Match List - I with List - II. Choose the correct answer from the options given below :List - I (Transducers) List - II (Typical Applications) (A) Potentiometric device (I) Relative humidity (B) Resistance hygrometer (II) Velocity (C) Dielectric gauge (III) Displacement (D) Moving coil generator (IV) Thickness
(A)-(III), (B)-(I), (C)-(IV), (D)-(II)
Each transducer's name contains its measurand or its principle: (A)-(III), (B)-(I), (C)-(IV), (D)-(II), option 3.
(B) Resistance hygrometer and relative humidity. "Hygro-" means moisture, so the pairing is settled by the word itself. The device uses a hygroscopic film — lithium chloride or a conductive polymer — whose resistance falls sharply as it absorbs water vapour from the air. The dependence is strongly non-linear, typically several decades of resistance across the humidity range, so the reading is linearised electronically.
(A) Potentiometric device and displacement. A wiper slides along a resistive track, and the output is a simple ratio:
\(V_{out}=V_{in}\dfrac{x}{L}\)
Because it is a ratio of resistances, the reading is independent of supply variation and of the track's absolute resistance and its temperature coefficient — which is why the arrangement is so robust. It is the simplest displacement transducer there is, needing no excitation electronics at all, though the sliding contact wears and generates noise.
(D) Moving coil generator and velocity. A coil moving in a magnetic field generates an EMF by Faraday's law:
\(e=-N\dfrac{d\phi}{dt}=Blv\)
The output is proportional to velocity, not to position — the derivative is built into the physics. It is self-generating, needing no excitation, which is why it is used in vibration pick-ups and geophones.
(C) Dielectric gauge and thickness. A capacitance depends on the geometry of its plates:
\(C=\dfrac{\varepsilon A}{d}\)
Pass a sheet of material between two plates and the capacitance changes with the sheet's thickness, since the dielectric now fills a known fraction of the gap. The measurement is non-contact, which makes it suitable for moving webs of paper, plastic film or coated strip.
Note the contrast between (A) and (D), which is the pairing most easily confused: one measures where something is and needs an excitation supply; the other measures how fast it is moving and generates its own signal. Choosing between them amounts to choosing which quantity the instrument should measure directly rather than by differentiating or integrating.
Hence, the correct code is (A)-(III), (B)-(I), (C)-(IV), (D)-(II).
Similar Questions
Which of the following statements are correct ?
A. Hygrometer measures the value of humidity directly
B. Hygrometer measures the value of humidity indirectly
C. Wien's bridge is used to measure the frequency of the signal
D. Wien's bridge is used to measure the amplitude of the signal
E. Bimetallic strip is a thermal expansion detector.
Choose the most appropriate answer from the options given below :
Which of the following statements are correct
A. Megnetostrictive transducer operation depends on the change of permeability of magnetic material is when strained.
B. Potentiometer is an active transducer.
C. Turbine flow meters are volumetric flow meters
D. Any metal can be thermistor.
E. Thermocouples are used in high accuracy measurements.
Choose the most appropriate answer from the options given below :
Match List I with List II
LIST I LIST II A. Stroboscope I. Changes its electrical resistance with temperature B. Bolometer II. Generate thermoelectric emf C. Thermocouple III. Changes pressure to displacement D. Diaphragm IV. For measurement of rotary motion Choose the correct answer from the options given below:
Match the following lists :
List – I List – II a. Electromechanical Device i. Seismic Device b. Optical Device ii. Piezo-electric c. Gyroscopic device iii. Interferometers d. Absolute motion device iv. Aerospace vehicle Choose the correct answer from the codes given below:
Consider the following transducers or transducer systems :
(a) Float elements
(b) Seismic system
(c) Gyroscope
Arrange the above transducers/systems in decreasing order of the availability of possible number of output signals.
Consider the following statements associated with electrical and electronic transducers
A. Little power is consumed by transducer
B. Mass intertia effects are not minimized
C. The response time is small
D. Transmission and processing the signal for the purpose of measurement are easier.
Choose the correct answer from the options given below:
Match List I with List II
LIST I LIST II A. Relative error I. The ability of tde device to give identical O/P when repeated measurements are made witd tde same I/P signal B. Precision II. The ratio of difference between measured value and tde true value to tde true value of tde measurand C. Caliberation III. The smallest increment in measure tdat can be detected witd certainity by tde instrument D. Resolution IV. The process of making adjustments or tde scale so tdat tde instrument reading conform to an accepted standard. Choose the correct answer from the options given below:
The fundamental law that is used in temperature measurement is known as
Assertion (A) : Normally, some standard signal conditioner and display devices are used with a transducer, unless they are custom-built to suit the requirements of the transducers.
Reason (R) : A transducer is a device which receives energy in one form and transfer it to a convenient form.
Select your answer using the codes given below :
Which of the following transducers are not linear ?
i. thermistor
ii. thermocouple
iii. IC sensor
Important Questions from Basics of Transducers
Which of the following can act as an inverse transducer?
For transducers, following statements are given:
(A) An optical interferometer is useful for measuring extremely small motions
(B) The damping ratio of a seismic instrument should be low for good dynamic performance
(C) A rate gyro is a relative motion measuring device
(D) A pneumatic motion transducer is non-linear over a wide range of motion
(E) A piezoelectric accelerometer can only be used for static motion measurement
Choose the correct answer from the options given below:
Choose the INCORRECT statement with respect to the use of electrical transducers.
Consider the following transducers:
1. LVDT
2. Piezoelectric
3. Thermocouple
4. Photovoltaic cell
5. Strain gauge
Which of these are active transducers?
Under which condition, Transducers must operate?
