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US 6,318,169 B1Granted
Heat sensitive flow meter
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorsNaruki Suetake, Minoru Abe
Life of this patent
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Abstract
A heat sensitive flow meter comprising a power source for changing an offset voltage ΔE at the time of application of a power voltage. The power source is connected to the non-inversion input terminal of an operation amplifier for amplifying a potential difference between a first heat sensitive element for measuring the temperature of a fluid and a second heat sensitive element which is cooled by the fluid. The heat sensitive flow meter can suppress an output error right after the application of a power voltage and shorten a target signal reach time.
Claims6
A heat sensitive flow meter comprising:
- a bridge circuit having a first heat sensitive element for measuring a temperature of a fluid in a first bridge branch and a second heat sensitive element which generates heat with a heating current and is cooled by a flow of the fluid in a second bridge branch;
- a differential amplifier for amplifying a potential difference between the first and second heat sensitive elements;
- a fixed temperature difference control circuit for controlling the heating current so that a temperature difference between the first and second heat sensitive elements becomes fixed;
- a power source for supplying an offset voltage to an input circuit of the differential amplifier;
- and
- an offset voltage changing means for temporarily changing the offset voltage at the time of application of a power voltage.
3 more elements
Dependencies are inferred from the claim text.