2. Questions On Measurement Of Inductance And Capacitance 20695f

AC Bridges Basics - Electrical Measurements Q...

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AC Bridges Basics - Electrical Measurements Questions and Answers by Manish 3-4 minutes

This set of Electrical Measurements & Measuring Instruments Multiple Choice Questions & Answers (MCQs) focuses on “Introduction to AC Bridges”. 1. In the simplest form, an AC bridge consists of ____________ a) arms, source and a detector b) arms and source c) source and detector d) arms and detector View Answer Answer: a Explanation: In its simplest form, an AC bridge consists of four arms, a source for excitation and a null detector. The source is connected across a pair of arms while the detector is connected to the pair of opposite arms. 2. Source is ________ a) dc supply 1 of 5

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b) ac supply c) mixed mode supply d) high voltage supply View Answer Answer: b Explanation: For an AC bridge we require an AC supply as the source of voltage. It supplies AC voltage at the required frequency. 3. At high frequency, source consists of ________ a) amplifiers b) regulators c) oscillators d) op amps View Answer Answer: c Explanation: Op amps are basically differential amplifiers. Amplifiers are used in analog circuits for increasing the strength of the signal. Electronic oscillators form sources at high frequencies. 4. Commonly used balance detectors for AC bridges are headphones, tuned amplifiers and vibration galvanometers. a) True b) False View Answer Answer: a Explanation: Headphones, tuned amplifier circuits and vibration galvanometers are used for detecting the balance condition in AC bridges. 2 of 5

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5. What is the frequency range for a headphone as a detector? a) 20 Hz to 20 kHz b) 10 kHz to 1 MHz c) 10 MHz to 1 GHz d) 250 Hz to 4 kHz View Answer Answer: d Explanation: Headphones can be used as detectors in AC bridges in the low audio frequency range. Low audio frequency range varies from 250 Hz to 4 KHz. 6. For single frequency value, the most sensitive detector is ________ a) tuned detector b) vibration galvanometer c) headphone d) oscillator View Answer Answer: a Explanation: Vibration galvanometer is used for detecting the balance condition. Oscillator is used as a source of supply voltage. Tuned detector is the most sensitive detector for a single frequency value. 7. Tuned detectors are used in the frequency range of ________ a) 1 Hz to 100 Hz b) 10 Hz to 100 Hz c) 1 kHz to 100 kHz 3 of 5

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d) 1 MHz to 100 MHz View Answer Answer: b Explanation: Tuned amplifier circuits are used as detectors in the low frequency range. Low frequency range usually ranges from 10 Hz to 100 Hz in AC bridges. 8. Vibration galvanometers are used for ________ a) very high frequency b) very low frequency c) low audio frequency d) high audio frequency View Answer Answer: c Explanation: Vibration galvanometers are used as detectors in AC bridges for low audio frequency. Low audio frequency ranges from 5 Hz to 1000 Hz. 9. AC bridge is an outcome of ________ a) Kelvin bridge b) Megger c) De Sauty bridge d) Wheatstone bridge View Answer Answer: d Explanation: Wheatstone bridge is the simplest form of bridge for the measurement of resistance and forms the basis for an AC bridge. Kelvin bridge is used for the measurement of low resistance and a megger is used for the measurement of high resistances. 4 of 5

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Sanfoundry Global Education & Learning Series – Electrical Measurements. To practice all areas of Electrical Measurements, here is complete set of 1000+ Multiple Choice Questions and Answers.

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Sources & Detectors - Electrical Measurements...


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Sources & Detectors - Electrical Measurements Questions and Answers by Manish 3-4 minutes

This set of Electrical Measurements & Measuring Instruments Multiple Choice Questions & Answers (MCQs) focuses on “Sources and Detectors”. 1. At very low frequencies in a AC bridge, the source is _________ a) power line b) e.m.f c) galvanometer d) tuned circuit View Answer Answer: a Explanation: Galvanometer is used for detecting the balance condition. The power line acts as a source of supply for bridge measurements in an AC bridge circuit at very low frequencies. 2. At high frequencies in a AC bridge, the source is _______ 1 of 4

