One of the down sides of being a techie traveler is figuring out how to plug everything in. Advances in multi-voltage gadgetry have made it much easier to travel with your electronics, but there’s still some difference between electrical systems around the world. At the very least, you’re probably going to need a plug adapter. Why Is It Such a Mess, Anyway?North America tends to use 110 or 120 volt lines with electricity running at 60Hz, which was promoted by Tesla, Westinghouse, and eventually General Electric in the U.S. Many other countries use 220 or 240 volts and 50Hz, which was promoted by German firms after World War II. It’s more efficient to transmit electricity at a higher voltage, but not enough more that it’s worth retrofitting millions of existing appliances. Much of Europe’s electrical infrastructure was destroyed in World War II. Europe as a whole used the German standard as part of the overall European economic unification and rebuilding projects in the 1950s. Because Japan bought generators after World War II from the U.S. and Germany, it has the unusual situation of hosting 50Hz and 60Hz current in the same country. Gizmodo has a m...