Question

Question 1 Each one of the multiple choice questions is worth 3.5 points 1. Which one of the following is correct about D'Arsonvals E. DC sensitivity is 3462/V and the required multiplier resis tance is 207.6kN which must be connected in series with the D'Arsonval A. the deflection stops in D'Arsonvals due to restoring torque produced by control spring. The unit of control spring con- stant is Nm B. the deflection stops in D'Arsonvals due to deflection torque produced by control spring. The unit of control spring con stant is Nm/deg C the detection stops in D'Arsonvals due to restoring torque produced by stopping spring The unit of stopping spring constant is Nm/deg D. the deflection stops in D'Arsonvals due to restoring torque produced by control spring. The unit of control spring con stant is Nm/deg E. the deflection stops in D'Arsonvals due to deflection torque produced by control spring. The unit of control spring con- stant is Nm/deg 3 Potentiometer method in measuring resistance uses differen tinl voltmeter. Which one of the following is correct about the potentiometer method when measuring very low resistances A. The measured value of the resistance R, is given as Rs B. its accuracy is almost entirely dependent on the standard resistance R C. none of the mentioned answers is correct D. its accuracy is affected by the accuracy of the potentiometer since it has large errors E. its accuracy is dependent on the standard resistance R., but the ammeter must also be very accurate 2. A D'Arsonval is used with full-wave rectifier to measure AC voltage. If the range of the AC voltage to be measured is required to be 60V and the full-scale deflection current and internal te sistance of the D'Arsonval are 260 pA and 1302, respectively, which one of the following is correct A DC sensitivity is 3846 2/V and the required multiplier resis- tance is 207.6k2 which must be connected in parallel with the D'Arsonval 4. We desire to extend the range of a voltmeter whose maxi- mum voltage reading is 200 V to measure a voltage range of 600 V to 1200 V. Thus, a multiplier resistance is connected across it. Which one of the following is correct A. The multiplier resistance must be 7 times larger than R The measured voltage must be multiplied by 6 to scale for the voltage across the load B. The multiplier resistance must be 5 times larger than R... The measured voltage must be divided by 6 to scale for the voltage across the load C. The multiplier resistance must be 5 times larger than R The measured voltage must be multiplied by 6 to scale for the voltage across the load D. The multiplier resistance must be 3 times larger than R The measured voltage must be multiplied by 4 to scale for the voltage across the load E. The multiplier resistance must be 6 times larger than R The measured voltage must be multiplied by 7 to scale for the voltage across the load B. DC sensitivity is 3462 N/V and the required multiplier resis- tance is 230.6 kN2 which must be connected in series with the D'Arsonval C. DC sensitivity is 3846 N/V and the required multiplier resis- tance is 207.6 kl which must be connected in series with the D'Arsonval D. DC sensitivity is 3846 2/V and the required multiplier resis- tance is 230.6 kN2 which must be connected in series with the D'Arsonval

Answer 1

1) The deflection stops in D'Arsonval due to restoring torque produced by the by control springs. The unit of control springs constant is Nm/deg.

3)E) In potentiometer metre method for measuring low resistance the accuracy is almost dependent on the standard resistance Rs but the ammetre must also be accurate

2) o) V=60 V IfSpa 260 MLA Rm= 130 Sensitivity Inco Záo x10-6 = 3846 2/V Series resistance Rs(T-1) Rm multiplier - (1280x130xio* -1) 130 2 (1775.15-1) XI 30 = 230,6 ks 4) VE 2001 V-1200V - series multiplier resistance Rsz (7 - 1) Rm (1200 - 1) Rm Rs 25 Rm . B) The multiplice rectance must be s times larger than Rm The measured voltage must be divided by 6 for to seale for the voltage across load. 200