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:
Jan. 21, 1992
Filed:
Aug. 22, 1990
Peter L Madaffari, Camden, ME (US);
Knowles Electronics, Inc., Itasca, IL (US);
Abstract
An amplifier having improved input impedance and reduced susceptibility to power supply ripple, particularly suited for use with a high impedance signal source, utilizes at least two field-effect transistors; the signal source is connected to the gate of the first FET, which is connected to a reference potential by a high resistance, whereas the source electrode of the first FET is connected to the reference potential (usually ground) through a much smaller load resistance and is also connected to the gate of the second FET. The source of the second FET is connected to the drain of the first FET and the drain of the second FET is connected to a power source, usually a low voltage source.