A Free Damped Oscillation Method for AC Electrical Impedance Measurement of Conductive Medium
Yonggui Dong · Nanotechnology and Precision Engineering · 2012
Many physical or chemical parameters can be obtained by measuring the AC electrical impedance characteristics of conductive medium.By adding an inductor or capacitor to the one-order sensing system,a second-order resonant element can be constructed.When the element is excited by continuous square wave signals,it is forced into a free damped oscillation mode.The decay factor and resonant frequency can be simultaneously obtained.Experiments were done with an eddy current detection system for plate metals and a conductivity measurement system for saline solution,respectively.The results indicate that this method can suppress the non-ideal influences of lift off or the lead of electrodes.Potential application can be prospected in sensorization of AC electrical impedance measurement technology.