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Valve Technology Timeline

    
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1600-

 

Early History

1640

Vacuum Pumps

The first vacuum. Otto von Guericke's air pump

1643

Mercury Barometer

The barometer first demonstrated by Evangelista Torricelli

1654

Vacuum Pumps

Magdeberg Hemispheres a demonstration of the force of air pressure

1672

Air Pumps

Improved air pump and treatise on vacuum experiments published.

1716

Pressure explained?

Jacob Hermann suggests that gas pressure is proportional to density and to the square of the average velocity of the gas particles in motion

1811

Avogadro's Law

A principle stated in 1811 by the Italian chemist Amedeo Avogadro (1776-1856) that equal volumes of gases at the same temperature and pressure contain the same number of molecules regardless of their chemical nature and physical properties

1855

Geissler Tube

Johann Geissler produces a mercury vacuum pump and with it he produces the first good vacuum discharge tubes

1856

Gas Properties

Karl Kronig suggests that gas molecules in equilibrium travel in straight lines unless they collide with something

1858

Cathode Rays

Julius Plucker demonstrated that magnetic fields bend what later became known as cathode rays.

1860

Lamps

Joseph Swann patents the the carbon filament incandescent lamp that operates in a partial vacuum

1862

Vacuum Pumps

Geissler-Topler mercury vacuum pump developed

1865

Vacuum Pumps

Hermann Sprengel develops the mercury drop pump

1870

Vacuum Pumps

Sir William Crookes vacuum pumping system

1871

Cathode Rays

C F Varley suggests that cathode rays are particles

1871

Cathode Rays

Sir William Crookes advances the idea that cathode rays are negatively charged particles

1874

Photo-emission

G R Carey invents the photo-electric cell

1876

Gettering

Sir William Crookes demonstrates pumping by chemical getters

1876

Vacuum Pumps

L von Babo develops a self-recycling Sprengel vacuum pump

1876

Telephone

Alexander Graham Bell invents and demonstrates the telephone

1877

Loudspeakers

In Germany on December 14th Ernst Siemens patented the first loudspeaker.

1879

Lamps

Thomas A Edison files US patent on high vacuum carbon filament incandescent lamp

1879

Cathode Rays

Sir William Crookes develops the Crookes Tube, an early form of cathode ray tube

1879

Vacuum Pumps

Edison improves the self-recycling Sprengel-Geissler mercury vacuum pump

1880

Vacuum Pumps

Apparatus for evacuating Edison's electric lamps. Based on Crookes design

1883

Manufacturer

In May 1883 the American company Western Electric opened a small business in London. This was to become Standard Telephones and Cables (STC)

1883

Edison Effect

Thomas A Edison first observes thermionic emission in a vacuum

1883

Edison Effect

John Ambrose Fleming presents a paper on the 'molecular shadow' to the Physical Society of London on May 26

1883

Lamps

In October 1883 the amalgamation of Edison Electric Light Co Ltd and Swan Electric Lighting Co to form Edison and Swan United Electric Light Co. Ltd.

1885

Edison Effect

Sir William Preece duplicates Edison's experiment, makes quantitative measurements and presents a paper to The Royal Society

1886

Positive Ions

Eugen Goldstein observes 'canal' rays (German = Kanalstrahlen). So called because they were emitted through a hole in the cathode.

1887

Cathode Rays

Sir William Crookes performs the Maltese Cross experiment

1889

Cathode Rays

Jonathan Zenneck improves Braun's CRT and adds time base deflection

1889

Valves

The British General Electric Co. Ltd was formed

1890

Valves

A C Cossor Ltd was formed.

1891

Cathode Rays

George J Stoney suggests the name of electron for cathode ray particles

1896

Gettering

Mallgnani Corp demonstrates the use of phosphorus gettering

1896

Valves

The British Thomson-Houston Co. Ltd. was formed

1897

The Electron

Sir Joseph Thomson discovers 'corpuscles' later called electrons

1897

Radio

Guglielmo Marconi sets-up in July 1897 the Wireless Telegraph and Signal Company Limited to commercially exploit his patents

1898

Loudspeakers

Sir Oliver Lodge was granted a patent for a loudspeaker on April 27

1899

Valves

The British Westinghouse Electrical and Manufacturing Co. Ltd was formed. This later became the Metropolitan-Vickers Co. Ltd, (Metrovick)

1900

Vacuum Pumps

James Dewar builds a cryosorption pump using activated charcoal and liquid air

1900

Valves

John Ambrose Fleming becomes scientific adviser to Marconi's company

1901

X-Rays

W C Roentgen wins Nobel prize for Physics for discovery of x-rays

1901

Radio

Gugliemo Marconi transmits signal from England to North America , and in Marconi's own words.

1901

Electron

Richardson produces an equation for the emission of electrons from incandescent metal filaments

1901

Lamps

Peter Cooper Hewitt develops the fluorescent lamp

1901

Valves

1901: valves introduced and adverts published.

1902

Lamps

Georges Claude builds the first neon lamp

1902

Lamps

E Weintraub develops the mercury arc lamp and rectifier

1902

Lamps

Charles Proteus Steinmetz files a patent on mercury vapour lamp with halide salts to improve colour

1902

Lamps

Peter Cooper Hewitt develops the mercury vapour lamp

1902

Cathode Rays

A C Cossor Ltd make the first British examples of Braun's CRT

1902

Valves

1902: valves introduced and adverts published.

1903

Cathode Rays

Harris J Ryan builds magnetic deflection CRT's

1903

Valves

1903: valves introduced and adverts published.

1904

Cathodes

Arthur Wehnelt publishes details of the oxide coated hot cathode CRT

1904

Valves

January 1904, Arthur Wehnelt patents a diode. The patent does not mention use for rectification of RF. The device is described in connection with charging accumulators

1904

Valves

October 1904, John Ambrose Fleming produces rectification of RF in a valve. Valve history begins

1904

Valves

November 16 1904, John Ambrose Fleming applies for a patent on the Oscillation Valve, later known as the Thermionic Valve and Fleming Diode.

1904

Valves

1904: valves introduced and adverts published.

1905

Cathode Rays

Philip Eduard Anton von Lenard wins Physics Nobel prize for Cathode Rays

1905

Vacuum Pumps

Wolfgang Gaede makes rotary mercury-sealed mechanical vacuum pump

1905

Physics

Albert Einstein explains the photoelectric effect

1905

Valves

1905: valves introduced and adverts published.

