Download AKTU B-Tech 4th Sem 2014-15 Analog And Digital Electronics 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 Analog And Digital Electronics Question Paper

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(Following Paper 1]) and Roll No. to be ?lled in your Answer Book)
PAPER ID: 131410
Roll No.
B. Tech.
(SEM. IV) THEORY EXAMINATION, 2014?15
ANALOG AND DIGITAL ELECTRONICS
Time : 3 Hours] 1 [Total Marks : 100
1 ' Attempt any four parts: ' 5X4=20
(a) Discuss how the variable capacitance is achieved in
varactor diode. Enlist the application of varactor diode.
(b) Explain the pn'nciple and working of light emitting diode
(LED) with V-I characten'stics.
(c) Draw the V-I characteristics of tunnel diode and indicate
. the useful region in the curve.
(d) Draw the output characteristics of transistor and also
explain how it is used as a switch.
(e) An LED is connected across a voltage source of +10V
through a se?es resistance of 820 9 Calculate the LED
cui'rent. Assume the voltage drop across an LED of
15 Volt.
(t) De?ne the following terms :
(1) Rise time
(1i) Fall time
(iii) Delay time
(Iv) Storage time.
131410] ' 1 ? [Contd...

(a)
(b)
(c)
(d)
(e)
(f)
(a)
(b)
(C)
131410]
Attempt any four parts : 5X4=20
Derive the input and output resistance of a
Transconductance and Voltage ampli?er.
Calculate the voltage gain, input and output resistance
of voltage series feedback ampli?er having Av = 300,
R1 =. 1.5kg, R0=50kQ and B=1/15.
Describe the properties of series-shunt and shunt-shunt
feedback ampli?er. '
Draw the high frequency equivalent circuit or the typical
RC coupled common emitter ampli?er.
An RC coupled ampli?er has voltage gain of 1000,
f1 = 50 Hz, f2 = 200 kHz and a distortion of 5% without
feedback. Find the ampli?er voltage gain, f1, f2 and
distortion when negative feedback is applied with
feedback ratio 0.01, ?
List ?ve characteristics of an ampli?er which are
modi?ed by negative feedback.
Attempt any two parts : 10><2=20
(1) Discuss how does the circuit of a hantley oscillator
differ from that of a Colpitt oscillator.
(11) Explain the properties of a quartz crystal which
are responsible for its use in oscillator.
What is the Barkhausen criterion for the F eedback
oscillator? Draw a neat diagram of phase shift oscillator
using BJT. Derive an expression for its ?'equency of
oscillation
A coupling oscillator is designed with C1=100 pF and
C2=7500 pf. The inductance is van'able. Determine the
range of inductance values, if the frequency of oscillation
is to vary between 950 kHz and 2050 kHz.
2 [ Contd...
Attempt any two parts : 10X2=20
(a) (1) Implement the following Boolean ?inc?on using
821 multiplexer
F(A,B,C,D)= z(2,4,5,7,10,14)
(11) Explain the working of SR ?ip-?op using NAND
gates.
(b) (1) Differentiate between an encoder and decoder.
(11) Tabulate the excitation table of J-K ?ip ?op.?
(c) Draw and explain the working of 4-bit up and dowii ?
synchronous counter. Also describe the working of shift
register.
Attempt any two pans : 10><2=20
(a) Explain the organisation of RAM with the help of neat
diagram. Also describe the switching regulators. .
(b) Explain A/D convertor using voltage to frequency
convertor. Describe any one method of ND Convenor?
(c) What are the voltage regulators? Discuss the working
of shunt and sen'es op-amp based voltage regulators.
131410] 3 [17425]