A platinum wire resistor is exposed to a temperature to be measured. The voltage drop across the resistor is input to a differential amplifier. The platinum resistor is connected to ground through a sensing resistor. Variations in voltage across the sensing resistor drive the differential amplifier to maintain a constant current through the resistance thermometer and the sensing resistor. A second differential amplifier connected across the resistive thermometer forms an output signal which is related to the temperature of the sensor and, hence, proportional to the measured temperature.
National Aeronautics and Space Administration Report
- Pub Date:
- October 1971
- Electrical Resistance;
- Temperature Measurement;
- Instrumentation and Photography