Download AKTU B-Tech 4th Sem 2014-15 Electronics Circuits Question Paper

Download AKTU (Dr. A.P.J. Abdul Kalam Technical University (AKTU), formerly Uttar Pradesh Technical University (UPTU) B-Tech 4th Semester (Fourth Semester) 2014-15 Electronics Circuits Question Paper

Printed Pages : 4
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(Following Paper ID and Roll No. to be ?lled in your Answer Book)
PAPER ID : 130401
Roll No.
B. Tech.
(SEM. IV)'THEORY EXAMINATION, 2014-15
ELECTRONICS CIRCUITS
Time : 3 Hours] [Total Marks : 100
Note : (1) Attempt all questions.
(2) All questions carry equal marks.
1 Attempt any four parts of following : 5X4=20
(a) Derive an expression for the voltage gain, vo/vi
of the circuit in the Figure 1.1
:
Figure 1 .1
(b) Discuss how the performance of an OP-AMP is
affected by the open loop gain of ampli?er.
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130401] 1 [ Contd...

(o)
(d)
(e)
(f)
Describe the difference between inverting and
non-inverting ampli?er.
Derive an expression for the input resistance of
the invetting ampli?er of the Figure1.2 taking into
account the ?nite open loop gain A of the OP-
2R;
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Figure 1.2
For an ampli?er having a slew rate of 60 V/ p. 5,
what is the highest frequency at which a 20-V
peak-to-peak sine wave can be produced at the
output?
What are the ideal characteristics of op-amp?
Explain the concept of voltage follower.
Attempt any four parts of following : 5><4=20
(a)
(b)
(e)
((0
130401]
Discuss the iD- VDs characteristics of n-channel
enhancement type MOSFET. Indicate the three
distinct regions of operation.
For a particular MOSFET operating in the
saturation region at a constant VGS, i1) is found to
be 2 mA for VDS = 4 V and 2.2 mA for
VDS = 8 V. What values of r0, VA, and A
correspond?
What is bias stabilization? Explain the basic
current minor with suitable diagram.
For the CS amplifier, determine its high ??equency
transfer ?mction.
2 [Contd...
(e) The bias circuit of Figure.2.1 is used in a
design with V0 = S V and R5 = 1 kQ.
For an enhancement MOSFET with
k'n(W/L) = 2mA/V2, the source voltage was
measured and found to be 2 V. What must
Vt be .t'or this device? If a device for which Vt
is 0.5 V less is used, what does Vs become?
What bias current results?
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F igure 2.1'
(f) Draw the high frequency model of MOSFET and
explain the MOS capacitances.
Attempt any two parts of following: 10X2=20
(a) Why transistor action cannot be achieved by
connecting two diodes back to back. Explain input
and output characteiistics of Common emitter BJT.
(b) A pnp transistor operates with an emitter-to
collector voltage of 5 V, an emitter current of
10 A, and VEB = 0.85 V. For B = 15, what
base current is required? What is Is for this
transistor? Compare the emitter-base junction
areas of this transistor with that of a small-signal
transistor that conducts i0 = 1 mA with
VEB = 0.70 V. How much larger is it?
130401] ? 3 [ Contd...

(e) What is emitter stabilization in self-bias circuit of
an npn transistor in CB ampli?er? Explain the high
frequency response of common emitter ampli?er.
4 Attempt any two parts of following : 10X2?20
(a) Explain the small signal operation of BJT differential
pair and derive the expressions for differential
input resistance and gain.
(b) Explain CS MOS differential pair and discuss the
non ideal characteristics of MOS differential pair.
(c) Calculate the output resistance and CMRR for
active loaded BIT differential pair.
5 Attempt any two parts of following : 10><2=2lll
(a) Draw a neat sketch of a generalized resonant
circuit oscillator using three impedances. Explain
. Hartley oscillator and derive the frequency of
oscillation '
(b) De?ne the Barkhausen criterion for oscillation:
Derive an expression for frequency of oscillation
of Wein bridge oscillator.
(0) Discuss the effect of negative feedback on
noise and Bandwidth of an ampli?er. Calculate
the gain, input resistance and output resistance
of trans-resistanoe ampli?er.
130401] 4 [1425]