Resumen de A Cheap, Semiquantitative Hand-Held Conductivity Tester
This article describes the construction and use of a simple hand-held conductivity tester which gives roughly quantitative results when solutions ranging in electrolyte concentration from 0.001 to 0.10 M are tested. The tester uses a bar-graph LED driven by an LM3914 IC and is powered by a single 9V battery. This tester can be constructed from parts available at Radio Shack stores for about $10 using a soldering iron and a few other tools.
