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:
Aug. 19, 1980
Filed:
Nov. 09, 1978
Katsuji Marumoto, Ibaraki, JP;
Tsutomu Ohmae, Ibaraki, JP;
Hitachi, Ltd., , JP;
Abstract
A power switching apparatus for use in the control of a D.C. load such as a D.C. motor comprises a power transistor with its emitter-collector path connected in series with the D.C. motor and a battery. A base current of the power transistor is supplied from the battery through a controllable impedance element. A control unit is provided to vary the impedance of the controllable impedance element in response to the current flowing through the emitter-collector path in such a manner that the base current changes as substantially the inverse-function of a characteristic curve indicating a D.C. amplification factor versus collector current of the power switch transistor.