To qualitatively distinguish different brands of mineral water

detection circuit is designed. Because different brands of mineral water has different ion content and p H value

a method by testing ion concentration and p H value in solution is proposed to qualitatively identify mineral water. Ion sensor array is used to qualitatively detect ion content of mineral water

and output by voltage signal. The whole signal detection circuit is divided into three parts

constant potential circuit

current / voltage（ I / V） conversion circuit and differential amplifier circuit

the final output voltage reflects ion content and p H value. Selection problem of operational amplifiers in designed circuit is solved and overall performance of the system is assured by using TINA simulation software. Experimental verification are carried out on the basis of simulation

experimental result shows that the designed circuit can effectively distinguish different mineral water

and has practical significance.