Electrical Measurements & Instrumentation interview questions

1. A.total VA impedance connected across the current transformer secondary, which must stay within the rated value to preserve accuracy class
2. B.permanent-magnet moving-coil meter with a uniform scale that reads only the average of DC, extended with shunts and multipliers
3. C.bridge for low resistances below 1 Ω that removes lead and contact resistance error with a second pair of ratio arms
4. D.measures total three-phase power as W1 plus W2, with power factor obtained from tan φ equal to √3 (W1 − W2)/(W1 + W2)

Answer + AI explanation with Pro

1. A.Kelvin double bridge
2. B.Schering bridge
3. C.PMMC instrument
4. D.Moving-iron instrument

Answer + AI explanation with Pro

1. A.PMMC instrument — total VA impedance connected across the current transformer secondary, which must stay within the rated value to preserve accuracy class
2. B.PMMC instrument — permanent-magnet moving-coil meter with a uniform scale that reads only the average of DC, extended with shunts and multipliers
3. C.PMMC instrument — four-arm resistance bridge balanced when the products of opposite arms are equal, used for medium resistances of about 1 Ω to 100 kΩ
4. D.PMMC instrument — reads rms of AC or DC because deflection is proportional to current squared, which gives a non-uniform cramped scale

Answer + AI explanation with Pro

1. A.reads rms of AC or DC because deflection is proportional to current squared, which gives a non-uniform cramped scale
2. B.permanent-magnet moving-coil meter with a uniform scale that reads only the average of DC, extended with shunts and multipliers
3. C.slow rotation of an induction meter disc with no load current, prevented by two diametrically opposite holes drilled in the disc
4. D.measures total three-phase power as W1 plus W2, with power factor obtained from tan φ equal to √3 (W1 − W2)/(W1 + W2)

Answer + AI explanation with Pro

1. A.Moving-iron instrument
2. B.PMMC instrument
3. C.Kelvin double bridge
4. D.Two-wattmeter method

Answer + AI explanation with Pro

1. A.Moving-iron instrument — measures total three-phase power as W1 plus W2, with power factor obtained from tan φ equal to √3 (W1 − W2)/(W1 + W2)
2. B.Moving-iron instrument — total VA impedance connected across the current transformer secondary, which must stay within the rated value to preserve accuracy class
3. C.Moving-iron instrument — reads rms of AC or DC because deflection is proportional to current squared, which gives a non-uniform cramped scale
4. D.Moving-iron instrument — bridge for low resistances below 1 Ω that removes lead and contact resistance error with a second pair of ratio arms

Answer + AI explanation with Pro

1. A.permanent-magnet moving-coil meter with a uniform scale that reads only the average of DC, extended with shunts and multipliers
2. B.total VA impedance connected across the current transformer secondary, which must stay within the rated value to preserve accuracy class
3. C.slow rotation of an induction meter disc with no load current, prevented by two diametrically opposite holes drilled in the disc
4. D.four-arm resistance bridge balanced when the products of opposite arms are equal, used for medium resistances of about 1 Ω to 100 kΩ

Answer + AI explanation with Pro

1. A.Schering bridge
2. B.Wheatstone bridge
3. C.PMMC instrument
4. D.Two-wattmeter method

Answer + AI explanation with Pro

1. A.Wheatstone bridge — four-arm resistance bridge balanced when the products of opposite arms are equal, used for medium resistances of about 1 Ω to 100 kΩ
2. B.Wheatstone bridge — bridge for low resistances below 1 Ω that removes lead and contact resistance error with a second pair of ratio arms
3. C.Wheatstone bridge — an instrument's maximum error as a percentage of full scale, such as class 0.5 CT for metering and class 5P for protection
4. D.Wheatstone bridge — permanent-magnet moving-coil meter with a uniform scale that reads only the average of DC, extended with shunts and multipliers

Answer + AI explanation with Pro

1. A.total VA impedance connected across the current transformer secondary, which must stay within the rated value to preserve accuracy class
2. B.reads rms of AC or DC because deflection is proportional to current squared, which gives a non-uniform cramped scale
3. C.measures total three-phase power as W1 plus W2, with power factor obtained from tan φ equal to √3 (W1 − W2)/(W1 + W2)
4. D.AC bridge for measuring capacitance and dissipation factor (tan δ) of high-voltage insulation with a standard capacitor in one arm

Answer + AI explanation with Pro

1. A.Moving-iron instrument
2. B.Kelvin double bridge
3. C.Schering bridge
4. D.Two-wattmeter method

Answer + AI explanation with Pro

1. A.Two-wattmeter method — measures total three-phase power as W1 plus W2, with power factor obtained from tan φ equal to √3 (W1 − W2)/(W1 + W2)
2. B.Two-wattmeter method — slow rotation of an induction meter disc with no load current, prevented by two diametrically opposite holes drilled in the disc
3. C.Two-wattmeter method — four-arm resistance bridge balanced when the products of opposite arms are equal, used for medium resistances of about 1 Ω to 100 kΩ
4. D.Two-wattmeter method — AC bridge for measuring capacitance and dissipation factor (tan δ) of high-voltage insulation with a standard capacitor in one arm

Answer + AI explanation with Pro

1. A.an instrument's maximum error as a percentage of full scale, such as class 0.5 CT for metering and class 5P for protection
2. B.reads rms of AC or DC because deflection is proportional to current squared, which gives a non-uniform cramped scale
3. C.measures total three-phase power as W1 plus W2, with power factor obtained from tan φ equal to √3 (W1 − W2)/(W1 + W2)
4. D.total VA impedance connected across the current transformer secondary, which must stay within the rated value to preserve accuracy class

