Microprocessor is the device that does the actual computing in a computer. A microprocessor consists of electronic switches called transistors and other parts built into a chip—usually made of silicon—no larger than a postage stamp. Some microprocessors have billions of transistors.
In a typical microprocessor, most of the parts are arranged into two groups of circuits: (1) the control unit and (2) the arithmetic logic unit. The control unit directs the operation of the entire computer. The arithmetic logic unit performs the computations. The remaining parts make up memory devices that hold information for the control and arithmetic logic units.
Some personal computers have more than one microprocessor—a primary processor and one or more co-processors to handle special kinds of work. Some computers, for example, have sound co-processors. Much less powerful microprocessors operate such devices as digital wristwatches, microwave ovens, and the ignition systems of automobiles.
