Explanation

An integrated circuit is a set of electronic circuits on one small flat piece  of semiconductor material, usually silicon.

Large numbers of tiny MOSFETs  integrate into a small chip. 

First generation (1940 - 1956)  vacuum tubes as a major piece of technology.

 The ENIAC is  example of 1st generation computer.

Second generation (1956 - 1963) use of transistors.

Third generation (1964 - 1971)  use of Integrated circuits.

Fourth generation (1972 - 2010) use of the microprocessor

Fifth generation (2010 to present) use Artificial intelligence