Simplification of compound statements becomes especially concrete in switching networks. A switch may be open or closed, just as a statement may be false or true. Logical equivalence then says when two networks behave the same under every switch configuration. In this lesson, switching networks and logical equivalence will connect series and parallel circuits with conjunction and disjunction.

A \textbf{switching network} is a network made of wires and switches connecting two terminals $T_1$ and $T_2$. The purpose of the network is to determine whether current can flow from $T_1$ to $T_2$.