When a NO switch is represented by the symbol ... that you might find interesting is Applications of Boolean Algebra: Claude Shannon and Circuit Design: a summary of switching algebra.

Shannon's innovation made the design of switch networks vastly easier ... Under this interpretation, it's possible to assemble Boolean circuits that, simply by correctly combining two binary ...

Ladder logic uses switch or relay contacts to implement Boolean expressions. In years past ... Each gate is actually a circuit, typically consisting of transistors and biasing resistors. As an example ...