Signal detection circuit of acoustic emission sensor using Pb-free (Na, K)NbO 3 system ceramics

In this study, the signal detection circuit of acoustic emission (AE) sensors was presented using Pb-free (Na, K)NbO 3 system ceramics with excellent g 33 (=40.10(× 10 −3 Vm/N) piezoelectric voltage constant. Signal detection circuit was 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. Also, the amplified signal was converted and displayed from AC to DC through rectifying circuit.