Treebeard's Homepage : Stumpers

Treebeard's Stumper
6 Mar 98

An Electric Stumper

We've been building electric circuits in science class at school, so here's an electric stumper. Below is a picture of a simple circuit with an old-fashioned knife switch, a light bulb, and a couple of posts to connect to a battery. But in this circuit, the light goes ON when the switch is open, and it goes OFF when the switch is closed! Of course the circuit is a trick. There is some extra wiring hidden in the box. But there are only hidden wires, no relays or secret switches. How does this stumper circuit work?


last modified .

Marc Kummel /