1906

Vacuum Pumps

W Voege and Rohn build the thermocouple vacuum gauge

1906

Valves

Lee de Forest invents the Audion (triode) as a sensitive detector

1906

Cathode Rays

Dieckmann, Glage, Rosing, Campbell-Swinton propose the use of the Braun tube to display television images

1906

Valves

1906: valves introduced and adverts published.

1907

Valves

1907: valves introduced and adverts published.

1908

Cathodes

Fleming replaces the carbon filament in his valve with a tungsten filament. This is before a process of making ductile tungsten had been devised

1908

Valves

1908: valves introduced and adverts published.

1909

Vacuum Pumps

Otto von Baeyer develops the ionisation vacuum gauge

1909

Electron

Robert Milikan measures the charge on the electron by the oil drop experiment

1909

Radio

Guglielmo Marconi and Carl F Braun win Physics Nobel prize for wireless telegraphy

1909

Valves

1909: valves introduced and adverts published.

1910

Vacuum Pumps

Pfeiffer Co produce the rotary oil-sealed mechanical vacuum pump

1910

Lamps

Georges Claude demonstrates the neon lamp in public

1910

Valves

German telephone relay soft valve by Leiben-Reiz

1910

Valves

The early production Audion's looked like this

1910

Valves

1910: valves introduced and adverts published.

1911

Radio

Edwin H Armstrong invents the regenerative circuit

1911

Radio

'Doc' Herrold begins first radio broadcast service in San Jose California

1911

Radio

Henry Round of the Marconi company commences work on the design of a diode valve

1911

Wireless World

First edition of The Marconigraph is published. The name changed to Wireless World in 1913

1911

Valves

1911: valves introduced and adverts published.

1912

Wireless World

Review of 1911 - from Wireless World Golden Jubilee edition April 1961

1912

Wireless World

Synopsis of The Marconigraph - Published as 60 years ago in 1972.

1912

Vacuum Pumps

Wolfgang Gaede develops first theory and experiment on the molecular-drag vacuum pump

1912

Lamps

Irving Langmuir produces gas filled incandescent lamp

1912

Lamps

W D Coolidge introduces a small percentage of Thoria to tungsten power in order to produce ductile tungsten wire for use in G E incandescent lamps.

1912

Radio

Lee de Forest makes the first valve amplifier

1912

Radio

H M Fassenden develops the Heterodyne receiver

1912

Wireless World

Review of 1912 - from Wireless World Golden Jubilee edition April 1961

1912

Valves

1912: valves introduced and adverts published.

1913

Vacuum Pumps

Wolfgang Gaede first diffusion pump using mercury

1913

Cathode Rays

A Dufour develops a high voltage, continuously pumped CRT and records directly onto photographic plates

1913

Cathode Rays

John Johnson and H J Van der Bijl develop the first commercial CRT. Western Electric 224-A

1913

Valves

Marconi receiver with Captain Round's C valve

1913

Valves

Captain Round's T transmitting valve developed

1913

Valves

Saul Dushman produces a 40 kV vacuum rectifier

1913

X-Rays

W D Coolidge produces a High Voltage X-ray tube

1913

Wireless World

Review of 1913 - from Wireless World Golden Jubilee edition April 1961

1913

Valves

1913: valves introduced and adverts published.

1914

Valves

ATT purchase licence from de Forest in August 1914

1914-

 

First World War

1914

Valves

Marconi files suit against Lee de Forest over triode

1914

Valves

AEG-Telefunken develops standardised valves for radio reception. EVN94 and EVN129

1914

Valves

ATT purchase de Forest's patent for the triode

1914

Valves

Irving Langmuir makes a patent application for Electron emission from a thoriated cathode

1914

Wireless World

Review of 1914 - from Wireless World Golden Jubilee edition April 1961

1914

Valves

1914: valves introduced and adverts published.

1915

Valves

Edison and Swan Co. produce Round valves for the Marconi Co.

1915

Valves

GE in America begin production of Pliotrons (triodes)

1915

Valves

In France the first hard vacuum triode was made. During the war over 100,000 were made by the companies Metal and Fotos

1915

Cathodes

Western Electric patents the indirectly heated cathode

1915

Valves

October 1915 Cunningham develops the tubular Audion

1915

Wireless World

Review of 1915 - from Wireless World Golden Jubilee edition April 1961

1915

Valves

1915: valves introduced and adverts published.

1916

Valves

Lee de Forest builds tubular Audions. See DV5

1916

Valves

The White soft valve produced. This has been developed by a British team working at the Cavendish Laboratory under the direction of J J Thomson

1916

Valves

Siemens and Halske in Germany develop the Type 'A' vacuum tube. About 50,000 are subsequently made

1916

Valves

A British version of the French valve was introduced. This was the R Type

1916

Valves

The British Thomson Huston Co. commence making R Type valves for military use

1916

Valves

GEC (Osram) commence making R Type valves for military use

1916

Vacuum Pumps

Irving Langmuir develops a high-speed diffusion pump and all-metal condensation pump

1916

Lamps

The Edison and Swan United Electric Light Co. Ltd. changes name to Edison Swan Electric Co. Ltd.

1916

Valves

1916: valves introduced and adverts published.

1917

Valves

The Metropolitan-Vickers Co commences production of the R Type

1917

Valves

July 3rd 1917, F Lowenstein's patent for negative bias

1917

Valves

1917: valves introduced and adverts published.

1918

Valves

1918: valves introduced and adverts published.

1919

Valves

October 1919. Marconi and GEC set up a joint company to manufacture valves. This was the Marconi-Osram Valve Co. Ltd. Later known as M-OV

1919

Wireless World

Review of 1919 - from Wireless World Golden Jubilee edition April 1961

1919

Valves

1919: valves introduced and adverts published.

1919

Computing

The Eccles-Jordan Flip-Flop circuit was first described.

1920

Valves

In September Capt. S R Mullard forms the Mullard Radio Valve Co. Ltd.

1920

Radio

Edwin Howard Armstrong invents the superhet receiver in the USA and M Lucien Levy does the same in France.

1920

Radio

The Daily Mail is the first London newspaper to receive a message by wireless.

1920

Radio

The Submarine's Wireless.

1920

Cathodes

Irving Langmuir develops the thoriated tungsten filament

1920

Vacuum Pumps

Wolfgang Gaede develops the box pump

1920

Wireless World

Review of 1920 - from Wireless World Golden Jubilee edition April 1961

1920

Valves

1920: valves introduced and adverts published.

