Check out this cool tutorial on switches from the folks over at Sparkfun.
One of the most elementary and easy-to-overlook circuit component is the switch. They don’t require any fancy equations to evaluate. All they do is select between an open circuit and a short circuit. Simple. But how could we live without buttons and switches!? What good is a blinky circuit with no user input? Or a deadly robot with no kill switch? What would our world be without with big red buttons you should never, ever press.
via Switch Basics – Learn.SFE.
