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:
Nov. 01, 1994
Filed:
Jan. 26, 1993
Fridolin Wiget, Neuchatel, CH;
Asulab S.A., Bienne, CH;
Abstract
The device comprises a piezoelectric transducer, a primary battery, and a circuit which applies a control voltage to the transducer or which short-circuits the latter depending on the state of a control signal. The control voltage is produced by a voltage increasing circuit comprising a coil, a diode and a capacitor constituted by the transducer, that are connected in series, in that order, across the terminals of the primary battery, and an oscillator responsive to the control signal to control a transistor in such a manner that it either alternately produces and cancels a short circuit across the terminals of the circuit formed by the diode and the transducer or is permanently blocked. A second transistor is also responsive to the control signal to short-circuit the transducer when the first transistor is blocked. The device is simpler, cheaper and consumes less electrical power than known devices.