1921

Physics

Albert Einstein is awarded the physics Nobel prize for the photoelectric effect

1921

Wireless World

Review of 1921 - from Wireless World Golden Jubilee edition April 1961

1921

Valves

1921: valves introduced and adverts published.

1922

Valves

Mullard introduce the ORA general purpose valve

1922

Valves

Cossor introduce the P1 its first valve design post WW1. The electrode shapes avoided patents held by others

1922

Physics

For and Against the Ether - Sir Oliver Lodge.

1922

Radio

Popular Wireless has Sir Arthur Conan Doyle on front cover

1922

Radio

The Marconi experimental station 2MT Writtle. This station was known affectionately as Two Emma Toc after the phonetics of the day.

1922

Radio

Broadcasting - Its inception and management - Sir William Noble's view.

1922

Radio

18th October the British Broadcasting Company was formed.

1922

Radio

On the 14th Novenber 1922 the BBC went on the air from 2LO in London.

1922

Radio

15th November the 5IT and 2ZY BBC transmitters commenced broadcasting from Birmingham and Manchester respectively.

1922

Wireless World

Review of 1922 - from Wireless World Golden Jubilee edition April 1961

1922

Valves

1922: valves introduced and adverts published.

1923

Physics

Robert A Milikan is awarded the physics Nobel prize for measuring the charge on the electron

1923

Valves

Cossor valve patent 197853 to W R Bullimore. Arched filament, arched grid with flattened sides, anode also with flattened sides. All electrodes held from stem.

1923

Valves

Marconi v Mullard patent dispute at the Court of Appeal.

1923

Valves

Demonstration of cathode-ray oscillograph.

1923

Valves

Lee de Forest introduces DV/DL tubular Audions. See DV5

1923

Valves

M-OV introduce Captain Round's DEQ high impedance detector

1923

Wireless World

Review of 1923 - from Wireless World Golden Jubilee edition April 1961

1923

Wireless Weekly

Sterling Wireless advert with typical domestic scene?

1923

Valves

1923: valves introduced and adverts published.

1924

Loudspeakers

In America researchers Chester Rice and Edward Kellogg, working for General Electric, patented the moving coil loudspeaker

1924

Cathode Rays

L T Jones and H G Tasker demonstrate electrostatic focusing of a CRT with magnetic deflection

1924

Physics

Lisa Meitner of Germany discovers the radiationless electron transition known as the Auger effect. Named after Pierre Auger of France who discovered the effect in 1926. See Augetron

1924

Valve Repair

Revalco advert from April 9.

1924

Radio

Time signals first broadcast: Greenwich from 5th Februry and Big Ben from 17th February.

1924

Radio

Music and the 'Middlebrow'. A commentary on the music on the BBC.

1924

Wireless Weekly

C valves available as Government Surplus

1924

Wireless World

Review of 1924 - from Wireless World Golden Jubilee edition April 1961

1924

Valves

BTH Granted an Injunction

1924

Valves

House of Lords judgement in Mullard v Marconi's Wireless Telegraph Co.

1924

Valves

Early Triode Valves

1924

Valves

1924: valves introduced and adverts published.

1925

Valves

Bakelite based valves with the evacuation 'pip' concealed within were introduced

1925

Television

First public demonstrations of television by John Logie Baird from the first floor of Selfridges Store on Wednesday 1st April.

1925

Stereophony

Capt. H J Round comments in 1958 on 1920's stereophony experiments.

1925

Wireless World

Review of 1925 - from Wireless World Golden Jubilee edition April 1961

1925

Valves

1925: valves introduced and adverts published.

1926

Loudspeakers

Radiola moving coil loudspeakers, designed by Rice and Kellogg were first sold to consumers

1926

Valves

Mullard introduce the first series of their PM valves. See The Azide Process

1926

Valves

Loewe vacuum 'integrated circuit' multi valves introduced

1926

Television

Farnsworth image dissector produced

1926

Vacuum Pumps

M Siegbahn introduces the disk type of molecular drag pump

1926

Wireless World

Review of 1926 - from Wireless World Golden Jubilee edition April 1961

1926

Valves

1926: valves introduced and adverts published.

1927

Television

Philo T Farnsworth demonstrates an all-electronic television system in San Francisco

1927

Television

Kenjiro Takayanagi demonstrates a gas focused oscillograph CRT to display television images

1927

Valves

In the UK the S625 the world's first screened grid valve is produced

1927

Valves

In the UK M-OV introduced the KL1. This was the first indirectly heated production valve and paved the way for all mains sets.

1927

Valves

May 1927, the landmark UX280 rectifier was introduced. This was subsequently manufactured for over 50 years

1927

Amplifiers

Harold S Black discovers the benefits of negative feedback

1927

Valves

Albert W Hull builds the first Thyratron

1927

Lamps

Friedrich Meyer, Hans J Spanner and Edmund Germer, in Germany, patent the high-pressure metal vapour UV and fluorescent lamp

1927

Wireless World

Review of 1927 - from Wireless World Golden Jubilee edition April 1961

1927

Valves

1927: valves introduced and adverts published.

1928

Television

Television the world's first television journal.

1928

Wireless Components

Mullard introduce a new Audio Transformer.

1928

Social Comment

A cartoon of the time illustrates those 'enjoying' the wireless hobby, as does this one.

1928

Home Entertainment

Lissen introduce a Pick-up adaptor to allow a wind-up gramophone to feed a valve amplifier. Plus components advert.

1928

Home Entertainment

S G Brown also introduce a Pick-up adaptor as do Amplion - two well respected manufacturers.

1928

Home Entertainment

The introduction of the electric gramophone - but with a conventional acoustic sound box as well.

1928

Home Entertainment

Advert for Magnavox Loud Speakers - the moving coil speaker. Also BTH Rice-Kellog Speakers advert.

1928

Home Entertainment

Amplion Reed Loud Speaker - At this time the moving coil speaker was expensive in price and power.

1928

Music

Professor Theremin in London.

1928

Valves

The B5 base was introduced

1928

Valves

The Mullard company introduce the first Pentode to the UK market

1928

Transmitter

Marconi 3 kW aerodrome ground transmitter at Croydon.

1928

Wireless World

Review of 1928 - from Wireless World Golden Jubilee edition April 1961

1928

Valves

1928: valves introduced and adverts published.

