50 Fun Facts About Electrical Engineering

In what year did Georg Ohm publish the treatise setting out Ohm's law?

Georg Ohm published Die galvanische Kette, mathematisch bearbeitet in 1827, stating that current is proportional to voltage. Henry Cavendish had found the same relationship in 1781 but never published it.

Which Italian scientist announced the first continuous-current battery in 1800?

Alessandro Volta described his pile of alternating zinc and copper discs in a March 1800 letter to the Royal Society; within weeks Nicholson and Carlisle used one to electrolyse water.

The Leyden jar, invented independently in 1745-46, was the original form of which component?

The capacitor descends from the Leyden jar: Ewald Georg von Kleist and Pieter van Musschenbroek of Leiden both found that a glass jar with inner and outer conductors stores charge.

In which year did Michael Faraday discover electromagnetic induction?

Faraday discovered electromagnetic induction in 1831: his diary for 29 August 1831 records the induction ring, and on 28 October he spun a copper disc between the poles of the Royal Society's great magnet.

The SI unit of inductance is named after which American scientist?

Joseph Henry, the American who discovered self-induction, gives his name to the henry: a coil has one henry of inductance when a current changing at one ampere per second induces one volt.

A farad is defined as which unit of electric charge per volt?

The Coulomb is the SI unit of charge, and one farad is one coulomb per volt; a one-farad capacitor is enormous next to the microfarads and picofarads in most circuits.

In what year did Gustav Kirchhoff first describe his current and voltage laws for circuits?

Gustav Kirchhoff stated both laws in 1845, while a student at Königsberg: currents into a node sum to zero, and voltages around a closed loop sum to zero.

Who rewrote Maxwell's equations into the compact four-equation vector form used today?

Oliver Heaviside recast Maxwell's twenty equations into the four vector equations used today; he also patented coaxial cable in 1880 and coined 'inductance', 'conductance' and 'permeability'.

Which of these terms did the man who rewrote Maxwell's equations coin in July 1886?

Impedance was his July 1886 coinage for the AC counterpart of resistance; he also gave us admittance, permittivity, reluctance and inductance, while reactance and susceptance came from others.

Nikola Tesla's AC induction motor and polyphase patents were licensed in 1888 by which company?

Westinghouse Electric bought the licence to Tesla's polyphase patents in July 1888, making them the cornerstone of the AC system George Westinghouse marketed against Edison's DC.

The tesla was adopted as the SI unit of what in 1960?

Magnetic flux density got the tesla as its SI unit when the 11th CGPM adopted it in 1960, seventeen years after Tesla's death in 1943.

What was Tesla's unfinished Wardenclyffe Tower on Long Island intended to be?

Tesla built Wardenclyffe from 1901 as a wireless power and communication transmitter, a 187-foot tower meant to send messages and energy across the Atlantic; J. P. Morgan's funding dried up before it worked.

In the war of the currents, what did the DC camp claim in 1888 about Westinghouse's AC system?

Edison Electric's February 1888 pamphlet 'A Warning' claimed of Westinghouse's AC that it was hazardous and infringed their patents; Edison later backed a Westinghouse AC generator for the first electric chair in 1890.

The Adams station at Niagara Falls, opened in 1895, was the world's first what?

The Adams station was the first large-scale AC generating plant: its Westinghouse generators began sending Niagara power to Buffalo in November 1896, and only its transformer house survives, a National Historic Landmark.

Which country runs both 50 Hz and 60 Hz mains grids?

Japan has used both since the 1890s, when Tokyo bought 50 Hz generators from AEG in Germany and Osaka bought 60 Hz machines from General Electric, splitting the country roughly at the Fuji River.

Who invented the first vacuum tube, the two-element valve, in 1904?

John Ambrose Fleming patented the two-electrode 'oscillation valve' in November 1904; it rectified radio signals, and adding a control grid later produced the amplifying triode.

What did Lee de Forest call his three-element amplifying tube, the first practical electronic amplifier?

The Audion, patented in 1907, added a third electrode, the grid, to the valve; de Forest styled himself the 'Father of Radio', the title of his 1950 autobiography.

Which three Bell Labs physicists shared the 1956 Nobel Prize for the transistor?

