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. 28, 1984
Filed:
Apr. 14, 1982
Colin J Hanson, Valencia, CA (US);
Penril Corp., Rockville, MD (US);
Abstract
Apparatus for measuring moisture content of gypsum board and like products as a function of dielectric constant comprising an rf signal source, an antenna disposed for rf field coupling to a test material, first and second reference inpedances, and a control circuit for selectively connecting the reference and antenna impedances to the output of the rf source. A rectifier is responsive to source output for providing the corresponding d.c. signal to measurement electronics. The measurement electronics first subtract a first reference signal indicative of the reference impedances from both a differing second reference signal indicative of the reference impedances and from a signal indicative of impedance at the antenna. Moisture content is then determined as a function of the ratio of the differences. A threshold detector is responsive to the difference between the antenna and reference signals for indicating the presence of test material adjacent the antenna.