| 摘要 |
In a configuration wherein a circuit element is connected in parallel with a resistor of a bridge circuit between two wires that extract voltage from the ends of the resistor, it had been difficult to detect breaks in the two wires. To address this, a thermal flow meter, comprising a heating body (2) and a temperature controlling bridge circuit (3) that controls the temperature of the heating body (2) and for which a plurality of resistors (4 to 8) constitute a bridge circuit, comprises: a circuit element (15) which, by way of two wires (L2, L3) that are connected to both ends of at least one of the resistors (7) constituting the temperature controlling bridge circuit (3), is connected in parallel with the resistor (7); a voltage detecting circuit (17) for detecting when the magnitude of the voltage occurring between the two wires (L2, L3) drops below a first prescribed value; and a failure signal output circuit (20) for outputting a signal indicating failure when detecting that the magnitude of the voltage from the voltage detecting circuit (17) dropped below the first prescribed value. |