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a) tuned amplifiers b) oscillators c) vibration galvanometer d) high voltage source View Answer Answer: b Explanation: Tuned amplifiers are used as a source of voltage in AC bridges. Electronic oscillators are used as a source of supply for bridge measurements in an AC bridge circuit at high frequencies. 3. The frequency range of a typical oscillator is _______ a) 1 Hz to 50 Hz b) 1 kHz to 100 KHz c) 40 Hz to 125 kHz d) 1 MHz to 150 MHz View Answer Answer: c Explanation: An oscillator has a frequency range slightly above the audio frequency. A typical oscillator has a frequency range of 40 Hz to 125 kHz. 4. The power output for a typical oscillator is _______ a) 1 kW b) 1 MW c) 1 mW d) 7 W View Answer Answer: d Explanation: Oscillator usually has a low power output. A 2 of 4

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typical oscillator has a power output of around 7 W. 5. The output waveform in a oscillator is _______ a) sinusoidal b) cosinusoidal c) tangential d) logarithmic View Answer Answer: a Explanation: AC supply is generally in the form of sinusoidal signal. In an electronic oscillator, output waveform is very close to sinusoidal. 6. The output frequency of an oscillator is _______ a) unstable and fixed b) stable and adjustable c) stable and fixed d) unstable and variable View Answer Answer: b Explanation: In an electronic oscillator, the output frequency is stable. It can be determined accurately and is also adjustable. 7. The output power of an oscillator is not enough to drive power circuits. a) True b) False View Answer Answer: b

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Explanation: Power circuits generally require a low output in order to function. An electronic oscillator provides sufficient output power to drive power circuits. 8. Tuned amplifiers can be set to _______ a) low frequencies b) high frequencies c) any frequency d) audio frequencies View Answer Answer: c Explanation: Tuning refers to varying a parameter. Tuned amplifier circuits can be set to any desired frequency. 9. Tuned amplifier circuits respond to broad bandwidth at bridge frequency. a) True b) False View Answer Answer: b Explanation: Amplifiers can be used to detect the balance condition in AC bridges. Tuned amplifier circuits consist of transistors that respond to a narrow bandwidth at the bridge frequency. Sanfoundry Global Education & Learning Series – Electrical Measurements. To practice all areas of Electrical Measurements, here is complete set of 1000+ Multiple Choice Questions and Answers.

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Bridge Balance Equation Questions and Answers


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Bridge Balance Equation Questions and Answers by Manish 3-4 minutes

This set of Electrical Measurements & Measuring Instruments Multiple Choice Questions & Answers (MCQs) focuses on “Bridge Balance Equation”. 1. Bridge balance equation for magnitude is given by the relation a) Z1 Z4 = Z2 Z3 b) Z1 Z2 = Z3 Z4 c) Z2 Z4 = Z1 Z3 d) Z1 Z3 = Z2 Z4 View Answer Answer: a Explanation: In an AC bridge, the balance condition for magnitude is given by the equation Z1 Z 4 = Z 2 Z 3 where, Z1, Z2, Z3 and Z4 are the impedance arms of the AC bridge circuit. 2. Angular balance equation is given by the relation a) θ1 × θ4 =θ2 × θ3

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b) θ1 + θ4 =θ2 + θ3 c) θ2 + θ4 =θ1 + θ3 d) θ2 × θ4 =θ1 × θ3 View Answer Answer: b Explanation: The angular balance condition in an AC bridge is given by the relation θ1 + θ4 = θ2 + θ3 Where, θ1, θ2, θ3 and θ4 are the phase angles of the impedances Z1, Z2, Z3 and Z4. 3. Bridge must be balanced for ________ a) magnitude b) angle c) magnitude and angle d) power View Answer Answer: c Explanation: The ratio arms consist of impedances which have magnitude as well as phase. In an AC bridge, balance condition implies magnitude balance as well as angular balance. 4. Phase angle is based on _______ a) source b) detector c) power d) impedance View Answer 2 of 4

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Answer: d Explanation: The four ratio arms comprise of impedances which consist of not only magnitude but some phase as well. Value of the phase angles are based on the component of individual impedances. 5. For inductive impedances, the phase angle is _______ a) positive b) negative c) zero d) exponential View Answer Answer: a Explanation: The current through an inductor does not increase instantaneously. For inductive impedances, the voltage leads the current and as a result the phase angle is positive. 6. For capacitive impedances, the phase angle is _______ a) tangential b) negative c) positive d) logarithmic View Answer Answer: b Explanation: The voltage across a capacitor does not rise instantaneously. For capacitive impedances, the current leads the voltage and as a result the phase angle is negative. 7. Bridge balance equation for magnitude in of 3 of 4

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ittances is given by the relation. a) Y1Y3 = Y2Y4 b) Y1Y2 = Y3Y4 c)Y1Y4 = Y2Y3 d) Y1 Y3 = Y2 Y4 View Answer Answer: c Explanation: ittance is the reciprocal of impedance. The balance condition for magnitude is given by the equation

8. When bridge is balanced? a) no voltage drop across the circuit b) power dissipation is high c) temperature of the circuit is high d) no current flows View Answer Answer: d Explanation: At balance condition, no current flows through the headphones present in the AC bridge circuit. As a result the detector indicates null deflection at balance condition. Sanfoundry Global Education & Learning Series – Electrical Measurements. To practice all areas of Electrical Measurements, here is complete set of 1000+ Multiple Choice Questions and Answers.

