Understanding Acoustic Emission Testing- Reading 1 Part B-A

A brief description of the most important parts of this system is as follows:
1. Transducers: Piezoelectric transducers (generally made of lead zirconate
titanate, PZT) are used to convert the surface displacements into electric
signals. The voltage output from the transducers is directly proportional to
the strain in the PZT, which depends in turn on the amplitude of the
surface waves. Since these transducers are high impedance devices, they
yield relatively low signals, typically less than 100μV. There are basically
two types of transducers. (a) Wide-band transducers are sensitive to
acoustic events with frequency responses covering a wide range, often
several hundred kHz. (b) Narrow-band transducers are restricted to a
much narrower range of frequencies, using bandpass filters. Of course, the
transducers must be properly coupled to the specimen, often using some
form of silicone grease as the coupling medium.
Keywords:
• Since these transducers are high impedance devices, they yield relatively
low signals, typically less than 100μV.
• Wide band & Narrow Band
Charlie Chong/ Fion Zhang