Moore's law is the observation that the number of transistors in an integrated circuit (IC) doubles about every two years. Moore's law is an observation and projection of a historical trend. Rather than a law of physics, it is an empirical relationship linked to gains from experience in production.
An Osborne Executive portable computer, from 1982, with a Zilog Z80 4 MHz CPU, and a 2007 Apple iPhone with a 412 MHz ARM11 CPU; the Executive has 100 times the weight, almost 500 times the volume, approximately 10 times the inflation adjusted cost, and 1/103rd the clock frequency of the smartphone.
Scanning probe microscopy image of graphene in its hexagonal lattice structure
A transistor is a semiconductor device used to amplify or switch electrical signals and power. It is one of the basic building blocks of modern electronics. It is composed of semiconductor material, usually with at least three terminals for connection to an electronic 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. Some transistors are packaged individually, but many more in miniature form are found embedded in integrated circuits. Because transistors are the key active components in practically all modern electronics, many people consider them one of the 20th century's greatest inventions.
Size comparison of bipolar junction transistor packages, including (from left to right): SOT-23, TO-92, TO-126, and TO-3
Julius Edgar Lilienfeld proposed the concept of a field-effect transistor in 1925.
John Bardeen, William Shockley, and Walter Brattain at Bell Labs in 1948; Bardeen and Brattain invented the point-contact transistor in 1947 and Shockley invented the bipolar junction transistor in 1948.
A replica of the first working transistor, a point-contact transistor invented in 1947