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Capacitance Comparison Bridge - Electrical Me...


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Capacitance Comparison Bridge Electrical Measurements Questions and Answers by Manish 3-4 minutes

This set of Electrical Measurements & Measuring Instruments Multiple Choice Questions & Answers (MCQs) focuses on “Capacitance Comparison Bridge”. 1. In a capacitance bridge, the arms are _________ a) resistive b) capacitive c) inductive d) mixture of resistance, capacitance and inductance View Answer Answer: a Explanation: The capacitance bridge is mainly used for the measurement of unknown capacitance. The ratio arms in a capacitance bridge are resistive in nature. 2. How is the bridge balanced? a) using resistance R1 b) using resistance R3 c) through capacitance C3 1 of 4

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d) through capacitance Cx View Answer Answer: b Explanation: Bridge balance is obtained by varying the resistance R3. At balance we get the value of the unknown resistance as Rx = R1 R3⁄R2.

3. Impedance Z4 consists of _________ a) resistance Rx b) capacitance Cx c) combination of capacitance Cx and resistance Rx d) consists of a detector View Answer Answer: c Explanation: Ratio arm Z4 consists of the unknown impedance. Impedance Z4 consists of capacitance Cx in series with a leakage resistance Rx. 4. Impedance Z3 consists of_________ a) resistance R3 b) capacitance C3 c) vibration galvanometer d) capacitance C3 in series with resistance R3 View Answer Answer: d Explanation: Impedance usually refers to the combination of resistance and either capacitance or inductance. As we are considering the case of capacitance measurement, impedance Z3 comprises capacitance C3 in series with

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resistance R3. 5. Unknown capacitance value is obtained by _________ a) comparison with standard b) using a tuned detector c) using capacitance of other ratio arms d) using a vibration galvanometer View Answer Answer: a Explanation: Tuned circuit is used for detecting balance condition. Vibration galvanometer is used for the same purpose. Unknown value of capacitance is obtained by comparing it with a standard value. 6. Unknown resistance is obtained by using the relation

View Answer Answer: b Explanation: The value of the unknown resistance is obtained by using the relation Rx = R2 R3⁄R1 at balance condition. 7. Unknown capacitance is found by using the relation

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View Answer Answer: c Explanation: The value of unknown capacitance is found using the relation Cx = C3 R1⁄R2 at balance condition. 8. Actual balance condition can be obtained by _________ a) varying R1 b) varying R3 c) varying R2 d) varying R1 and R3 View Answer Answer: d Explanation: Resistances R1 and R3 are variable, while resistance R2 is fixed. By varying the resistances R1 and R3, we get the actual balance condition. Sanfoundry Global Education & Learning Series – Electrical Measurements. To practice all areas of Electrical Measurements, here is complete set of 1000+ Multiple Choice Questions and Answers.

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Inductance Comparison Bridge Questions and ...


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Inductance Comparison Bridge Questions and Answers by Manish 3-4 minutes

This set of Electrical Measurements & Measuring Instruments Multiple Choice Questions & Answers (MCQs) focuses on “Inductance Comparison Bridge”. 1. Inductance comparison bridge is used to compute a) unknown inductance and resistance b) unknown resistance c) unknown inductance d) unknown capacitance View Answer Answer: a Explanation: By making use of an inductance comparison bridge, the values of unknown inductance and its internal resistance can be determined. 2. Ratio arms of the bridge consists of _________ a) pure inductances b) pure resistances c) pure capacitances d) inductance and capacitance

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View Answer Answer: b Explanation: An inductance comparison bridge is basically used to compute the unknown resistance and inductance values. Ratio arms of an inductance bridge consists of pure resistances. 3. Value of unknown resistance is found by using the relation

View Answer Answer: c Explanation: The inductance comparison bridge mainly consists of pure resistances in its ratio arm. The value of unknown resistance is given by the relation Rx = R2 R3⁄R1. 4. The value of unknown inductance is found by using the relation

