Nowadays, electricity has become an indispensable part of people's production and life. As an objective substance, electricity has been gradually recognized by people after a long historical process. After Faraday invented the generator, it was widely used in all fields of human production and life.
Human understanding of electricity has gone through a long process.
In the 6th century BC, Greek philosophers recorded that amber rubbed with cloth to attract hair. There is also a record of "amber picking mustard greens" in China ancient books. In the18th century, people found that there are two kinds of electricity, which are called "positive electricity" and "negative electricity", and established the law of "like charges repel, opposite charges attract".
1752, American scientist Franklin risked his life and made a so-called "Philadelphia experiment" that will never go down in history in the history of science, proving that electricity and lightning are the same substance. 1785, Coulomb determined the law of interaction between charges by experimental method, and at the same time determined the quantitative significance of charges. Coulomb's law laid the foundation of electrostatics.
1780, Italian scientist galvanic experimented with frog muscle contraction and discovered electric energy. Volt, an Italian physics professor, explained the experiment and thought that galvanic current was caused by an "electric excitation force". 1800 In the spring, Volt invented the battery and successfully converted chemical energy into electrical energy. As a result, the current can be obtained continuously and become an important object of scientific research, and its chemical effect and thermal effect have also been discovered. Volt's invention of the battery brought mankind from the electrostatic age to the dynamic age.
18 19 Oster discovered the magnetic effect of current, which can deflect the magnetic needle, and human beings realized the internal relationship between magnetic phenomena and electrical phenomena.
During the period from 1820 to 1830, the research of electricity developed rapidly. Ohm, Ampere, Biot, Savart and others made many discoveries. Among them, apart from ohm's law of current intensity, there are mainly Biot-Savart's law of the relationship between current and magnetic field generated by current, and Ampere's law of the effect of magnetic field on conductors and coils with current. Ampere also preliminarily clarified the microscopic nature of magnetism. A series of inventions and discoveries have gradually stripped electricity of its magical coat and exposed its shining scientific light.
The greatest contribution to the development of electromagnetism is undoubtedly Faraday in Britain.
18 13 In March, the famous chemist David recommended Faraday as his assistant experimenter in the laboratory of the Royal Institute, and Faraday embarked on the road of scientific research.
1820, Oster discovered the magnetic effect of current, which attracted the attention of the scientific community. 182 1 year, the editor-in-chief of the British philosophy yearbook invited David to write an article to comment on the theoretical development of electromagnetic experiments since Oster's discovery. David gave Faraday the job. In the process of collecting data, Faraday became very enthusiastic about electromagnetic phenomena and began to turn to the study of electromagnetism. He carefully analyzed the phenomena such as the magnetic effect of current, and thought that since electricity can produce magnetism, conversely, magnetism should also produce electricity. Therefore, he tried to use the static magnetic force acting on the wire or coil to generate current, but his efforts failed. After nearly 10 years of continuous experiments, by 183 1, Faraday finally found that although the magnetic force of one electrified coil could not cause current in the other coil, when the current of the electrified coil was just turned on or off, the ammeter pointer in the other coil slightly deviated. Faraday's heart is bright. After repeated experiments, it is confirmed that there is current in the other coil when the magnetic force changes. He also designed various experiments, such as the relative motion of two coils, and the change of magnetic force can also generate current. In this way, Faraday finally unveiled the law of electromagnetic induction with experiments. Faraday's discovery cleared the way for exploring the essence of electromagnetism and opened up a new way to generate a large amount of current outside the battery.
183 1 year1October 28th, Faraday invented the disk generator according to this experiment. Although the structure of this disc generator is simple, it is the first generator created by human beings. It is the generator that produces electricity in the modern world that started from it.
183 1 year165438+1October 24th, Faraday classified the induced current into five categories in his paper: changing current; A changing magnetic field; Constant current of motion; Moving magnetic field; A conductor moving in a magnetic field. He pointed out that the induced current is related to the change of the original current, but not to the original current itself. He compared this phenomenon with electrostatic induction on a conductor and named it "electromagnetic induction". In order to explain the electromagnetic induction phenomenon, Faraday once put forward the concept of "electric tension". Later, after considering various situations of electromagnetic induction, he thought that the induced current could be attributed to the conductor's "cutting magnetic field lines". Twenty years after Faraday discovered electromagnetic induction, someone put forward the law of electromagnetic induction in 185 1.
1886, Westinghouse established Westinghouse Electric Company, set up an experimental factory in Grand barrington, Massachusetts, and started to generate electricity. Later, the first commercial exchange lamp factory was established in Buffalo, new york. In order to solve a series of technical problems in electrical applications, such as transmission, DC to AC, high voltage to low voltage, etc. A group of engineers from Westinghouse Electric Company played an important role. For example, William Stanley improved the transformer, Auliffe Shallenberger invented the AC induction ammeter, Nikola Trass invented the induction motor (1889) and obtained many patents for the motor, L Stilwell made the voltage regulator, Benjamin Langman improved the squirrel-cage induction motor and the first practical tram motor, and changed the alternating current to the DC rotary converter,/kloc-0. From 1894 to 1895, three hydro-generators were installed in Niagara Falls, each with a power generation capacity of 5000 HP. 1892, at the urging of Charles Coffin, Edison General Electric Company and Thomson Houston Company merged to form General Electric Company. Elihu Thomson invented the wattmeter and the resistance method of electric welding.
Mankind began to enter the electric power age.