Bud Brown explains how to know when to use a voltage adapter in the Philippines. The United States and the Philippines have different voltage systems. In the United States 110 volts are used, and in the Philippines 220 volts are used. If you plug something from one system into the other system, it will not work correctly and may ruin your equipment. Consider that computers and phone chargers are equipped to handle both systems. Check the labels on your electrical equipment to determine if it is compatible with different systems. If your equipment has only one setting that is incompatible with the system you're using, you will need to buy an adapter.