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:
Jul. 01, 1997
Filed:
Jul. 30, 1996
Craig A Miller, Pittsburgh, PA (US);
Joseph C Fray, Turtle Creek, PA (US);
Westinghouse Air Brake Company, Wilmerding, PA (US);
Abstract
A current limiter for protecting a circuit at a predetermined driving voltage in excess of 50 volts which includes a plurality of PTC resistors connected in series, with a zener diode connected in parallel with each of the PTC resistors, and wherein each of the PTC resistors has a predetermined voltage capacity limit such that the total of the predetermined capacity limits of the PTC resistors exceeds the predetermined driving voltage, and each of the zener diodes has a zener voltage rating less than the predetermined voltage capacity limit of the individual PTC resistor connected in parallel therewith, and the total of the zener voltage ratings of the zener diodes also exceed the predetermined driving voltage.