Consider an ordinary mercuryinglass thermometer as a measure

Consider an ordinary mercury-in-glass thermometer as a measurement system and indicate which parts of the thermometer correspond to the boxes in the diagram of Fig. 2.2.

Solution

1.External Power: If it is measuring air temperature then external power is air temperature. If it is measuring body temperature, then it is the body temperature.

2.Detector Transducer stage: The mercury in the bulb is the detector transducer stage because it converts the heat into a volume change.

3. Intermediate Stage: Intermediate stage is the bulb-tube arrangement because it converts small change in volume of the mercury into a considerable rise of mercury along the tube.

4.Physical variable to be measured: Rise in mercury column

5. Calibration signal source: Relationship between rises in mercury to Temperature.

6.Recorder/Indicator: Dashes/marks on the tube indicating temperature

7.Controller: It is the thermal equilibrium between external source and thermometer.