50 Fun Facts About Electrical Engineering

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

Henry Cavendish had found the same relationship in 1781 but never published; Maxwell revealed his notes in 1879. Kirchhoff later reformulated the law in its modern form.

Which Italian chemist built the first continuous-current battery and published his experiments in 1799?

His pile of zinc and copper discs enabled the electrolysis of water within a year and Humphry Davy's isolation of sodium, potassium and calcium soon after.

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

Ewald Georg von Kleist and Pieter van Musschenbroek of Leiden both stumbled on it. It stores charge between conductors on the inside and outside of a glass jar.

In which year did Michael Faraday discover electromagnetic induction?

His lab diary for 28 October records experiments with the Royal Society's great magnet. Joseph Henry found the same effect independently in America at about the same time.

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

A coil has one henry of inductance when a current changing at one ampere per second produces one volt across it. He discovered induction independently of Faraday.

The farad, the SI unit of capacitance, is defined as one unit of charge per volt. Which unit?

A one-farad capacitor is enormous by everyday standards; most circuits use microfarads or picofarads. It is named after Michael Faraday.

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

The current law says currents into a node sum to zero; the voltage law says voltages around a loop do. They hold for DC and for AC where wavelengths dwarf the circuit.

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

He also patented the coaxial cable, formulated the telegrapher's equations and coined 'inductance', 'conductance' and 'permeability'.

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

He also gave us admittance, permittivity, reluctance and inductance. He is often wrongly credited with reactance and susceptance.

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

They became the cornerstone of the polyphase system Westinghouse marketed against Edison's DC. Tesla was born in Smiljan in 1856.

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

The naming by the General Conference on Weights and Measures pulled Tesla's reputation out of decades of obscurity after his 1943 death.

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

He ran out of funding before completing it, after high-voltage experiments in New York and Colorado Springs.

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

AC's advantage was that transformers could step high transmission voltages down for indoor use. Edison even recommended AC and a Westinghouse generator for the first electric chair.

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

Only its transformer house survives, now a National Historic Landmark. It followed an 1886 plan to tap the falls with a 7,500-foot brick-lined tunnel.

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

Most of the world uses 50 Hz with 220-240 V; the Americas mostly use 60 Hz with 100-127 V. There is no strong technical reason to prefer either.

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

Adding a control grid produced the triode, which could amplify as well as rectify and made radio and early computing possible.

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

He styled himself the 'Father of Radio' and used the phrase as the title of his 1950 autobiography. His Yale doctorate was on Hertzian waves.

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

The first point-contact device came in December 1947 when two gold contacts on a germanium crystal produced more output power than input. Bardeen won a second Nobel for superconductivity theory.

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

Silicon took over later, in part because of Mohamed Atalla's work on surface passivation and thermal oxidation at Bell Labs.

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

It is now the most manufactured device in history. Lilienfeld and Heil had patented field-effect ideas decades earlier but never built a working one.

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

Robert Noyce at Fairchild independently produced the first monolithic silicon chip months later. Kilby received the 2000 Nobel Prize in Physics.

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

He was one of the 'traitorous eight' who left Shockley Semiconductor in 1957 to found Fairchild.

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

Shockley called them the 'traitorous eight'. He had set up his lab in Mountain View in 1955 to build a four-layer diode.

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

Gordon Moore's original 1965 observation was a doubling every year; the 1975 revision to two years is a compound growth rate of about 41% a year.

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

The AIEE dated to 1884; the IRE was its rival from 1912. The merged body is now the world's largest technical professional organisation.

Which of these distinctions belongs to Edith Clarke?

She was also the country's first female professor of electrical engineering, and the Department of Energy calls her power-network analysis 'the first step toward smart grid technology'.

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

At 4.2 K the resistance abruptly vanished. He was using newly produced liquid helium as the refrigerant in Leiden.

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

Wheatstone improved and popularised it a decade later, and his name stuck. It balances two legs of a bridge circuit to find an unknown resistance.

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

Bell Labs introduced the 'transmission unit' in 1924, later renamed the decibel; the bel honours Alexander Graham Bell but is rarely used on its own.

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

His 1880s experiments confirmed Maxwell's predictions. The unit replaced 'cycles per second' in the SI.

James Watt's 1776 improvement of what machine drove the Industrial Revolution?

One watt is one joule per second, or one volt times one ampere. A labourer can sustain about 75 watts over an eight-hour day.

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

One ampere is now about 6.24 × 10^18 elementary charges passing per second. Before 2019 it was defined by the force between two parallel conductors.

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

Ørsted noticed in 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)?

A typical smartphone battery holds about 10,800 coulombs, or 3,000 mAh. The unit honours Charles-Augustin de Coulomb.

The ohm's symbol is which letter?

One ohm is one volt per ampere. Since 2019 it is defined exactly in terms of fundamental constants, like the ampere and kilogram.

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

Until then transistors cost about $20 each against $1 for a tube, so they had appeared in consumer goods only in hearing aids. Texas Instruments supplied the transistors.

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

He did the work at Nichia in Tokushima and now teaches at UC Santa Barbara. Isamu Akasaki and Hiroshi Amano shared the prize.

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

Practical LEDs did not appear until 1962, and the first visible ones were dim and red. Nick Holonyak demonstrated the first visible-light semiconductor laser diode at GE that year.

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

He was 21. 'A Symbolic Analysis of Relay and Switching Circuits' laid the theory behind digital computing; his 1948 paper founded information theory.

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

Faraday's discovery underlies both generators and transformers, and it took nearly 50 years for the technology, including Swan's filament lamps, to reach common use.

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

He was at Fairchild at the time and later co-founded Intel. He originally projected the trend would hold for at least another decade.

Which of these did Faraday discover in 1845, a weak repulsion of materials from a magnetic field?

He also established the laws of electrolysis. The homopolar motor he built in 1821 was the first device to turn electricity into continuous motion.

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

Bardeen and Brattain ran the experiments at Murray Hill, New Jersey, between 17 November and 23 December 1947.

Which 17th-century scientist is credited with coining the term 'electricity'?

He also designed the versorium, a device for detecting statically charged objects.

Georges-Louis Le Sage's 1782 electrostatic telegraph used how many wires?

Demonstrated in Berlin, it connected just two rooms and moved gold leaf by electrical conduction.

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

It introduced the first degree course in the subject the following year.

How many Manhattan customers did Edison's first large-scale power network serve in 1882?

It supplied 110-volt direct current, two years before Charles Parsons invented the steam turbine.

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

It became a crucial enabling technology for electronic television.

Where did Britain's first radar station begin operating in August 1936?

The work began in 1934 under Dr Wimperis and relied on the magnetron, developed by Albert Hull in 1920.

Roughly how many members does the IEEE have worldwide?

It claims to produce 30% of the world's electrical engineering literature and holds more than 3,000 conferences a year.