1929

Vacuum Pumps

Kenneth C D Hickman develops low vapour pressure synthetic oils

1929

Vacuum Pumps

Cecil R Burch produces a gas diffusion pump employing low vapour pressure oils

1929

Litigation

Loudspeakers in the Law Courts. Patent infringement?

1929

Radio

Complete amateur radio station with one valve transmitter and one valve receiver

1929

Radio

Pioneers of Wireless. A lecture by Dr W H Eccles FRS

1929

Television

On 20th August the first experimental 30 line television pictures from Baird's studio were broadcast.

1929

Television

Manfred von Ardenne demonstrates an all-electronic television in Berlin.

1929

Valves

Farnsworth electron multiplier developed

1929

Television

Vladimir K Zworykin files a patent on the kinescope. Zworykin later developed the Iconoscope camera tube

1929

Wireless World

Review of 1929 - from Wireless World Golden Jubilee edition April 1961

1929

Wireless World

Valves at Olympia - from Wireless World September 18th 1929.

1929

Valves

1929: valves introduced and adverts published.

1930

Valves

The Mazda AC/Pen, introduced in 1930, was the first technically successful indirectly-heated power pentode capable of enough output to drive a moving-coil loudspeaker at good volume

1930

Wireless World

Review of 1930 - from Wireless World Golden Jubilee edition April 1961

1930

Broadcasting

Centralisation, Alternative Programmes and Something Personal. Reith on BBC policy in 1930.

1930

Broadcasting

The wireless set of the future.

1930

Valves

Changing burnt-out filaments.

1930

Valves

Valves for Your Set, types available and suitable use.

1930

Television

Television in America

1930

Valves

1930: valves introduced and adverts published.

1931

Valves

The external metalising of valves was introduced. Generally the metal-loaded paint was coloured Red, Gold or Grey.

1931

Valves

New American Screen-Grid Valves. The variable mu tetrode.

1931

Valves

National Union in the USA produce the first valves for car radios

1931

Radio

The July, 1931 issue of Radio News in America has the De Forest 451 advert and compares the 'old' Type 24 with the Vari-mu 51

1931

Valves

World's biggest valve

1931

Valves

Raycraft photocell and Experiments with Light Control article.

1931

Test Gear

Pifco Radiometer advert and a surviving meter.

1931

Wireless World

Review of 1931 - from Wireless World Golden Jubilee edition April 1961

1931

Valves

1931: valves introduced and adverts published.

1932

Radio

On 12th March, Broadcasting House in London made its first transmission.

1932

Radio

Exide HT accumulators advert.

1932

Audio

The 'Primustatic' Loud Speaker - an electrostatic speaker.

1932

Television

Alan B Du Mont starts to apply CRT's to television.

1932

Television

New television System - variable speed scanning.

1932

Film

The 'Talkatome' sound for home movies.

1932

Radio

Short Wave broadcasts to the British Empire started from the Daventry transmitter on 19th December.

1932

Radio

Testing Superhets with Cathode Ray The operator adjusts the IF transformers with a viaual display.

1932

Valves

Valves at Radiolympia and This Seasons Valves

1932

Valves

New ETA SG Valve

1932

Valves

A Selection of Valve Boxes

1932

Test Equipment

Meter Sensitivity - The Avo meter.

1932

Wireless World

21 Years Since The Wireless World Began - from Wireless World April27, 1932.

1932

Quiescent Push-Pull

Quiescent Push-Pull started to appear in designs from the end of 1932.

1932

Wireless World

Review of 1932 - from Wireless World Golden Jubilee edition April 1961.

1932

Valves

1932: valves introduced and adverts published.

1933

Electric Piano

Keyboard and Loudspeaker - the Neo-Bechstein.

1933

Valves

The B7 base was introduced.

1933

Valves

Westinghouse introduce a mercury-arc rectifier, the Ignitron.

1933

Valves

High Vacuum Valves a report on Hivac valves.

1933

Valves

Recent Valve Developments

1933

Valves

The Latest Valves

1933

Valves

Ferranti D4 and LP4

1933

Audio

Parmeko 25-Watt Amplifier Kit.

1933

Radio

Pye portable receiver.

1933

Radio

The Death Ray what Marconi says.

1933

Radio

E H Armstrong announces frequency modulation

1933

Radio

Behind the Scenes of the Radio Industry some factory images.

1933

Radio

The Pifco Radiometer advert

1933

Radio

Ultra Short-Wave Record, Snowdon on 5 Metres.

1933

Radio

Fog Landing by Wireless.

1933

Radio

Celestion Speaker and Class B amplifier.

1933

Microwaves

Beamcasting

1933

Valves

Short Wave Valves. The acorn valve.

1933

Wireless World

Review of 1933 - from Wireless World Golden Jubilee edition April 1961

1933

Television

Television Explained

1933

Radio

The RGD Radio-gram advert

1933

Radio

Budapest Tomorrow A new transmitter and interesting mast.

1933

Radio

Thermo Superjet Three A gas powered radio!.

1933

Valves

New Hivac Valves

1933

Valves

Valves at Olympia. Review of the show and The New Valves - multi-electrode valves

1933

Valves

1933: valves introduced and adverts published.

1934

Audio Recording

Abbey Road Studios. Behind the scenes at the HMV recording studios.

1934

Valves

Multiple Valves. Are they worthwhile asks this editorial.

1934

Valves

The B9 base was introduced

1934

Valves

In the USA the 6.3 Volt filament is adopted as standard for both AC and DC filaments and heaters

1934

Valves

The GE 6E5 'Magic Eye' tuning indicator is introduced. RCA produce 6E5 in 1935

1934

Valves

The introduction of miniature Acorn valves for VHF. See 955

1934

Valves

In the UK M-OV introduced the Catkin range of valves with external anodes

1934

Valves

Valves at Olympia. A report on the show.

1934

Radio

E H Armstrong announces frequency modulation

1934

Radio

Radio Assembly 1930s Style.

1934

Radio

Centi-metre-wave Transmitter.

1934

Radio

Ferranti Arcadia Advert. Advertising with gender stereotypes.

1934

Radio

New Droitwich Transmitter.

1934

Radio

Straight HF v The Superheterodyne.

1934

Radio

Philco Shadow Tuning Meter.

1934

Wireless World

Review of 1934 - from Wireless World Golden Jubilee edition April 1961

1934

Wireless World

The Quality Loud Speaker High flux density in a gap of generous diameter.

