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:
May. 12, 1998
Filed:
Jun. 20, 1995
Norihiko Murata, Yokohama, JP;
Tatsuo Miyachi, Tokyo, JP;
Ricoh Co., Ltd., Tokyo, JP;
Abstract
Both of voltage range and supplied power range of a heater can be enlarged, one-sided power source for a driving circuit can be realized easily, power source voltage can be lowered, and flowing velocity can be measured with high accuracy. First reference resistor is connected in series to fluid temperature measuring body, and second reference resistor is connected in series to heater temperature sensor. Temperature setting resistor for determining set temperature difference between the heater temperature sensor and the fluid temperature sensor is connected in series to the fluid temperature sensor. Bridge circuit is constructed in such way. The voltage of heater temperature sensor is inputted to non-inverted input terminal of differential amplifier, while the voltage of fluid temperature measuring body and temperature setting resistor is inputted to inverted input terminal of the same. The output terminal of the differential amplifier is connected to a buffer circuit.