The IC Time Machine

The 555 timer Integrated Circuit was introduced in 1971. I remember reading about it and then playing with them. What a very cool thing! It was originally designed to do very basic timing functions but because so much of the internal circuitry was brought out from the chip, you could use the internal building blocks for lots of other functions. Here are a few links about this wonderful chip: LM555 and LM556 Timer Circuits An awesome collection of cookbook circuits using the 555. It has web-based calculators for determining the values for your external components. The 555 Timer IC A wonderful oral interview with Dr. Hans R. Camenzind -- he is the guy who developed this chip. From the interview:

Hans, let�s start the Oral History with your recollections of the initial success of the 555 integrated circuit.
That 555 family was a total surprise. I wanted to make it flexible, that was the whole purpose, but I didn�t realize it was so flexible. There are applications now that still sound crazy to me. And the quantity! In the second year it moved to the largest quantity sold of any IC and it has stayed that way for 30 years. The original application was as a timer and oscillator, but it has moved well beyond that.

And finally, Wikipedia has a nice entry.