Patent ID: 8336376
Filing Date: 2012-12-25
Classification: G01F

Abstract:
1. A thermal flow meter comprising a control circuit to control a heating temperature in a heat-generating resistor that generates heat when a current flows therethrough, and measuring a flow rate of a fluid, wherein the control circuit includes: a first series circuit in which a fixed resistance, a first resistor, and a second resistor are connected to one another in series; a second series circuit in which a third resistor and a fourth resistor are connected to each other in series; and a voltage generation circuit that takes out voltages at both terminals of the fixed resistance and outputs a voltage adjusted within a range between the voltages at both terminals, a terminal at a side of the fixed resistance of the first series circuit is connected to a first reference potential, a terminal at a side of the third resistor of the second series circuit is connected to an output voltage of the voltage generation circuit, and the other terminal of the first series circuit and the other terminal of the second series circuit are connected to a second reference potential, and at least the first resistor and one among the second resistor and the third resistor are formed respectively of temperature-sensitive resistors each having a resistance temperature coefficient higher than that of the fixed resistance.