| 摘要 |
PURPOSE:To utilize the circuit in precise temperature measurement, by connecting a highly stable fixed resistor having a specified resistance value to a thin film temperature sensor made of palladium-iron alloy or platinum-iron alloy in series, thereby correcting the dipped characteristic. CONSTITUTION:As a temperature sensor RB a thin film of palladium-iron alloy or a thin film of platinum-iron alloy is used. Resistors RA, RC, and RD, which are used for constituting a circuit, are selected so that resistance temperature coefficient is small and quality is stable for a long period. A highly stable fixed resistor RA has a resistance value, which is 2.5-5times that of the temperature sensor RB at the lowest temperature point in the temperature measuring range. By using said resistor RA, an output voltage having excellent linearity can be obtained from the sensor having a dipping characteristic. When the resistance temperature coefficient of the sensor is 6,000PPM/ deg.C, RA/RBis 2.5. When the coefficient is 4,000PPM/ deg.C, RA/RB is 4. The circuit is combined with a digital voltmeter, and a highly accurate, inexpensive thermometer can be obtained. |