1934

Wireless World

Valve Design Trends Introduction to the 1934 Valve Supplement

1934

Wireless World

Editorial. Television: the BBC's responsibility.

1934

Wireless World

HMV Recording Studios. Behind the scenes at Abbey Road.

1934

Wireless World

Time by Telephone. The speaking clock in Paris.

1934

Valves

1934: valves introduced and adverts published.

1935

Vacuum Pumps

Wolfgang Gaede produces the gas ballast pump

1935

Vacuum Pumps

Kenneth C D Hickman produces a fractionating oil diffusion pump and associated oils

1935

Valves

RCA introduce the IO base with the launch of the metal tube valve 6L7

1935

Valves

J H Owen Harries establishes Harries Thermoinics Ltd to licence his output valve design to valve makers.

1935

Valves

326 Valves introduce the PX50 triode.

1935

Valves

RCA nine original valves appear in the RCA metal valve family

1935

Radar

Watson Watt demonstrates that aircraft reflect radio waves

1935

Radar

Radar Pre-History details published in 1945 of the 1935 French 'Obsticle Detector'.

1935

Television

John Logie Baird demonstrates a 700 line high resolution television system

1935

Television

German Telefunken - Karolus television with 10,000 pixels.

1935

Television

Magnifying the television image - with X-Rays.

1935

Industrial Electronics

The CRT in the motor industry.

1935

Transistor

Oskar Heil patents the field effect transistor. The device, however, did not work

1935

Wireless World

Review of 1935 - from Wireless World Golden Jubilee edition April 1961

1935

Valves

1935: valves introduced and adverts published.

1936

Television

Monday November 2nd. The BBC begins broadcasting from Alexandra Palace transmitter to the London area (Baird system and Marconi-EMI system on alternate weeks).

1936

Valves

Taking the control grid to a top cap was becoming popular. Triodes as well as other types.

1936

Valves

Mahn and Mecalf present a paper on velocity modulated valves. The key principle within the klystron

1936

Audio Amplifier

Hartley Turner Amplifier - An inexpensive 12 Watt push-pull PX25 amplifier reviewed by Wireless World.

1936

Amateur Radio

G5VS - An ambitious amateur radio station.

1936

Wireless World

Review of 1936 - from Wireless World Golden Jubilee edition April 1961

1936

Valves

BVA Notice Manufacturers valves are not to be sold as Retail Valves

1936

Valves

Adverts show screw top caps as old and metal 'top hat' caps as new.

1936

Valves

1936: valves introduced and adverts published.

1937

Computer

Publication of Alan Turing's 1936 paper 'On computable numbers, with an application to the Entscheidungsproblem' that introduced the concept of a universal computing machine. This work presented the theoretical basis for the stored-programme computer.

1937

Valves

At Stanford University the Varian brothers produce the first working Klystron

1937

Valves

New Valves? When replacement is due

1937

Television

The BBC stop using the Baird system on 4th February in favour of the EMI all electronic 405 line system.

1937

Television

A television outside broadcast van was used for the first time on 12th May. The event was the coronation of King George VI and Queen Elizabeth.

1937

Vacuum Pumps

C M Van Alta produces a diffusion pump with a pumping rate in excess of 100 litres per second

1937

Vacuum Pumps

L Malter demonstrates a multi-stage, self fractionating diffusion pump

1937

Wireless World

Review of 1937 - from Wireless World Golden Jubilee edition April 1961

1937

Valves

1937: valves introduced and adverts published.

1938

Broadcasting

Can Broadcasting Prevent War?.

1938

Broadcasting

American Facsimile. Newspapers printed in the home.

1938

Valves

Mazda introduce the MO in the UK as an alternative to the International Octal

1938

Valves

New AVO Valve Tester

1938

Wireless World

Review of 1938 - from Wireless World Golden Jubilee edition April 1961

1938

Valves

HMV Table Television Model 904

1938

Valves

Two reports about the valves at Radiolympia. August 25th and September 1st. Some overlap naturally exists.

1938

Valves

1938: valves introduced and adverts published.

1939

National Service

The Wireless Register The UK Government looking at the human resources available in case of war

1939

Television

RCA and Du Mont demonstrate Television at the NY World's Fair

1939

Valves

The Loctal or B8B was introduced in America

1939

Valves

The Philips introduce the all glass valve and with it the B9G base

1939

Valves

The first all-glass valve for use above 30 MHz was produced. The EF50 played a major part in early Radar

1939

Valves

High-power Air-cooled Valves. Accelerating heat dissipation with forced air.

1939

Valves

Demountable triodes. High power valves.

1939

Valves

New CRTs. First appearance of post deflection acceleration.

1939

Valves

Light Amplifier.

1939

War Profit

Blackout. Breaking HT batteries for torch cells.

1939

Television

New TV sets at Radiolympia. On 1st September the Government closed down UK Television broadcasting.

1939

Radio

On 1st September the Home Service was formed as the national network and incorporated all regional services.

1939

Wireless World

Review of 1939 - from Wireless World Golden Jubilee edition April 1961

1939

Valves

1939: valves introduced and adverts published.

1940-

 

Second World War

1940

Valves

February 21st 1940 John Randall and Harry Boot make operational the cavity magnetron at Birmingham University

1940

Radar

On September 6th 1940 Sir Henry Tizard takes the cavity magnetron to the USA. This is one of the most secret inventions of the war

1940

Radar

In September 1940 the first RDF system using a cavity magnetron is made in the UK

1940

Valves

Generating Centimetre Waves. A design by STC in 1937 published in June 1940.

1940

Valves

Valve Construction. A pressed glass base announced by Sylvania in 1937 published in June 1940.

1940

Valves

In the USA the first all glass B7G 1.4 Volt miniature valves are introduced. These were the 1R5, 1T4, 1S5 and 1S4

1940

Obituary

Sir Oliver Lodge.

1940

Wireless World

Review of 1940 - from Wireless World Golden Jubilee edition April 1961

1940

Valves

1940: valves introduced and adverts published.

1941

Television

In America the 525 line system is approved by the FCC for commercial black and white broadcasting

1941

Radio

A UHF oscillator is made using Acorn valves. See 955

1941

Culture?

An extract from the 'Free Grid' column of Wireless World that we would find appalling in the 21st century.

