1947 – transistor

In 1947, John Bardeen, Walter Brattain and William Shockley led a team at Bell Labs that produced a semiconducter amplifier device that is now known as the transistor. While patents were filed in 1925 by Julius Lilienfeld and in 1934 by Oscar Heil for “field effect transistors”, historical credit for the transistor has gone to the Bell Labs team.

The first transistor was a semiconductor based version of a triode, a vacuum tube with three electrodes in it. By using one electrode to supply a modulating current, a stronger current could adopt the modulation pattern, creating a process of amplification. The transistor does the same thing, but the electrodes are inside a material that has variable conductivity (semiconductor).

1815 – Geissler
1855 – vacuum tube
1906 – amplifier tube

1958 – integrated circuit

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