| 摘要 |
In configurations in which a circuit element is connected in parallel with a resistor configuring a bridge circuit between two wires for taking out voltage from both ends of the resistor, it is difficult to detect a break in the two wires. A thermal flow meter includes a heating element 2 and a temperature controlling bridge circuit 3 that is formed of a plurality of resistors 4 to 8 and controls the temperature of the heating element 2. The thermal flow meter includes: a circuit element 15 connected in parallel with at least one resistor 7 configuring the temperature controlling bridge circuit 3 through two wires L2, L3 drawn from both ends of the resistor 7; a voltage detection circuit 17 that detects that the magnitude of voltage produced between the two wires L2, L3 has become smaller than a first predetermined value; and a fault signal output circuit 20 that, when it is detected at the voltage detection circuit 17 that the magnitude of the voltage has become smaller than the first predetermined value, outputs a signal indicating a fault. |
