The first computers used thousands of separate electrical components connected together with wires. In the late 1940s, computers were made using vacuum tubes, resistors, and diodes. These computers were called first generation сomputers.
In 1956, transistors were invented. Transistors are made from materials called semiconductors. Computers using transistors were called second generation computers. Second generation computers were smaller than first generation computers. Second generation computers also used less electrical power. Both first and second generation computers were very expensive.
Computer components, (such as transistors, diodes, resistors) can now be made from semiconductor materials of different shapes. Nowadays, complete circuits can be made from a single piece of semiconductor, called a chip. Such circuits are called integrated circuits (IC’s). Computers using integrated circuits were first produced in the 1960s. They were known as third generation computers. Their integrated circuits had about 200 components on a single chip. Today, we can produce more than 100,000 components on a single chip. A chip can be as small as 0.5 cm square.
With the invention of chips, computer manufacture has become much simpler. The manufacturer does not have to connect thousands of components together. Most of the connections are made inside the chip. It is even possible to builda complete processor in a single chip. A processor on a single chip is called a microprocessor.
