The household electricity in North American appliances use is delivered at 120VAC (volts alternating current) 60 Hz. (60 cycles/second). Most foreign 220–240 volt electricity is generated at 50 Hz Alternating Current (AC).
Adapters and Converters
Two components provide external power to your computer: adapters and converters. The adapter is the plug itself, adapting the prongs on a standard U.S. three-pronged power cord to match the prongs required by the power outlets at your destination. The converter (or transformer) changes the local voltage to that required by your laptop. U.S. outlets are 120V. Most new laptop computer and mobile devices accept a broad range of input voltages from 100-240 volts by default, so they will only need a plug adapter, but not a power converter. However, there might still be some devices or computers that work only on the U.S. standard of 120V. To be sure, check your device to see what voltage range it accepts as inputs. If your power adaptors can’t handle the voltage of the location you plan to visit, you will need to purchase a voltage converter. Also, power supply in many countries can be fairly erratic, with some countries having black-outs almost on a daily basis, often multiple times a day. Make sure that you have sufficiemnt battery back-up for your devices and protection against the constant shut-downs that result from these circumstances.
For more information on electricity conversion visit the Independent Traveler website.