Transformers or voltage converters enable travelers to use their domestic electrical devices (cameras, mp3 players, cell phones) when traveling internationally. This is especially true for Americans and Japanese traveling overseas. Travel transformers cost between $20 and $50.

Japanese domestic household voltage is 100 to 120 volts AC (alternating current) at a frequency of 60 hertz. Many other countries use 220 to 240 volts AC at 50 hertz. Transformers can step up (increase) or step down (decrease) voltage. Americans need a Japan Voltage transformer. Though the voltage is changed, the frequency isn’t. Changing between 60 and 50 hertz isn’t supported by simple travel transformers. It doesn’t normally matter as most appliances will convert the AC to DC (direct current, zero hertz) anyway.

Aside from the voltage, converter plugs will also be needed for the transformer to fit the electrical socket. While there are only two main electrical standards worldwide, there are many socket standards. Some equipment like AC Voltage Regulator can use both types of electrical power. A separate transformer is not needed. Notebook computers are a good example. The watts used and allowable voltage range will be written on the equipment, or on the power brick. Older equipment may have a manual switch to toggle between two voltages.