| 摘要 |
PROBLEM TO BE SOLVED: To suppress the generation of heat in an ultrasonic driving circuit and to attain miniaturization by reducing the number of parts. SOLUTION: This instrument is provided with a drive circuit composed of an output part 2 for applying a high-frequency voltage between the electrodes of an ultrasonic vibrator 1 and an FET 3 for controlling the output part 2 by inputting a pulse. In the drive circuit, the drain of the FET is connected to the center tap of a coil and the source of the FET is grounded through a negative feedback resistor 4. When the pulse is inputted to the base of the FET, the voltage of the resonance frequency of the ultrasonic vibrator is outputted from the output part and applied to the ultrasonic vibrator 1.
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