PS-ON Signal is a pin on a 20-pin or 24-pin ATX-specified power connector used to turn a

personal computer A personal computer, commonly referred to as PC or computer, is a computer designed for individual use. It is typically used for tasks such as Word processor, word processing, web browser, internet browsing, email, multimedia playback, and PC ...

power supply unit A power supply unit (PSU) converts mains AC to low-voltage regulated DC power for the internal components of a desktop computer. Modern personal computers universally use switched-mode power supplies. Some power supplies have a manual switch f ...

on/off. The PS_ON pin is normally pulled high in an open-circuit, but will turn on the power supply when it is pulled low, by shorting it to the GND (COM) terminal. Conversely the power supply is turned off when the PS-ON is in open-circuit. The PS_ON pin can be jumpered to manually turn a PSU on.

References

{{reflist Power supplies