Resistive and Capacitive Based Sensing Technologies
Winncy Y. Du, Scott W. Yelich · DOAJ (DOAJ: Directory of Open Access Journals) · 2008
Resistive and capacitive (RC) sensors are the most commonly used sensors. Their applications span homeland security, industry, environment, space, traffic control, home automation, aviation, and medicine. More than 30% of modern sensors are direct or indirect applications of the RC sensing principles. This paper reviews resistive and capacitive sensing technologies. The physical principles of resistive sensors are governed by several important laws and phenomena such as Ohm’s Law, Wiedemann-Franz Law; Photoconductive-, Piezoresistive-, and Thermoresistive Effects. The applications of these principles are presented through a variety of examples including accelerometers, flame detectors, pressure/flow rate sensors, RTDs, hygristors, chemiresistors, and bio-impedance sensors. The capacitive sensors are described through their three configurations: parallel (flat), cylindrical (coaxial), and spherical (concentric). Each configuration is discussed with respect to its geometric structure, function, and application in various sensor designs. Capacitance sensor arrays are also presented in the paper.