Digital Voltmeter MCQ || Digital Voltmeter Questions and Answers

21. A 3 ½ digit dual-slope integrated DVM, 2 V full scale is used to measure a time-varying voltage V(t) = 1.0 + 2 sin 50 πt. The voltmeter indicates

  1. 1.00 V
  2. 1.732 V
  3. 2.000 V
  4. Wrong value.

Answer:1. 1.00 V

Explanation: 

V(t) = 1 + 2 sin 50 πt

Dual slope integrated DVM measures the average value of input.

Vavg = 1 V

Hence the meter reading will be 1.000 V

 

22. To determine the continuity of the windings __________ is used:

  1. Frequency Meter
  2. Ammeter
  3. Multimeter
  4. Voltmeter

Answer:3. Multimeter

Explanation: 

  • Continuity testing is the act of testing the resistance between two points.
  • If there is very low resistance, the two points are connected electrically.
  • If there are more than a few ohms of resistance, then the circuit is open.
  • To determine the continuity of the windings Multimeter is used.

 

23. The ramp type digital voltmeter can measure accurately with

  1. A positive-going ramp voltage only
  2. A negative or positive going linear ramp voltage
  3. A negative-going ramp voltage only
  4. An asymptotic ramp voltage only

Answer:2. A negative or positive going linear ramp voltage

Explanation: 

The operating principle of ramp type digital voltmeter is to measure the time that a linear ramp voltage takes to change from the level of the input voltage to zero voltage (or vice versa.

 

24. An integrator-type DVM (digital voltmeter) contains a 100 kΩ resistor and 1 μF capacitor. If the voltage applied to the integrator input is 1 volt, what voltage will be present at the output of the integrator after 1 second?

  1. 1.1 V
  2. 1 V
  3. 10 V
  4. 100 V

Answer:3. 10 V

Explanation: 

Resistance (R) = 100 kΩ

Capacitance ( = 1 μF

Integrator input voltage (Vi­) = 1 V

For an integrator type DVM, output voltage is given by

${V_0} = – \frac{1}{{RC}}\mathop \smallint \limits_0^t {V_i}dt$

$ = – \frac{1}{{100 \times {{10}^3} \times 1 \times {{10}^{ – 6}}}}\mathop \smallint \limits_0^1 1dt = – 10\;V$

 

25. The input range of digital voltmeter is

  1. +1.000 V to +1000 V
  2. −1.000 V to +1000 V
  3. −1.000 V to −1000 V
  4. +1.000 V to −1000 V

Answer:1. +1.000 V to +1000 V

Explanation: 

The input range of the digital voltmeter is from +1.000 V to +1000 V with the automatic range selection and the overload indication.

 

26. IC chips ______ the cost of DVM.

  1. Increase
  2. Decrease
  3. Both 1 and 2
  4. None of the above

Answer:2. Decrease

Explanation: 

With the development of IC chips, the cost of DVMs, size, and power requirements of DVMs.

 

27. The accuracy of Digital voltmeter is upto

  1. 0.001%
  2. 0.0010%
  3. 1%
  4. + 0.005%

Answer:4. + 0.005%

Explanation: 

The accuracy of digital voltmeter is high upto + 0.005% of the reading.

 

28. The input impedance of DVM should be ____

  1. Low
  2. Medium
  3. Very High
  4. Very Low

Answer:3. Very High

Explanation: 

The input impedance of DVM should be high as possible so as to reduce the loading effects. Typically it is of the order of 10 MΩ.

 

29. The charcterstics of Digital voltmeter is

  1. High accuracy
  2. Input Impedance
  3. Noise Rejection
  4. All of the above

Answer:4. All of the above

Explanation: 

The charcterstics of Digital voltmeter are

Accuracy: The accuracy depends on resolution and resolution depends on the number of digits. Hence more number of digits indicates more accuracy. The accuracy is as high as + 0.005% of reading

Input impedance: The input impedance of DVM should be high as possible so as to reduce the loading effects. Typically it is of the order of 10 MΩ.

Common mode noise rejection: This is usually obtained by guarding. A guard is a sheet metal box surrounding the circuitry. A terminal at the front panel makes this ‘box” available to the circuit under measurement.

 

30. Which of the following are types of Digital Voltmeter?

  1. Ramp Type
  2. Potentiometric Type
  3. Successive Approximation Type
  4. All of the above

Answer:4. All of the above

Explanation:

The DVM is classified mainly based on the technique used for analog to digital conversion. For the sake of simplicity, there are four types of DVM as

  1. Ramp Type
  2. Potentiometric Type
  3. Successive Approximation Type
  4. Dual Slop Integrating Type

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