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.

Date of Patent:
Sep. 03, 1991

Filed:

Aug. 03, 1990
Applicant:
Inventor:

James G Stuart, Mont Clare, PA (US);

Assignee:

Calspan Corporation, Buffalo, NY (US);

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G01N / ;
U.S. Cl.
CPC ...
374 43 ; 374 44 ; 324105 ; 324 711 ; 7320414 ; 364481 ; 364487 ;
Abstract

The thermal time constant of fine metal wire segments, such as those used to initiate explosive reactions, is measured by passing a variable frequency source of current through the wire. The magnitudes of the sine and cosine components of the third harmonic of the voltage developed across the wire are detected and compared to each other to provide a control signal which is applied to the frequency source to change the its frequency in a direction which tends to make those components equal in magnitude. The magnitude of the control signal, when the third harmonic sine and cosine components are equal, is displayed as a function of the thermal time constant of the wire segment.


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