respective plugs/outlets and voltages/frequencies used for domestic appliances. The table shows that in most countries the mains supply is between 220 and 240 volts (50 or 60 Hz); countries that operate on an electrical current of 100-127 volts are greatly outnumbered. The list also reveals that types A and C are the most frequently used electric plugs worldwide.
If you take a scroll down the page, you will notice that most countries have a well-defined plug and voltage standard. Many Latin-American, African and Asian countries, however, use a motley collection of – often incompatible – plugs and sometimes also the voltage differs from region to region. Obviously, this makes it very hard for travellers to assess what kind of plug adapter or transformer they will need for their trip. Whenever the electricity situation in a country requires additional information, the country name in question is highlighted in red. That link will take you to an in-depth description.