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Electronics Timeline


Brilliant inventors from the late 19th century to the present day have built on each other's work to launch a revolution in electronics. In recognizing the team of Bardeen, Brattain, and Shockley for their invention of the transistor, the Nobel Prize also paid tribute to their predecessors, the discoverers of electrons, the vacuum tube, purified crystals, and diodes. The transistor spurred experimentation with new materials such as silicon and with a host of manufacturing techniques, leading to electronic devices that have altered every aspect of daily life.

  1904   Thermionic valve, or diode invented

Sir John Ambrose Fleming, a professor of electrical engineering and the first scientific adviser for the Marconi Company, invents the thermionic valve, or diode, a two-electrode rectifier. (A rectifier prevents the flow of current from reversing.) Building on the work of Thomas Edison, Fleming devises an "oscillation valve"—a filament and a small metal plate in a vacuum bulb. He discovers that an electric current passing through the vacuum is always unidirectional.

  1907   Triode patented

Lee De Forest, an American inventor, files for a patent on a triode, a three-electrode device he calls an Audion. He improves on Fleming’s diode by inserting a gridlike wire between the two elements in the vacuum tube, creating a sensitive receiver and amplifier of radio wave signals. The triode is used to improve sound in long-distance phone service, radios, televisions, sound on film, and eventually in modern applications such as computers and satellite transmitters.

  1940   Ohl discovers that impurities in semiconductor crystals create photoelectric properties

Russell Ohl, a researcher at Bell Labs, discovers that small amounts of impurities in semiconductor crystals create photoelectric and other potentially useful properties. When he shines a light on a silicon crystal with a crack running through it, a voltmeter attached to the crystal registers a half-volt jump. The crack, it turns out, is a natural P-N junction, with impurities on one side that create an excess of negative electrons (N) and impurities on the other side that create a deficit (P). Ohl’s crystal is the precursor of modern-day solar cells, which convert sunlight into electricity. It also heralds the coming of transistors.

  1947   First pointcontact transistor

John Bardeen, Walter H. Brattain, and William B. Shockley of Bell Labs discover the transistor. Brattain and Bardeen build the first pointcontact transistor, made of two gold foil contacts sitting on a germanium crystal. When electric current is applied to one contact, the germanium boosts the strength of the current flowing through the other contact. Shockley improves on the idea by building the junction transistor—"sandwiches" of N- and P-type germanium. A weak voltage applied to the middle layer modifies a current traveling across the entire "sandwich." In November 1956 the three men are awarded the Nobel Prize in physics.

  1952   First commercial device to apply Shockley’s junction transistor

Sonotone markets a $229.50 hearing aid that uses two vacuum tubes and one transistor—the first commercial device to apply Shockley’s junction transistor. Replacement batteries for transistorized hearing aids cost only $10, not the nearly $100 of batteries for earlier vacuum tube models.

  1954   First truly consistent mass-produced transistor is demonstrated

Gordon Teal, a physical chemist formerly with Bell Labs, shows colleagues at Texas Instruments that transistors can be made from pure silicon—demonstrating the first truly consistent mass-produced transistor. By the late 1950s silicon begins to replace germanium as the semiconductor material out of which almost all modern transistors are made.

  1954   First transistor radio

Texas Instruments introduces the first transistor radio, the Regency TR1, with radios by Regency Electronics and transistors by Texas Instruments. The transistor replaces De Forest’s triode, which was the electrical component that amplified audio signals—making AM (amplitude modulation) radio possible. The door is now open to the transistorization of other mass production devices.

  1955   Silicon dioxide discovery

Carl Frosch and Link Derick at Bell Labs discover that silicon dioxide can act as a diffusion mask. That is, when a silicon wafer is heated to about 1200°C in an atmosphere of water vapor or oxygen, a thin skin of silicon dioxide forms on the surface. With selective etching of the oxide layer, they could diffuse impurities into the silicon to create P-N junctions. Bell Labs engineer John Moll then develops the all-diffused silicon transistor, in which impurities are diffused into the wafer while the active elements are protected by the oxide layer. Silicon begins to replace germanium as the preferred semiconductor for electronics.

