Miniature Electric Circuit containing large numbers of electronic devices-including Transistors, Resistors, Capacitors, and Diodes - and packaged as a single unit with leads extending from it for input,
output, and power-supply connections. All the electronic devices are formed by
selective treatment (doping) of a single chip of Semiconductor material. Integrated circuits are used as computer memory circuits and
microcomputer central processing units (see Personal Computer (PC), Microprocessor). They are categorized according to the number of transistors or other active
circuit devices they contain; an active circuit device is one that receives
power from a source other than its input signal. An ordinary, or small-scale,
integrated circuit (SSI) may contain up to several tens of such devices; a
medium-scale integrated circuit (MSI), many tens to several hundred; a large-scale
integrated circuit (LSI), several hundred to a few thousand; an extra-large-scale
integrated circuit (ELSI), a few thousand or more; and a very-large-scale
integrated circuit (VLSI), several hundred thousand or more. The first VSLI device
was introduced in 1981.