Essential Guide to Semiconductors, The

Microprocessor History and Evolution

The first microprocessor chip ever invented is regarded to be the 4004, which Intel first sold to Busicom in February 1971 for use in the latter's calculator. The 4004 was pitifully slow and simple by today's standards: It had only 2,300 transistors and ran at a pedestrian 750 KHz (that's 0.000075 GHz). Over the next five years, Intel updated the 4004 chip with the 8008, the 4040, the 8080, and then the 8086, which is still in use today (albeit heavily modified and updated). The 4004 microprocessor was simple enough that you could actually see the transistors and wires, and even a tiny logo in the (enlarged) photograph shown in Figure 6.2.

Figure 6.2. This photograph of the Intel 4004 silicon chip shows the ...