Download VTU ((Visvesvaraya Technological University) B.E/B-Tech 2019 July ( Bachelor of Engineering) First & Second Semester (1st Semester & 2nd Semester) 18 Scheme I8ELN14 Basic Electronics Question Paper
18ELN14
First Semester B.E. Degree Examination, Dec.2018/Jan.2019
Basic Electronics
Time: 3 hrs.
Max. Marks: 100
Note: Answer any FIVE full questions, choosing ONE full question from each module.
,.;
.= Module-1
0
a
1 a. Explain the working of PN junction diode under forward and reverse biased conditions.
-..
P
(06 Marks)
cc l
b. Explain how zener diode helps in voltage regulation with neat circuit diagram. (06 Marks)
-zi
O c. Explain with neat circuit diagram and waveforms the working of center-tap full wave
ct
2 rectifier. Show that efficiency of full-wave rectifier is 81%. _ (08 Marks)
0
. ,
OR
.. '
2
'
-
`
..-
i -;
2 a. Explain the operation of half-wave rectifier with capacitor filter with neat circuit diagram
til
?
l'
and waveforms. (06 Marks)
. z
=
+
oc
,,, b. Show that the ripple factor of a half-wave rectifier is 1.21 and efficiency is 40.5%.
-
'
-
?i 71-
tz
(06 Marks)
$... i)
Z
c. Explain VI characteristics of photodiode and its operation. (04 Marks)
..= a)
? .'6
d.
For the circuit shown in Fig.Q2(d) find (i) current and voltages in the circuit for RL = 450 O.
0
.5
?
g
_a---'
.n...-
i__. ii 9)
?
P
g 1
V
u 0 (04 Marks)
,.
cd o
o
?
-ol
ti) =
,1 m:
-ic .-
O Module-2
-6
-
,, 'c'cl
? 3 a. Explain the drain and transfer characteristics of a JFET with neat circuit diagram. (08 Marks)
? t,
h. Explain the basic structure and operation of JFET with neat diagrams. (08 Marks)
f.
-
_,' .
a ?
c. For a JFET IDss = 9 mA and VGso)fr) = -
8 V
(rnax)
determine drain current for VGS = ?
4V.
rz ..,
(04 Marks)
? 0.
c ct
, d
OR
3 11
4 a. Explain the operation of an enhancement MOSFET with neat circuit diagram. (06 Marks)
cr:
a --,
b. Explain CMOS as an inverter with neat circuit diagram. Give its equivalent circuit and its
,...,
?
,- ?, ,,
O
advantages.
(08 Marks)
ti) 0
Explain VI characteristics of SCR.
.= g
(06 Marks)
E g
E
Module-3
O 2
5 a. Explain the block diagram of an operational amplifier. (06 Marks)
*
I of 2
Fig.Q2(d)
b. Explain the operation of an op-amp as a non-inverting amplifier with neat diagram and
waveforms.
(06 Marks)
c. Define the following terms with respect to op-amp.
(i) CMRR (ii) Slewrate (iii) pp offset voltage and current ) pp bias current
(08 Marks)
0
0.
OR
6 a. Explain op-amp as a subtractor with neat circuit diagram. (08 Marks)
b. 'Explain the different iv modes of an op-amp.
(06 Marks)
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18ELN14
First Semester B.E. Degree Examination, Dec.2018/Jan.2019
Basic Electronics
Time: 3 hrs.
Max. Marks: 100
Note: Answer any FIVE full questions, choosing ONE full question from each module.
,.;
.= Module-1
0
a
1 a. Explain the working of PN junction diode under forward and reverse biased conditions.
-..
P
(06 Marks)
cc l
b. Explain how zener diode helps in voltage regulation with neat circuit diagram. (06 Marks)
-zi
O c. Explain with neat circuit diagram and waveforms the working of center-tap full wave
ct
2 rectifier. Show that efficiency of full-wave rectifier is 81%. _ (08 Marks)
0
. ,
OR
.. '
2
'
-
`
..-
i -;
2 a. Explain the operation of half-wave rectifier with capacitor filter with neat circuit diagram
til
?
l'
and waveforms. (06 Marks)
. z
=
+
oc
,,, b. Show that the ripple factor of a half-wave rectifier is 1.21 and efficiency is 40.5%.
