MCQOPTIONS
Saved Bookmarks
MCQOPTIONS
This section includes 55 Mcqs, each offering curated multiple-choice questions to sharpen your Vlsi knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
The MOSFETS are arranged in this configuration to provide __________ |
| A. | Zero static power dissipation |
| B. | High Input impedance |
| C. | Both zero static power dissipation and high input impedance |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 2. |
The BJTs in the BICMOS circuit is in _____________ configuration. |
| A. | Push-pull |
| B. | Totem pole |
| C. | Active high |
| D. | Active low |
| Answer» C. Active high | |
| 3. |
For improved base current discharge ________ enhancement type nMOS devices have to be added. |
| A. | two |
| B. | three |
| C. | one |
| D. | four |
| Answer» B. three | |
| 4. |
BiCMOS has _______ standby leakage current. |
| A. | higher |
| B. | lower |
| C. | very low |
| D. | none of the mentioned |
| Answer» B. lower | |
| 5. |
The inverter has __________ |
| A. | low input impedance |
| B. | high input impedance |
| C. | high output impedance |
| D. | high input and output impedance |
| Answer» B. high input impedance | |
| 6. |
The nMOS and pMOS transistors used in BiCMOS is ____________ |
| A. | depletion mode |
| B. | enhancement mode |
| C. | only pMOS |
| D. | only nMOS |
| Answer» C. only pMOS | |
| 7. |
In BiCMOS, MOS switches are used to __________ |
| A. | drive input loads |
| B. | drive output loads |
| C. | to perform logic functions |
| D. | to amplify the input voltage |
| Answer» D. to amplify the input voltage | |
| 8. |
In BiCMOS, bipolar transistors are used to ___________ |
| A. | drive input loads |
| B. | drive output loads |
| C. | to perform logic functions |
| D. | to amplify the input voltage |
| Answer» C. to perform logic functions | |
| 9. |
A single-phase full-bridge inverter can operate in load commutation mode in case load consists of: |
| A. | RLC critically damped |
| B. | RL |
| C. | RLC underdamped |
| D. | RLC overdamped |
| Answer» D. RLC overdamped | |
| 10. |
In a resonance pulse inverter: |
| A. | DC output voltage variation is wide |
| B. | The frequency is low |
| C. | The output voltage is never sinusoidal |
| D. | DC saturation of transformer core is minimized |
| Answer» B. The frequency is low | |
| 11. |
A three-phase voltage source inverter with ideal devices operating in 180° conduction mode is feeding a balanced star-connected resistive load. The DC voltage input is Vdc. The peak of the fundamental component of the phase voltage is |
| A. | \(\frac{{{V_{dc}}}}{\pi }\) |
| B. | \(\frac{{2{V_{dc}}}}{\pi }\) |
| C. | \(\frac{{3{V_{dc}}}}{\pi }\) |
| D. | \(\frac{{4{V_{dc}}}}{\pi }\) |
| Answer» C. \(\frac{{3{V_{dc}}}}{\pi }\) | |
| 12. |
If the amplitude of the output voltage of a full bridge inverter is 2Us and its output power is 4P, then the corresponding quantities in case of half bridge inverter is: |
| A. | 2Us and P respectively |
| B. | Us and 2P respectively |
| C. | Us and P respectively |
| D. | 2Us and 2P respectively |
| Answer» D. 2Us and 2P respectively | |
| 13. |
In a single-phase inverter using single pulse modulation for control of output voltage, Harmonics of the order ‘n’ can be eliminated by making the pulse width equal to |
| A. | 4π/n |
| B. | 2π/n |
| C. | π/n |
| D. | π/2n |
| Answer» C. π/n | |
| 14. |
A 3-phase inverter operates with 180-degree conduction mode. It is fed from a 500 V DC source and is supplying a purely resistive Y connected load. RMS values of the fundamental component of line and phase voltage, respectively, at the inverter output, is: |
| A. | 408 V, 225.16 V |
| B. | 390 V, 235.56 V |
| C. | 408 V, 235.56 V |
| D. | 390 V, 225.16 V |
| Answer» E. | |