View Answer Answer: d

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Explanation: At balance condition in an inductance comparison bridge, the value of unknown inductance is found by using the relation Lx = R2 L3⁄R1. 5. Inductance control is obtained by _________ a) using R2 b) using R1 c) using R3 d) using Lx View Answer Answer: a Explanation: In an inductance comparison bridge, the resistance R2 and R3 are variable. The value of resistance R2 is varied so as to control the inductance of the bridge. 6. Bridge depends on frequency. a) True b) False View Answer Answer: b Explanation: In an inductance comparison bridge, the balance equation is independent of frequency. As a result the bridge balance condition remains unaffected by variation in the value of frequency. 7. Bridge can be used at audio frequency. a) True b) False View Answer Answer: a

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Explanation: An inductance comparison bridge can be used for measurement of unknown inductance at a wide range of audio frequencies in the order of a few Hz to KHz. 8. Bridge is used for the measurement of _________ a) high Q factor b) medium Q factor c) low Q factor d) very low Q factor View Answer Answer: b Explanation: The inductance comparison bridge is used for the measurement of low Q factor values of the order of 1 to 10. It cannot be used for the measurement of Q factors below 1. As a result, the bridge is used for the measurement of medium Q factor values. Sanfoundry Global Education & Learning Series – Electrical Measurements. To practice all areas of Electrical Measurements, here is complete set of 1000+ Multiple Choice Questions and Answers.

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Electrical Measurements Interview Questions a...


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Electrical Measurements Interview Questions and Answers by Manish 6-7 minutes

This set of Electrical Measurements Interview Questions and Answers focuses on “Anderson Bridge, Advantages & Disadvantages of Anderson Bridge”. 1. Anderson bridge is used for _________ a) the measurement of self-inductance b) the measurement of resistance c) the measurement of capacitance d) the measurement of impedance View Answer Answer: a Explanation: The Anderson bridge is one of the important bridges used for the measurement of self-inductances in of a standard capacitance value. Resistance is usually measured by making use of a Wheatstone’s bridge or Kelvin’s double bridge. 2. Anderson bridge is a modified form of ________ a) Wheatstone’s bridge b) Maxwell bridge

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c) Kelvin double bridge d) Schering bridge View Answer Answer: b Explanation: The Anderson’s bridge is a modified form of Maxwell’s bridge which is used for the measurement of selfinductances in of a standard capacitance value. Wheatstone bridge and Kelvin bridge are used for the measurement of medium and low resistances respectively. 3. Anderson’s bridge is basically used for ________ a) measurement of capacitance b) measurement of resistance c) measurement of inductance d) measurement of voltage View Answer Answer: c Explanation: Anderson’s bridge is used basically for the precise measurement of self-inductances in of a standard capacitance value over a wide range of values. 4. Balance equation for computing the inductance is ________ a) Lx = R3 R5 b) Lx = CR5 c) Lx = CR3 d) Lx = CR3 R5 View Answer Answer: d Explanation: The balance equation for computing the self2 of 7

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inductance in an Anderson’s bridge is given by the equation, Lx = CR3 R5. where, C is the standard capacitance R3 and R5 are the known non-inductive resistances. 5. Balance equation for computing the resistance is a) R1 = R2 R3⁄R4 b) R1 = R2 ⁄ R4 c) R1 = R3 ⁄ R4

d) R1 = R2 R3 View Answer Answer: a Explanation: The balance equation for computing the resistance in an Anderson’s bridge is given by the equation R1 = R2 R3⁄R4. where, R2, R3 and R4 are the known non-inductive resistances. 6. When the capacitor used is imperfect, the inductance value changes. a) True b) False View Answer Answer: b Explanation: For an imperfect capacitor used in the Anderson bridge, the value of inductance remains unaffected. The value of R1 changes. 7. Anderson’s bridge is used for the measurement of capacitance.