1941

Valves

The UK government introduce the common valve (CV) lists to streamline procurement and increase flexibility in sourcing the valves required by all branches of government especially the military

1941

Valves

The B7G all-glass valve base was introduced in America. Its commercial introduction to the UK was in 1947 but was used for military valves during WWII

1941

Valves

The CV35 Reflex Klystron Oscillator was developed at Cambridge by a team under Sir Mark Oliphant.

1941

Appeal

Lord Hankey's Appeal to the UK radio trades.

1941

Valves

1941: valves introduced and adverts published.

1942

Valves

Marconi Microwave Oscillator from 1939 published in August 1942.

1942

Valves

Rudi Kompfner at Oxford University produces the first travelling wave tube

1942

Television

Intensifying Television Pictures. The iconoscope as a basis for a DLP projector?

1942

Training

Wren Radio Mechanics. Three year course in 16 weeks. See update in 1943.

1942

Space Communication

Views on Interplanetary Communication.

1942

Valves

1942: valves introduced and adverts published.

1943

Computer

Dr Tommy Flowers builds the first electronic computer for code breaking at Bletchley Park

1943

Television

A colour television development by John Logie Baird.

1943

Television

Television Receivers A novel projection method.

1943

Television

Philips describe television projection principles. Later to be used with the MW6-2 CRT.

1943

Broadcasting

High Fidelity. HI-fi audio with TV transmitters?

1943

Valves

Percy Spencer of the Raytheon Co designs the laminated anode cavity magnetron which increased production rates

1943

Valves

Resonator Valves. Increasing the output of velocity modulated oscillators.

1943

Valves

Electron-Beam Modulators. Another use of velocity modulation.

1943

Valves

Television Projection. Philips approach to projection TV.

1943

Valve History

Early complex valves and why they developed

1943

Valve Bases

Belling & Lee advert for valve bases

1943

Recorded Music

The Wireless World Brains Trust debate the future of disc recording.

1943

Valves

1943: valves introduced and adverts published.

1944

Television

The Baird 'Telechrome'. The world's first Colour TV and Stereo TV CRT.

1942

Training

Wren Radio Mechanics. Maintaining Naval Air Arm equipment. See original 1942 article.

1944

Valves

Improved Pentagrid.

1944

Valves

1944: valves introduced and adverts published.

1945-

 

Post War developments

1945

Valves

Double triodes 6SN7 and 7F8 are introduced

1945

Obituary

Sir John Ambrose Fleming.

1945

Radio

29th July saw the reintroduction of regional broadcasting and the formation of the Light Programme.

1945

Television

Mid year the future of television in the UK was subject of a government report, plus Wireless World editorial, Television Standards, Definition in the Cinema and Colour TV?

1945

Wireless World

Review of 1945 - from Wireless World Golden Jubilee edition April 1961

1945

Valves

Valves in the Services CV valves and nearest commercial equivalents.

1945

Microwave Link

Army No. 10 Set Centremetre waves, pulse modulation and multi channel.

1945

Valves

1945: valves introduced and adverts published.

1946

Wireless World

Signals From the Sun The 'hiss' phenomenon on Short Waves

1946

Wireless World

Valve Standardisation BVA moves towards standard bases and open design specifications

1946

Wireless World

American VT equivalents American Service Valve Equivalents

1946

Wireless World

Review of 1946 - from Wireless World Golden Jubilee edition April 1961

1946

Valves

1946: valves introduced and adverts published.

1947

Transistor

Bardeen, Brattain and Shockley demonstrate the first semiconductor amplifier

1947

Valves

The B8A 'Rimlock' valve base is introduced

1947

Valves

B8B 'Loctal' used on UK made valves for the first time

1947

Valves

B7G used on UK valves for the first time

1947

Valves

Velocity-modulated electron multiplier an STC development

1947

Valves

Valves at the Physical Society's Exhibition

1947

Valves

40 Years After the application by De Forest for a patent for a third electrode

1947

Valves

New Receiving Valves Mazda and Mullard ranges

1947

Valves

SW Oscillator. Space charge correction in velocity modulated oscillator

1947

Wireless World

DC defence League - an insight to the pre-universal AC mains era in Great Britain

1947

Wireless World

Review of 1947 - from Wireless World Golden Jubilee edition April 1961

1947

Wireless World

Hopes for the National Radio Exhibition at Olympia in 1947

1947

Radar

Radial Time Bases How they were developed for Radar.

1947

Wireless World

Review of valves shown at the National Radio Exhibition at Olympia October 1947

1947

Valves

1947: valves introduced and adverts published.

1948

Computer

F C Williams describes the use of a CRT as a digital memory.

1948

Computer

21 June. The Manchester Small-Scale Experimental Machine (SSEM, nicknamed Baby), the first stored-programme computer, runs its first programme.

1948

Valves

B9A based all glass double triodes 12AU7, 12AX7 and 12AT7 are introduced

1948

Valves

Mullard announce five new AC/DC valves

1948

Printed Circuits

Printed Circuits printed wiring using silver loaded colloids

1948

Wireless World

Ex-service CRTs more information on these tubes, uses and connections

1948

Wireless World

Review of 1948 - from Wireless World Golden Jubilee edition April 1961

1948

Television

The Pye B18T chassis uses lots of EF50's and is the UKs first transformerless set

1948

Valves

1948: valves introduced and adverts published.

1949

Computer

Valve memory is introduced

1949

Wireless World

Review of 1949 - from Wireless World Golden Jubilee edition April 1961

1949

Radio

Possibly the world's first radio microphone

1949

Valves

In 1949 the British Valve industry produced 19 million valves and 310,000 CRTs.

1949

Valves

Philips published details of valve developments made in 1940-19424111. D series, E series and U series. Plus the all-glass valves.

1949

Valves

1949: valves introduced and adverts published.

1950

Transistor

October 3rd 1950 the transistor is patented

1950

Television

Premier Radio VCR97 based UK Television Receiver

1950

Television

RCA demonstrate the shadow mask colour TV tube

1950

Television

Review of Philips Projection Television

1950

Sound Reproduction

The LP is introduced

1950

Wireless World

Review of 1950 - from Wireless World Golden Jubilee edition April 1961

1950

Valves

Valves at the 1950 Radio Exhibition

1950

Computing

Pilot ACE the NPL computer

1950

Valves

1950: valves introduced and adverts published.

1951

Wireless World

Review of 1951 - from Wireless World Golden Jubilee edition April 1961

1951

Television

Barrel Vision Unusual homemade UK Television Receiver

1951

Valves

1951: valves introduced and adverts published.

