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:
Sep. 09, 1997
Filed:
Dec. 27, 1995
Hideki Wakamatsu, Hyogo, JP;
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
A method is used which reduces measurement errors, especially of permittivity, which result when electromagnetic induction-type probes measure electrical properties of solutions. Part of the electromagnetic induction current, which the electromagnetic induction-type probe tries to induce in the test solution, flows in the stray capacitance, which is formed by the dielectric in the probe. This partial current reduces the current that is linked to the current detector transformer, and affects the measured value of the electrostatic capacity component, i.e., the permittivity, of the test solution. This phenomenon is modeled and is expressed by a distributed constant circuit which is simplified to a T-shaped 2-terminal pair equivalent circuit. A correction equation that corrects the errors due to the aforementioned currents is obtained by means of this simplified equivalent circuit, and the measurement errors are reduced. Co is the probe's stray capacitance and is evaluated by substituting the correction equation for the measured value of a standard solution. By this means, measurement errors can be reduced to 1/10 of their uncorrected value.