After the invention of electricity in the 20th century, computers began using electric power. This led to the rapid development of computers. As a result computer evolved generation after generation.
First Generation Computers
The period of first generation was 1940-1956. Used Vacuum Technology. Was very expensive. Supported machine language only.
A vacuum tube
The UNIVAC and ENIAC computers are examples of first-generation computing devices. The UNIVAC was the first commercial computer delivered to a business client, the U.S. Census Bureau in 1951.
Second Generation Computers
The period of second generation was 1956-1963. Used Transistors. Reliable in comparison to first generation computers still very costly. Used assembly languages.
Transistors
IBM 7000, NCR 304, IBM 650, IBM 1401, ATLAS and Mark III are the examples of second generation computers.
Third Generation Computers
The period of third generation was 1964-1971. Used Integrated Circuits. Less expensive than previous two generations. Supported high level language.
Integrated Circuits
PDP-8, PDP-11, ICL 2900, IBM 360 and IBM 370 are the examples of third generation computers.
Fourth Generation Computers
The period of fourth generation is from 1971-present. Use Microprocessor. Very cheap, reliable and portable. Use high level languages.
Microprocessor
IBM 4341, DEC 10, STAR 1000, PUP 11 and APPLE II are the examples of fourth generation computers.
Fifth Generation Computers
Fifth generation computing devices, based on artificial intelligence, are still in development, though there are some applications, such as voice recognition, that are being used today.
Voice Recognition