Although there is no rigid definition, a microcomputer (sometimes shortened to micro) is most often taken to mean a computer with a microprocessor (µP) as its CPU. Another general characteristic of these computers is that they occupy physically small amounts of space.
The microcomputer came after the minicomputer, most notably replacing the many distinct components that made up the minicomputer's CPU with a single integrated microprocessor chip. Such early models were primitive, the earliest microprocessors being little more than general-purpose calculator chips. However, as microprocessor design advanced rapidly from the early 1970s onwards, microcomputers in turn grew faster and cheaper, resulting in an explosion in their popularity.
Whilst the microcomputer may have taken over from older-style designs in many cases, its most significant effects are to have widened access to computers, and to have expanded their usage into completely new areas.