Power good signal
(重定向自Power good)
The Power Good signal prevents a computer from attempting to operate on improper voltages and damaging itself by alerting it to improper power supply.
The ATX specification defines the Power-Good signal as a +5 volt (V) signal generated in the power supply when it has passed its internal self-tests and the outputs have stabilized. This normally takes between 0.1 and 0.5 seconds after the power supply is switched on. The signal is then sent to the motherboard, where it is received by the processor timer chip that controls the reset line to the processor.