Electronic Devices and Circuits Questions and Answers – BJTs Device Strucutres and Physical Operations

This set of Electronic Devices and Circuits Multiple Choice Questions & Answers (MCQs) focuses on “BJTs Device Strucutres and Physical Operations”.

1. Which of the following is not a part of a BJT?
a) Base
b) Collector
c) Emitter
d) None of the mentioned
View Answer

Answer: d
Explanation: BJT consists of three semiconductor regions, base region, emitter region and collector region.

2. The number of pn junctions in a BJT is/are
a) 1
b) 2
c) 3
d) 4
View Answer

Answer: b
Explanation: There are two pn junctions, base-emitter junction and collector-emitter junction respectively.

3. In which of the following modes can a BJT be used?
a) Cut-off mode
b) Active mode
c) Saturation mode
d) All of the mentioned
View Answer

Answer: d
Explanation: These three are the defined regions in which a BJT operates.
advertisement
advertisement

4. If a BJT is to be used as an amplifier, then it must operate in___________
a) Cut-off mode
b) Active mode
c) Saturation mode
d) All of the mentioned
View Answer

Answer: b
Explanation: A BJT operates as an amplifiers in active mode and as a switch in cut-off or saturation mode.

5. If a BJT is to be used as a switch, it must operate in____________
a) Cut-off mode or active mode
b) Active Mode or saturation mode
c) Cut-off mode or saturation mode
d) Cut-off mode or saturation mode or active mode
View Answer

Answer: c
Explanation: A BJT operates as an amplifiers in active mode and as a switch in cut-off or saturation mode.
Note: Join free Sanfoundry classes at Telegram or Youtube

6. In cut off mode
a) The base-emitter junction is forward biased and emitter-collector junction is reversed biased
b) The base-emitter junction is forward biased and emitter-collector junction is forward biased
c) The base-emitter junction is reversed biased and emitter-collector junction is reversed biased
d) The base-emitter junction is reversed biased and emitter-collector junction is forward biased
View Answer

Answer: c
Explanation: In cut-off mode there is no current flowing through the BJT hence both junctions must be reversed biased else if either of them is forward biased then the current will flow.

7. On which of the following does the scale current not depends upon?
a) Effective width of the base
b) Charge of an electron
c) Electron diffusivity
d) Volume of the base-emitter junction
View Answer

Answer: d
Explanation: The saturation current does not depends upon the volume of the base-emitter junction. Instead it depends upon the area of the cross section of the base-emitter junction in a direction perpendicular to the flow of current.
advertisement

8. On which of the following does the collector current not depends upon?
a) Saturation current
b) Thermal voltage
c) Voltage difference between the base and emitter
d) None of the mentioned
View Answer

Answer: d
Explanation: Collector current depends linearly of the saturation current and exponentially to the ratio of the voltage difference between the base and collector and thermal voltage.

9. The range for the transistor parameter also referred as common-emitter current gain has a value of__________ for common devices.
a) 50-200
b) 400-600
c) 750-1000
d) > 1000
View Answer

Answer: a
Explanation: Most commonly used transistors have a voltage gain of in the range of 50-200. Only some specially designed transistors have a transistor parameter in the range of 1000.
advertisement

10. The collector current Ic is related to the emitter current Ie by a factor k. If b is the transistor parameter then the value of k in terms of b is
a) k = b/(b + 1)
b) k = (b + 1)/b
c) b = (k + 1)/k
d) None of the mentioned
View Answer

Answer: a
Explanation: Ic = k Ie (given) and also Ie = (b + 1)/b Ic (standard result). Equating these two results we get k = b/(b + 1).

Sanfoundry Global Education & Learning Series – Electronic Devices and Circuits.

To practice all areas of Electronic Devices and Circuits, 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]

advertisement
advertisement
Subscribe to our Newsletters (Subject-wise). Participate in the Sanfoundry Certification contest to get free Certificate of Merit. Join our social networks below and stay updated with latest contests, videos, internships and jobs!

Youtube | Telegram | LinkedIn | Instagram | Facebook | Twitter | Pinterest
Manish Bhojasia - Founder & CTO at Sanfoundry
Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

Subscribe to his free Masterclasses at Youtube & discussions at Telegram SanfoundryClasses.