So how do I know whether or not my appliance is compatible with 110-120 volts?
If your appliance is American or Canadian, then it is. That's the standard in North America.
Otherwise, the short answer is: The only way to know is to check, and there's absolutely no getting around that crucial step
. Electricity is nothing to mess around with, and assuming can be bad news. If you're wrong, you could "fry" your appliance, or worse yet, start a fire.
That being said, generally speaking, most modern "digital-age" appliances (especially ones that run on batteries) are being built to be compatible with all worldwide voltages, from 100 volts in Japan to 240 volts in the United Kingdom. This usually includes things like laptops, PDAs, cell phones, digital cameras, digital camcorders, many portable video game devices, digital music players, etc. More and more personal grooming items like hair dryers curling irons, shavers (especially cordless ones) and such are being built to be compatible with multiple voltages as well, but most of them aren't.
"Conventional appliances" like kitchen items, audio/video equipment, vacuum cleaners, lamps and lights, and most bath appliances are not
compatible with multiple voltages. Again, the only way to know is to check
. A common misconception is that there's any such thing as a "standard" electrical input for appliances. There's not. They're all different.
Okay, so how do I find this info for my specific appliance?
The electrical input specifications will appear on a label on the appliance itself, or on its charger or AC adapter if it uses one, near where the brand name and model number appear. Look for the word "input." As a last resort, you could check the back of the manual, but 99 times out of 100, it will be on the appliance's or charger's label. The input voltage is usually abbreviated to "V" and it should look something like this:
Input: ~100-240V 50/60Hz 65W
-- This means the appliance is compatible with multiple voltages. This item can be brought just about anywhere in the world, and any difference in voltage is basically irrelevant. The appliance (or charger) adjusts itself to whatever voltage it receives. The only issue is whether or not the plug can physically interface with the socket. The appropriate travel plug adapter is all that's needed.
---or--- Input: 115/230V 50/60Hz 200W
-- This means that the appliance can be switched between 110-120 volts in North America, and 220-240 volts in other parts of the world. This is common of desktop computers and some hair dryers/curling irons/etc. You probably have to physically flip a switch somewhere, but as long as that switch is in the proper position and you have the appropriate plug adapter, you're fine.
---or--- Input: 220V 60Hz 2.8A
-- This means that the appliance is only compatible with a single voltage, in this case, 220 volts. If the socket is 110-120V, then an adapter by itself isn't enough, because travel plug adapters do not change the voltage supplied by the socket. Plugging it in with just an adapter can "fry" it because the voltage is different from what the appliance requires. To use this appliance safely, the voltage needs to be changed from 110-120 volts to 220-240 volts by way of a voltage transformer.