Measurement Technology - The Electronic Nose Artificial Olfaction Technology - page 15

1.9 Measurement Techniques

Measurement involves the use of instruments as a physical means of determining
quantities or variables. Number of instruments are available to be used for mea-
suring the same physical quantity as shown in Table 1.5 and schematic of mea-
surement systems is shown in Fig. 1.5 .
Number of techniques are available to measure the following physical

quantities:

• Flow
• Pressure
• Temperature
• Level
• Conductivity
• pH
• Density
• Viscosity
• Voltage
• Radiation
• Inductance
• Capacitance
• Resistivity
• Frequency
• Chemical composition
• Various physical properties

Table 1.5 Physical quantity measurement
Physical quantity Instrument

Length Ruler, vernier calipers, and micrometer

Mass Electronic balance, lever balance

Weight Spring balance, Newton meter

Time Stopwatch, calibrated time base of a CRO

Temperature Resistance thermometer, thermocouple, and RTD

Electric current Galvanometer, ammeter

Potential difference Voltmeter, digital multimeter

Fig. 1.5 Measurement systems