Electronic Devices and Circuits Questions and Answers – Small Signal Operations and Model

This set of Electronic Devices and Circuits Multiple Choice Questions & Answers (MCQs) focuses on “Small Signal Operations and Model”.

1. A transistor with ß = 120 is biased to operate at a dc collector current of 1.2 mA. Find the value of gm.
a) 12mA/V
b) 24 mA/V
c) 36 mA/V
d) 48 mA/V
View Answer

Answer: d
Explanation:
Find the value of gm if transistor with ß = 120 is biased at dc collector current of 1.2mA

2. A transistor with ß = 120 is biased to operate at a dc collector current of 1.2 mA. Find the value of R?p.
a) 625 ohm
b) 1250 ohm
c) 2500 ohm
d) 5000 ohm
View Answer

Answer: c
Explanation:
Find the value of gm if transistor with ß = 120 is biased at dc collector current of 1.2mA

3. A transistor with ß = 120 is biased to operate at a dc collector current of 1.2 mA. Find the value of Re.
a) 2.5 ohm
b) 20.6 ohm
c) 25.2 ohm
d) 30.4 ohm
View Answer

Answer: b
Explanation:
Find the value of gm if transistor with ß = 120 is biased at dc collector current of 1.2mA
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4. A transistor operating with nominal gm of 60 mA/V has a ß that ranges from 50 to 200. Also, the bias circuit, being less than ideal, allows a 20% variation in Ic. What is the smallest value found of the resistance looking into the base?
a) 347 ohm
b) 694 ohm
c) 1041 ohm
d) 1388 ohm
View Answer

Answer: b
Explanation:
The smallest value found of the resistance looking into the base is 694 ohm

5. A transistor operating with nominal gm of 60 mA/V has a ß that ranges from 50 to 200. Also, the bias circuit, being less than ideal, allows a 20% variation in Ic. What is the largest value found of the resistance looking into the base?
a) 1050 ohm
b) 21000 ohm
c) 3150 ohm
d) 4200 ohm
View Answer

Answer: d
Explanation:
The smallest value found of the resistance looking into the base is 694 ohm

6. A designer wishes to create a BJT amplifier with a gm of 50 mA/V and a base input resistance of 2000 O or more. What is the minimum ß he can tolerate for the transistor used?
a) 100
b) 150
c) 200
d) 250
View Answer

Answer: a
Explanation:
Minimum ß can tolerate for transistor used is 100 if base input resistance of 2000 O

7. A designer wishes to create a BJT amplifier with a gm of 50 mA/V and a base input resistance of 2000 O or more. What emitter bis current should he choose?
a) 1.06 mA
b) 1.16 mA
c) 1.26 mA
d) 1.36 mA
View Answer

Answer: c
Explanation:
Minimum ß can tolerate for transistor used is 100 if base input resistance of 2000 O
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8. Which of the following is true?
a) Ib = ß Ic
b) Ib = ß + 1/ Ic
c) Ib = Ic/ß
d) Ib = Ic/ ß – 1
View Answer

Answer: c
Explanation: The correct relationship between Ic and Ie is Ib = Ic/ß.

9. The SI units of transconductance is
a) Ampere/ volt
b) Volt/ ampere
c) Ohm
d) Siemens
View Answer

Answer: a
Explanation: Transcoductance is given by Ic/Vt.
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10. Which of the following represents the correct mathematical form of the term denoted by the symbol Rp?
a) ß/gm
b) Vt/Ib
c) All of the mentioned
d) None of the mentioned
View Answer

Answer: c
Explanation: Both of the expressions are identical.

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]

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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.

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