Control circuit for piezoelectric element of translator - uses integrated feedback signal to reduce nonlinearity problems

摘要

The trigger input (3) is fed between one input of a comparator (2) and earth. The output of the comparator is fed via a voltage amplifier (4) to one terminal of the ceramic piezo-electric element (P). The other terminal of the piezo-electric element is connected via a resistance (Rs) to earth. The junction between the element and the resistor provides a feedback signal which is integrated (1) and fed to the other input of the comparator. The circuit ensures a linear relationship between the trigger input signal and the dimensional change of the element. It also limits unwanted hysteresis and time-denpendent 'creep' effects which would occur without the feedback loop.