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 an example of 1st generation computer.

Second generation (1956 - 1963) use of transistors .

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