QUESTION ONE A: A K-type thermocouple is used to measure temperature in the range 30°C to 100°C. Specify the range and resolution of the voltmeter. [10 marks]
B: A K-type thermocouple is used to measure the temperature of a system that is connected across the RTD. The RTD is exposed to an ambient temperature of 65°C. What will be the voltmeter reading? If the RTD has a dissipation constant of 0.001 W/°C, what will be the reading of the voltmeter? [10 marks]
C: A certain thermistor has a resistance of 10,000 Ohms at a temperature of 25°C. The material constant of the thermistor is 3,480 K and the dissipation constant is 0.40 mW/°C. Determine the actual temperature when the thermistor carries a current of 1.0 mA and has a resistance of 1,500 Ohms. [10 marks]
D: A thermistor is connected in series with a series resistor of 1,000 Ohms. The supply voltage is 20 V DC and the material constant of the thermistor is 4,000 K. A voltmeter of internal resistance 100 Ohms is connected across the series resistor. At room temperature of 25°C, the voltmeter gives a reading of 2V. The thermistor is used to measure the temperature of a material and the reading of the voltmeter is 4V. What is the temperature of the material? [10 marks]