1952

Gettering

Ring getter with U-shaped cross section for valve manufacture is introduced

1952

Wireless World

Review of 1952 - from Wireless World Golden Jubilee edition April 1961

1952

Audio

Advert by the Acoustical Manufacturing Co Ltd for the Q.U.A.D amplifier.

1952

Valves

Valves at the Radio Exhibition.

1952

Valves

November - New Videcon Camera Tube

1952

Valves

December - New valves from Mullard

1952

Valves

1952: valves introduced and adverts published.

1953

People

Armstrong Award for Capt. Round

1953

People

Victorian Wireless Engineer Andrew Gray

1953

Television

The Television Society Starts Experimental 625-Line Transmissions.

1953

Television

Television chassis advert - with six inch VCR97 green tube.

1953

Television

Television chassis advert - with 15 inch tube!

1953

Valves

B8A 'Rimlock' valves of all glass construction are introduced in the UK

1953

Valves

Valves at the 1953 Radio Exhibition

1953

Printed Circuits

Cellular Circuits a form of modular construction.

1953

Wireless World

Review of 1953 - from Wireless World Golden Jubilee edition April 1961

1953

Valves

The new Mullard EF86

1953

Valves

1953: valves introduced and adverts published.

1954

Valves

Mullard introduce the EL34 25 Watt dissipation audio output pentode

1954

Television

Mullard offer Factory servicing of projection TV optics

1954

Transistor

Texas Instruments produces the first silicon transistor

1954

Wireless World

Review of 1954 - from Wireless World Golden Jubilee edition April 1961

1954

Valves

The new Mullard QV06-20 a direct equivalent of the American 6146

1954

21st National Radio Show

21st National Radio Show Report - from The Radio Constructor October, 1954.

1954

Valves

Mullard announce Special Quality voltage stabilisers and reference tubes

1954

Audio

Mullard 5-10 Amplifier. Full construction article here.

1954

Valves

1954: valves introduced and adverts published.

1955

Television

On September 22nd the first commercial television program was transmitted in the UK

1955

Radio

STC Tymatic clock radio.

1955

Radio

Frequency Modulation Demonstration at the Science Museum

1955

Wireless World

Review of 1955 - from Wireless World Golden Jubilee edition April 1961

1955

Valves

Testing Television Valves: M-OV table

1955

Valves

Trade news: Mullard EL34 audio output pentode

1955

Valves

Valves at the June Exhibition.

1955

Audio

An advert for the Mullard 5-10 Amplifier.

1955

Valves

Glassware for TV CRTs.

1955

Valves

1955: valves introduced and adverts published.

1956

Wireless World

Review of 1956 - from Wireless World Golden Jubilee edition April 1961

1956

Stereophony

Stereophony in the Home

1956

Circuit Assembly

Automatic Wiring A machine for wire-wrapping.

1956

Radio

Phoenetic Alphabet The standard phoenitic alphabet still used in the 21st century.

1956

Valves

GEC introduce valve type W729 for multi channel VHF television receivers. The valve is designed for minimum cross modulation distortion.

1956

Radio

New Life for the personal portable?

1956

Valves

In 1956 the British Valve industry produced 64 million valves and 2 million CRTs. 9% of world receiving valve production. World production was 743 million with the USA making 67% of them.

1956

Valves

Hivac open a pressurised valve factory

1956

Valves

Mullard High Power Triode for Industrial RF Generators

1956

Valves

GEC KT88 introduced

1956

Valves

BVA Statement Collective price fixing abandoned

1956

Television

STC Video Cables Advert.

1956

Television

More Lines or Colour a discussion paper.

1956

Mumetal Shields

Telcon Mumetal screens Advert.

1956

Transatlatic Cable

Completion of TAT-1 transatlantic telephone cable.

1956

Valves

1956: valves introduced and adverts published.

1957

Valves

UHF receiving valves come to market

1957

Valves

The 110 degree TV tube is announced in America

1957

Valves

The Nixie display tubes are introduced

1957

Sputnik 1

Artificial Satellites of the Earth - from Wireless World December 1957.

1957

Change

Crossroads of technology

1957

Wireless World

Review of 1957 - from Wireless World Golden Jubilee edition April 1961

1957

Audio

The QUAD electrostatic loudspeaker is announced and goes into production

1957

Valves

1957: valves introduced and adverts published.

1958

Loudspeakers

In France the Cabesse company invented the box-enclosed loudspeaker

1958

Lamps

Elmer Fridrich and Emmett Wily file a patent application on the tungsten halogen lamp

1958

Vacuum Pumps

Varian Associates introduce the 'modern' Vacsorb cryosorption pump

1958

Audio

Stereophony from discs. The specification for stereo records.

1958

Audio

Standards for Stereo Disc Records.

1958

Computer

The IMB 709 was introduced. This was the last major valve computer and featured magnetic core memory.

1958

Wireless World

Review of 1958 - from Wireless World Golden Jubilee edition April 1961.

1958

Wireless World

Stereo Radiograms A pedantic look at changing language.

1958

Computer

Computer Exhibition report - from Wireless World January 1959. This is fascinating!

1958

Valves

Wireless World review of the Physical Society's exhibition. Valves and CRT's.

1958

Television

The new BBC Television Centre development, further details, and VERA the video recorder.

1958

Metals

Telcon Mumetal shields advert.

1958

Metals

Corona Stabiliser Range advert.

1958

Valves

Radio Valve Data 6th edition published.

1958

Valves

1958: valves introduced and adverts published.

1959

History

Anecdotage - Spark and Arc plus Anecdotage - Beam and Broadcast and Anecdotage - Television and Transistor recollections of the early years of Wireless and Television by P P Eckersley - the first BBC chief engineer.

1959

Computer

IBM 7090 introduced, this is the world's first all transistor computer

1959

Valves

The Varian Klystron VA842 introduced. This multi-cavity liquid-cooled Radar klystron is the largest documented production klystron

1959

Valves

Making and Selling Valves - a Wireless World editorial.

1959

Audio

IEE Convention on Stereophony, a Wireless World report.

1959

Audio

Stereophony on Trial, a Wireless World editorial from February.

1959

Audio

Single Amplifier Stereo, simplex stereo described.

1959

Audio

Quad electrostatic speaker advert and description.

1959

Ultrasonics

Ultrasonic Devices. An iconoscope with quartz faceplate.

