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:
Aug. 07, 1984
Filed:
Mar. 11, 1982
Robert C Franklin, Los Gatos, CA (US);
Other;
Abstract
A portable device for locating a wall stud or similar object positioned behind a wall surface comprises means for detecting a change in the dielectric constant of the wall due to the presence of a stud or similar object and, in combination therewith, means for detecting the presence in the wall of a source of alternating current. In addition, a display is provided for visually indicating the presence of a source of alternating current in the wall in response to a signal from the means for detecting. The circuit also includes an amplifier to compensate for variations in characteristics of the electrical components used in the structure and an improved circuit for bleeding a bias charge used to calibrate the device when the device is shut off while preventing this charge from being bled when the device is turned on, and structure for indicating to the user that the device is being calibrated.