Snap Circuits Science: Cable Tester
Friday, August 16, 2013 - 16:20
in Physics & Chemistry
In my previous article, you learned how to build a hot liquid level indicator for the vision impaired to help them fill cups with hot liquids such as tea or coffee. The 555 test circuit was used to generate a tone when the liquid in the cup reached the desired level--when the liquid level reached the red and black snaps of the Jumper Wires inside the cup. The liquid (my coffee) conducts electricity because tapwater contains small amounts of contaminants. read more