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. 23, 1977
Filed:
Jul. 23, 1974
Rudiger Ratzel, Buhl, DT;
Helmut Steinmann, Baden-Baden, DT;
Robert Bosch GmbH, Stuttgart, DT;
Abstract
A constant current source is provided for the energizing circuit of an electromotor driving a blower. The constant current source includes a battery connected in parallel with a series circuit including the energizing circuit of the motor, the emitter-collector circuit of a transistor and a control resistance. The transistor and control resistance are part of the constant current source. The base of the transistor is connected to the output of a differential amplifier the first input of which receives a reference voltage while the second input receives a voltage corresponding to the voltage across the control resistance and thus the energizing current. The reference voltage is derived from a potentiometer connected in parallel with the battery.