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. 16, 1981
Filed:
Jan. 19, 1979
Yoshinori Fukasaku, Hitachi, JP;
Kunihiro Noto, Katsuta, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A rotational speed control circuit for a D.C. motor includes a power transistor with its emitter-collector path connected in series with the D.C. motor and a power supply. A base current of the power transistor is controlled by an output of a differential amplifier which is supplied at its one of input terminals with a constant voltage and at the other input terminal with a voltage changing in accordance with a terminal voltage of the D.C. motor. Further the latter input terminal of the differential amplifier is given a variable bias potential by means of an adjustable mechanism. By this circuit configuration, the rotational speed of the D.C. motor can be continuously and proportionally adjusted over a wide range and once the rotational speed is set to predetermined value by the adjustable mechanism, a stable and constant speed control for the D.C. motor can be achieved.