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. 23, 1982
Filed:
Apr. 25, 1979
Makoto Ueda, Tokyo, JP;
Akira Torisawa, Tokyo, JP;
Shuji Otawa, Tokyo, JP;
Masaaki Mandai, Tokyo, JP;
Masaharu Shida, Tokyo, JP;
Katsuhiko Sato, Tokyo, JP;
Kabushiki Kaisha Daini Seikosha, Tokyo, JP;
Abstract
An electronic timepiece of the type having a frequency dividing circuit, and a drive circuit for driving a motor having a rotor, a stator and a driving coil, is provided with a magnetic field detection device comprised of a low impedance closed loop including a low resistance element and the driving coil and a high impedance closed loop including a high resistance element and the driving coil. The driving coil develops an induced voltage when placed in an external alternating magnetic field and also functions to drive the rotor. The strength of the alternating magnetic field is measured by the voltage level developed across the high resistance element and the measuring sensitivity is improved by alternately switching between the low impedance closed loop and the high impedance closed loop. In response to the detection output of the magnetic field detection device, the effective power applied to the driving coil is increased so that the motor performance is not adversely affected by the external alternating magnetic field.