Portable pH detector

摘要

A portable pH detector. A pH-ISFET is immersed into a solution, and the gate voltage of the pH-ISFET is detected by a signal detection unit. The level of the detected voltage is adjusted by a gain control and level shift unit and is converted by an A/D converter circuit and then output to a 8051 microcontroller to compute the pH of the solution, with the computed result displayed on a LCD.