Modul is primary intended for meassuring water conductivity. Output signal is frequency wich grows linear with conductivity between EC probe conntacts. For meassuring in water solution the most proven probe is made from two NiCr wire. But probe can be arbitrarily changed e.g. by exchange for probe for meassuring soil moisture. Meassuring circuit is galvanic isolated witch prevent unwanted distortion in use with another pH modul or EC modul. Modul is supply by 5V from ardunino.