Roll No.

JSS MAHAVIDYAPEETHA
JSS ACADEMY OF TECHNICAL EDUCATION, NOIDA
DEPARTMENT OF ELECTRONICS & COMMUNICATION ENGINEERING

AY 2020-21 (Even Semester) Model Questions from UNIT

Course : B.Tech. : Date : 9Aug21

Semester : II : Subject Code : KEC201T
Subject : Emerging Domain in Electronics
: Engineering
COURSE UTCOMES
CO1/C105.1: Identify and implement the application of PN junction diode and basics of special purpose diodes.
CO2/C105.2: Acquire basic knowledge on the construction, operation and characteristics of major three terminal
devices.
CO3/C105.3: Develop competence in Operational Amplifier and IoT systems.
CO4/C105.4: Interpret the concept of digital electronics and IC technology.
CO5/C105.5: Develop the ability to compare and contrast the working principle of different types of communication
systems and their techniques.
Q.
Questions BL
No.
Multiple choice Questions
1 What will be the value of collector current 𝐼𝐶 if the transistor has current gain =250 and 2
base current 𝐼𝐵 = 20𝜇𝐴?
(a) 500mA (b) 5mA (c) 50A (d) 5A
2 In a certain BJT, what will be the current gain, when the output current varies from 80mA to 1
82mA, for the input current variation form 50A to 70A?
(a) 200 (b) 100 (c) 10 (d) 1000
3 Read the statements carefully and then select the most appropriate comment- 2
(i) In the active region of a common-emitter amplifier, the base–emitter junction is forward-
biased, whereas the collector–base junction is reverse-biased.
(ii) In the cutoff region the base–emitter and collector–base junctions of a transistor are both
reverse-biased.
(iii) In the saturation region the base–emitter and collector–base junctions are forward-biased
(iv) In the active region the base–emitter junction is reverse biased, whereas the collector–
base junction is forward-biased.

(a). All the statements are TRUE

(b). Statements (i), (ii) and (iii) are TRUE
(c). Statement (ii) is FALSE
(d). Statements (ii) and (iii) are TRUE
4 The relation between  and  of transistor is 1
 
(a)  = +1 (b) = (c) = (d)  =  +1
 +1  −1
5 The reverse saturation current ICBO in BJT _____ (Select the most appropriate choice to complete 2
the sentence)
(a). depends on emitter-base bias
(b). increases with increase in temperature
(c). depends largely on doping level of emitter region
(d). is generally greater in Si transistor than Ge transistor
6 Which of the following is the most important construction property that ensures transistor 2
operation __?
(a). Emitter must be heavily doped and its collector –base junction must be forward biased
(b). Emitter is the most heavily doped region; collector has largest area and base moderate
to lightly doped with smallest are among the three regions
(c). Collector and emitter are most heavily doped regions; collector has largest area and
base is very lightly doped.
(d). Emitter is the most lightly doped region; collector has largest area and base heavily doped
with smallest are among the three regions
1
 7 In Common collector configuration the input VI characteristics are plotted __ 1
(a). Between 𝑉𝐵𝐶 and 𝐼𝐶 at constant 𝐼𝐸
(b). Between 𝑉𝐵𝐶 and 𝐼𝐵 at constant 𝑉𝐸𝐶
(c). Between 𝑉𝐵𝐸 and 𝐼𝐵 at constant 𝑉𝐸𝐵
(d). Between 𝑉𝐸𝐶 and 𝐼𝐸 at constant 𝐼𝐶

8 Estimated value of  in BJT when =90 is ______ 2

(a) 1 (b)0.9 (c)0.09 (d)9
9 Find the region of operation of a BJT if the biasing is as indicated in the figure below 3
+ (a) Saturation Region (b) Active Region
VCB
5V
- Q (c) Cut-off Region (d) Reverse- active Region
+
VBE
2V
-
10 Consider the following statements and choose the most appropriate comment 1
(i) The β of a bipolar transistor reduces if the base width is increased.
(ii)The β of a bipolar transistor increases if the doping concentration in the base is increased.
(a). Statement (i) is FLASE and (ii) is TRUE
(b). Statement (i) is TRUE and (ii) is FALSE
(c). Both statements (i) and (ii) are TRUE
(d). Both statements (i) and (ii) are FLASE
11 For a BJT, the common -base current gain 𝛼 = 0.99 and the collector base junction reverse bias 1
saturation current 𝐼𝐶𝑂 = 10𝜇𝐴. This BJT is connected in the common emitter mode and operated
in the active region with a base drive current 𝐼𝐵 = 100𝜇𝐴. Compute the value of collector current
𝐼𝐶 for this mode of operation?
(a) 109mA (b) 10.9 mA (c) 1090A (d)10.9 A
12 In a bipolar junction transistor at room temperature, if the emitter current is doubled, the voltage 3
across its base - emitter junction (hint consider base-emitter junction operations forward biased
pn-junction diode) ___
(a) Become half the original value (b) increases by approx. 20mV
(c) Becomes double (d) reduces by 20 mV approx.
13 In a transistor having finite β, the forward bias across the base emitter junction is kept constant 3
and the reverse bias across the collector base junction is increased. Ignoring the leakage
phenomena across the collector- base junction and the depletion region change, what will be the
overall impact on the base current?
(a) It will increase (b) It will decrease
(c)It will remain the same (d) It will become zero
14 Match the terms with their corresponding definition or expression that defines them 3
A. Current gain  𝐼
(i) 𝐼𝐶 ⌉ (in CB configuration)
B. Current Gain  𝐸
𝐼
C. 𝐼𝐶𝐸𝑂 (ii) 𝐶 ⌉ (in CC configuration)
𝐼𝐵
D. Emitter follower 𝐼
(iii) 𝐼𝐶 ⌉ (in CE configuration)
𝐵
(iv) Common collector configuration
(v) ≅ 𝛼𝐼𝐶𝐸𝑂
𝐼𝐶𝐸𝑂
(vi)≅ 1−𝛼

(a) A-(i) , B- (iii), C- (iv), D-(v) (b) A-(i) , B- (iii), C- (vi), D-(iv)
(c) A-(i) , B- (ii), C- (iv), D-(iv) (d) A-(i) , B- (ii), C- (vi), D-(iv)
15 Identify the incorrect expression from the following that describe operation of BJT 2
(a) 𝐼𝐸 = (𝛽 + 1)𝐼𝐵 (b) 𝐼𝐶 = 𝐼𝐸 + 𝐼𝐵
𝛼
(c) 𝛽 = (d) 𝐼𝐶𝐸𝑂 = (𝛽 + 1)𝐼𝐶𝐵𝑂
1−𝛼

Solution → for all the questions choice (b) is the correct answer