Which Appliances and Electronics Need Voltage Converters?
Every device or appliance that operates on AC current will tell you the voltage, wattage and amperage it requires either on the package, on an attached label or on the device itself. To determine whether your particular device requires a voltage converter, check the label.
If the label says "110v", "110 volts" or anything in the 110 to 120 volt range, you'll need a step down voltage converter if you're going to plug it into 220 to 240 volt outlet, such as those in most European countries. The converter will decrease the voltage from 220 to 110 so that it doesn't burn out your electrical device.
If the label says "220v", "220 volts" or anything in the 210 to 230 volt range, and you intend to plug it into a 110-volt outlet, a step up voltage converter will increase the voltage from the wall outlet so that your electrical device can use it. Plugging in without a converter may not damage your device, but there's a high likelihood that it won't run at all, or that your 220-volt battery charger may take a long time to charge up.
More manufacturers are selling devices that will run on either voltage. Their labels will read "110 to 240 volts" or some variation of that phrase. 110v to 240 volts consumer electronics don't require voltage converters to operate in other countries. Some may require you to flip a switch between a 110 volt setting and a 220 volt setting, while others automatically determine which currency range the appliance needs. Be sure to check which type your appliance is and always make sure that the switch is set properly before plugging in.
Your personal electronics and chargers such as cell phones, laptop battery chargers and ebook readers, for example, are most likely to be 110v to 220 volt consumer electronics. Battery chargers for your camera may also work in different countries without voltage converters. Hair dryers, electric shavers, coffee makers and other small personal appliances are most likely to require voltage converters when you travel.
If you're not certain what type of voltage converters, voltage transformers, plug adapters and other electronics accessories you need for your trip, check an online supplier of electronics and electrical equipment. Most offer a buying guide that will help you decide which equipment you need in order to use your personal electronic equipment while you travel.