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:
Apr. 24, 1984
Filed:
Jul. 26, 1982
Robert J Smith, Lynnwood, WA (US);
Solid State Systems, Corporation, Lynnwood, WA (US);
Abstract
An energizing circuit (10) for automatically driving a piezoelectric crystal transducer (Y1) at its resonant frequency includes a resonant circuit (12) of which the transducer (Y1) forms a capacitive element and the secondary winding (80) of a transformer (T2) forms an inductive element. In addition, the piezoelectric crystal itself acts as a series RLC circuit disposed in parallel with the parallel capacitive and inductive elements of the resonant circuit (12). Secondary winding (80) is inductively coupled with a primary winding (74) of the transformer (T2) which forms part of a driving circuit (14). The driving circuit (14) includes a switching circuit (20) connected between a power supply circuit (16) and the resonant circuit (12). Driving circuit (14) also includes a control circuit (28) which senses the difference between the vibrational frequency of transducer (Y1) and its resonant frequency and produces an appropriate level control signal which is transmitted to an oscillatory circuit (24) which in turn produces a switching signal of the desired frequency to actuate the switching circuit (20) at the proper rate to drive resonant circuit (12) at the resonant frequency of transducer (Y1) through the inductive coupling formed by transformer (T2).