Pay attention that the commercial power voltage for home use in Japan is,in many cases, 100V as a rule although it varies depending on the country.In most foreign countries, either the 100V system (110V through 127V) or the 200V system (200V through 250V) is used.
As a result, most of PC power sources use a "switchover system" through which the input voltage to the PC can be selected by the user between the 100V and 200V systems with a switch installed in the power source.
In contrast to the above-mentioned system, the "worldwide input system" eliminates switches to comply with an input voltage range of 85V through 265V.
<Note for reference>
The input voltage of many power sources made in foreign countries is 115/230V to be manually selected. These products are mainly for use in the U.S.A whose main voltage is 115V.
In this case, since the voltage normally guaranteed by power companies is ”Ž10% of the nominal voltage (115V in this case), the lower limit of guaranteed value is 103.5V. When using such foreign-made power sources in Japan, usage with 90V, i.e. the lower limit of 100V”Ž10% makes the operation unstable since that voltage is completely out of guarantee and few of them have tolerance enough to correspond to the value below the guaranteed lower limit.
Note that apparatus connected with such power sources might break down if output power is set close to the rated power.