This set of FACTS Multiple Choice Questions & Answers (MCQs) focuses on “Types of Power Electronic Devices – Set 2”.
1. SCS stands for ________
a) Silicon Conjugated Switch
b) Silicon Commuted Switch
c) Silicon Converted Switch
d) Silicon Controlled Switch
View Answer
Explanation: SCS stands for Silicon Controlled Switch. Its structure of four layers ‘pnpn’ is same to that of an SCR. However, SCS (unlike SCR) has two gate terminals in addition to anode and cathode.
2. SITH stands for ________
a) Static Induction Thyristor
b) Silicon Induction Thyristor
c) Static Induction Transistor
d) Silicon Induction Transistor
View Answer
Explanation: SCS stands for Static Induction Thyristor. Its structure of four layers ‘pnpn’ is same to that of an SCR. However, SCS (unlike SCR) can be turned on and off by applying positive and negative pulses respectively between gate and cathode.
3. LASCR stands for ________
a) Light Activated SCR
b) Light Activated Switch
c) LED Activated SCR
d) LED Activated Switch
View Answer
Explanation: LASCR stands for Light Activated SCR or Light Activated Thyristor. Instead of current or voltage, a pulse of light is thrown on its gate terminal. When adequate electron-hole pairs are generated due to the radiation of fallen light, the device is turned on.
4. DIAC is a unidirectional thyristor device.
a) True
b) False
View Answer
Explanation: DIAC is a bidirectional thyristor device, not a unidirectional one. It is so because it can conduct current in both ways. It has symmetrical breakdown characteristics.
5. TRIAC is a unidirectional thyristor device.
a) True
b) False
View Answer
Explanation: TRIAC is a bidirectional thyristor device, not a unidirectional one. It is so because it can conduct current in both ways. It exhibits similar operation if two SCRs connected to each other anti-parallely are considered.
6. DIAC is exactly same to TRIAC.
a) True
b) False
View Answer
Explanation: DIAC is NOT exactly same to TRIAC. Both of them conduct in both directions. DIAC has two terminals and TRIAC has three terminals. The gate terminal is absent in DIAC but is present in TRIAC.
7. MOSFETs are only of enhancement type.
a) True
b) False
View Answer
Explanation: MOSFETs are NOT only of enhancement type. MOSFETs can be of depletion type also. The transfer characteristics of enhancement type MOSFETs are different from that of depletion type MOSFETs.
8. The hybrid parameters of transistors in common emitter configuration are same to that in common base configuration.
a) True
b) False
View Answer
Explanation: The hybrid parameters of transistors in common emitter configuration are different to that in common base configuration. Actually in the former the emitter is taken as common terminal while in the later the base is taken as the common terminal. Accordingly the parameters deduced with respect to common terminal (which is different in the two cases) come out to be different.
9. The input resistance is lowest in ________ of the transistor amplifier.
a) common emitter configuration
b) common collector configuration
c) any configuration
d) common base configuration
View Answer
Explanation: The input resistance is lowest in common base configuration of the transistor amplifier. CB amplifier is used as a current source. It is also used to drive a high impedance load.
10. The output resistance is highest in ________ of the transistor amplifier.
a) common emitter configuration
b) common collector configuration
c) any configuration
d) common base configuration
View Answer
Explanation: The output resistance is highest in common base configuration of the transistor amplifier. CB amplifier is commonly not used for amplification. It is used for matching a very low impedance source.
11. The current gain is less than unity in________
a) common emitter configuration
b) common collector configuration
c) all configurations
d) common base configuration
View Answer
Explanation: The current gain is less than unity in common base configuration. The current gain is high in CE configuration. Likewise the current gain is also high in CC configuration. Thus the current gain is NOT same in all configurations.
12. The voltage gain is less than unity in________
a) common emitter configuration
b) common collector configuration
c) all configurations
d) common base configuration
View Answer
Explanation: The voltage gain is less than unity in common collector configuration. The voltage gain is high in CE configuration. Likewise the voltage gain is also high in CB configuration. Thus the voltage gain is NOT same in all configurations.
13. For amplification purpose, ________ of transistor amplifier is widely used.
a) common emitter configuration
b) common collector configuration
c) all configurations
d) common base configuration
View Answer
Explanation: For amplification purpose, common emitter configuration of transistor amplifier is widely used. This is so because CE configuration can provide voltage gain and current gain. This feature of providing both the voltage gain and current gain are not prevalent on other two configurations.
14. For buffering purpose, ________ of transistor amplifier is widely used.
a) common emitter configuration
b) common collector configuration
c) all configurations
d) common base configuration
View Answer
Explanation: For buffering purpose, common collector configuration of transistor amplifier is widely used. CC amplifier is used as a buffer between high impedance source and low impedance load. This feature of providing buffering is not prevalent on other two configurations.
15. The output resistance is lowest in ________ of the transistor amplifier.
a) common emitter configuration
b) common collector configuration
c) any configuration
d) common base configuration
View Answer
Explanation: The input resistance is lowest in common collector configuration of the transistor amplifier. CC amplifier is not used as a current source. It cannot be used to drive a high impedance load.
Sanfoundry Global Education & Learning Series – Flexible AC Transmission System (FACTS).
To practice all areas of Flexible AC Transmission System (FACTS), here is complete set of 1000+ Multiple Choice Questions and Answers.
If you find a mistake in question / option / answer, kindly take a screenshot and email to [email protected]