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a) True b) False View Answer Answer: a Explanation: When a calibrated self-inductance is available, the value of unknown capacitance can be computed by making use of an Anderson’s bridge. 8. Anderson’s bridge is used for the measurement of ________ a) capacitance b) resistance c) inductance d) impedance View Answer Answer: a Explanation: Anderson’s bridge is used for the measurement of capacitance. Unknown capacitance value can be measured accurately in of the self-inductance of one of the ratio arms of the bridge. 9. Anderson’s bridge makes use of a variable capacitance. a) True b) False View Answer Answer: b Explanation: An Anderson’s bridge makes use of a fixed capacitance value. Most of the other AC bridges used for the measurement of either capacitance, inductance or impedance make use of a variable capacitance. 4 of 7

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10. Anderson’s bridge is very basic. a) True b) False View Answer Answer: b Explanation: An Anderson’s bridge is basically used for the measurement of unknown capacitance value in of the self-inductance of one of the standard ratio arms. It is a complex bridge comprising of equivalent star-delta networks for computation of resistance and inductance. 11. Bridge balance equations are ________ a) easy to derive b) independent of the components c) complex in nature d) real in nature View Answer Answer: c Explanation: An Anderson’s bridge is basically used for the measurement of unknown capacitance value in of the self-inductance of one of the ratio arms. It consists of real as well as complex . It also comprises of star-delta equivalent networks for impedance computations. 12. Components in an Anderson’s bridge are ________ a) less b) zero c) intermediate d) more View Answer 5 of 7

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Answer: d Explanation: An Anderson’s bridge is a complex type of bridge used basically for the measurement of unknown capacitance. It consists of several resistances, inductances and capacitances in the ratio arms. 13. Anderson’s bridge ________ a) can’t be shielded b) can be fully shielded c) can be partially shielded d) can be shielded based on the components used View Answer Answer: a Explanation: An Anderson’s bridge is a complex circuit and a modified form of the Maxwell bridge. An Anderson’s bridge cannot be shielded due to the presence of an additional junction point. 14. What is the significance of Anderson bridge with respect to Q factor? a) difficult to balance the bridge b) easy to balance the bridge c) intermediate balance can be achieved d) no balance can be done View Answer Answer: b Explanation: An Anderson’s bridge is a modified form of the Maxwell bridge and is used for the measurement of unknown capacitance in of self-inductance of a standard value. It is easy to achieve balance condition in an 6 of 7

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Anderson bridge. 15. An Anderson’s bridge can be used to ________ a) measure mutual inductance b) measure impedance c) measure self inductance d) measure stray capacitance View Answer Answer: c Explanation: An Anderson bridge can be used for the measurement of the self-inductance of a coil. A coil with unknown capacitance can be used to determine its selfinductance by making use of an Anderson bridge. Sanfoundry Global Education & Learning Series – Electrical Measurements. To practice all areas of Electrical Measurements for Interviews, here is complete set of 1000+ Multiple Choice Questions and Answers.

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Schering Bridge - Electrical Measurements Que...


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Schering Bridge - Electrical Measurements Questions and Answers by Manish 4-5 minutes

This set of Electrical Measurements & Measuring Instruments Multiple Choice Questions & Answers (MCQs) focuses on “Schering Bridge”. 1. Schering bridge is one of the most widely used AC bridges. a) True b) False View Answer Answer: a Explanation: Schering bridge is an AC bridge used for the measurement of unknown capacitance, dielectric loss and power factor. It is one of the most commonly used AC bridges. 2. Schering bridge is used for _________ a) low voltages only b) low and high voltages c) high voltages only 1 of 5

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d) intermediate voltages only View Answer Answer: b Explanation: Schering bridge is used for both low as well as high voltages. A particular bridge connection is used for low voltage. High voltages employ the use of a different type of Schering bridge. 3. Power factor of a Schering bridge is _________ a) p.f. = sin∅x = Zx⁄Rx

b) p.f. = cot∅x = Rx⁄Zx

c) p.f. = cos∅x = Rx⁄Zx d) p.f. = tan∅x = Rx⁄Zx View Answer Answer: c Explanation: The power factor of the RC combination in a Schering bridge is given by the relation p.f. = cos∅x = Rx⁄Zx . where, Rx is the series resistance Zx is the series impedance comprising of Rx and Cx. 4. For phase angles close to 90°, the power factor of the bridge is _________ a) p.f. = ωRx b) p.f. = ωCx c) p.f. = Rx Cx d) p.f. = ωRx Cx View Answer Answer: d Explanation: When phase angle reaches 90°,

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reactance equals the impedance and the power factor of the bridge is calculated using the relation,

5. For a series RC circuit, what is δ? a) voltage between series RC combination and C b) voltage between series RC combination c) voltage across C d) voltage across R View Answer Answer: a Explanation: In a series RC circuit, δ refers to the angle between the series combination of Rx, Cx and the voltage across the capacitance Cx. δ is also known as the loss angle. 6. What is the expression for the loss angle? a) tan δ = ωR4 b) tan δ = ωR4 C4 c) tan δ = ωC4 d) tan δ = R4 C4 View Answer Answer: b Explanation: The expression for the loss angle can be computed as the ratio of the tangent of the voltage drop across resistance Rx to the voltage drop across the capacitance Cx.

