Invention

The Transistor

Electrical Engineering

The transistor is a small solid state device that can amplify or switch an electronic signal, built from a semiconductor material such as germanium or silicon. It was invented at Bell Telephone Laboratories in December 1947 by John Bardeen, Walter Brattain and William Shockley, who shared the 1956 Nobel Prize in Physics for the discovery, and it rapidly replaced the bulky, fragile and power hungry vacuum tube in electronic equipment.

Facts

Patent or First-Use Date

1948-06-26 1

William Shockley's bipolar junction transistor patent application date; Bardeen and Brattain's earlier point-contact transistor was demonstrated in December 1947 but this is the confirmed patent filing date.

Year

1947 2

Significance

The transistor made possible the integrated circuit, the modern computer, and virtually every electronic device that followed, by replacing the vacuum tube with a small, reliable, low power switch and amplifier. 2

FAQs

Why is the transistor dated 1947 when its patent was filed in 1948?

1947 is when the device was first demonstrated; 26 June 1948 is when Shockley applied for the junction transistor patent.

The two dates mark different steps. John Bardeen and Walter Brattain at Bell Labs observed signal amplification in a germanium crystal between 17 November and 23 December 1947, which is the invention date. William Shockley, who led their group, applied for the patent on the first bipolar junction transistors on 26 June 1948, which is the patent date shown on this page.

Connections

Associated With

Electrical Engineering

Gallium Arsenide

Gallium arsenide's higher electron mobility than silicon makes it the preferred semiconductor for high-frequency and high-power transistors used in radio-frequency and satellite electronics, at a higher manufacturing cost than silicon.

Semiconductor Doping

Controlled doping of germanium and later silicon is what makes a transistor junction possible.

Silicon

Source Technology: A World HistoryDaniel R. Headrick