2 Using external AC power
External AC power is supplied through one of the following devices:
WARNING! To reduce potential safety issues, use only the AC adapter provided with the computer, a replacement AC adapter provided by HP, or a compatible AC adapter purchased from HP.
●Approved AC adapter
●Optional docking device or expansion product
Connect the computer to external AC power under any of the following conditions: 
WARNING! Do not charge the computer battery while you are onboard aircraft.
●When you are charging or calibrating a battery
●When you are installing or modifying system software
●When you are writing information to a CD or DVD
When you connect the computer to external AC power, the following events occur:
●The battery begins to charge.
●If the computer is turned on, the battery meter icon in the notification area changes appearance. When you disconnect external AC power, the following events occur:
●The computer switches to battery power.
●The display brightness is automatically decreased to save battery life. To increase display brightness, press the fn+f8 hotkey or reconnect the AC adapter.
6 | Chapter 2 Using external AC power |