When I disconnect my laptop from AC power, its screen becomes more dim, in order to save battery. When I connect it back to AC power, it becomes bright, because now it's not concerned with battery level.

I appreciate this logic, but I prefer my laptop stay at the same brightness level regardless of whether it's plugged-in or not. How can I accomplish this?

(I'm using Windows XP.)


Look at your power management settings (try Control Panel | Power) or your laptop may have a manufacturer-supplied program to handle this. Usually these let you create and/or select power management profiles, which can include screen brightness settings.

  • I've looked there before asking this question, nothing there. – Ram Rachum Nov 9 '11 at 16:56
  • In that case, perhaps check with the laptop manufacturer, or mention here what make and model it is; perhaps someone will know how to change the setting. – Steve Rindsberg Nov 12 '11 at 3:59
  • It's a Samsung Series 9. The manufacturer's support line told me to look for a power manager program myself, but I don't know any good one that does this, and I hope someone here knows. – Ram Rachum Nov 12 '11 at 12:38
  • I'm adding a new answer ... take a look there. – Steve Rindsberg Nov 13 '11 at 16:55

My XP laptop is a Lenovo; they do supply a power manager that has quite few more options than XP's control panel. I had a look in the registry to see what's there and found this:

HKEY_CURRENT_USER\Control Panel\PowerCfg\PowerPolicies\11

(the finall number will vary depending on which policy you've chosen, apparently)

Interesting entries (all REG_SZ strings, not DWORDS)




You might be able to add these entries to your existing profile to get what you're after.

  • I tried playing with all of these, but nothing happened. – Ram Rachum Nov 14 '11 at 12:27
  • That leaves me w/ no more suggestions, I'm afraid. – Steve Rindsberg Nov 15 '11 at 16:36

Some laptops have a screen dimming option in the BIOS. If this option is set to dim on battery, then no amount of fiddling in the OS will turn it off.

I had a Lenovo X61 that did exactly this. No idea about the Samsung Series 9. That's a "Designed for Windows 7" laptop, anyway. While XP may be supported, it might not be supported well.

  • I searched the BIOS now and found nothing related to screen brightness in there. – Ram Rachum Nov 16 '11 at 17:07

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.