 of mid-2008.
