Ultrasonic generator for dental treatment - has switched magnetostrictive transducer which maintains oscillator supplying switching pulses at transducer resonance frequency

摘要

The magneto-strictive transducer of an ultrasonic generator is switched via an oscillator signal. A regulation voltage maintains the oscillator frequency at the resonance frequency of the magneto-strictive transducer. The regulation voltage is supplied from an integration stage (11,12) which is charged or discharged at the required switching rate and which uses the sum of a fixed voltage and the reaction voltage through a transducer winding (7) caused by the periodic switching. The oscillator comprises a multivibrator (1) supplying a signal via an RC element (3,4) to a switching transistor (6) with the transducer winding (7) connected in the collector circuit. The collector is connected via a diode (10) to an integration stage (11,12).