Friends who have been abroad must know that when we go abroad, we always consider whether to buy a switch head. The International Electrotechnical Commission (IEC) points out that there are 15 different kinds of plugs in the world, and the voltage varies from country to country. If you want to use electronic equipment when you go abroad, you often encounter the problem of inappropriate plug and socket.
The following figure can simply show the types of plugs and sockets used all over the world.
When you are used to seeing your own country's socket, and then look at other people's Jack, there is a trace of joy. Panic is often seen in North America, Central America and Japan. The two flat and one round design seems to be a bit like the classic painting "The scream" by Norwegian painter Edvard Munch.
And smile cute little cute socket, appear in Denmark and Greenland and other countries. Every plug in and out, there is a little cute was inserted into the eyes..
Here are the sockets in other countries.
So here comes the question, why there is no unified plug and socket in the world?
At the end of the 19th century, Edison experimented with direct current and realized the use of electricity as the main energy source for the first time. However, the use of direct current for long-distance transmission will cause a lot of voltage loss. At that time, Nikola Tesla, an electrical engineer, developed AC transmission, which greatly reduced the voltage loss caused by long-distance power transmission, and directly competed with Edison's direct current. The voltage of this alternating current technology was exactly 110V, and he firmly believed that it was the best power transmission technology.
Since then, on the basis of AC transmission, various countries have also begun to study the most appropriate power supply standard: with the continuous development of science and technology, some countries believe that 110V voltage is not enough for the electrical demand of electrical appliances, so it doubled and increased the voltage to 220-240V. Therefore, the household power supply has been divided into two major voltage schools: 110-120V, 220-240V.
It is not that we have not tried to unify the world socket power standards: the International Electrical Commission tried to develop universal power plugs and sockets in 1986. However, after so many years, each country's own industry has developed. The home-made electrical appliances are suitable for their own sockets, and the demand for unified power supply is not so strong. Moreover, if we want to unify the power supply standards of the whole world, we should not only replace the electrical appliances produced in the factory, but also redecorate every building. The high cost and feasibility can be imagined.
A spokesman for the Spanish Association for standardization said that although people are trying to come up with a unified plug, that will not happen soon. Because there are already countless plugs and sockets in the world. "Who can persuade a country to change its infrastructure?" he asked.
