USA, 110V A.C - 60cps - Europe 220V A.C - 50cps
1. You don?t get seriously injured from 110V (you have to stand barefoot on wet floor, or be a little kid).
2. You can get much more injured from 220V(personal experience).
3. If you have an instrument that uses 2200 Watts (hair dryer), the electrical current under 220V is 10A.
Under 110V, the current is 20A. It is called ?ohm law? Wattage=Voltage X Current, 1Watt=1Volt X 1A. Higher electrical current needs more copper in the wires, more copper cost more money (you make the inference).
American Instruments that work directly from the plug (hair dryers, vacuum cleaners, toaster oven etc.) can not work on 220v they will burn (you can get adtaptor that will make some of them work ? see your local Radio Shack). Instruments that have inside power supply and work on DC can work as long as the entry point to the instrument has switch for 220V. That includes computers, monitors, printers, scanners.
Instruments that are depending on reception like TV will not work out of the US, because US uses NTSC protocol. In Europe PAL or SECAM are used. Radio transmission is universal so there is no problem there.
Computer Monitor (looks like TV), but they get the signal from the video card thus have no problem working everywhere (as long as there switch to plug it to 220V).
Lap Top computer, no problem as long as your charger can work off 220V.
Dialup Internet connection varies from one country to the other. You must check before you go.