The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 19, 1991
Filed:
May. 01, 1990
Stanley Electric Co., Ltd., Tokyo, JP;
Abstract
In an oscillation control apparatus for an ultrasonic oscillator, an FET circuit is connected to an oscillation circuit for varying a resistant value of a resistor unit of the oscillation circuit, which determines a free-running frequency thereof. A phase-difference detecting circuit is provided for detecting a relative phase difference between voltage and current in the ultrasonic oscillator. A threshold discrimination circuit outputs a signal when the phase difference inputted from the phase-difference detecting circuit exceeds at least a predetermined value. A pump circuit integrates the signal from the threshold discrimination circuit. A resistant value of the FET circuit varies when an output signal from the pump circuit exceeds a predetermined value.