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Microprocessor, Microprocessor Unit (MPU)

The integrated circuit that first put a central processing unit on one chip of silicon.


The microprocessor, which first emerged in late 1960s and early 1970s, put all the components of a computer’s central processing unit (CPU) onto one integrated circuit. Before the microprocessor, the control unit and processing unit of a computer’s CPU were made up of discrete components, including transistors, and later small-scale integration (SSI) IC devices —  ICs with a few dozen transistors. All these parts were attached to a board to make the CPU. The microprocessor made embedded systems and desktop computers — microcomputers — possible because a dense amount transistors could be put into a smaller area. Some of the first products using microprocessors were calculators and computers.

The Intel 4004, released in 1971, was the first single-chip microprocessor. It used MOS (metal–oxide–semiconductor) silicon gate technology (SGT).

The microprocessor is digital, using binary numbers and logic.

Today the word ‘microprocessor’ means a single chip or single core CPU or processing unit. The word almost doesn’t have its original meaning because it obsoleted all the larger, component-based systems that it replaced.

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