Temperature Stability Properties and Signal Detection Circuit of Acoustic Emission Sensor Using Lead-Free (Na,K)NbO3 System Ceramics

In this study, an acoustic emission (AE) sensor using lead free (Na,K)NbO3 system ceramics was fabricated. Also, the signal detection circuit and temperature stability properties of the AE sensor were presented and investigated, respectively. Signal detection circuit consisted of the impedance converter, high-pass filter, the signal amplification circuit, and rectifying circuit. The signal converted by impedance converter was amplified by amplifier, and the amplified signal was converted and displayed from AC to DC through a rectifying circuit. The Δkp/kp 20°C shows the maximum value of −0.015 at 30°C. Also, the Δf r/f r 20°C shows the maximum value of 0.075 at 80°C. Taking into consideration the above excellent temperature stability, it is considered that the AE sensor is suitable for detecting the partial discharge of power facilities.