An embedded measurement system for electrical characterization of EGFET as pH sensor

This work presents the development of an electronic system for the electrical characterization of pH sensors based on the extended gate field effect transistor (EGFET). We designed an electronic circuit with a microcontroller (PIC15F14K50) as the main component in order to provide two programmable outputs voltage as well as circuits to measure electric current and voltages. The instrument performance analyze was carried out using a glass electrode as a sensitive membrane for investigating the EGFET operation as pH sensor. The results show that the system is an alternative to commercial equipment for the electrical characterization of sensors based on field effect devices. In addition, some of the key features expected of this electronic module are: low cost, flexibility, portability and communication with a personal computer using a USB port.