Microprocessor

In 1971 Intel releases the 4004, a 4-bit processor designed for a calculator, with all the arithmetic and control on one chip. Marcian Hoff, Federico Faggin, and Stanley Mazor are the names usually attached. It is weak. It is also a whole central processor you can buy as a part.

The contribution is the general-purpose chip. Before this, a custom circuit did one product's job. After this, you change the program and the same chip does a different job. Personal computers, washing-machine controllers, and robot joint controllers are all that idea.

The 4004 is not the chip in a modern laptop. The 8080 and then the x86 line, and later ARM, are the families that spread. The 4004 is the first time the function fit on one piece of silicon.

A microprocessor still needs memory, input, and output around it. It is the brain of a computer, not the whole computer.