Bardeen, Brattain and Shockley shared the 1956 prize for the transistor, first demonstrated at Bell Labs in December 1947; Bardeen won a second Nobel in 1972 for the theory of superconductivity.

What semiconductor crystal was used in the first point-contact transistor in 1947?

Germanium was the crystal in Bell Labs' December 1947 point-contact transistor; silicon took over in the 1950s thanks to its stable oxide layer and better high-temperature behaviour.

Who invented the first working MOSFET at Bell Labs in 1959?

Mohamed Atalla and Dawon Kahng built the device at Bell Labs in 1959 on a silicon wafer with an oxide layer; Lilienfeld and Heil had patented field-effect ideas in the 1920s and 1930s but never built a working one.

Jack Kilby demonstrated the first working integrated circuit in 1958 while newly employed by which company?

Texas Instruments hired Jack Kilby in May 1958; that September he demonstrated the first working integrated circuit there, work recognised with the 2000 Nobel Prize in Physics.

Which 'Mayor of Silicon Valley' made the first monolithic silicon integrated circuit and co-founded Fairchild and Intel?

Robert Noyce, nicknamed the 'Mayor of Silicon Valley', built the first monolithic silicon integrated circuit at Fairchild in 1959 and co-founded Intel with Gordon Moore in 1968.

How many engineers left Shockley Semiconductor Laboratory in 1957 to found Fairchild Semiconductor?

Eight engineers, dubbed the 'traitorous eight', walked out of Shockley Semiconductor in September 1957 and founded Fairchild Semiconductor with Sherman Fairchild's backing.

In its 1975 revision, Moore's law says the transistor count on an integrated circuit doubles roughly how often?

Every two years was the pace Moore set in his 1975 revision, down from the yearly doubling of his original observation; it equals compound growth of about 41% a year.

The IEEE was formed in 1963 by merging the IRE with which older body, founded in 1884?

The American Institute of Electrical Engineers, founded in 1884, merged with its younger rival the Institute of Radio Engineers (1912) on 1 January 1963 to form the IEEE.

Which of these distinctions belongs to Edith Clarke?

First woman professionally employed as a US EE: General Electric made Edith Clarke an engineer in 1922, and in 1947 she became the country's first female professor of electrical engineering, at the University of Texas.

Superconductivity was discovered in 1911 by Heike Kamerlingh Onnes while cooling which metal?

Mercury's resistance vanished abruptly at 4.2 K in Onnes's Leiden laboratory in April 1911, cooled by the liquid helium he had first produced in 1908.

The Wheatstone bridge for measuring resistance was actually invented in 1833 by whom?

Samuel Hunter Christie described the circuit in 1833; Charles Wheatstone improved and popularised it in 1843 and his name stuck. It balances two legs of a bridge to find an unknown resistance.

The decibel grew out of measuring transmission loss in which industry?

Telephony engineers at the Bell System defined the 'transmission unit' for line loss in 1924 and renamed it the decibel in 1928; the bel honours Alexander Graham Bell.

The hertz is named after Heinrich Hertz for being the first to do what?

Heinrich Hertz was the first to conclusively prove electromagnetic waves exist: his 1886-88 spark-gap experiments in Karlsruhe generated and detected the waves Maxwell had predicted.

The watt, the SI unit of power, honours James Watt for improving which machine?

The Newcomen steam engine gained Watt's separate condenser, and the first Watt engines entered service in 1776; the watt, one joule per second or one volt times one ampere, honours him.

Since the 2019 SI revision, the ampere has been defined by fixing the exact value of what?

The elementary charge was fixed at exactly 1.602176634 × 10^-19 C on 20 May 2019, and the ampere follows from it; before that the ampere was defined by the force between two parallel wires.

Along with André-Marie Ampère, which Danish physicist is considered a father of electromagnetism?

Hans Christian Ørsted noticed in April 1820 that a current deflected a compass needle; Ampère then laid the mathematical foundations of electrodynamics.

Roughly how many elementary charges make up one unit of charge in the SI (symbol C)?

About 6.24 × 10^18 elementary charges make one C, since each carries 1.602 × 10^-19 C; a 3,000 mAh phone battery holds roughly 10,800 C.

