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:
Oct. 21, 1986
Filed:
Aug. 24, 1984
Klaus Horn, Braunschweig, DE;
Siemens Aktiengesellschaft, Munich, DE;
Abstract
An evaluation circuit for a passive measurement variable pickup having resistor sensors disposed in a bridge circuit is disclosed. In one embodiment, a double throw switch alternately connects a balancing resistor across resistors of the bridge circuit. A balancing difference signal is generated by a preamplifier coupled to the output of the bridge circuit. The preamplifier transmits d-c components of the balancing difference signal. The output of the preamplifier is coupled to a phase sensitive rectifier. The preamplifier has a linear phase frequency response and a linear modulation characteristic. The output of the rectifier is coupled to a null amplifier and the balancing resistor is coupled to a polarity reversing switch feeding the bridge circuit by circuitry which passes d-c components, e.g., a conductor, an operational amplifier or a switching device.