The resulting circuit measures voltage ... but at least it is a fairly uncomplicated way to measuring things. Electric fences do work best with a voltage on them, after all.

He built an electric fence to keep these pests at bay ... The wires are connected to a nine-volt battery. No boost circuit, no transistors, just nine volts across two wires.

An electric fence can be useful for keeping out raccoons, squirrels, chipmunks, porcupines, woodchucks, rabbits, possums, and ...