alt Hacker NewsI've been browsing his free sample chapter on basic electromechanical devices[1], and I must say that it is incredibly well written. Take a look at his explanation of switch bounce:
If you pry open a typical switch, you’ll probably find that its internals are quite complex. Inside, there might be a small spring-loaded roller that travels over a tiny hump or an intricately shaped metal leaf that “pops” when pressed firmly enough. The purpose of these mechanisms is to keep the switch firmly in place until sufficient force is applied, at which point it snaps immediately into the new position. This nonlinear behavior provides satisfying tactile feedback, reduces sensitivity to vibration and other accidental inputs, and prevents the switch from resting in any state other than “fully off” or “fully on.”
The flip side of this approach is that once the mechanism gives in, things happen quickly: The contacts are pulled apart or slammed together at a considerable speed. Because metal is elastic, this motion produces some vibration that manifests as electrical glitches lasting from tens of microseconds to a few milliseconds. The effect is known as switch bounce.
I know about switch bounce but I've never seen it explained so clearly. Usually electronics books will say "mechanical switches will bounce before settling" and will then describe a circuit or algorithm to deal with it. What's always missing is a plain English discussion of the why and how.
I checked out that chapter because the critical topic after switch bouncing is debouncing! ctrl-f says not that chapter tho. Lots of other good stuff tho!