The phenomena of electricity and magnetism were discovered very early in China. In ancient books, there are records of "magnet calling iron" and "amber picking mustard". Magnets were first used to indicate the direction and correct the time, which is what the "four acceptances" mentioned in Han Feizi Lun Heng written by Wang Chong in the Eastern Han Dynasty refers to. Later, due to the development of navigation, China invented the compass in the 11th century. In Shen Kuo's Talk on Meng Xi in the Song Dynasty, it is recorded that "the Fang family can be guided by a magnet grinding needle, but it is often slightly east, but not all south". This not only shows the manufacture of the compass, but also finds the magnetic declination. It was not until the 12 century that the compass was introduced to Europe by Arabs.
1at the end of the 8th century1at the beginning of the 9th century, due to the needs of production, the research work in electromagnetic phenomena has developed rapidly.
Coulomb first determined the interaction force between charges from the laboratory in 1785, and the concept of charge began to have quantitative significance. 1820, Oster discovered the powerful effect of current on magnetic needle in the experiment, which opened a new page of electrical theory.
Because electronic technology has been highly developed and widely used (such as space electronic technology, biomedical electronic technology, information processing and remote sensing technology, microwave application and so on). ) has also played a transformative role in promoting the development of social productive forces. Electronic level is an important symbol of modernization, and electronic industry is an important material and technical foundation to realize modernization. The development speed and technical level of electronic industry, especially the high development of electronic computers and their wide application in production fields, directly affect the construction of industry, agriculture, science and technology and national defense, and are related to the development speed of socialist construction and national security; It also directly affects the material and cultural life of hundreds of millions of people and concerns the vital interests of the broad masses of the people.