| 15. |
For the speed control of AC drive the preferred method using thyristor is: |
| A. | phase control |
| B. | integral cycle control |
| C. | sinusoidal PWM control |
| D. | unipolar PWM control |
| Answer» D. unipolar PWM control | |
| 16. |
A PWM switching scheme is used in single phase inverters to: |
| A. | Reduce the higher order harmonics |
| B. | Minimize the effect of load |
| C. | Reduce the lower order harmonics |
| D. | Reduce the total harmonic distortion |
| Answer» D. Reduce the total harmonic distortion | |
| 17. |
In practice, a current source inverter consists of an AC/ DC converter with a large inductance ‘L’ in the input. This inductance maintains a ……….…………through the switching devices over short interval of time. |
| A. | constant current |
| B. | constant voltage |
| C. | constant power |
| D. | none of the (A), (B), (C) |
| Answer» B. constant voltage | |
| 18. |
A single phase voltage source inverter is feeding a purely inductive load as shown in the figureThe inverter is operated at 50 Hz in 180o square mode. Assume that the load current does not have any DC component. The peak value of the inductor current i0 will be |
| A. | 6.37 A |
| B. | 10 A |
| C. | 20 A |
| D. | 40 A |
| Answer» D. 40 A | |
| 19. |
Modified McMurray full-bridge inverter works on |
| A. | Voltage commutation |
| B. | Current commutation |
| C. | Load commutation |
| D. | Complementary commutation |
| Answer» E. | |
| 20. |
A voltage source inverter is used to control the speed of a three-phase, 50 Hz squirrel cage induction motor. Its slip for rated torque is 4%. The flux is maintained at rated value. If the stator resistance and rotational losses are neglected, then the impressed voltage to obtain twice the rated torque at starting should be |
| A. | 10 Hz |
| B. | 5 Hz |
| C. | 2 Hz |
| D. | 4 Hz |
| Answer» E. | |
| 21. |
A voltage source inverter is used when source and load inductances are respectively |
| A. | Small and large |
| B. | Large and small |
| C. | Large and large |
| D. | Small and small |
| Answer» B. Large and small | |
| 22. |
In a 3-phase inverter fed induction motor drive, the total harmonic distortion is 4 %. If the maximum value of fundamental component of load current is 4 A, the rms value of net harmonic current is |
| A. | 0.08 A |
| B. | 0.08√2 A |
| C. | 0.16 A |
| D. | 0.16√2 A |
| Answer» C. 0.16 A | |
| 23. |
A single-phase voltage-source-square wave inverter feeds pure inductive load. The waveforms of the load current will be: |
| A. | Sinusoidal |
| B. | Rectangular |
| C. | Trapezoidal |
| D. | Triangular |
| Answer» E. | |
| 24. |
For a 1-phase full-bridge inverter fed from 48 V dc and connected to load resistance of 2.4 Ω, the rms value of fundamental component of output voltage is |
| A. | 20 V |
| B. | 21.6 V |
| C. | 34.4 V |
| D. | 43.2 V |
| Answer» E. | |
| 25. |
A PWM switching scheme is used with three phase inverter to |
| A. | reduce low order harmonics and increase high order harmonics |
| B. | minimize the load on the DC side. |
| C. | increase the life of the batteries. |
| D. | reduce the total harmonic distortion with modest filtering |
| Answer» B. minimize the load on the DC side. | |
| 26. |
In a 3-phase inverter with 180° conduction mode the number of switches that is on at any instant of time is |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» D. 4 | |
| 27. |
In which of the following both frequency and voltage can be controlled? |
| A. | Inverter, cyclo-converter and ac voltage controller |
| B. | Cyclo-converter and ac voltage controller |
| C. | Inverter and cyclo-controller |
| D. | Inverter and ac voltage controller |
| Answer» D. Inverter and ac voltage controller | |
| 28. |
