Telephone handset with transducer assembly

Abstract

PZ Brass RubberPZT Stack ] Nul =L•= Stress Boll this stress can be dynamically varied, and hence the resonance frequency can be tuned over a useful range of values, by incorporating a stack of PZT annular disks to which adc bias voltage is applied thereby causing the disks to expand and apply stress to the rubber layer.--WT