This set of FACTS Multiple Choice Questions & Answers (MCQs) focuses on “Power Semiconductor Devices – IGCT, IGBT and MCT”.
1. IGCT is an acronym for ________
a) Integrated Gate Commuted Thyristor
b) Insulated Gate Commuted Thyristor
c) Insulated Gate Commuted Transistor
d) Integrated Gate Commuted Transistor
View Answer
Explanation: IGCT is an acronym for Integrated Gate Commuted Thyristor. It offers a wide range of low and medium power applications ranging up to several megawatts and even a few tens of megawatts. It has its own importance in FACTS.
2. IGBT is the abbreviation of ________
a) Insulated Gate Bipolar Transistor
b) Integrated Gate Bipolar Thyristor
c) Insulated Gate Bipolar Thyristor
d) Integrated Gate Bipolar Transistor
View Answer
Explanation: IGBT is the abbreviation of Insulated Gate Bipolar Transistor. it possesses characteristic third terminal. This third terminal is gate which is used in its control as well the devoice in which IGBT is incorporated.
3. GCT is an acronym for ________
a) Gate Commuted Thyristor
b) Gate Controlled Thyristor
c) Gate Commuted Transistor
d) Gate Controlled Transistor
View Answer
Explanation: GCT is an acronym for Gate Commutated Thyristor. GCT consists of a GTO with hard turn-off facility. In combination with desired devices, it achieves a fast turning-off feature and low turn-off switching losses.
4. ETO is the abbreviation of ________
a) Emitter Turn-On Thyristor
b) Emitter Turn-Off Thyristor
c) Emitter Turn–On Transistor
d) Emitter Turn-Off Transistor
View Answer
Explanation: ETO is the abbreviation of Emitter Turn-Off Thyristor. It utilizes MOSFET for its turning-off and turning-on. It has fundamentally two gates for its operation.
5. MCT is an acronym for ________
a) Metal-Oxide Semiconductor Controlled Thyristor
b) Metal-Oxide Semiconductor Commuted Thyristor
c) Metal-Oxide Semiconductor Controlled Transistor
d) Metal-Oxide Semiconductor Commuted Transistor
View Answer
Explanation: MCT is an acronym for Metal-Oxide Semiconductor Controlled Thyristor. MCT incorporates integrated MOS structure. MCT uses it to achieve both fast turning-on and turning-off.
6. IGBT is an example of a passive switch.
a) True
b) False
View Answer
Explanation: IGBT is NOT an example of a passive switch. It is an active switch. This is because it is controlled by its third terminal which is gate.
7. IGBT is similar to BJT considering the quadrant of operation as a switch.
a) True
b) False
View Answer
Explanation: IGBT is similar to BJT considering the quadrant of operation as a switch. IGBT and BJT have the same property of single-quadrant operation. Both of them exhibit positive on-state conduction of current and positive off-state blocking of voltage.
8. Which of the following is preferred as the switch A in the circuit?
a) Resistance
b) BJT
c) IGBT
d) Diode
View Answer
Explanation: As evident from the given figure, the switch A requires to be a controllable one. Diode is an uncontrollable switch. Both BJT and IGBT are controllable switches. But to make the BJT operate with efficiency, a large gate current is required which is not the case in utilizing IGBT. So here IGBT is preferred to realize switch A.
9. Which of the following is preferred as the switch B in the circuit?
a) Short circuit
b) BJT
c) IGBT
d) Diode
View Answer
Explanation: As evident from the given figure, the switch B requires to be an uncontrollable one. Diode is an uncontrollable switch. Both BJT and IGBT are controllable switches which are not required here for free-wheeling purpose. So here diode is preferred to realize switch B.
10. IGCT consists of ______ facility.
a) a GTO with hard turn-off
b) a MTO with hard turn-off
c) a GTO with soft turn-off
d) a GTO with hard turn-on
View Answer
Explanation: IGCT consists of a GTO with hard turn-off facility. In combination with desired devices, it achieves a fast turning-off feature. Also it exhibits low turn-off switching losses.
11. MCT exhibits ________
a) low switching losses and low conduction losses
b) high switching losses and low conduction losses
c) low switching losses and high conduction losses
d) high switching losses and high conduction losses
View Answer
Explanation: MCT exhibits very low switching losses and low conduction losses. MCT, therefore, poses itself as a good potential for low power applications and also in FACTS Controllers. Its processing technology is essentially the same as that of IGBT.
12. Structural analysis reveals that MCT incorporates only p-type or n-type MOSFET.
a) True
b) False
View Answer
Explanation: MCTs themselves can be n-type and p-type. Again structural analysis reveals that n-MCT incorporates both p-type and n-type MOSFETs. Its equivalent circuit displays that for turning-on there is an n-type MOSFET connected across the cathode and another p-type MOSFET for turning-off functionality.
13. The power needed for turning-on and turning-off MCT is very small.
a) True
b) False
View Answer
Explanation: The power needed for the turning-on and turning-off is very small. Also MCT exhibits less delay time or storage time. Additionally it has a low on-state voltage drop.
14. Identify the terminal A of the given figure.
a) virtual earth terminal
b) earth terminal
c) light emitting diode terminal
d) turn-on & turn-off gate
View Answer
Explanation: The given figure represents both a GCT and a GTO. The terminal A in the given figure is the turn-on turn-off gate. The same gate terminal is used to turn-on and turn-off the device. No light emitting diode or earth is incorporated in this devices-configuration.
15. Identify the terminal B of the given figure.
a) cathode
b) switching terminal
c) turning-on terminal
d) earth terminal
View Answer
Explanation: The given figure represents both a GCT and a GTO. The terminal B in the given figure is the cathode. Proper voltage must be maintained between anode and cathode to keep the device in latched condition. Switching is devoted to gate terminal.
Sanfoundry Global Education & Learning Series – Flexible AC Transmission System (FACTS).
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