electrical knowlege

History

The discoveries of Michael Faraday formed the foundation of electric motor technology.

Electricity has been a subject of scientific interest since at least the early 17th century. The first electrical engineer was probably William Gilbert who designed the versorium: a device that detected the presence of statically charged objects. He was also the first to draw a clear distinction between magnetism and static electricity and is credited with establishing the term electricity.^[2] In 1775 Alessandro Volta's scientific experimentations devised the electrophorus, a device that produced a static electric charge, and by 1800 Volta developed the voltaic pile, a forerunner of the electric battery.^[3]

19th century

However, it was not until the 19th century that research into the subject started to intensify. Notable developments in this century include the work of Georg Ohm, who in 1827 quantified the relationship between the electric current and potential difference in a conductor, Michael Faraday, the discoverer of electromagnetic induction in 1831, and James Clerk Maxwell, who in 1873 published a unified theory of electricity and magnetism in his treatise Electricity and Magnetism.^[4]
Beginning in the 1830s, efforts were made to apply electricity to practical use in the telegraph. By the end of the 19th century the world had been forever changed by the rapid communication made possible by engineering development of land-lines, submarine cables, and, from about 1890, wireless telegraphy.
Practical applications and advances in such fields created an increasing need for standardized units of measure. They led to the international standardization of the units volt, ampere, coulomb, ohm, farad, and henry. This was achieved at an international conference in Chicago 1893.^[5] The publication of these standards formed the basis of future advances in standardisation in various industries, and in many countries the definitions were immediately recognised in relevant legislation.^[6]

Thomas Edison built the world's first large-scale electrical supply network.

During these years, the study of electricity was largely considered to be a subfield of physics. It was not until about 1885 that universities and institutes of technology such as Massachusetts Institute of Technology (MIT) and Cornell University started to offer bachelor's degrees in electrical engineering. The Darmstadt University of Technology founded the first department of electrical engineering in the world in 1882. In that same year, under Professor Charles Cross at MIT began offering the first option of electrical engineering within its physics department.^[7] In 1883, Darmstadt University of Technology and Cornell University introduced the world's first bachelor's degree courses of study in electrical engineering, and in 1885 the University College London founded the first chair of electrical engineering in Great Britain.^[8] The University of Missouri established the first department of electrical engineering in the United States in 1886.^[9] Several other schools soon followed suit, including Cornell and the Georgia School of Technology in Atlanta, Georgia.

Nikola Tesla developed transformers and induction motors for use in AC

During these decades use of electrical engineering increased dramatically. In 1882, Thomas Edison switched on the world's first large-scale electric power network that provided 110 volts — direct current (DC) — to 59 customers on Manhattan Island in New York City. In 1884, Sir Charles Parsons invented the steam turbine. Turbines now provide the mechanical power for about 80 percent of the electric power in the world using a variety of heat sources.
The late 1880s saw a rivalry in systems for electric power distribution with the introduction of alternating current (AC) systems, setting off what has been called the War of Currents.^[10] The method of AC won over DC for generation and power distribution because of its superior technology, especially the use of transformers to increase and decrease voltages (not possible with DC). The use of high-voltage AC vastly extended the range of electric power distribution, and the use of transfomers improved both the efficiency and the safety of electric power distribution.

More modern developments

During the development of radio, many scientists and inventors contributed to radio technology and electronics. In his classic physics experiments of 1888, Heinrich Hertz transmitted radio waves with a spark-gap transmitter, and detected them by using simple electrical devices. The mathematical work of James Clerk Maxwell during the 1850s had shown the possibility of radio waves but Hertz was the first to demonstrate their existence. In 1895, Nikola Tesla was able to detect radio signals from his transmitter in his laboratory in New York City about 50 miles away in West Point, New York (about 80 kilometers).^[11]
In 1897, Karl Ferdinand Braun introduced the cathode ray tube as part of an oscilloscope, a crucial enabling technology for electronic television.^[12] John Fleming invented the first radio tube, the diode, in 1904. Two years later, Robert von Lieben and Lee De Forest independently developed the amplifier tube, called the triode.^[13] In 1895, Guglielmo Marconi furthered the art of hertzian wireless methods. Early on, he sent wireless signals over a distance of one and a half miles. In December 1901, he sent wireless waves that were not affected by the curvature of the Earth. Marconi later transmitted the wireless signals across the Atlantic between Poldhu, Cornwall, and St. John's, Newfoundland, a distance of 2,100 miles (3,400 km).^[14] In 1920 Albert Hull developed the magnetron which would eventually lead to the development of the microwave oven in 1946 by Percy Spencer.^[15][16] In 1934 the British military began to make strides toward radar (which also uses the magnetron) under the direction of Dr Wimperis, culminating in the operation of the first radar station at Bawdsey in August 1936.^[17]
In 1941 Konrad Zuse presented the Z3, the world's first fully functional and programmable computer using electromechanical parts. In 1943 Tommy Flowers designed and built the Colossus, the world's first fully functional, electronic, digital and programmable computer.^[18] In 1946 the ENIAC (Electronic Numerical Integrator and Computer) of John Presper Eckert and John Mauchly followed, beginning the computing era. The arithmetic performance of these machines allowed engineers to develop completely new technologies and achieve new objectives, including the Apollo program which culminated in landing astronauts on the Moon.^[19]

A complete breakthrough in electronics - solid-state transistors

The invention of the transistor in late 1947 by William B. Shockley, John Bardeen, and Walter Brattain of the Bell Telephone Laboratories opened the door for more compact devices and led to the development of the integrated circuit in 1958 by Jack Kilby and independently in 1959 by Robert Noyce.^[20] Starting in 1968, Ted Hoff and a team at the Intel Corporation invented the first commercial microprocessor, which foreshadowed the personal computer. The Intel 4004 was a four-bit processor released in 1971, but in 1973 the Intel 8080, an eight-bit processor, made the first personal computer, the Altair 8800, possible.^[21]