Design of capacitive sensor for water level measurement

8th International Conference on Physics and its Applications

Qurthobi, A.^1 ; Iskandar, R.F.^1 ; Krisnatal, A.^1 ; Weldzikarvina^1

Department of Engineering Physics, Telkom University, Indonesia^1

关键词: Electrical characteristic;    High impedance;    Inverting amplifiers;    Non-contacting devices;    Output voltages;    Rectifier circuit;    Water level detections;    Water level sensors;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/776/1/012118/pdf
DOI  :  10.1088/1742-6596/776/1/012118

来源: IOP

【 摘 要 】

Capacitive sensor for water level detection has been fabricated. It has, typically, high-impedance sensor, particularly at low frequencies, as clear from the impedance (reactance) expression for a capacitor. Also, capacitive sensor is a noncontacting device in the common usage. In this research, water level sensor based on capacitive principal created using two copper plates with height (h), width (b), and distance (l) between two plates, respectively, 0.040 m, 0.015 m, and 0.010 m. 5 Vpp3 kHz AC signal is used as input signal for the system. Dielectric constant between two plates is proportional to water level. Hence, it can be used to determine water level from electrical characteristic as it inversely proportional to sensor impedance. Linearization, inverting amplifier, and rectifier circuits are used as signal conditioning for the system. Based on conducted experiment, the relationship between water level (x), capacitance (C), and output voltage (Vdc) can be expressed as C(x) = 2.756x + 0.333 nF and Vdc(x) = 15.755 + 0.316 V.