Electronic weighing apparatus utilizing surface acoustic waves

摘要

A weighing apparatus includes a base (12) supporting a cantilevered elastic member (14) bearing a load platform (16). The interior of the elastic member (14) is hollowed and is provided with first (20) and second (22) piezoelectric transducers mounted on respective opposed posts. The transducers are arranged substantially parallel to each other with a small gap between them and are coupled to an amplifier (950, 952) to form a "delay line" and a positive feedback loop, to form a natural oscillator.