Instrumentation Transducers

Capacitive Transducers

Question 1
Marks : +2 | -2
Pass Ratio : 100%
Capacitive transducers cannot be used as strain gauges.
True
False
Explanation:
Strain to be measured is applied to parallel plates of a capacitor and total displacement change will be proportional to strain.
Question 2
Marks : +2 | -2
Pass Ratio : 100%
For a material capacitance increases with _____________
Decrease in area of plates, all other factors constant
Increase in distance between plates, all other factors constant
Decrease in distance between plates, all other factors constant
None of the mentioned
Explanation:
Capacitance can be represented as C=ε0εrA / d
Question 3
Marks : +2 | -2
Pass Ratio : 100%
Which of the following is correct for moisture transducers?
Dielectric constant of pure water greater than other materials
Dielectric constant of pure water much less than other materials
Dielectric constant of pure water and of other materials are equal
None of the mentioned
Explanation:
Dielectric constant of pure water is 80 which is much greater than other materials, this characteristic helps in measurement of moisture content.
Question 4
Marks : +2 | -2
Pass Ratio : 100%
Capacitive transducers can be used by _______________
Measuring change in distance between plates
Measuring change in area of plates
Change in a dielectric material
All of the mentioned
Explanation:
Capacitance of a material is affected by area and distance of separation of plates and dielectric material.
Question 5
Marks : +2 | -2
Pass Ratio : 100%
Which of the following have high relative permittivity?
Bakelite
Marble
Paraffin
All of the mentioned
Explanation:
Dielectric constant or relative permittivity of Bakelite is about 4.4, for marble, it vary from 8 to 10 and for paraffin it is only 2.2.
Question 6
Marks : +2 | -2
Pass Ratio : 100%
Which of the following device is used for measuring relative humidity?
Capacitive pressure transducer
Hygrometer
Capacitive strain transducer
Capacitive moisture transducer
Explanation:
Hygrometers are special devices, which are applicable for measuring the relative humidity of a medium.
Question 7
Marks : +2 | -2
Pass Ratio : 100%
Thermometers are not possible using a capacitive transducer.
True
False
Explanation:
Capacitive transducers can be used to measure temperature in a way similar to moisture measurement.
Question 8
Marks : +2 | -2
Pass Ratio : 100%
Which of the following quantities cannot be measured by capacitive transducers?
Displacement
Speed
Moisture
None of the mentioned
Explanation:
Capacitive transducer finds application in measuring almost all quantities like displacement, thickness, moisture speed etc.
Question 9
Marks : +2 | -2
Pass Ratio : 100%
Which of the following is correct for the capacitive transducer?
Capacitive strain gauges
Capacitive tachometers
Capacitive pressure transducer
All of the mentioned
Explanation:
Capacitive transducers find application in measurement of both strain, pressure and angular displacement. Hence all of the mentioned can be treated as application of capacitive transducer.
Question 10
Marks : +2 | -2
Pass Ratio : 100%
Capacitive microphone is an application of ______________
Capacitive displacement transducer
Capacitive moisture transducer
Hygrometer
None of the mentioned
Explanation:
In microphone electric signals are produced according to pressure variations caused by acoustic waves, which can be easily measured by displacement transducer.