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:
Nov. 26, 1996
Filed:
Sep. 13, 1994
Applicant:
Inventors:
Masaharu Ikeda, Yokohama, JP;
Ryoji Abe, Yokohama, JP;
Assignee:
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H04R / ;
U.S. Cl.
CPC ...
381113 ; 381120 ;
Abstract
A common-source type buffer amplifier circuit has a microphone capsule, a diode and an FET. An output end of the buffer amplifier circuit, or a drain of the FET is connected to an input end of the current mirror circuit. An output end of the current mirror circuit is connected to one end of a load resistor of which the other end is grounded. A voltage across the load resistor corresponds to an output of the amplifier and is supplied to the speaker amplifier.