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A transistor is a semiconductor device used to amplify or switch electronic signals and electrical power. It is composed of semiconductor material usually with at least three terminals for connection to an external circuit. A voltage or current applied to one pair of the transistor's terminals controls the current through another pair of terminals. Because the controlled (output) power can be higher than the controlling (input) power, a transistor can amplify a signal. Today, some transistors are packaged individually, but many more are found embedded in integrated circuits.

The transistor is the fundamental building block of modern electronic devices, and is ubiquitous in modern electronic systems. Julius Lilienfeld patented a field-effect transistor in 1926^[1] but it was not possible to actually construct a working device at that time. The first practically implemented device was a point-contact transistor invented in 1947 by American physicists John Bardeen, Walter Brattain, and William Shockley. The transistor revolutionized the field of electronics, and paved the way for smaller and cheaper radios, calculators, and computers, among other things. The transistor is on the list of IEEE milestones in electronics,^[2] and Bardeen, Brattain, and Shockley shared the 1956 Nobel Prize in Physics for their achievement.^[3]

Contents

• 1History
• 2Importance
• 3Simplified operation
  • 3.1Transistor as a switch
  • 3.2Transistor as an amplifier
• 4Comparison with vacuum tubes
  • 4.1Advantages
  • 4.2Limitations
• 5Types
  • 5.1Bipolar junction transistor (BJT)
  • 5.2Field-effect transistor (FET)
  • 5.3Usage of bipolar and field-effect transistors
  • 5.4Other transistor types
• 6Part numbering standards/specifications
  • 6.1Japanese Industrial Standard (JIS)
  • 6.2European Electronic Component Manufacturers Association (EECA)
  • 6.3Joint Electron Devices Engineering Council (JEDEC)
  • 6.4Proprietary
  • 6.5Naming problems
• 7Construction
  • 7.1Semiconductor material
  • 7.2Packaging
    • 7.2.1Flexible transistors
• 8See also
• 9Directory of external websites with datasheets
• 10References
• 11Further reading
• 12External links

History

Main article: History of the transistor

A replica of the first working transistor.

The thermionic triode, a vacuum tube invented in 1907, enabled amplified radio technology and long-distance telephony. The triode, however, was a fragile device that consumed a substantial amount of power. Physicist Julius Edgar Lilienfeld filed a patent for a field-effect transistor (FET) in Canada in 1925, which was intended to be a solid-state replacement for the triode.^[4][5] 

Lilienfeld also filed identical patents in the United States in 1926^[6] and 1928.^[7][8] However, Lilienfeld did not publish any research articles about his devices nor did his patents cite any specific examples of a working prototype. Because the production of high-quality semiconductor materials was still decades away, Lilienfeld's solid-state amplifier ideas would not have found practical use in the 1920s and 1930s, even if such a device had been built.^[9] In 1934, German inventor Oskar Heil patented a similar device in Europe.^[10]

John Bardeen, William Shockley and Walter Brattain at Bell Labs, 1948.

From November 17, 1947 to December 23, 1947, John Bardeen and Walter Brattain at AT&T's Bell Labs in the United States performed experiments and observed that when two gold point contacts were applied to a crystal of germanium, a signal was produced with the output power greater than the input.^[11] Solid State Physics Group leader William Shockley saw the potential in this, and over the next few months worked to greatly expand the knowledge of semiconductors.

The term transistor was coined by John R. Pierce as a contraction of the term transresistance.^[12][13][14] According to Lillian Hoddeson and Vicki Daitch, authors of a biography of John Bardeen, Shockley had proposed that Bell Labs' first patent for a transistor should be based on the field-effect and that he be named as the inventor. Having unearthed Lilienfeld’s patents that went into obscurity years earlier, lawyers at Bell Labs advised against Shockley's proposal because the idea of a field-effect transistor that used an electric field as a "grid" was not new. Instead, what Bardeen, Brattain, and Shockley invented in 1947 was the first point-contact transistor.^[9] In acknowledgement of this accomplishment, Shockley, Bardeen, and Brattain were jointly awarded the 1956 Nobel Prize in Physics "for their researches on semiconductors and their discovery of the transistor effect".^[15]

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https://en.wikipedia.org/wiki/Transistor