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7. Quality factor is given by the expression a) Q = 1⁄R b) Q = R c) Q = X⁄R d) Q = XR View Answer Answer: c Explanation: The quality factor the Schering bridge circuit is defined as Q = X⁄R.

where, X = 1⁄wC is the capacitive impedance. 8. Dissipation factor is the reciprocal of quality factor. a) True b) False View Answer Answer: a Explanation: Dissipation factor for a circuit is defined as the reciprocal of the quality factor. It is given by the expression Q = 1⁄wCR. It basically provides information about the quality of a capacitor. 9. Commercial Schering bridge can be used for the measurement of capacitances a) from 10pF to 0.1nF b) from 100pF to 1µF c) from 50nF to 10mF d) from 25mF to 5F View Answer Answer: b Explanation: Commercial Schering bridges are used for the 4 of 5

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measurement of capacitances in the range of a few pico farads to a few micro farads. Accuracy varies in the range of –2% to +2%. 10. A Schering bridge can be used for the a) measuring voltages b) measuring currents c) testing capacitors d) protecting the circuit from temperature rises View Answer Answer: c Explanation: A Schering bridge can be used with both low voltage as well as high voltages. A Schering bridge is basically used for the measurement of small capacitances at low voltages with high precision. Sanfoundry Global Education & Learning Series – Electrical Measurements. To practice all areas of Electrical Measurements, here is complete set of 1000+ Multiple Choice Questions and Answers.

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High Voltage Schering Bridge - Electrical Meas...


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High Voltage Schering Bridge Electrical Measurements Questions and Answers by Manish 4 minutes

This set of Electrical Measurements & Measuring Instruments Multiple Choice Questions & Answers (MCQs) focuses on “High Voltage Schering Bridge”. 1. A Schering bridge can be used for capacitance measurements at low voltages. a) True b) False View Answer Answer: b Explanation: When a Schering bridge is used for the measurement of small capacitances at low voltages, it comprises of errors. In order to avoid this a high voltage Schering bridge is used. 2. How is high voltage obtained? a) by using a step up transformer b) by using a high voltage source c) by using a step down transformer 1 of 4

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d) by using a high current source View Answer Answer: a Explanation: High voltage supply for a Schering bridge is obtained by making use of a step up transformer. The frequency for the high voltage supply used in a Schering bridge is 50 Hz. 3. The detector used in a high voltage Schering bridge is _________ a) tunable circuit b) e.m.f source c) vibration galvanometer d) headphone View Answer Answer: c Explanation: A high voltage Schering bridge is used for the measurement of low capacitance values at high voltages. A vibration galvanometer is used as a detector in a high voltage Schering bridge. 4. Detector is very sensitive in a high voltage Schering bridge. a) True b) False View Answer Answer: a Explanation: In a high voltage Schering bridge the ratio arms have high impedance values. As a result, a very small current is drawn by the ratio arms. Hence the detector must 2 of 4

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be very sensitive in a high voltage Schering bridge. 5. How are the inter-capacitance errors minimized? a) by separating the plates of the capacitance b) by using earthing c) by reducing the area of cross section of the capacitors d) by increasing the distance between the capacitor plates View Answer Answer: b Explanation: In a high voltage Schering bridge, errors due to inter-capacitance between the high and low impedance ratio arms can be eliminated through earthing screens. 6. How to minimize the effect of earth capacitance? a) by increasing the supply voltage b) by using a series resistance c) by using a Wagner ground connection d) by using an inductor across the circuit View Answer Answer: c Explanation: In a high voltage Schering bridge, the effect of earth capacitance on the circuit including the galvanometer and the leads is minimized by making use of a Wagner ground connection. 7. What is the effect of breakdown of high voltage capacitor? a) No effect b) voltage drop across the circuit reduces c) circuit components rupture d) a high voltage appears across the branches 3 of 4

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View Answer Answer: d Explanation: In a high voltage Schering bridge, a very high voltage appears across the branches when the breakdown of high voltage capacitor occurs. This is prevented by making use of a spark gap across the branches involved. 8. What is dependence of frequency on the balance equation? a) independent b) varies by a factor of 2 c) depends on the supply magnitude d) depends on the detector used View Answer Answer: a Explanation: In a high voltage Schering bridge, the balance equation does not depend on the frequency of operation of the circuit. A detector is only used for detecting the balance condition in a bridge circuit. Sanfoundry Global Education & Learning Series – Electrical Measurements. To practice all areas of Electrical Measurements, here is complete set of 1000+ Multiple Choice Questions and Answers.

