Things You'll Need
Instructions
Find the wattage required to operate the appliance you intend to plug into a voltage converter. Converters are available with different wattage ratings; wattage is a measure of the power an appliance consumes. Most appliances have the wattage listed on a label pasted somewhere on the unit itself. If the wattage isn't listed, the amperage will be given. You can calculate the wattage by multiplying the voltage times the amperage, or "amps." For example, if the voltage is 120 volts and the appliance draws 2 amps, the wattage is 120 times 2, or 240 watts.
Multiply the wattage of your appliance times two. This is the minimum power wattage rating the converter should have to safely run your appliance. Purchase a voltage converter with the appropriate wattage rating that changes 220-250 volts to 110-120 volts. These are readily available at electronic stores. They are sometimes referred to as "foreign voltage adapters."
Check the type of electrical plug used in the country where you will be traveling. Foreign voltage converters will either come with a set of interchangeable electrical plugs or the plugs will be available for the converter as a separate accessory.
Use a voltage transformer rather than a voltage converter if the device you plan to use will require a high wattage or will be used for extended periods of time. "Step-down" voltage transformers are bigger, bulkier and heavier than consumer voltage converters, but they are able to deliver more power and for longer periods of time.