  1958-1959   Integrated circuit invented

Jack Kilby, an electrical engineer at Texas Instruments and Robert Noyce of Fairchild Semiconductor independently invent the integrated circuit. In September 1958, Kilby builds an integrated circuit that includes multiple components connected with gold wires on a tiny silicon chip, creating a "solid circuit." (On February 6, 1959, a patent is issued to TI for "miniaturized electronic circuits.") In January 1959, Noyce develops his integrated circuit using the process of planar technology, developed by a colleague, Jean Hoerni. Instead of connecting individual circuits with gold wires, Noyce uses vapor-deposited metal connections, a method that allows for miniaturization and mass production. Noyce files a detailed patent on July 30, 1959.

  1962   MOSFET is invented

The metal oxide semiconductor field effect transistor (MOSFET) is invented by engineers Steven Hofstein and Frederic Heiman at RCA's research laboratory in Princeton, New Jersey. Although slower than a bipolar junction transistor, a MOSFET is smaller and cheaper and uses less power, allowing greater numbers of transistors to be crammed together before a heat problem arises. Most microprocessors are made up of MOSFETs, which are also widely used in switching applications.

  1965   Automatic adaptive equalizer invented by Robert Lucky

The automatic adaptive equalizer is invented in 1965 at Bell Laboratories by electrical engineer Robert Lucky.  Automatic equalizers correct distorted signals, greatly improving data performance and speed. All modems still use equalizers.

  1966   Self-aligned gate process for fabricating field effect transistors

In 1966 Dr. Robert W. Bower invents the self-aligned gate process for fabricating field effect transistors, providing the foundation for later developments establishing the core technology for the fabrication of high performance MOS integrated circuits.

  1967   First handheld calculator invented

A Texas Instruments team, led by Jack Kilby, invents the first handheld calculator in order to showcase the integrated circuit. Housed in a case made from a solid piece of aluminum, the battery-powered device fits in the palm of a hand and weighs 45 ounces. It accepts six-digit numbers and performs addition, subtraction, multiplication, and division, printing results up to 12 digits on a thermal printer. 

  1968   Bell Labs team develops molecular beam epitaxy

Alfred Y. Cho heads a Bell Labs team that develops molecular beam epitaxy, a process that deposits single-crystal structures one atomic layer at a time, creating materials that cannot be duplicated by any other known technique. This ultra-precise method of growing crystals is now used worldwide for making semiconductor lasers used in compact disc players. (The term epitaxy is derived from the Greek words epi, meaning "on" and taxis, meaning "arrangement.")

  1969   Dynamic random access memory

In 1969 Dr. Robert H. Dennard invents the 1-transistor dynamic random access memory (DRAM), providing a large increase in memory density and speed. Dennard’s design remains today as the critical memory component in all computers.

  1970   The first CD-ROM patented


  1971   Intel introduces "computer on a chip"



  1972   Home video game systems become available



  1974   Texas Instruments introduces the TMS 1000


  1980   First circuit boards that have built-in self-testing technology


  1997   IBM develops a copper-based chip technology

IBM announces that it has developed a copper-based chip technology, using copper wires rather than traditional aluminum to connect transistors in chips. Other chip manufacturers are not far behind, as research into copper wires has been going on for about a decade. Copper, the better conductor, offers faster performance, requires less electricity, and runs at lower temperatures, This breakthrough allows up to 200 million transistors to be placed on a single chip.

  1998   Plastic transistors developed

A team of Bell Labs researchers—Howard Katz, V. Reddy Raju, Ananth Dodabalapur, Andrew Lovinger, and chemist John Rogers—present their latest findings on the first fully "printed" plastic transistor, which uses a process similar to silk screening. Potential uses for plastic transistors include flexible computer screens and "smart" cards, full of vital statistics and buying power, and virtually indestructible.


     1 - New Gadget
     2 - Foundation
     3 - Vacuum Switches
     4 - Transistors
     5 - Microprocessors
     Essay - Gordon E. Moore


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