This set of Power Electronics Multiple Choice Questions & Answers (MCQs) focuses on “MOSFETs-2”.
1. In the output characteristics of a MOSFET with low values of Vds, the value of the on-state resistance is
Explanation: The o/p characteristics Is a plot of Id verses Vds, which for low values of Vds is almost constant. Hence, the on-state resistance is constant & the slop is its constant value.
2. At turn-on the initial delay or turn on delay is the time required for the
a) input inductance to charge to the threshold value
b) input capacitance to charge to the threshold value
c) input inductance to discharge to the threshold value
d) input capacitance to discharge to the threshold value
Explanation:It is the time required for the input capacitance to charge to the threshold value, which depends on the device configuration. The device can start conducting only after this time.
3. Choose the correct statement
a) MOSFET suffers from secondary breakdown problems
b) MOSFET has lower switching losses as compared to other devices
c) MOSFET has high value of on-state resistance as compared to other devices
d) All of the mentioned
Explanation: MOSFET has lower switching losses due to its unipolar nature & less turn off time. All of the other statements are false.
4. Which among the following devices is the most suited for high frequency applications?
Explanation: MOSFET has the least switching losses among the rest of the devices.
5. Choose the correct statement
a) MOSFET has a positive temperature co-efficient
b) MOSFET has a high gate circuit impedance
c) MOSFET is a voltage controlled device
d) All of the above statements are correct
Explanation: MOSFETs are voltage controlled devices. They have high gate circuit impedance and are PTC devices.
6. Consider an ideal MOSFET. If Vgs = 0V, then Id = ?
Explanation: Gate current = 0 so device is off (ideally).
7. For a MOSFET Vgs=3V, Idss=5A, and Id=2A. Find the pinch of voltage Vp
Explanation: Use Id = Idd x [1-Vgs/Vp]2
8. How does the MOSFET differ from the JFET?
a) JFET has a p-n junction
b) They are both the same
c) JFET is small in size
d) MOSFET has a base terminal
9. The basic advantage of the CMOS technology is that
a) It is easily available
b) It has small size
c) It has lower power consumption
d) It has better switching capabilities
Explanation: Complementary MOS consumes very less power as compared to all the earlier devices.
10. The N-channel MOSFET is considered better than the P-channel MOSFET due to its
a) low noise levels
b) TTL compatibility
c) lower input impedance
d) faster operation
Explanation: The N-channel are faster than the P-channel type.
Sanfoundry Global Education & Learning Series – Power Electronics.
To practice all areas of Power Electronics, here is complete set of 1000+ Multiple Choice Questions and Answers.