| 摘要 |
PURPOSE:To improve a measurement precision, by a method wherein at least two or more reference resistances, whereof, together with two temperature dependence resistances, a bridge consists, are formed as a filmform resisting substance on a ceramic substrate or other substrates. CONSTITUTION:An electric heater 10 is set at the inside of a flow measuring pipe 9 mounted at the inside of a fluid (air) conduit, and temperature dependence resistance 11 and 12, made of platinum resistance wire, are attached at the upstream and the downstream of the heater 10 to form a bridge circuit. Reference resistance 21 and 22 are adhered as a filmform resisting substance on a ceramic substrate 90, and electrodes 91-93 are mounted. Voltages at diagonal points (a) and (b) of the bridge circuit are differentially amplified by means of a differential amplifying circuit 6b, and an output (c) thereof and a reference voltage Rref of a reference power source are differentially amplified by means of a differential amplifier 6a to output a voltage corresponding to a flow of a fluid (air) at terminals 36 and 37 of an output resistance 6e through a power amplifying circuit 6d. This permits the improvement of the measurement precision. |
