JPS5651619A - Hot-wire flow sensor driving circuit - Google Patents

Hot-wire flow sensor driving circuit

Info

Publication number
JPS5651619A
JPS5651619A JP12678979A JP12678979A JPS5651619A JP S5651619 A JPS5651619 A JP S5651619A JP 12678979 A JP12678979 A JP 12678979A JP 12678979 A JP12678979 A JP 12678979A JP S5651619 A JPS5651619 A JP S5651619A
Authority
JP
Japan
Prior art keywords
voltage
hot wire
temperature
constant
saw
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
JP12678979A
Other languages
Japanese (ja)
Other versions
JPS639170B2 (en
Inventor
Takao Sasayama
Shinichi Sakamoto
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hitachi Ltd
Original Assignee
Hitachi Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hitachi Ltd filed Critical Hitachi Ltd
Priority to JP12678979A priority Critical patent/JPS5651619A/en
Priority to DE3037340A priority patent/DE3037340C2/en
Priority to US06/192,994 priority patent/US4334186A/en
Publication of JPS5651619A publication Critical patent/JPS5651619A/en
Publication of JPS639170B2 publication Critical patent/JPS639170B2/ja
Granted legal-status Critical Current

Links

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  • Measuring Volume Flow (AREA)

Abstract

PURPOSE: To improve air flow measurement precision by varying a time ratio so that the difference between the temperature of a hot wire and the ambient temperature detected by a resistance for temperature compensation will be held constant.
CONSTITUTION: With switch 102 on, constant pulsating current is supplied to hot wire 103 and a voltage drop across the resistance of hot wire 103 is sampled and held in capacitor 112. This sampled value and the across voltage of temperature compensating resistance 104 provided in the same duct with hot wire 103 and applied with the constant current are compared and the result is integrated to obtain a voltage, which is outputted from integrating circuit 108. This voltage is compared to a saw-tooth wave voltage outputted from saw-tooth wave generator 113 by comparing circuit 110, which outputs a pulse signal in the on-state when the saw-tooth wave voltage is at Hi, thereby determinig the time ratio. According to this time ratio, switches 102 and 106 are driven to hold hot wire 103 at a constant temperature and the output signal of comparing circuit 110 is inputted to microcomputer 114.
COPYRIGHT: (C)1981,JPO&Japio
JP12678979A 1979-10-03 1979-10-03 Hot-wire flow sensor driving circuit Granted JPS5651619A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
JP12678979A JPS5651619A (en) 1979-10-03 1979-10-03 Hot-wire flow sensor driving circuit
DE3037340A DE3037340C2 (en) 1979-10-03 1980-10-02 Driver for hot wire air flow meters
US06/192,994 US4334186A (en) 1979-10-03 1980-10-02 Apparatus for driving hot-wire type flow sensor

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP12678979A JPS5651619A (en) 1979-10-03 1979-10-03 Hot-wire flow sensor driving circuit

Publications (2)

Publication Number Publication Date
JPS5651619A true JPS5651619A (en) 1981-05-09
JPS639170B2 JPS639170B2 (en) 1988-02-26

Family

ID=14943971

Family Applications (1)

Application Number Title Priority Date Filing Date
JP12678979A Granted JPS5651619A (en) 1979-10-03 1979-10-03 Hot-wire flow sensor driving circuit

Country Status (1)

Country Link
JP (1) JPS5651619A (en)

Also Published As

Publication number Publication date
JPS639170B2 (en) 1988-02-26

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