This set of Power Electronics Multiple Choice Questions & Answers (MCQs) focuses on “IGBTs-2”.
1. When latch-up occurs in an IGBT
a) Ig is no longer controllable
b) Ic is no longer controllable
c) the device turns off
d) Ic increases to a very high value
Explanation: After latch-up the collector emitter current is no longer in control of the gate terminal.
2. A latched up IGBT can be turned off by
a) forced commutation of current
b) forced commutation of voltage
c) use of a snubber circuit
d) none of the mentioned
Explanation: Forced commutation of current is the only way to turn off a latched up IGBT.
3. The static V-I curve of an IGBT is plotted with
a) Vce as the parameter
b) Ic as the parameter
c) Vge as the parameter
d) Ig as the parameter
Explanation: V-I curves are plotted for Ic vs Vce with the controlling parameter (Vge) as a parameter.
4. Latch-up occurs in an IGBT when
a) Vce reaches a certain value
b) Ic reaches a certain value
c) Ig reaches a certain value
d) the device temperature reaches a certain value
Explanation: Latch up occurs when the current through the device (Ic) collector current increases beyond a certain value.
5. In an IGBT, during the turn-on time
a) Vge decreases
b) Ic decreases
c) Vce decreases
d) none of the mentioned
Explanation: Vce decreases from 0.9 to 0.1 of the initial value whereas others increase.
6. Choose the correct statement
a) IGBTs have higher switching losses as compared to BJTs
b) IGBTs have secondary breakdown problems
c) IGBTs have lower gate drive requirements
d) IGBTs are current controlled devices
Explanation: Due to its high gate impedance, IGBTs require less gate drive current.
7. The approximate equivalent circuit of an IGBT consists of
a) a BJT & a MOSFET
b) a MOSFET & a MCT
c) two BJTs
d) two MOSFETs
Explanation: Gate of the MOSFET forms the gate terminal of the IGBT, the source of MOSFET is connected to the base of the BJT and drain to the collector.
8. An IGBT is also know as
a) MOIGT (Metal oxide insulated gate transistor)
b) COMFET (Conductively modulated FET)
c) GEMFET (Grain modulated FET)
d) all of the mentioned
Explanation: All of the above mentioned are alternate names of IGBTs.
9. The body of an IGBT consists of a
c) p-n layer
Explanation: IGBT has a p-n-p structure with fingers of n+ layers into the p layer. The p layer has the largest cross section and forms the body of the IGBT.
10. At present, the state-of-the-art semiconductor devices are begin manufactured using
a) Semiconducting Diamond
Explanation: All of the above mentioned can be used but Si-Ca has certain advantages over the other materials.
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.