-
'
-
?i 71-
tz
(06 Marks)
$... i)
Z
c. Explain VI characteristics of photodiode and its operation. (04 Marks)
..= a)
? .'6
d.
For the circuit shown in Fig.Q2(d) find (i) current and voltages in the circuit for RL = 450 O.
0
.5
?
g
_a---'
.n...-
i__. ii 9)
?
P
g 1
V
u 0 (04 Marks)
,.
cd o
o
?
-ol
ti) =
,1 m:
-ic .-
O Module-2
-6
-
,, 'c'cl
? 3 a. Explain the drain and transfer characteristics of a JFET with neat circuit diagram. (08 Marks)
? t,
h. Explain the basic structure and operation of JFET with neat diagrams. (08 Marks)
f.
-
_,' .
a ?
c. For a JFET IDss = 9 mA and VGso)fr) = -
8 V
(rnax)
determine drain current for VGS = ?
4V.
rz ..,
(04 Marks)
? 0.
c ct
, d
OR
3 11
4 a. Explain the operation of an enhancement MOSFET with neat circuit diagram. (06 Marks)
cr:
a --,
b. Explain CMOS as an inverter with neat circuit diagram. Give its equivalent circuit and its
,...,
?
,- ?, ,,
O
advantages.
(08 Marks)
ti) 0
Explain VI characteristics of SCR.
.= g
(06 Marks)
E g
E
Module-3
O 2
5 a. Explain the block diagram of an operational amplifier. (06 Marks)
*
I of 2
Fig.Q2(d)
b. Explain the operation of an op-amp as a non-inverting amplifier with neat diagram and
waveforms.
(06 Marks)
c. Define the following terms with respect to op-amp.
(i) CMRR (ii) Slewrate (iii) pp offset voltage and current ) pp bias current
(08 Marks)
0
0.
OR
6 a. Explain op-amp as a subtractor with neat circuit diagram. (08 Marks)
b. 'Explain the different iv modes of an op-amp.
(06 Marks)
VO
?Pam() I-
Fig.Q6(c)
Also write the function of each op-amp used.
18ELN14
c.
For an op-amp circuit shown in Fig.Q6(c), find the output Vo 1 and Vo
l
.
ita).
14
-
Vol
(06 Marks)
Module-4
7 a. With neat circuit diagram explain how transistor is used as an voltage amplifier. Derive an
equation for A. (08 Marks)
b. Explain the voltage series feedback circuit and derive an equation for voltage gain A
v
with
feedback. (04 Marks)
c. Explain RC phase-shift oscillator with circuit diagram and necessary equations. (08 Marks)
OR
8 a. With neat circuit diagram explain how transistor can be used to switch an LED ON/OFF ana
give the necessary equation. (08 Marks)
b. The transistor in common emitter configuration is shown in Fig.Q8(b) with It
c
= 10 kfl and
PDC = 200 determine
(i) VCE at V
i
? = 0 (ii) IB(min) to saturate the collector current (iii) Rti(nax) when Vi
n
= 5V.
Vcr(.1) can be neglected. (04 Marks)
VocAk-
^ 0200
Fig.Q8(b)
c. Explain the operation of IC-555 as an Astable oscillator with neat circuit diagram and
necessary equation. (08 Marks'
Module-5
9 a. Design Full adder circuit and implement it using basic gates. (10 Marks)
b. Explain the basic elements of communication system with block diagram. (06 Marks)
c. Find
(i) (1010111011110101)
2
= ( ? )
6
(ii) (FA876)
1 6 = ? )2
(04 Marks)
OR
10 a. State and prove De Morgan's theorems. (04 Marks)
b. Explain the working of a 3-bit ripple counter with neat circuit diagram and timing diagrams.
(08 Marks)
c. Explain the working of RS flip flop with truth table and diagram. (06 Marks)
d. Subtract the following using 2's complement:
(i) 11100 - 10011 (02 Marks)
2 of 2
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This post was last modified on 01 January 2020