On Fri, Aug 21, 2009 at 23:36, Ray Saintonge <saintonge@telus.net> wrote:

My wife raised this since she is bringing her laptop.  I hope that I was
right in saying that a laptop works off its DC battery, and the public
AC only charges the battery.  A direct connection from the computer to
the wall power would likely scramble the timing when a 60 hertz device
is run with 50 hertz power.

The AC adapter converts the public AC to DC before the electrons reach the laptop.  The laptop then distributes that DC wherever it's needed: charging the battery, spinning the hard drives, lighting the display, whatever.  No need to worry about timing as long as the adapter is rated for 50Hz and 220V.