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:
Dec. 11, 1990
Filed:
Oct. 24, 1989
Masuo Akamatsu, Katsuta, JP;
Masayoshi Suzuki, Ohta, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
In a drive processing circuit comprising a flow velocity measuring resistor and a temperature compensating resistor of a hot wire type air flow meter, a resistor is inserted between a connecting point of two resistors and an inverting input terminal of an operational amplifier. A condenser is inserted between an inverting input terminal of the amplifier and the non-inverting input terminal of the amplifier. A resistant value of the inserted resistor is set larger than a resistant value of the temperature compensating resistor. A low pass filter comprises the inserted resistor and the inserted condenser. The high frequency noises, which intrude through the temperature compensating resistor, are cut-off by the low pass filter.