Answer + AI explanation with Pro

1. A.Accuracy class
2. B.CT burden
3. C.Schering bridge
4. D.Two-wattmeter method

Answer + AI explanation with Pro

1. A.Accuracy class — four-arm resistance bridge balanced when the products of opposite arms are equal, used for medium resistances of about 1 Ω to 100 kΩ
2. B.Accuracy class — slow rotation of an induction meter disc with no load current, prevented by two diametrically opposite holes drilled in the disc
3. C.Accuracy class — reads rms of AC or DC because deflection is proportional to current squared, which gives a non-uniform cramped scale
4. D.Accuracy class — an instrument's maximum error as a percentage of full scale, such as class 0.5 CT for metering and class 5P for protection

Answer + AI explanation with Pro

1. A.reads rms of AC or DC because deflection is proportional to current squared, which gives a non-uniform cramped scale
2. B.permanent-magnet moving-coil meter with a uniform scale that reads only the average of DC, extended with shunts and multipliers
3. C.bridge for low resistances below 1 Ω that removes lead and contact resistance error with a second pair of ratio arms
4. D.an instrument's maximum error as a percentage of full scale, such as class 0.5 CT for metering and class 5P for protection

Answer + AI explanation with Pro

1. A.Kelvin double bridge
2. B.Energy meter creep
3. C.Moving-iron instrument
4. D.PMMC instrument

Answer + AI explanation with Pro

1. A.Kelvin double bridge — measures total three-phase power as W1 plus W2, with power factor obtained from tan φ equal to √3 (W1 − W2)/(W1 + W2)
2. B.Kelvin double bridge — four-arm resistance bridge balanced when the products of opposite arms are equal, used for medium resistances of about 1 Ω to 100 kΩ
3. C.Kelvin double bridge — bridge for low resistances below 1 Ω that removes lead and contact resistance error with a second pair of ratio arms
4. D.Kelvin double bridge — slow rotation of an induction meter disc with no load current, prevented by two diametrically opposite holes drilled in the disc

Answer + AI explanation with Pro

1. A.measures total three-phase power as W1 plus W2, with power factor obtained from tan φ equal to √3 (W1 − W2)/(W1 + W2)
2. B.total VA impedance connected across the current transformer secondary, which must stay within the rated value to preserve accuracy class
3. C.an instrument's maximum error as a percentage of full scale, such as class 0.5 CT for metering and class 5P for protection
4. D.slow rotation of an induction meter disc with no load current, prevented by two diametrically opposite holes drilled in the disc

Answer + AI explanation with Pro

1. A.Schering bridge
2. B.Kelvin double bridge
3. C.CT burden
4. D.PMMC instrument

Answer + AI explanation with Pro

1. A.CT burden — four-arm resistance bridge balanced when the products of opposite arms are equal, used for medium resistances of about 1 Ω to 100 kΩ
2. B.CT burden — total VA impedance connected across the current transformer secondary, which must stay within the rated value to preserve accuracy class
3. C.CT burden — an instrument's maximum error as a percentage of full scale, such as class 0.5 CT for metering and class 5P for protection
4. D.CT burden — reads rms of AC or DC because deflection is proportional to current squared, which gives a non-uniform cramped scale

Answer + AI explanation with Pro

1. A.bridge for low resistances below 1 Ω that removes lead and contact resistance error with a second pair of ratio arms
2. B.slow rotation of an induction meter disc with no load current, prevented by two diametrically opposite holes drilled in the disc
3. C.an instrument's maximum error as a percentage of full scale, such as class 0.5 CT for metering and class 5P for protection
4. D.AC bridge for measuring capacitance and dissipation factor (tan δ) of high-voltage insulation with a standard capacitor in one arm

Answer + AI explanation with Pro

1. A.Schering bridge
2. B.Wheatstone bridge
3. C.Energy meter creep
4. D.PMMC instrument

Answer + AI explanation with Pro

1. A.Energy meter creep — slow rotation of an induction meter disc with no load current, prevented by two diametrically opposite holes drilled in the disc
2. B.Energy meter creep — AC bridge for measuring capacitance and dissipation factor (tan δ) of high-voltage insulation with a standard capacitor in one arm
3. C.Energy meter creep — permanent-magnet moving-coil meter with a uniform scale that reads only the average of DC, extended with shunts and multipliers
4. D.Energy meter creep — total VA impedance connected across the current transformer secondary, which must stay within the rated value to preserve accuracy class

Answer + AI explanation with Pro

1. A.AC bridge for measuring capacitance and dissipation factor (tan δ) of high-voltage insulation with a standard capacitor in one arm
2. B.four-arm resistance bridge balanced when the products of opposite arms are equal, used for medium resistances of about 1 Ω to 100 kΩ
3. C.slow rotation of an induction meter disc with no load current, prevented by two diametrically opposite holes drilled in the disc
4. D.measures total three-phase power as W1 plus W2, with power factor obtained from tan φ equal to √3 (W1 − W2)/(W1 + W2)

Answer + AI explanation with Pro

1. A.Kelvin double bridge
2. B.Two-wattmeter method
3. C.Energy meter creep
4. D.Schering bridge

Answer + AI explanation with Pro

1. A.Schering bridge — slow rotation of an induction meter disc with no load current, prevented by two diametrically opposite holes drilled in the disc
2. B.Schering bridge — permanent-magnet moving-coil meter with a uniform scale that reads only the average of DC, extended with shunts and multipliers
3. C.Schering bridge — an instrument's maximum error as a percentage of full scale, such as class 0.5 CT for metering and class 5P for protection
4. D.Schering bridge — AC bridge for measuring capacitance and dissipation factor (tan δ) of high-voltage insulation with a standard capacitor in one arm

Answer + AI explanation with Pro