About the 555 Timer IC
The 555 timer IC was invented in 1970 by company called Signetics who bought the idea from an engineer named Hans Camenzind. This wasn't a breakthrough concept, just 23 transistors and a handful of resistors would function as a programmable timer. The timer was versatile, stable, and simple, but these virtues paled in comparison with the circuits primary selling point. Using the emerging technology of integrated circuits, Signetics reproduced the entire circuit on a silicon chip. Camenzind spent weeks using a drafting table and a specially mounted X-Acto knife to scribe his circuit into a large plastic sheet. Signetics then reduced this image photographically, etched it into tiny wafers , and embedded each wafer in half an inch of rectangular plastic with the product number printed on top. Thus, the 555 was born.
It turned out to be the most successful chip in history, in both the number of units sold (tens of billions and still counting) and the longevity of its design which has been unchanged for almost 50 years. The 555 has been used everywhere from toys to spacecraft. In the year 2008 a single one of these chips could be bought for only 25 cents.