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:
Jun. 09, 1981
Filed:
May. 03, 1979
Applicant:
Inventors:
Nathan K Weiner, Stoughton, MA (US);
David D Ketchum, Ipswich, MA (US);
Assignee:
Electronics Corporation of America, Cambridge, MA (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G01R / ;
U.S. Cl.
CPC ...
3244 / ; 324 51 ; 324 52 ;
Abstract
An interface circuit for indicating the state of a set of switch contacts having high noise immunity and high reliability. The switch contacts to be monitored are connected in series with the primary winding of a transformer having a magnetic core with a highly rectangular hysteresis loop. A voltage is periodically applied through the switch to the transformer primary. A test pulse of current is then passed through a secondary winding on the transformer. The signal across the secondary winding produced in response to the test pulse current indicates the closed or opened condition of the contacts.