APPARATUS FOR SELECTIVELY MEASURING IONS IN A LIQUID

摘要

Apparatus for selectively measuring ions in a liquid, said apparatus comprising a measuring circuit including a chemically sensitive ion sensor in the form of an ion sensitive field effect transistor (ISFET), a reference electrode, and an amplifier, wherein said measuring circuit is connected to a protection system comprising at least one electrode connected via a low-impedance contact to the liquid and coupled to said ISFET by a protective element having a low impedance for high voltages and a high resistance to low voltages.