Ohmmeter and Resistance
MEASUREMENTS AND ELECTRONIC INSTRUMENTS (EE21004)
TUTORIAL-I
SECTION 1: QUALITY OF MEASUREMENTS
Q1. (a) A meter ‘I’ has ± 5% accuracy on true value while another ‘II’ has ±5% accuracy on scale range. Both the meters have the same scale range. Calculate the ratio of accuracy of the two meters for a deflection of 10% of full scale range in each meter. [1:10]
(b) A 0-100V voltmeter has 200 scale divisions which can be read to half a division. Determine resolution of meter in volt. [0.25 V]
(c) A Wheatstone bridge is balanced with all the four resistances equal to 1kΩ each. The bridge supply voltage is
100V. Now one of the resistances is changed to 1010Ω. The output voltage is measured by a voltmeter of infinite resistance. Calculate the bridge sensitivity. [25V or 0.025 V/Ω]
(d)Each of the following numbers has a uncertainty of one in the last figure. Determine the number of significant figures in the following: (i) 46.2x3.15, (ii) 46.2x2.15, (iii) 4246.2x3.15, (iv) 62.3+2.73+0.612
[(i)146, (ii)99, (iii)13400, (iv)65.6]
Q2. The power factor and phase angle in a circuit carrying sinusoidal current and voltage are determined by measurement of current, voltage and power. The voltage is read as 125.0V on a 150 V scale; the current as 3.00A on a 5A ammeter; the power, 225 watts on a 500W wattmeter. The ammeter and voltmeter are guaranteed to be accurate within ± 0.5% of the full scale value, and the wattmeter within ±0.25% of full scale.
(a) To what percentage accuracy can you guarantee the power factor obtained from these readings? [0.6 ±1.99%]
(b) For the possible error in (a), show the amount of contribution by each instrument. [30%, 42%, 28%]
(c) What is the possible error in phase angle? [53.13 ± 0.015degree]
Q3. An oscilloscope having an input resistance of 1MΩ shunted by a 50pF capacitance is connected across a circuit of effective output resistance 10kΩ. If the open circuit voltage has 1 volt peak of 100 kHz sine wave. What voltage will be
TUTORIAL-I
SECTION 1: QUALITY OF MEASUREMENTS
Q1. (a) A meter ‘I’ has ± 5% accuracy on true value while another ‘II’ has ±5% accuracy on scale range. Both the meters have the same scale range. Calculate the ratio of accuracy of the two meters for a deflection of 10% of full scale range in each meter. [1:10]
(b) A 0-100V voltmeter has 200 scale divisions which can be read to half a division. Determine resolution of meter in volt. [0.25 V]
(c) A Wheatstone bridge is balanced with all the four resistances equal to 1kΩ each. The bridge supply voltage is
100V. Now one of the resistances is changed to 1010Ω. The output voltage is measured by a voltmeter of infinite resistance. Calculate the bridge sensitivity. [25V or 0.025 V/Ω]
(d)Each of the following numbers has a uncertainty of one in the last figure. Determine the number of significant figures in the following: (i) 46.2x3.15, (ii) 46.2x2.15, (iii) 4246.2x3.15, (iv) 62.3+2.73+0.612
[(i)146, (ii)99, (iii)13400, (iv)65.6]
Q2. The power factor and phase angle in a circuit carrying sinusoidal current and voltage are determined by measurement of current, voltage and power. The voltage is read as 125.0V on a 150 V scale; the current as 3.00A on a 5A ammeter; the power, 225 watts on a 500W wattmeter. The ammeter and voltmeter are guaranteed to be accurate within ± 0.5% of the full scale value, and the wattmeter within ±0.25% of full scale.
(a) To what percentage accuracy can you guarantee the power factor obtained from these readings? [0.6 ±1.99%]
(b) For the possible error in (a), show the amount of contribution by each instrument. [30%, 42%, 28%]
(c) What is the possible error in phase angle? [53.13 ± 0.015degree]
Q3. An oscilloscope having an input resistance of 1MΩ shunted by a 50pF capacitance is connected across a circuit of effective output resistance 10kΩ. If the open circuit voltage has 1 volt peak of 100 kHz sine wave. What voltage will be