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VISUAL TUNING ELECTRONIC DRIVE CIRCUITRY FOR ULTRASONIC DENTAL TOOLS

  • US 3,586,936 A
  • Filed: 10/16/1969
  • Issued: 06/22/1971
  • Est. Priority Date: 10/16/1969
  • Status: Expired due to Term
First Claim
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1. Electronic drive circuitry for exciting a magnetostrictive transducer used in ultrasonic dental tools and the like comprising, in combination, a source of DC potential, a solid state ultrasonic oscillator energized by said source of DC potential and providing a substantially sawtooth waveform output signal voltage, a power amplifier energized by said source of DC potential and having an input controlled by said output signal voltage, said power amplifier providing a power output signal, an ultrasonic transducer energized as the load of said power output signal, indicator means responsive to current flowing through said transducer to visually indicate tuning to resonance thereof upon variation of said frequency of said sawtooth waveform output, (Electronic drive circuitry for exciting a magnetostrictive transducer, as defined in claim 1, wherein) said indicator means (comprises) comprising a current-responsive visual indicator and a differential amplifier stage having an input transistor and an output transistor, circuit means responsive to load current flowing through said power amplifier and providing a substantially proportional DC reference voltage, said reference voltage being applied to a controlling element of said input transistor, a predetermined comparison DC voltage applied to a controlling element of said second transistor, and a load resistor for said second transistor providing a variable output voltage for energization of said current-responsive visual indicator.

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