This Portion of Electrical andElectronic Measurements and Measuring instruments contains AC Bridges / Impedance Bridges MCQs (Multiple Choice Questions and Answers) / Objective Type Questions and Answers.

This Section covers below lists of topics.

1. A.C Bridges
2. Measurement of Self-inductance
3. Measurement of Capacitance
4. Measurement of Mutual inductance
5. Measurement of Frequency
6. Universal impedance Bridge
7. Source of errors in Bridge Circuits
8. Wagner Earthing Devices
9. Transformer Ratio Bridge

PRACTICE IT NOW TO SHARPEN YOUR CONCEPT AND KNOWLEDGE

1. Please check figures here to answer the Questions from 1-3. in order that the bridge shown in fig be balanced

• I1 = I3  and I2 = I4
• Z1Z4  = Z2Z3
• θ1  + θ= θ2  + θ3
• All of the above.

• 187.5Ω ∠-70°
• 187.5Ω ∠-10°
• 333.3Ω ∠10°
• 120Ω ∠70°

3. For the bridge shown in figure above , arm ab consists of resistance in series with an inductance, arms bc and ad consists of pure resistance. in order to achieve balance arm cd should consist of

• A variable resistance in series with an variable inductance
• A variable resistance
• A variable resistance in series or parallel with a variable capacitance
• A variable capacitance.

4. The equations under balance conditions for a bridge are : R1 = R2 R3 / R4 and L1 = R2R3C4 Where R1 and L1  are respectively unknown resistance and inductance. In order to achieve converging balance

• R2  and R3  should be chosen as variables
• R2  and C4  should be chosen as variables
• R4  and C4  should be chosen as variables
• R and C4  should be chosen as variables

5. Maxwell’s inductance-capacitance bridge is used for measurement of inductance of :

• Low Q coils
• Medium Q coils
• High Q coils
• Low and medium Q coils.

6. The advantage of Hay’s bridge over Maxwell’s inductance-capacitance bridge is because

• Its equations for balance do not contain any frequency term
• It can be used for measurement of inductance of high Q coils
• It can used for measurement of inductance of low Q coils
• None of the above.

7. In D’Sauty’s bridge (unmodified form) it is :

• Possible to obtain balance even if both the capacitors are imperfect
• Possible to obtain balance if one of the capacitors is perfect
• Possible to obtain balance only if both the capacitors are perfect
• All the above.

8. Frequency can be measured by using :

• Maxwell’s bridge
• Schering bridge
• Heavyside Campbell bridge
• Wien’s bridge.

9. A bridge circuit works at a frequency of 2 kHz. The following can be used as detectors for detection of null conditions in the bridge

• Vibration galvanometers and tunable amplifiers
• Vibration galvanometers, headphones and tunable amplifiers.

10. Wagner’s Earth devices are used in a.c bridge circuit for :

• Eliminating the effect of earth capacitances
• Eliminating the effect of inter-component capacitances
• Eliminating the effect of stray electrostatic fields
• Shielding the bridge elements.

11. A bridge circuit works at a frequency of 2 kHz. Which of the following can be used as null detector in such a bridge?

• Vibration galvanometers and tunable amplifiers
• All of the above

12. Under balanced condition of a bridge for measuring unknown impedance, if the detector is suddenly taken out

• measured value of the impedance will be lower
• measured value of the impedance will be higher
• measured value of the impedance will not change
• the impedance can not be measured

13. Harmonic distortions in power supply does not affect the performance of Maxwell’s bridge since

• filters are used to remove harmonics
• final expression for unknown inductance contain only fundamental frequency
• mechanical resonance frequency of null detectors are beyond the range of harmonic frequencies
• final expression for unknown inductance is independent of frequency

14. Maxwell’s bridge can be used for measurement of inductance with

• high Q factors
• very low Q factors
• medium Q factors
• wide range of Q factor variations

15. The advantage of Hay’s bridge over Maxwell’s inductance–capacitance bridge is that

• its final balance equations are independent of frequency
• it reduces cost by not making capacitor or inductor as the variable parameters
• it can be used measuring low Q inductors
• it can be used measuring high Q inductors

16. The advantage of Anderson’s bridge over Maxwell’s bridge is that

• its final balance equations are independent of inductor losses
• it reduces cost by not making capacitor or inductor as the variable parameters
• number of bridge components required are less
• attaining balance condition is easier and less time consuming

17. The main advantage of Owen’s bridge for measurement of unknown inductance is that

• it has two independent elements R and C for achieving balance
• it can be used for measurement of very high Q coils
• it is very inexpensive
• it can be used for measurement of unknown capacitance as well

18. DeSauty’s bridge is used for measurement of

• high Q inductances
• low Q inductances
• loss less capacitors
• capacitors with dielectric losses

19. Schering bridge can be used for measurement of

• capacitance and dissipation factor
• dissipation factor only
• inductance with inherent loss
• capacitor but not dissipation factor

20. Frequency can be measured using

• Anderson’s bridge
• Maxwell’s bridge
• De Sauty’s bridge
• Wien’s bridge

Share with :