The influence of preamplifiers on the piezoelectric sensor's dynamic property

A charge amplifier or a voltage amplifier can be used as a signal conditioning circuit between a piezoelectric element and a meter or a data acquisition board. The outputs of the piezoelectric sensor are in an open-circuit state and a short-circuit state if a voltage amplifier and a charge amplifier are used, respectively. When the electrodes are in different states, the piezoelectric element has rather different stiffness and thus different sensor resonant frequency. This phenomenon is theoretically analyzed in detail and validated by a carefully designed experiment. The results indicate that a much wider range of working frequency is achieved when a voltage amplifier is used. (c) 2007 American Institute of Physics.