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Maxwell's Inductance Capacitance Bridge Ques...


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Maxwell's Inductance Capacitance Bridge Questions and Answers by Manish 3-4 minutes

This set of Electrical Measurements & Measuring Instruments Multiple Choice Questions & Answers (MCQs) focuses on “Maxwell’s Inductance Capacitance Bridge”. 1. Maxwell inductance capacitance bridge can be used for _________ a) measurement of inductance b) measurement of capacitance and inductance c) measurement of resistance d) measurement of voltage and current View Answer Answer: a Explanation: A Maxwell inductance capacitance bridge is used for the measurement of inductance by making comparison with a standard capacitance value. Voltmeter is used to measure voltage, while an ammeter is used to measure current. 2. Balance equation for computing the unknown resistance is

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View Answer Answer: b Explanation: The balance condition for determining the value of the unknown resistance is given by the relation Rx = R2 R3⁄R1.

where, R1 and R3 are variable resistances and R2 is a fixed resistance. 3. Balance equation for computing the value of the unknown inductance is a) Lx = R2 R3 b) Lx = R2 C1 c) Lx = R2 R3 C1 d) Lx = R3 C1 View Answer Answer: c Explanation: The balance equation for determining the value of the unknown inductance is given by the relation Lx= R2 R3 C1. where, C1 is the capacitance across the resistance R1 R3 is a variable resistance and R2 is a fixed resistance. 4. Quality factor of the circuit is given by _________ a) Q = ωC1 2 of 4

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b) Q = ωR1 c) Q = ω d) Q = ωR1 C1 View Answer Answer: d Explanation: The quality factor of a Maxwell inductance capacitance bridge is given by the relation

5. Standard inductor requires no shielding. a) True b) False View Answer Answer: b Explanation: Stray magnetic fields are present in a circuit consisting of inductances and capacitances. In order to eliminate the stray magnetic fields proper shielding is required for the standard inductance. 6. Standard inductor provides rated inductance directly. a) True b) False View Answer Answer: b Explanation: When the current flow through the standard inductance is adjusted precisely, it provides its rated value of inductance. 7. What is the significance of capacitors in a Maxwell

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bridge? a) they are used to block dc b) they are used to block ac c) they are cheap d) they are expensive View Answer Answer: c Explanation: In a Maxwell inductance capacitance bridge, the capacitors are cheaper when compared to stable and accurate standard value of inductors. 8. The bridge balance equation can be written in _________ a) impedance form b) resistance form c) conductance form d) ittance form View Answer Answer: d Explanation: The bridge balance equation for a Maxwell inductance capacitance bridge consists of ittances. This is due to the connection of a capacitance in parallel across the resistance in one of the ratio arms. Sanfoundry Global Education & Learning Series – Electrical Measurements. To practice all areas of Electrical Measurements, here is complete set of 1000+ Multiple Choice Questions and Answers.

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Electrical Measurements Questions for Campus ...


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Electrical Measurements Questions for Campus Interviews by Manish 4 minutes

This set of Electrical Measurements Questions and Answers for Campus interviews focuses on “Advantages and Limitations of Maxwell Bridge”. 1. What is the significance of the balance equation on losses? a) independent of losses in inductance b) independent of losses in capacitance c) independent of losses in resistance d) independent of losses in the circuit View Answer Answer: a Explanation: The balance equation in a Maxwell inductance capacitance bridge is independent of the losses associated with an inductance. According to the balance equation the unknown inductance is computed as Lx = R2 R3 C1 2. Balance equation is dependent on frequency. a) True b) False

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View Answer Answer: b Explanation: The balance equation in a Maxwell inductance capacitance bridge is independent on the measurement of frequency. The balance equation does not contain frequency such as ω and as a result, it is independent of frequency. 3. How can R1 be scaled? a) by using a scale b) by using an ohmmeter c) by calibration d) by using a galvanometer View Answer Answer: c Explanation: The resistance R1 in a Maxwell inductance capacitance bridge can be scaled through calibration. The value of the Quality factor Q can be read directly through calibration. 4. Scale of resistance can be calibrated. a) True b) False View Answer Answer: a Explanation: The resistance R1 in a Maxwell inductance capacitance bridge can be calibrated directly. As a result the value of the unknown inductance can be read directly. 5. Bridge can be used for the measurement of _________

