Power On When AC Detected

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 Loss
• AC Power Recovery
• After Power Failure
• Power 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

1. Reboot your computer and enter BIOS/UEFI (commonly by pressing Del, F2, or Esc during startup).
2. Navigate to Power Management or similar section.
3. Find the AC recovery option and set it to Power On.
4. 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.