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. 04, 1985
Filed:
Oct. 20, 1982
Ernst Ruberl, Guntramsdorf, AT;
Abstract
In an impedance transformer circuit which is intended for capacitive voltage sources having a high output impedance, particularly for capacitor microphones, comprises two sequential amplifier stages with an overall gain of close to one. The output of the first amplifier stage having a large input impedance, and of itself, a high gain, is applied to the inverting input 2 of the second amplifier stage V.sub.2, which, of itself, again exhibits a high gain and whose output is fed back to its non-inverting input through at least one feedback loop containing the first amplifier as a resistor controlled by the capacitive transducer. Further, in AC current terms, the load resistor of the first amplifier stage is located between the inverting input and the non-inverting input of the second amplifier stage, and the reference potential '0' for the input and output AC voltage signals is not provided by any of the inverting or non-inverting inputs of the two amplifier stages.