1959

Wireless World

Review of 1959 - from Wireless World Golden Jubilee edition April 1961

1959

Television

Annular electron Gun a development by RCA Laboratories in the USA.

1959

Television

Lead for Safety shielding against X-rays.

1959

Television

The 110° tubes were starting to appear and displace the older 70° and 90° types

1959

Television

First TV with 110° scanning angle.

1959

Television

Vacwell Engineering advert for TV CRT pumping machinery.

1959

Valves

Making of Klystron Grids

1959

CRT's

Ferranti CRT with Magnetic and electrostatic deflection

1959

Valves

1959: valves introduced and adverts published.

1960

Vacuum Pumps

Varian Associates Inc. produce the 1000 Litre per second Valcon pump

1960

Legal

Mullard granted injuction.

1960

Television

Large Screen Colour TV the Eidophor system

1960

Television

Studio 5 A vast area for large productions

1960

Valves

Microwave Valves International Congress at Munich

1960

Valves

Ross Aiken develops CRT for aircraft and 14 inch thin CRT

1960

Valves

The Nuvistor is developed. See 6CW4

1960

Radar

New Valves for High Quality Radar Systems and New Valves for Small-Boat Radar

1960

Audio

P P Eckersley's take on Hi-Fi in Wireless World.

1960

Space

Electronic Rocket Motors?

1960

Laser

Ali Javan invents the Helium-Neon gas discharge laser

1960

Wireless World

Review of 1960 - from Wireless World Golden Jubilee edition April 1961

1960

Valves

1960: valves introduced and adverts published.

1961

Vacuum Pumps

C H Kruger and A H Shapiro unveil statistical theory of turbo-molecular pumping

1961

Vacuum Pumps

Varian Associates Inc produce very large sorption pumps for roughing large chambers

1961

Television

The problems of modernising the UK television service

1961

Lamps

Gilbert Reiling files a US patent for 'modern' metal-halogen incandescent lamp

1961

Valves

William R Wheeler introduces the UHF metal-gasket captured step-seal

1961

Wireless World

Review of 1961 - from Wireless World Golden Jubilee edition April 1961

1961

Valves

National Radio Show report from Wireless World

1961

Tape Recorder

New tape recorder, Grundig TK14.

1961

Valves

1961: valves introduced and adverts published.

1962

Transistor

Fairchild Semiconductors produce the first integrated circuit

1962

Valves

Varian VA126 high power travelling wave tube introduced

1962

Valves

1962: valves introduced and adverts published.

1963

Valves

In Mullard announced the PC86, PC88 and the DY86.

1963

Valves

Cathodeon introduce three storage tubes, Types C990, C991 & C992.

1963

Valves

AVO Valve Tester Mk4 adverts.

1963

Valves

Mullard ECH84.

1963

Valves

New English Electric Pulse Tetrode Type C1149/1.

1963

Valves

A rare BVA advert in a trade joiurnal.

1963

Valves

New M-OV Modulator Thyratron Type E2986.

1963

Valves

1963: valves introduced and adverts published.

1964

Retail

Storm over proposed ending of Retail Price Maintenance.

1964

Valves

High Resolution CRT's from Ferranti.

1964

Valves

Gigantic new valve.

1964

Valves

Advert for electron guns.

1964

Valves

Mullard automatic envelope making machines.

1964

Valves

1964: valves introduced and adverts published.

1965

Valves

1965: valves introduced and adverts published.

1966

People

Vidor Batteries. With small transistor radios the teenager bacame the advertisers target audience.

1966

Television

Shadow-mask Tubes. Mullard at The Television & Radio Show 1966.

1966

People

Obituary - Captain H J Round.

1966

Valves

1966: valves introduced and adverts published.

1967

Valves

Mullard Kradlepak - Easier opening.

1967

Valves

1967: valves introduced and adverts published.

1968

Transistor

July 1968, Robert Noyce and Gordon Moore founded Intel

1968

Transistor

A Y Cho et al develop molecular-beam epitaxy

1968

Valves

1968: valves introduced and adverts published.

1969

Vacuum Pumps

K H Mirgel produces the vertical uni-directional turbomolecular pump

1969

Valves

M-OV Golden Jubilee.

1969

Valves

English Electric Low Light Level TV Camera Tube.

1969

Valves

1969: valves introduced and adverts published.

1970

Valves

New English Electric K3071 Oscillator Klystron.

1970

Valves

1970

Valves

New Mullard Q13-110GU Flying Spot Scanner Tube.

1970

Valves

STC introduce a low-light camera.

1970

Valves

1970: valves introduced and adverts published.

1971

Computer

Intel introduce the 4004, the world's first microprocessor. This was a 4-bit device in a 16 pin DIL package.

1971

Typesetting

Electronic Typesetting.

1971

Valves

1971: valves introduced and adverts published.

1972

Valves

1972: valves introduced and adverts published.

1973

People

Centenary of Lee de Forest's birth.

1974

Vacuum Pumps

First oil-free vacuum pump

1975

Computer

Altair computer with microprocessor introduced for home use

1975

Vacuum Pumps

NASA Cryo-pumps for space simulation and semiconductor manufacture

1975

Valves

1975: valves introduced and adverts published.

1976

Computer

April 1976, Steve Jobs and Steve Wozniak found Apple computer

1977

Valves

Mass production of valves ends in most Western European countries and the USA

1978

Computer

June 1978, the industry standard 8086 16-bit microprocessor is made. It has 29,000 transistors and a clock speed of 4.77 MHz. It was made in quantity on 4-inch silicon wafers

1978

Valves

1978: valves introduced and adverts published.

1979

People

Death of Stanley R Mullard

1980

Valves

Methane Yields Improved Transmitting Valve Grids.

1980

Television

Mullard to 'Axe' TV Tube 900 Jobs

1980

Television

405-Line Television to Close in UK

1980

History

Dame Nellie and Winifred share Broadcasting Anniversary

1981

Television

Flat CRT from Sinclair

1983

Valves

Is this year really the centenary of electronics? find out here

1982

Valves

Tetrode Klystron

1986

Valves

Raytheon close the last major valve production line in the USA

1989

Computer

The 1.2 million transistor Intel 80486 is produced. The initial clock frequency is 25 MHz

1993

Computer

Intel introduce the Pentium processor. This is fabricated on 8-inch wafers. The 8-inch wafer process having been developed in April 1992

2000

Valves

The Valve Museum opens its virtual doors for the first time.

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