Potentiometric sensor with state monitoring for pH sensing has ion-sensitive field effect transistor, evaluation switch, measurement resistance and monitoring switch

摘要

The sensor measures the potentiometric value of a measurement medium. It includes an ion-sensitive field effect transistor (ISFET) (1) with ion-sensitive gate region surface, an evaluation switch with a measurement input for the output signal from the ISFET, a measurement resistance (3) between the ISFET output and the evaluation switch input, a monitoring switch (4) for voltage drop at the resistance, and a bridge branch (5) parallel to the resistance with a switch (6).