11. Calculate peak-peak voltage if Vmax=1 V and Vmin=-1 V.
A. 6 V
B. 2 V
C. 3 V
D. 1 V
Answer: B
Peak-Peak voltage is equal to the difference between the maximum and minimum voltage. It is mathematically represented as
Vp-p=Vmax-Vmin=1+1=2 V.
12. Calculate the value of the Crest factor if Vpeak=0 V and Vr.m.s=24 V.
A. 0
B. 3
C. 5
D. 8
Answer: A
The value of the crest factor is Vpeak÷Vr.m.s=0÷24=0 V. It signifies the peak value is 0 times the r.m.s value.
13. Calculate the output voltage of the Buck converter if the supply voltage is 789 V and the duty cycle value is .9.
A. 711.1 V
B. 710.1 V
C. 722.2 V
D. 713.2 V
Answer: B
The output voltage of the buck converter is
Vo = Vin×D =789×.9=710.1 V.
The value of the duty cycle is less than one which makes the Vo < Vin. The buck converter is used to step down the voltage.
14. Calculate the average value of thyristor current in a 3-Φ Full-wave converter for the load current=27 A and α=6°.
A. 9 A
B. 4 A
C. 5 A
D. 9 A
Answer: D
The average value of thyristor current in a 3-Φ Full-wave converter is Io÷3. It is the average value of the thyristor current.
I(r.m.s)= Io÷3=9 A.
15. Calculate the output voltage of the Boost converter if the supply voltage is 156 V and the duty cycle value is .4.
A. 260 V
B. 264 V
C. 261 V
D. 268 V
Answer: A
The output voltage of the boost converter is
Vo = Vin×(1-D).=156×1.66=260 V.
The value of the duty cycle is less than one which makes the Vo > Vin. The boost converter is used to step up the voltage.
16. Inverters are used to convert DC power into variable AC power.
A. True
B. False
Answer: A
Inverters are used to convert DC power into variable AC power. The variable AC power means variable frequency and variable voltage level.
17. Short circuit problem is severe in case of Voltage source inverter.
A. True
B. False
Answer: A
Short-circuit problem is severe in the case of voltage source inverter. The output voltage of VSI is fixed but the output current depends upon the load. When Z=0, I=V÷Z=∞.
18. Switches used in VSI are ___________
A. Unipolar & Unidirectional
B. Bipolar & Bidirectional
C. Unipolar & Bidirectional
D. Unidirectional
Answer: C
Switches used in VSI are unipolar and bidirectional. MOSFET and BJT are examples of switches used in VSI. The output voltage of VSI is fixed but the output current depends upon the load.
19. Switches used in CSI are ____________
A. Bipolar & Unidirectional
B. Bipolar & Bidirectional
C. Unipolar & Unidirectional
D. Bidirectional
Answer: A
Switches used in CSI are bipolar and unidirectional in nature. GTO and thyristors are examples of switches used in CSI. The output voltage of CSI is variable but the output current is fixed.
20. Full form of VSI is ___________
A. Voltage source inverter
B. Volume source inverter
C. Voltage severe inverter
D. Voltage source inserter
Answer: A
VSI stands for Voltage source inverter. The output voltage of VSI is fixed but the output current depends upon the load. Switches used in VSI are unipolar and bidirectional in nature.
