부산대학교 도서관

In this article, a low-cost hydrostatic liquid level transmitter is presented, utilizing a diaphragm as the primary sensing element and a capacitive sensor as the secondary transducer. We investigate a capacitive pressure sensor configuration that employs two metal plates separated by a specific gap distance. Traditionally, capacitive pressure sensors utilize an elastic diaphragm with fixed edges and a sealed cavity. However, the proposed design manipulates the capacitance at the observer unit to detect changes in capacitance resulting from the hydrostatic pressure exerted by the liquid. This configuration enables accurate measurement of liquid level based on frequency, making it suitable for low-power and telemetric applications. Capacitive pressure sensors are particularly advantageous as they operate without drawing dc power and can form passive inductor-capacitor ( ${L}$ – ${C}$ ) tank circuits. The hydrostatic liquid level transducer described in this article offers a reliable and efficient solution for measuring liquid levels in various applications, such as industrial processes, environmental monitoring, and liquid storage systems. The proposed sensor design provides accurate and real-time level measurements, contributing to enhanced control and monitoring of liquid systems.