The ohm's symbol is which letter?

The uppercase omega, Ω, was proposed for the ohm by William Preece in 1867 for its opening sound; one ohm is one volt per ampere.

What was the Regency TR-1, introduced in 1954?

The first commercial transistor radio, the Regency TR-1 went on sale in November 1954 for $49.95 with four transistors; until then transistors had reached consumer goods only in hearing aids.

Which engineer co-invented the blue LED and shared the 2014 Nobel Prize in Physics for it?

Shuji Nakamura grew the bright gallium-nitride blue LED at Nichia in Tokushima in 1993 and shared the 2014 Nobel with Isamu Akasaki and Hiroshi Amano, who had made the earlier Nagoya breakthroughs.

Henry Joseph Round first reported electroluminescence from a solid-state diode in 1907 at which company's labs?

Marconi was Round's employer: as a Marconi Company engineer he saw yellowish light from a carborundum (silicon carbide) crystal under current in 1907 and reported it in Electrical World; practical LEDs came only in 1962.

Claude Shannon's 1937 MIT master's thesis showed that digital circuits could be designed using what?

Boolean algebra, Shannon showed at 21, maps onto relay and switching circuits; his thesis 'A Symbolic Analysis of Relay and Switching Circuits' laid the theory behind digital logic, and his 1948 paper founded information theory.

Which principle explains why a transformer only works with alternating, not steady direct, current?

Induction needs a changing magnetic field, as Faraday found: a steady direct current sets up a constant flux that induces no voltage in the secondary winding, while alternating current does.

In what year did Gordon Moore first publish the observation that became Moore's law?

Moore's article 'Cramming more components onto integrated circuits' ran in Electronics magazine on 19 April 1965, while he was at Fairchild; he projected the yearly doubling would hold for at least another decade.

Which form of magnetism, a weak repulsion from a magnetic field, did Faraday discover?

Diamagnetism, the weak repulsion of materials such as bismuth and water from a magnetic field, was discovered by Faraday, who also established the laws of electrolysis and built the first homopolar motor in 1821.

In the 1947 point-contact transistor experiments, what were the two contacts on the crystal made of?

Gold foil, slit at the tip of a plastic wedge, formed the two contacts pressed onto the crystal; Bardeen and Brattain ran the experiments at Murray Hill, New Jersey, between 17 November and 23 December 1947.

Which scientist coined the Latin 'electricus' in the 1600 treatise De Magnete?

William Gilbert, physician to Elizabeth I, used 'electricus' in De Magnete (1600) for amber-like attraction; Thomas Browne turned it into the English word 'electricity' in 1646. Gilbert also designed the versorium, an early charge detector.

In what year did Samuel Morse send 'What hath God wrought' from Washington to Baltimore?

On 24 May 1844 Morse tapped 'What hath God wrought' from the Capitol in Washington over the experimental line along the Baltimore and Ohio railroad to Baltimore.

Which university founded the world's first electrical engineering department, in 1882?

TU Darmstadt created the world's first chair of electrical engineering for Erasmus Kittler in 1882 and started the first degree course in the subject in 1883.

Which lower Manhattan street gave Edison's 1882 central power station its name?

Pearl Street Station, at 255-257 Pearl Street, began generating on 4 September 1882, its Edison 'Jumbo' dynamos supplying 110-volt direct current to nearby offices.

Who introduced the cathode-ray tube as part of an oscilloscope in 1897?

Karl Ferdinand Braun built the first cathode-ray oscilloscope in Strasbourg in 1897; the 'Braun tube' became the enabling technology for electronic television, and he shared the 1909 Nobel Prize in Physics for wireless telegraphy.

Where was Britain's first operational Chain Home radar station?

Bawdsey Manor, bought by the Air Ministry in 1936, housed Watson-Watt's team after it moved from Orford Ness and became the first operational Chain Home station in the early-warning network.

The 1858 transatlantic telegraph cable linked Ireland with which island?

Newfoundland's Trinity Bay received the 1858 cable from Valentia Island in Ireland; Queen Victoria and President Buchanan exchanged messages in August before the cable failed within weeks.