What is a microprocessor?

A microprocessor is an integrated circuit on a tiny silicon chip that contains thousands or millions of tiny on/off switches, known as transistors. The transistors are laid out along microscopic lines made of superfine traces of aluminum that store or manipulate data. These circuits manipulate data in certain patterns, patterns that can be programmed by software to make machines do many useful tasks.

One of the biggest tasks microprocessors perform is acting as the brains inside a personal computer. The number of transistors on a chip has grown from 2,300 on the 4004 in 1971 to 5.5 million on today's Pentium® Pro processor. These advances have made today's microprocessors 1,000 faster than their predecessors.

Computers are not the only way in which microprocessors are used. Microprocessors also help many devices--your telephone, thermostat, car, or a traffic light, for instance--to remember and adjust to incoming information. This lets your phone redial, your thermostat automatically adjust, and thousands of other devices process details of daily life.