Many computers and embedded systems support the feature to automatically power on when AC (alternating current) power is applied or restored after a power outage. This is commonly used in servers, kiosks, digital signage, and industrial devices that must resume operation without manual intervention.
How It Works
The behavior is typically controlled by a BIOS/UEFI setting often labeled as:
Restore on AC Power LossAC Power RecoveryAfter Power FailurePower On When AC Detected
Options usually include:
- Power Off – Stay off after power returns.
- Power On – Turn on automatically when AC is restored.
- Last State – Return to the state before power loss (on or off).
Enabling the Feature
- Reboot your computer and enter BIOS/UEFI (commonly by pressing
Del,F2, orEscduring startup). - Navigate to Power Management or similar section.
- Find the AC recovery option and set it to Power On.
- Save changes and exit.
Use Cases
- Uninterrupted server operation after grid power resumes.
- Digital displays that must turn on with building power.
- Remote or headless devices that cannot be manually started.
Notes
Not all motherboards or devices support this feature. Check your hardware documentation. Some systems may require a connected battery (e.g., CMOS battery) for the setting to persist.