The first transistor was a point-contact, germanium crystal doped
with “certain impurities.” Shockley, Brattain, and
Bardeen were not the first to propose a solid-state transistor,
and German physicists independently invented the same thing only
months after. John R. Pierce, who supervised Bardeen, Brattain,
and Shockley at Bell Labs, coined the term transistor in
comparison to a property of the vacuum tube, transconductance.
In analog devices, transistors act as amplifiers. In digital
electronic devices, transistors act as switches. The transistor
can also act as a rectifier with a very low voltage drop.
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