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:
Feb. 10, 1976
Filed:
Nov. 12, 1974
Richard A Pidsosny, Detroit, MI (US);
John Zimmer, Ann Arbor, MI (US);
Ford Motor Company, Dearborn, MI (US);
Abstract
A warning circuit particularly suited for indicating that an intermittently operated device has been operated for a predetermined cumulative length of time. The circuit utilizes a coulometer as a current integrator that accumulates the intermittent periods of time during which the device operates. At the end of the predetermined cumulative length of time, the impedance of the coulometer changes from a low level to a relative higher level. This change in impedance renders a first transistor conductive and results in a warning indication. A second transistor is latched into a state of conductivity that causes a feedback current to flow through the coulometer to maintain it in its high impedance condition. The warning indication is controlled by an amplifier circuit which, in turn, is controlled by the second transistor. Once the high impedance of the coulometer is achieved, the second transistor at all times retains its state of conductivity indicative of this condition, but the amplifier circuit is operative only when the intermittently operated device is in operation.