The Central Processing Unit, CPU, or simply the processor. It is the component in a digital computer that interprets the instructions and processes the data contained in the computer programs. CPUs provide the fundamental characteristic of digital computer, programmability, and are one of the necessary components found in computers of any time, along with primary storage and input / output devices. The CPU that is manufactured with integrated circuits is known as a microprocessor. Since the mid-1970s, single-chip microprocessors have almost completely replaced all types of CPUs, and today, the term "CPU" is usually applied to all microprocessors.
The expression "Central Processing Unit" is, in general terms, a description of a certain class of logic machines that can execute complex computer programs. This broad definition can easily be applied to many of the first computers that existed long before the term "CPU" was in wide use. However, the term itself and its acronym have been in use in the computer industry at least since the beginning of the 1960s. The shape, design and implementation of the CPUs has changed drastically since the first examples, but its fundamental operation has remained quite similar.
The first CPUs were custom designed as part of a larger computer, usually a one-of-a-kind computer. However, this expensive method of custom-designed CPUs for a particular application has largely disappeared and has been replaced by the development of cheap and standardized processor classes adapted for one or many purposes. This trend of standardization generally began in the era of discrete transistors, central computers, and microcomputers, and was accelerated rapidly with the popularization of the integrated circuit (IC), which has allowed more complex CPUs to be designed and manufactured in small spaces (in the order of millimeters).
Both miniaturization and standardization of CPUs have increased the presence of these digital devices in modern life well beyond the limited applications of dedicated computing machines. Modern microprocessors appear in everything from cars, televisions, refrigerators, calculators, airplanes, to mobile or cell phones, toys, among others.