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. 15, 1988
Filed:
Jun. 24, 1986
Jeffrey D Campbell, Hawthorne, CA (US);
Zero Corporation, Burbank, CA (US);
Abstract
A static monitoring system for use with an electronic manufacturing work area, typically a conventional work bench having an electrical conducting strap for connecting the operator's wrist to earth ground, and including a circuit for indicating when there is an earth ground connection and circuitry for indicating when an electrostatically charged object, such as another human, approaches the work station. An antenna is positioned at the work station spaced from the working surface and from the operator, with the antenna connected as an input to an amplifier circuit which measures the change in electrostatic field strength and hence the approach of a charged object, with an indicator providing a visual or audible alarm or both. An oscillator provides an ac signal to each input of a differential amplifier, with one input connected to circuit ground through a capacitor and the other input connected to a wrist strap or the like on the operator. Phase difference at the amplifier inputs is detected as a measure of the capacitance to ground at the wrist strap thereby indicating appropriate use of the wrist strap.