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

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