1827, Georg Ohm's Law Ohm's Law explains the quantitative relationship among current, voltage and resistance in the circuit. 183 1 year, electromagnetic induction was discovered in michael faraday. 1873, james maxwell integrated the predecessors' work in his book "General Theory of Electromagnetism" and put forward Maxwell's equations, which opened the era of classical electrodynamics.
Since the 1830 s, all efforts made in the practical application of electromagnetic knowledge have finally achieved an important result, which is telegraph technology. At the end of 19 century, due to the appearance of land lines, submarine cables and wireless telegrams of about 1890, rapid communication was finally realized, which completely changed the communication structure of the whole world.
In order to ensure that we will not encounter difficulties and misunderstandings in weights and measures when expressing and applying electromagnetic theory, it is particularly necessary to draw up a simple and convenient standard unit of weights and measures. The research in this field has promoted the setting and adoption of international standard units, such as Volt, Ampere, Coulomb, Farah and Henry. This international standard system reached a consensus in Chicago on 1893, which laid the foundation for the progress of standard unit system in various industries in the future. Many countries immediately legislated to recognize the validity of these international standard units.
In these decades, electrical engineering is generally classified as a branch of physics. 1882, Darmstadt University of Technology in Germany established the world's first chair in electrical engineering. In the same year, the Physics Department of Massachusetts Institute of Technology began to offer a bachelor's degree course in electrical engineering. 1883, Darmstadt University of Technology and Cornell University established the Department of Electrical Engineering, becoming the first two universities in the world to establish the Department of Electrical Engineering. 1885, University College London established the first "Electrical Engineering Department" in Britain. The first dean was john fleming, and a few years later, the department was renamed the Department of Electrical Engineering. 1886, the university of Missouri also established the department of electrical engineering. According to some documents, the University of Missouri was the first American university to establish a department of electrical engineering. Soon, many universities, including Georgia Institute of Technology, followed suit and set up electrical engineering departments.
Thomas Edison built the world's first large-scale power grid.
After decades of development, the application field of electrical engineering has expanded dramatically. 1882, Thomas Edison built the world's first large-scale power grid, which can provide 59 customers in Manhattan Island, new york with DC voltage of110v. 1884, Sir Charles Parsons invented the steam turbine engine. At present, the mechanical energy converted by turbine engines from various thermal energy sources can provide about 80% of the global electricity consumption.
Nikola tesla developed transformers and induction motors, which are important equipment of AC system.
1In the late 1980s, it witnessed the civilized confrontation between two obviously different ways of power transmission. The original DC mode uses DC to transmit electric energy, and the new AC mode uses AC to transmit electric energy, which has triggered the so-called "current war". Alternating current power generation technology is superior to electric energy transmission technology, especially the voltage that alternating current allows transformers to step up or step down (this is a big lack of DC mode). In addition, the use of high-voltage alternating current greatly expands the scope of power transmission, and the use of transformers improves the safety and efficiency of power transmission. Because of these advantages, AC power supply mode gradually replaced DC power supply mode. In the development of radio technology, many scientists and inventors have made contributions to radio and electronics respectively. In the classic experiment of 1888, heinrich hertz used electrical equipment to transmit and receive radio waves in the wireless band, thus confirming the existence of radio waves. 1895, nikola tesla's radio signal from his laboratory in new york can be received at West Point, new york, about 50 kilometers away.
1897, karl braun began to assemble cathode ray tubes into oscilloscopes, and then cathode ray tubes became the key components of TV sets. 1904, john fleming first invented the diode. Two years later, Robert von Li Benhe and Lee Forrest independently invented a vacuum tube-triode (also known as "amplifier tube") that can amplify current.
1895, Guillermo Marconi further improved the radio transmission method of Hertz, extending the transmission distance of radio signals to 1.5 miles (2.4 kilometers). 19011February, in order to prove that he had mastered the more advanced technology of transmitting radio waves, which could be completely unaffected by the curvature of the earth, he sent a radio signal from the launch pad in Cornwall, England, and crossed the Atlantic Ocean. On the other side of the Atlantic, St. John in Newfoundland, Canada actually received the signal. The distance between the two places is 2 108. 1920, Albert hull invented the magnetron, a vacuum tube that can generate microwaves. Percy Spencer successfully developed the microwave oven at 1946. 1934, under the guidance of Harry Pelisse, the British army began to use microwave technology to develop radar, and set up the first radar station in Bodesi, which started operation in August 1936.
194 1 year, German scientist Konrad Zuse showed the world's first fully functional programmable computer made of electromechanical components, namely Z3 system. From 65438 to 0943, Tommy Flowers designed and manufactured the colossus computer, which is an unprecedented digital computer with fixed program and programmable, made entirely of electronic components. 1946 On February 5th, the electronic numerical integral calculator (ENIAC) invested and developed by the U.S. Army in World War II was born in the University of Pennsylvania under the guidance of pioneers John Moakley and johann eck. ENIAC is generally regarded as the world's first "universal" electronic computer, and its invention is an important milestone in the history of modern computer development. 1947, william shockley, john bardeen and walter brattain who worked in Bell Laboratories invented the solid-state transistor. This is one of the most important inventions of the twentieth century. Transistors have the advantages of mass production, miniaturization and low cost, and almost all modern electronic products need transistors. Shockley, Badin and bratton shared the 1956 Nobel Prize in Physics for their "research on semiconductors and the discovery of transistor effects".
1958, jack kilby and 1959, robert noyce independently invented the integrated circuit. With the application of integrated circuit technology, a large number of microtransistors can be integrated into a small chip, which provides the possibility for the emergence of microprocessors. Intel 4004 microprocessor introduced by Intel Corporation 197 1 is the first microprocessor in the world, designed and implemented by Marcien Hof and his team, and can run 4-bit operations. 1973, Intel successfully designed an eight-bit microprocessor Intel 8080, and the first personal computer Altair 8800 was equipped with an Intel 8080. At present, a single VLSI chip can integrate more than 1 1,000,000 transistors.