MCQOPTIONS
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MCQOPTIONS
This section includes 26 Mcqs, each offering curated multiple-choice questions to sharpen your Electrical Engineering Mcqs knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
In a square wave operation of 3 phase CSIs, the power values are on for___________? |
| A. | 60 degree |
| B. | 90 degree |
| C. | 120 degree |
| D. | 150 degree |
| Answer» D. 150 degree | |
| 2. |
If all the SCR s of 3 phase PAC is replaced by diodes, they would be triggered_____________? |
| A. | 120 degree after the zero crossing of the corresponding line voltages |
| B. | 60 degree after the zero crossing of the corresponding line voltages |
| C. | 120 degree before the zero crossing of the corresponding line voltages |
| D. | 60 degree before the zero crossing of the corresponding line voltages |
| Answer» C. 120 degree before the zero crossing of the corresponding line voltages | |
| 3. |
The ability of an electronic system to function properly in its intended electromagnetic environment and should not be a source of pollution to that electromagnetic environment is known as____________? |
| A. | Susceptibility |
| B. | Emission |
| C. | Interference |
| D. | Electromagnetic compatibility |
| Answer» E. | |
| 4. |
The output current in PWM DC DC converters is equal to___________? |
| A. | Average value of the output inductor current |
| B. | Product of an average inductor current and a function of duty ratio |
| C. | Either A. or B. |
| D. | None of these |
| Answer» D. None of these | |
| 5. |
A step down choppers can be used in___________? |
| A. | Electric traction |
| B. | Electric vehicles |
| C. | Machine tools |
| D. | All of these |
| Answer» E. | |
| 6. |
In a push pull converter, the filter capacitor can be obtained as____________? |
| A. | Cmin = V / ( Vr L f2 ) |
| B. | Cmin= ( 1 D ) V / ( Vr L f2 ) |
| C. | Cmin= ( 1 2 D ) V / 32 ( Vr L f2 ) |
| D. | Cmin= ( 1 2 D ) V / 42 ( Vr L f2 ) |
| Answer» D. Cmin= ( 1 2 D ) V / 42 ( Vr L f2 ) | |
| 7. |
For an SCR gate cathode characteristic is a straight line of 130. For triggered source volume of 15 V and allowable gate power dissipation of 0.5 W compute the gate source resistance_____? |
| A. | 111.9 . |
| B. | 11.19 . |
| C. | 108 . |
| D. | 115 |
| Answer» B. 11.19 . | |
| 8. |
Switching frequency of SITH is____________? |
| A. | 5 KHz |
| B. | 10 KHz |
| C. | 60 KHz |
| D. | 100 KHz |
| Answer» E. | |
| 9. |
Snubber circuit is used with SCR_________________? |
| A. | In series |
| B. | In parallel |
| C. | Either series or parallel |
| D. | Anti parallel |
| Answer» C. Either series or parallel | |
| 10. |
SITH is also known as___________? |
| A. | Filled controlled diode |
| B. | Filled controlled rectifier |
| C. | Silicon controlled rectifier |
| D. | None of these |
| Answer» B. Filled controlled rectifier | |
| 11. |
The reverse recovery time of diode is trr = 3 s and the rate off all of the diode current is di/dt = 30 A/ s. The storage charge current QRR is___________? |
| A. | 130 s |
| B. | 135 s |
| C. | 140 s |
| D. | 145 s |
| Answer» C. 140 s | |
| 12. |
Spread time is defined as the interval during which_____________? |
| A. | Anode voltage drops from 10 % of its initial value to zero |
| B. | Anode current rises from 90 % to its final value |
| C. | Both (A) and (B) |
| D. | Anode current rises from 10 % to 90 % of its final value |
| Answer» C. Both (A) and (B) | |
| 13. |
The turn-on time of an SCR with inductive load is 20 s. The puls train frequency is 2.5 KHz with a mark/space ratio of 1/10, then SCR will___________? |
| A. | Turn on |
| B. | Not turn on |
| C. | Turn on if inductance is removed |
| D. | Turn on if pulse frequency us increased to two times |