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a) high Q values b) intermediate Q values c) very low Q values d) low Q values View Answer Answer: d Explanation: A Maxwell inductance capacitance bridge can be used for the measurement of low Q values only of the order of 1 to 10. This is because at high Q factor values the angular balance condition is not satisfied. 6. The balance condition is _________ a) is easy to obtain b) is difficult to obtain c) can’t be obtained d) exists always View Answer Answer: b Explanation: The balance condition in a Maxwell inductance capacitance bridge is difficult to obtain. This occurs due to an interaction between resistance and reactance components in the bridge circuit. 7. Commercial Maxwell bridges measure a) inductances in the range of 1 to 1000H b) capacitances in the range of 10mF to 1F c) resistances in the range of 0.001 Ω to 1Ω d) power in the range of 1W to 50MF View Answer Answer: a 3 of 4

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Explanation: Basically a Maxwell bridge is used for the measurement of inductance in of known standard capacitance value. Inductances in the range of 1 to 1000H with an accuracy range of ±2% can be measured. 8. At high Q values, the angular balance condition a) is satisfied b) is not satisfied c) is independent of Q factor d) is partially affected View Answer Answer: b Explanation: For high Q factor values in a Maxwell inductance capacitance bridge, the angular balance condition is affected. The relation θ1 + θ4 = θ2 + θ3 is not satisfied at high Q factor values. This occurs as θ4 reaches 90°. θ1 must become –90° as per the angular balance condition. But for this the value of R1 should be very high, which is not practically feasible. Sanfoundry Global Education & Learning Series – Electrical Measurements. To practice all areas of Electrical Measurements for Campus Interviews, here is complete set of 1000+ Multiple Choice Questions and Answers.

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Bridges Shielding & Grounding - Electrical Mea...


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Bridges Shielding & Grounding Electrical Measurements Questions and Answers by Manish 3-4 minutes

This set of Electrical Measurements & Measuring Instruments Multiple Choice Questions & Answers (MCQs) focuses on “Shielding and Grounding of Bridges”. 1. In general bridges consist of __________ a) lumped inductances b) lumped resistances c) distributed capacitance d) distributed impedance View Answer Answer: a Explanation: AC bridges in general such as Maxwell, Anderson, Schering etc consist of lumped components such as inductance. 2. Stray capacitance exists between the components. a) True b) False View Answer 1 of 4

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Answer: a Explanation: In general in AC bridges, stray capacitance exists between the components of the bridge with respect to the ground. These stray capacitances short the ratio arms and lead to errors in the measurement. 3. The magnitude of stray capacitances is fixed. a) True b) False View Answer Answer: b Explanation: Stray capacitances are uncertain in nature. Their magnitude depends on the adjustment of the bridge arms and the position of the operator. 4. Stray capacitance effects can be minimized by __________ a) making use of an inductance b) connecting a resistance in series c) shielding and grounding d) using a galvanometer View Answer Answer: c Explanation: The stray capacitance effects in an AC bridge can be eliminated by shielding and grounding. This method helps in making the stray capacitances constant in value. They can be compensated. 5. Most popular method of avoiding the stray capacitance effects is __________ a) by grounding 2 of 4

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b) by using guard rings c) by using galvanometer d) by using Wagner device View Answer Answer: d Explanation: A Wagner earthing device is used in general to eliminate the stray capacitance effects in AC bridges. The stray capacitance effects between the components in the ratio arms with respect to ground can be eliminated through this method. 6. Wagner device is a ____________ a) capacitance bridge b) resistance bridge c) inductance bridge d) impedance bridge View Answer Answer: a Explanation: A Wagner earth device is generally used for shielding and grounding purpose. It consists of capacitances in the ratio arms along with a series RC combination connected across the ends of the bridge forming a potential divider. 7. Which is the guarding arm? a) parallel RC combination b) series RC combination c) resistance R d) capacitance C View Answer 3 of 4

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Answer: b Explanation: The series combination of R and C in a Wagner earth device forms a potential divider across the ratio arms. It is also known as the guard arm. 8. Bridge is suitable for _________ a) coils with high Q values b) coils with low Q values c) coils with intermediate Q values d) coils with very high Q values View Answer Answer: b Explanation: The Maxwell inductance capacitance bridge is basically used for the measurement of Quality factor (Q) of inductance coils with low Q values. Sanfoundry Global Education & Learning Series – Electrical Measurements. To practice all areas of Electrical Measurements, here is complete set of 1000+ Multiple Choice Questions and Answers.

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