In my previous article
, you learned how to use the 555 test circuit as a cable tester. It can also be used to test whether different materials conduct or don’t conduct electricity such as plastic, glass, cloth, wood, a coin from your pocket, a house key, aluminum foil, or any number of materials from around the house. You can also use it to see how well you conduct electricity to demonstrate one of the measurements, skin conductance, of a polygraph, or lie detector.
In the demonstration video I touch the snaps together to get a base line tone. Next I hold the snaps on the red and black Jumper Wires between my fingertips to demonstrate that your skin does indeed conduct electricity.