The development of low-cost, non-enzymatic glucose biosensors is crucial for advancing accessible diabetes management. This paper presents the experimental testing of an extended-gate field-effect transistor (EG-FET) that uses a gold film as the sensing structure. The system innovatively employs a custom-designed inverting operational amplifier circuit for precise signal acquisition and an Arduino Nano platform for real-time data processing and visualization, eliminating the need for expensive laboratory equipment. At the core of the design is a depletion-mode MOSFET, whose current-voltage properties were characterized. The function of the sensor was demonstrated by testing its response to phosphate-buffered saline containing glucose at different concentrations. A clear modulation of the drain current in the linear region of the EG-FET was observed, and a preliminary analysis revealed a linear correlation between the output current and glucose concentration, indicating the system’s potential for quantitative detection. This study successfully validates the feasibility of a compact, cost-effective, and non-enzymatic EG-FET biosensing platform, establishing a solid foundation for future development of point-of-care diagnostic devices.