This set of Electrical Measurements & Measuring Instruments Multiple Choice Questions & Answers (MCQs) focuses on “Resolution and Sensitivity”.
1. Resolution of a DVM is given by
a) R = 1⁄10n
b) R = 1
c) R = 10n
d) R = n⁄10
View Answer
Explanation: The resolution of a DVM is,
R = 1⁄10n
where, n is the number of full digits
R is the resolution.
2. For a 3 digit display the resolution is
a) 1 %
b) 0.1 %
c) 0.001 %
d) 10 %
View Answer
Explanation: The resolution of a DVM is,
R = 1⁄10n
Here, n is 3. Substituting n=3 in the equation for resolution we get,
R = 1⁄103 = 10-3 = 0.001 = 0.1 %.
3. Sensitivity is largest change in input.
a) True
b) False
View Answer
Explanation: Sensitivity of any instrument is defined as the smallest hange in the input signal to which the output responds.
4. Sensitivity of a DVM is given by
a) S = 1
b) S = (fs)min
c) S = (fs)min × R
d) S = R
View Answer
Explanation: Sensitivity of the DVM is obtained from the relation,
S = (fs)min × R
where, S is the sensitivity
R is the resolution
(fs)min is the full scale value on minimum range.
5. The resolution of a 3 digit display on 1 V range is
a) 1 V
b) 0.1 V
c) 0.01 V
d) 0.001 V
View Answer
Explanation: The resolution of a DVM is,
R = 1⁄10n
Here, n is 3. Substituting n=3 in the equation for resolution we get,
R = 1⁄103 = 10-3 = 0.001
For 1 V range, the resolution is,
R1V = 1×0.001 = 0.001 V.
6. How is 11.87 V displayed on a 10 V range for a 4 digit display?
a) 11.870
b) 1.1870
c) 118.7
d) 0.1187
View Answer
Explanation: The resolution of a DVM is,
R = 1⁄10n
Here, n is 4. Substituting n=4 in the equation for resolution we get,
R = 1⁄104 = 10-4 = 0.0001
Since there are 5 digit places in the resolution, 11.87 which already has four digits is represented as 11.870.
7. Consider a 3 digit display for a DVM with an accuracy of ± 0.5 % for a reading of ± 1 digit. Compute the error for 5 V reading on a 10 V range.
a) ± 10 V
b) ± 0.035 V
c) ± 0.05 V
d) ± 1 V
View Answer
Explanation: The resolution of a DVM is,
R = 1⁄10n
Here, n is 3. Substituting n=3 in the equation for resolution we get,
R = 1⁄103 = 10-3 = 0.001
For 10 V range, the resolution is,
R10V = 10 × 0.001 = 0.01 V
Consider the reading of 5 V.
Error = ± 0.5 % of 5 = 0.5⁄100 × 5 = ± 0.025 V
1 digit error = ± 0.01 V
Total error = ±(0.025 V+ 0.01 V)=± 0.035 V.
8. Clock pulses are controlled ______
a) automatically
b) using microcontrollers
c) using valves
d) manually
View Answer
Explanation: A manual range hold command is used to control the clock pulses and the autoranging. This is done through a signal that exceeds the maximum range for up counts by reaching the most sensitive range (down counts).
Sanfoundry Global Education & Learning Series – Electrical Measurements.
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