Download Visvesvaraya Technological University (VTU) BE/B.Tech First And Second Semester (1st sem and 2nd sem) 2019-2020 Jan ( Bachelor of Engineering) 18 Scheme 18ELIN1424 Basic Electronics Previous Question Paper

USN

111111111120171

First/Second Seme .E. Degree Examination, Dec.2019/Jan.2020

Basic Electronics

Time: 3 hrs. Max. Marks: 100

Note: Answer any FIVE full questions, choosing ONE full question from each !nodule.

Module-1

1 a. Explain the working of PN junction diode under forward and reverse biased conditions.

(06 Marks)

b. Explain the working of Photodiode. (05 Marks)

c. Explain with neat circuit diagram and waveforms, the working of kill wave bridge rectifier.

Show that the efficiency Of full wave bridge rectifier is 81%. (09 Marks)

OR

2 a. Explain the operation of Half wave rectifier with capacitor filter with neat circuit diagram

and waveforms. (06 Marks)

b. A full wave rectifier uses 2 diodes having internal resistance of 10 f each. The transformer

RMS secondary voltage from center to each end is 200V. Find 1

m

, Imis and Vd

c

if the

load is 800 a (06 Marks)

c. Explain how zener diode helps in voltage regulation with neat circuit diagram. Give detail

mathematical analysis. (08 Marks)

3 a.

b.

c.

Module-2

Explain the construction, working and characteristics of n-channel .IFET.

With a neat circuit diagram, explain the working of CMOS Inverter.

For a n-channel JFET if I

ons

= 9 mA and V

p

= ?6V. Calculate 11

)

at V

as

= ?

ID = 3 mA.

(09 Marks)

(06 Marks)

4V and V

as

at

(05 Marks)

OR

4 a. Explain the construction, working and characteristics of enhancement type MOSFET.

(09 Marks)

b. Explain the working of Silicon Controlled Rectifier [SCR} using two transistor model.

(06 Marks)

c. FOr an EMOSFET, determine the value of ID if I

D on)

= 4 mA, V

gson)=

6V, VT = 4V and

V

as

= 8V. (05 Marks)

Module-3

5 a. What is an OP-AMP? List the characteristics of an ideal OP-AMP. (06 Marks)

b. Explain the operation of an OP-AMP as inverting amplifier with neat diagram and

waveforms. (06 Marks)

c. Explain how OP-AMP can be used as 0) Integrator (ii) Voltage foll9wer. (08 Marks)

OR

6 a. Explain the different input modes of an OP-AMP. (06 Marks)

b. Design an adder circuit using OP-AMP to obtain an output voltage, V

o

= ?[2V1 + 3V

2

+5V

3

].

Assume Rf= 10k0. (06 Marks)

18ELIN14/24

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4;isoc,

USN

111111111120171

First/Second Seme .E. Degree Examination, Dec.2019/Jan.2020

Basic Electronics

Time: 3 hrs. Max. Marks: 100

Note: Answer any FIVE full questions, choosing ONE full question from each !nodule.

Module-1

1 a. Explain the working of PN junction diode under forward and reverse biased conditions.

(06 Marks)

b. Explain the working of Photodiode. (05 Marks)

c. Explain with neat circuit diagram and waveforms, the working of kill wave bridge rectifier.

Show that the efficiency Of full wave bridge rectifier is 81%. (09 Marks)

OR

2 a. Explain the operation of Half wave rectifier with capacitor filter with neat circuit diagram

and waveforms. (06 Marks)

b. A full wave rectifier uses 2 diodes having internal resistance of 10 f each. The transformer

RMS secondary voltage from center to each end is 200V. Find 1

m

, Imis and Vd

c

if the

load is 800 a (06 Marks)

c. Explain how zener diode helps in voltage regulation with neat circuit diagram. Give detail

mathematical analysis. (08 Marks)

3 a.

b.

c.

Module-2

Explain the construction, working and characteristics of n-channel .IFET.

With a neat circuit diagram, explain the working of CMOS Inverter.

For a n-channel JFET if I

ons

= 9 mA and V

p

= ?6V. Calculate 11

)

at V

as

= ?

ID = 3 mA.

(09 Marks)

(06 Marks)

4V and V

as

at

(05 Marks)

OR

4 a. Explain the construction, working and characteristics of enhancement type MOSFET.

(09 Marks)

b. Explain the working of Silicon Controlled Rectifier [SCR} using two transistor model.

(06 Marks)

c. FOr an EMOSFET, determine the value of ID if I

D on)

= 4 mA, V

gson)=

6V, VT = 4V and

V

as

= 8V. (05 Marks)

Module-3

5 a. What is an OP-AMP? List the characteristics of an ideal OP-AMP. (06 Marks)

b. Explain the operation of an OP-AMP as inverting amplifier with neat diagram and

waveforms. (06 Marks)

c. Explain how OP-AMP can be used as 0) Integrator (ii) Voltage foll9wer. (08 Marks)

OR

6 a. Explain the different input modes of an OP-AMP. (06 Marks)

b. Design an adder circuit using OP-AMP to obtain an output voltage, V

o

= ?[2V1 + 3V

2

+5V

3

].

Assume Rf= 10k0. (06 Marks)

18ELIN14/24

18ELN14/24

c. Explain the following terms with respect to OP-AMP:

(i) CMRR (ii) Slew rate (iii) Input bias current (iv) Supply Voltage Rejection ratio.

(08 Marks)

Module-4

7 a. With a neat circuit diagram, explain how transistor is used as an amplifier. Derive a.n

equation for A.. (08 Marks)

b. Explain RC phase shift oscillator with circuit diagram and necessary equations. (08 Marks)

c. Explain the voltage series feedback circuit and derive an equation fot voltage gain, A

v

, with

feedback. (04 Marks)

OR

8 a. With a neat circuit diagram, explain the working of Wein-bridge oscillator. (08 Marks)

b. Explain the operation of I.C555 as an Astable oscillator with neat circuit diagram and

necessary equations.

(08 Marks)

e_ The Transistor in CE configuration is shown in Fig.Q8(c) with RC = 1 ki2 and 13Dc = 125.

Determine

V

cE

at Vi

n

= 0 V_

(ii)

IB(min)

to saturate the collector current

(iii) Rn

(

m

oVhen Vi

n

? 8 V

VcEisat) can be neglected.

Fig.Q8(c)

Module-5

9 a_ Design Full adder circuit and implement it using basic gates.

b. Find (i) (1101 0111 0110 1

.

010).1 = ( ? )io

(ii) (EB986)

16

= ( ? )

2

.

(iii) (925.75)

1

0 = ( ?

.

)

8

c. Explain the basic elements of communication system with block diagram.

OR

10 a. State and prove De-Morgan's theorem.

b. With a block diagram, explain the working of a 3-hit ripple counter.

c. What is a Flip-flop? Explain the operation of master-slave JK flip-flop.

(04 Marks)

(08 Marks)

(06 Marks)

?

(0i Marks)

(06 Marks)

(06 Marks)

(08 Marks)

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This post was last modified on 02 March 2020