integrated circuit (IC)

Miniature (typically 5 millimeter square, 1 millimeter thick) electronic device containing a few to millions of solid-state components etched or printed on a silicon or other semiconductor chip (called silicon chip or microchip). A four megabit memory chip, for example, contains four million two-paired transistors (called 'sandwiches') plus components for control circuitry. Depending on the number of components, ICs are classified (in the ascending order) as 'small scale integration' (SSI), 'medium scale integration' (MSI), 'large scale integration' (LSI), 'very large scale integration' (VLSI), and 'ultra large scale integration' (ULSI). ICs consume very little current, generate comparatively little heat, and are far more shock-proof and reliable than the older discrete-component circuits. They are encased in ceramic or plastic material, and are connected to other ICs via external pins that fit into a socket of a circuit board. Invented in 1958 independently by Jack Kilby (born 1923) and Robert Noyce (1927-1990). Robert Noyce went on to become one of the founders of Intel Corporation (world's largest chipmaker) in 1968, and Jack Kilby won the physics Nobel Prize in 2000.