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. 09, 1979
Filed:
Aug. 09, 1977
Takao Arai, Yokohama, JP;
Shigeru Okada, Yokohama, JP;
Kouichi Tomatsuri, Katsuta, JP;
Hiroshi Toeda, Katsuta, JP;
Hitachi, Ltd., , JP;
Abstract
A gain control circuit comprising a pair of transistors constituting a differential amplifier, and a pair of resistors each connected to the emitter of one of the transistors and having a sufficiently great resistance value compared with 1/gm of the transistor in the transistor operating range, the resistors being connected to a common regulated current supply to supply the halves of control current from the regulated current supply to the respective transistors, a pair of diodes are connected to the collectors of the respective transistors as a load, and a first variable resistor means is disposed in the current path traced from the diodes to the regulated current supply via the transistors and resistors for compensating fluctuation of the diffused resistance of the diodes. Further, a second variable resistor means is disposed in the base bias circuit for the transistors for compensating fluctuation of the base-emitter voltage of the transistors.