an electronic device with a microprocessor as its central processing unit (CPU). Microcomputer was formerly a commonly used term for personal computers (personal computer), particularly any of a class of small digital computers (digital computer) whose CPU is contained on a single integrated semiconductor chip. Thus, a microcomputer uses a single microprocessor for its CPU, which performs all logic and arithmetic operations. The system also contains a number of associated semiconductor chips that serve as the main memory for storing program instructions and data and as interfaces for exchanging data of this sort with peripheral equipment—namely, input/output devices (e.g., keyboard, video display, and printer) and auxiliary storage units. Smaller microcomputers first marketed in the 1970s contain a single chip on which all CPU, memory, and interface circuits are integrated.

As large-scale integration and then very-large-scale integration have progressively increased the number of transistors (transistor) that can be placed on one semiconductor chip, so the processing capacity of microcomputers using such single chips has grown commensurately. During the 1980s microcomputers came to be used widely in other applications besides electronic game systems and other relatively simple computer-based recreations. Increasingly powerful microcomputers began to be used in personal computer systems and workstations, for instance. High-performance microcomputer systems are used widely in business, in engineering, in “smart” or intelligent machines employed in the factory and office, and in military electronics systems.

As personal computers started including multiple processors in the 2000s, microcomputer began to be relegated to descriptions of small “embedded” computers found in various electronic devices.