Lecture 7 – The Microchip
- Integrated circuits are small and use little energy; but they can implement
electronic circuits of immense complexities.
- Transistors – tiny electronic switches, that play the same role as vacuum tubes or
electromagnetic switches in early computers. (Three-terminal, solid-state
electronic device used for amplification and switching)
o The main advantages of transistors over other switches are that they can be
made small, very small!
o It allows or disallows the flow of electrical current through it.
o Made at Bell Labs by William Shockley, John Bardeen, and Walter
Brattain at the end of the 1940s that kick-started a transistor revolution.
o Brief Time-line of the Transistor:
1925-28: Physicist Julius Lilienfeld patented his transistor in
Canada and U.S. He did not provide a prototype or working
1947: William Shockley, John Bardeen, and Walter Brattain,
physicists at Bell Laboratories, created the first working transistor
(still large). – MAIN POINT*
1952: The first transistor-based commercial product: hearing aids
from Sonotone, Maico, and Acousticon.
1953: First transistor radios: before laptops and smartphones of
today they were the most popular electronic communication
devices in history.
1953: The University of M