Electrical Measurements & Measuring Instruments Multiple Choice Questions on “Digital Voltmeters”.
1. Digital voltmeters converts ________
a) analog to digital signal
b) digital to analog signal
c) current to voltage
d) resistance to voltage
Answer: a
Clarification: In general digital voltmeters are known as DVM. They convert analog signals into digital voltage. They also display the voltage to be measured in the form of discrete numerals in place of pointer deflection.
2. Digital voltmeters can be used to measure ________
a) voltage only
b) voltage, temperature, pressure, etc
c) voltage and current
d) voltage and resistance
Answer: b
Clarification: Digital voltmeters are used for the measurement of A.C. as well as D.C. voltages and also to measure physical quantities such as temperature, pressure, stress etc. through the use of appropriate transducer and signal conditioning circuits.
3. A digital voltmeter reduces parallax error.
a) True
b) False
Answer: a
Clarification: A digital voltmeter minimizes the errors due to human interference, interpolation mismatch and errors due to parallax. A digital display is used to show the output voltage on a front panel.
4. In a DVM, a transducer converts ________
a) input to a proportional current
b) input to a proportional power
c) input to a proportional voltage
d) input to a proportional resistance
Answer: c
Clarification: In a digital voltmeter, a transducer is used. In general a transducer converts a physical quantity into an electrical signal. In a DVM the transducer converts the input signal into a proportional voltage.
5. In a DVM, a signal conditioning circuit is used ________
a) to bring current to a suitable limit
b) to bring resistance to a suitable limit
c) to bring resistance to s suitable limit
d) to bring voltage to a suitable limit
Answer: d
Clarification: In a DVM, signal conditioning circuit is used. It converts the input signal into an voltage of suitable limit. This is done so that the voltmeter can read the magnitude of the signal correctly.
6. Input range of DVM is _________
a) 1 V to 1000 V
b) 0.1 V to 10 V
c) 0.01 V to 1 V
d) 0.001 V to 0.1 V
Answer: a
Clarification: In a DVM, the input voltage range is given as 1 V to 1000 V. It includes automatic range selection and overload indication.
7. Output in digital form can’t be used directly.
a) True
b) False
Answer: b
Clarification: The output obtained from a DVM can be used directly. It can be recorded and is also suitable for further processing.
8. What is the effect of IC chips on DVM?
a) increase in cost
b) increase in power
c) reduction in cost
d) increase in size
Answer: c
Clarification: Advancement in IC chips have ensured the reduction in the cost of the DVM’s. Size and power needs of DVM’s have been reduced by a huge margin.
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