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. 16, 1976
Filed:
Jul. 11, 1974
John L Myers, Dayton, OH (US);
Projects Unlimited, Inc., Dayton, OH (US);
Abstract
An electronic buzzer has a tuned oscillating striker and an electronic oscillator circuit matched to the striker tuned frequency and driving the striker by close coupling of a driving coil to a core member which forms part of an electromagnetic circuit with the striker. The oscillator circuit also includes a control coil in the transistor base circuit and mounted within the driving coil for close coupling to the driving coil and the electromagnetic circuit. The control coil is optimized to have the maximum number of turns while still matching the effective input impedance of the transistor. A diode may be connected in shunt with the driving coil for improved feedback coupling and frequency tuning.