In the United States, home wall outlets carry a voltage of 120 VAC, or voltage from alternating current. This is the standard amount, but some heavy-duty appliances require higher voltages.
Most stoves, washers and dryers have heavier power requirements and run on a 240 VAC outlet that requires its own circuit.
The United States is one of the few countries still operating on 120 VAC outlets. Many countries in the European Union have switched to 240 VAC for their standard outlets. Some countries use less; Japan makes use of 100 VAC outlets. When traveling to another country, make sure to carry voltage adapters to avoid damage to appliances.