Voltage Converters, Transformers and Regulators are used to convert electricity. North America and some other countries operate on 110/120 Volt AC 60 HZ. While most of the world operates on 220/240 volts AC 50 HZ. Voltage Converters change the electricity to make work electrical appliances in different countries.
Converters should be used only with "electric" appliances. Electric appliances are simple heating devices or have mechanical motors. Examples are hair dryers, steam irons, electric toothbrushes, incandescent lamps, and small fans. Converters should not be used for more than three hours at a time.
Transformers are used with "electronic" appliances. Electronic appliances have a chip or circuit. Examples are radios, CD players, shavers, battery rechargers, computer printers, fax machines, televisions, answering machines, and fluorescent lamps. Transformers can also be used with electric appliances and may be operated continually for many days. (The advantage of converters is that they are lighter and less expensive.)
Regulators are transformers that also have a built-in voltage stabilizer-regulator to save your appliances from damage caused by sudden power fluctuations. This is most important in 2nd/3rd world nations with unstable power grids.
Converters, regulators and transformers are available for appliances of different wattages. To find the wattage of your appliance, look at the label located on the appliance or in the owner's manual. The label or manual will show the input voltage, (100, 120, 220, 240, written as volts, V, volts AC or VAC), the wattage (written as watts or W) and sometimes the amperage (e.g. 0.5 Amps or 0.5 A or 500 mA). If only the amperage is shown, multiply the input voltage by the amps to find the watts. Volts x Amps = Watts. (Example - 120V x 0.5A = 60W; meaning a 120-volt appliance rated at 0.5 amps is a 60 watt appliance and requires a transformer or converter of at least 60 watts).