| Answer» B. Not turn on | |
| 14. |
For series connected SCR s dynamic equalising circuit consists of___________? |
| A. | R and C in series but with diode across C |
| B. | R and C in series but with diode across R |
| C. | Series R and diode with C across R |
| D. | Series R and diode with C across R |
| Answer» C. Series R and diode with C across R | |
| 15. |
In a load commutated DC DC chopper, the capacitor has a_____________? |
| A. | Symmetric triangular voltage across itself |
| B. | Symmetric rectangular voltage across itself |
| C. | Symmetric trapezoidal voltage across itself |
| D. | Symmetric sinusoidal voltage across itself |
| Answer» D. Symmetric sinusoidal voltage across itself | |
| 16. |
The control method used for PWM dc dc converter is______________? |
| A. | Voltage mode control |
| B. | Current mode control |
| C. | Hysteric control |
| D. | All of these |
| Answer» E. | |
| 17. |
The average value of the output voltage in a step down dc chopper is given by__________? |
| A. | V 0 = V s |
| B. | V 0 = D V s |
| C. | V 0 = V s / D |
| D. | V 0 = V s / ( 1 D ) |
| Answer» C. V 0 = V s / D | |
| 18. |
A single phase ac dc converter is also known as____________? |
| A. | Rectifier |
| B. | Inverter |
| C. | Chopper |
| D. | Regulator |
| Answer» B. Inverter | |
| 19. |
The on state voltage drop of IGBT consists of__________? |
| A. | Drop across the collector junction |
| B. | Drop across the drift region |
| C. | Drop across MOSFET portion |
| D. | All of these |
| Answer» E. | |
| 20. |
The most suited gate pulses given to the AC regulator with R L load can be in the form of____________? |
| A. | Continuous signal |
| B. | Large isolating pulse transformer |
| C. | A train of pulses |
| D. | None of these |
| Answer» D. None of these | |
| 21. |
Silicon controlled rectifier can be turned on____________? |
| A. | By applying a gate pulse and turned off only when current becomes zero |
| B. | And turned off by applying gate pulse |
| C. | By applying a gate pulse and turned off by removing the gate pulse |
| D. | By making current non zero and turned off by making current zero |
| Answer» B. And turned off by applying gate pulse | |
| 22. |
Single phase VSI are mainly used in___________? |
| A. | Power supplies |
| B. | Ups |
| C. | Multilevel configuration |
| D. | All of these |
| Answer» E. | |
| 23. |
The advantage of using free wheeling diode in half controlled bridge converter is that |
| A. | There is always a path for the dc current independent of the ac line |
| B. | There is always a path for the ac current independent of the ac line |
| C. | There is always a path for the dc current dependent of the ac line |
| D. | There is always a path for the ac current independent of the ac line |
| Answer» B. There is always a path for the ac current independent of the ac line | |
| 24. |
To detect an over current fault condition, the most reliable method is to connect a_____________? |
| A. | Current sensor across IGBT |
| B. | Voltage sensor across IGBT |
| C. | Current sensor in series with IGBT |
| D. | Voltage sensor in series with IGBT |
| Answer» D. Voltage sensor in series with IGBT | |
| 25. |
The carrier which are commonly used in constant frequency PWM is______________? |
| A. | Sawtooth carrier |
| B. | Inverted sawtooth carrier |
| C. | Triangle carrier |
| D. | All of these |
| Answer» E. | |
| 26. |
In ac dc conversion, when the switch is closed then the sum of voltages around the loop is____________? |
| A. | Zero |
| B. | Non zero |
| C. | Equal to the sum of voltage when switch is open |
| D. | Twice of the voltage when switch is open |
| Answer» C. Equal to the sum of voltage when switch is open | |