Jump phenomena of current in PZT-vibrators due to nonlinear damping of surrounding media

In some applications, surrounding media influence oscillating behavior of P ZT vibrators by non-linear damping. This usually results in current jump ph enomena of the supply. Such effects have been studied in detail under both atmospheric air pressure and vacuum. For a rate estimation about the influe nce of nonlinear crystal properties and of nonlinear damping the media infl uence has been minimized by driving the ceramic under low air pressure (I P a). Under these conditions the measurement showed a slightly higher current amplitude but no jump phenomena. This indicates that the velocity dependan t damping of the air surrounding the actuator is the main reason for the ju mp phenomena. (C) 2001 Elsevier Science Ltd. All rights reserved.