A line commutated phase-controlled inverter is operating at its inverter limit. There can be a commutation failure if |
| A. | The frequency decreases |
| B. | The voltage increases |
| C. | The frequency increases |
| D. | Both voltage and frequency change such that v / f is constant. |
| Answer» D. Both voltage and frequency change such that v / f is constant. | |
| 29. |
In a single-phase full bridge inverter what is the advantage of a unipolar switching over the bipolar switching? |
| A. | Increase of the fundamental component by a factor of 1.15 for the same DC input voltage |
| B. | Elimination of 5th and 7th harmonics |
| C. | Apparent doubling of the switching frequency |
| D. | None of the above |
| Answer» D. None of the above | |
| 30. |
In a McMurray inverter, diodes are connected in inverse parallel to thyristors to1. Protect the thyristor2. Make the turn off of the thyristor successful3. Make the turn on of the thyristor successful4. Provide path to the reactive component of the load currentWhich of the above statements are correct? |
| A. | 1 and 3 |
| B. | 1 and 4 |
| C. | 2 and 4 |
| D. | 2 and 3 |
| Answer» D. 2 and 3 | |
| 31. |
A single-phase full bridge inverter is connected to a load of 2.4 Ω. The dc input voltage is 48 V. What is the rms output at fundamental frequency? |
| A. | \(\frac{{4 \times 48}}{{\sqrt 2 \pi }}V\) |
| B. | \(\frac{{2 \times 48}}{{\sqrt 2 \pi }}V\) |
| C. | \(\frac{{4 \times 48}}{\pi }V\) |
| D. | \(\frac{{2 \times 48}}{\pi }V\) |
| Answer» B. \(\frac{{2 \times 48}}{{\sqrt 2 \pi }}V\) | |
| 32. |
Direction: The following item consists of two statements, one labelled as ‘Statement (I)’ and the other as ‘Statement (II)’. Examine these two statements carefully and select the answers to these items using the code given below:Statement (I): In sinusoidal pulse width modulation, width of each pulse is varied in proportion to amplitude of a sine-wave evaluated at the centre of the same pulse.Statement (II): The rms value of output voltage can be varied by varying the modulation index. |
| A. | Both Statement I and Statement II are individually true and Statement II is the correct explanation of Statement I |
| B. | Both Statement I and Statement II are individually true but Statement II is not the correct explanation of Statement I |
| C. | Statement I is true but Statement II is false |
| D. | Statement I is false but Statement II is true |
| Answer» C. Statement I is true but Statement II is false | |
| 33. |
In single pulse modulated PWM inverter, third harmonic is eliminated by making pulse width equal to 120°. To eliminate fifth harmonic the pulse width will be |
| A. | 36° |
| B. | 72° |
| C. | 144° |
| D. | 108° |
| Answer» C. 144° | |
| 34. |
A single-phase voltage source inverter (VSI) operating in square wave mode supplies a purely inductive load. If the inverter time period is ‘T’, then the time duration for each of the feedback diodes to conduct in a cycle is: |
| A. | T |
| B. | T/2 |
| C. | T/4 |
| D. | T/8 |
| Answer» D. T/8 | |
| 35. |
In the sinusoidal pulse-width modulation scheme, if the zero of the triangular wave coincides with the zero of the reference sinusoidal, then the number of pulses per half cycle is |
| A. | \(\frac{{{f_c}}}{{2f}}\) |
| B. | \(\frac{{{f_c}}}{{2f}} + 1\) |
| C. | \(\frac{{2{f_c}}}{f}\) |
| D. | \(\frac{{{f_c}}}{{2f}} - 1\) |
| Answer» E. | |
| 36. |
In single pulse modulation of PWM inverters, the pulse width is 120°. For an input voltage of 220 V dc, what is the r.m.s. value at the fundamental component of the output voltage? |
| A. | 171.5 V |
| B. | 254.0 V |
| C. | 127.0 V |
| D. | 89.81 V |
| Answer» B. 254.0 V | |
| 37. |
Consider the following points:1) Inherent short circuit operation2) Regenerative capability3) Need for inverter grade thyristors4) Voltage spikes across the loadWhich of the following are true with CSI (current source inverter) |
| A. | 1, 2 and 3 |
| B. | 2, 2 and 4 |
| C. | 1, 3 and 4 |
| D. | 1, 2 and 4 |
| Answer» E. | |
| 38. |
Current source inverters are suitable for supplying power to |
| A. | R-L loads |
| B. | Inductive loads |
| C. | All loads |
| D. | Capacitive loads |
| Answer» E. | |
| 39. |
In single pulse modulation PWM inverter third harmonics can be eliminate if the pulse – width is made equal to |
| A. | 30° |
| B. | 150° |
| C. | 60° |
| D. | 120° |
| Answer» E. | |
| 40. |
Directions: It consists of two statements, one labelled as the ‘Statement (I)’ and the other as ‘Statement (II)’. You are to examine these two statements carefully and select the answer using the codes given below:Statement (I): The output current of a current source inverter remains constant irrespective of load.Statement (II): The load voltage in CSI depends on the load impedance. |
| A. | Both Statement (I) and Statement (II) are individually true and Statement (II) is the correct explanation of Statement (I) |
| B. | Both Statement (I) and Statement (II) are individually true but Statement (II) is NOT the correct explanation of Statement (I) |
| C. | Statement (I) is true but Statement (II) is false |
| D. | Statement (I) is false but Statement (II) is true |
| Answer» C. Statement (I) is true but Statement (II) is false | |
| 41. |
In which condition does the voltage source inverter give better performance? |
| A. | Both load and source inductances are less |
| B. | Both load and source inductances are high |
| C. | Load inductance is high and source inductance is less |
| D. | Load inductance is less and source inductance is high |
| Answer» D. Load inductance is less and source inductance is high | |
| 42. |
A single pulse width-modulated inverter is used to drive a load. Find the angle of shift to produces rms output voltage of 100 V, if the input dc voltage is 120 V. |
| A. | 50° |
| B. | 125° |
| C. | 150° |
| D. | 90° |
| Answer» C. 150° | |
| 43. |
For a single-phase voltage source inverter (VSI), the output fundamental voltage is _____ for DC link voltage to be 48 V. Load is resistive in nature. |
| A. | 24 V |
| B. | 21.61 V |
| C. | 43.22 V |
| D. | 48 V |
| Answer» D. 48 V | |
| 44. |
In a three-phase inverter with 180° conduction, there are six modes of operation in a cycle where duration of each mode is |
| A. | 90° |
| B. | 75° |
| C. | 60° |
| D. | 45° |
| Answer» D. 45° | |
| 45. |
A single-phase full-bridge voltage source inverter (VSI) is fed from a \(300\;V\) battery. A pulse of \({120^o}\) duration is used to trigger the appropriate devices in each half-cycle. The rms value of the fundamental component of the output voltage, in volts, is |
| A. | 234 |
| B. | 245 |
| C. | 300 |
| D. | 331 |
| Answer» B. 245 | |
| 46. |
FOR_IMPROVED_BASE_CURRENT_DISCHARGE,__________ENHANCEMENT_TYPE_NMOS_DEVICES_HAVE_TO_BE_ADDED?$ |
| A. | two |
| B. | three |
| C. | one |
| D. | four |
| Answer» B. three | |
| 47. |
The MOSFETS are arranged in this configuration to provide:$ |
| A. | Zero static power dissipation |
| B. | High Input impedance |
| C. | Both zero static power dissipation and high input imedance |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 48. |
The BJTs in the BICMOS circuit is in_____________ configuration:$ |
| A. | Push-pull |
| B. | Totem pole |
| C. | Active high |
| D. | Active low |
| Answer» C. Active high | |
| 49. |
BiCMOS has _______ standby leakage curren? |
| A. | higher |
| B. | lower |
| Answer» B. lower | |
| 50. |
BiCMOS inverter requires high load current sourcing. |
| A. | true |
| B. | false |
| Answer» B. false | |