C B3C045 Total Pages:4
Page 1 of 4
Reg. No.
APJ ABDUL KALAM TECHNOLOGICAL UNIVERSITY
THIRD SEMESTER B.TECH DEGREE EXAMINATION, JANUARY 2017
Course Code: EE 203
Course Name: ANALOG ELECTRONIC CIRCUITS
Max. Marks: 100 Duration: 3 Hours
PART A
Answer all questions. Each question carries 5 marks.
1. Draw the dc and ac load lines for the transistor circuit. Given R1=18KΩ, R2=8.2KΩ,
RC=2.2KΩ, Vcc RE=2.7KΩ.
2. Why does gain of amplifier falls off at low and high frequencies?
3. List the characteristics of an amplifier that get modified by negative feedback.
4. What are the modes in which an op-amp can be operated?
An op-amp has a gain bandwidth product of 15 MHz. Determine the
bandwidth of op-amp when AcL =500. Also find maximum value of ACL when
frequency is 200 KHz.
5. Design an adder circuit to get the output expression as Vo V1 V2 10 V3]
where V1, V2 and V3 are the inputs to the Op-amps.
6. What are the limitations of an ideal integrator? Design a circuit which overcome the errors
of ideal integrator.
7. Distinguish between triangular wave and ramp generator using op-amp.
8. Design a phase shift oscillator with a frequency of 100 Hz using op-amp.
C B3C045 Total Pages:4
Page 2 of 4
PART B
Answer any 2 questions. Each question carries 10 marks.
9. Parameters of FET used in amplifier circuits are gm=4.2 and rd=30KΩ. Assume C
to be short circuit for signal frequency, given a small signal model for the amplifier.
Determine small signal voltage gain if RD =6.8KΩ, RG 1MΩ and RS=10 KΩ.

Compare JFET with MOSFET.
Why is voltage divider bias relatively stable against changes in hfe? ii) Design voltage
divider bias circuit to operate from a 12V supply. The bias conditions are
VCE=3V,VE=5V and Ic=1mA.
10. A transistor used in CE connection has the following set of h parameters when the d.c.
operating point is VCE =5V and IC 1 mA; hie =1700 Ω hre =1.3 ×10-4; hfe 38;
hoe 6 × 10 6 If the a.c. load rL seen by the transistor is 2 KΩ find the input
impedance current gain voltage gain
C B3C045 Total Pages:4
Page 3 of 4
Why the gate junction of FET is always reverse biased? List the parameters of JFET
from characteristics.
11. Explain any compensation technique adopted in transistor amplifier for reducing the
drift of operating point.
The datasheet of an N-channel JFET gives the following details IDss 9 mA and
pinch off voltage of -4.5V At what value of VGS will ID be equal to 3 mA?
ii) What is its gm at this ID?
PART C
Answer any 2 questions. Each question carries 10 marks.
12. A differential amplifier has inputs VS1 =10mV and VS2= 9mV. It has differential mode
gain of 60 dB and a CMRR of 80 dB. Find the percentage error in output and error
voltage.
State the Barkhausen criterion for sinusoidal oscillators and why this must be
fulfilled to sustain oscillations?
For a class B power amplifier using a supply of Vcc =12V and driving a load of 8Ω,
Determine maximum load power. DC input power and collector efficiency.
13. An amplifier with negative feedback has a voltage gain of 100. It is found that without
feedback an input signal of 50mV is required to produce a given output, whereas with
feedback, the input signal must be 0.6V for same output. Calculate the value of A and β.

Show how piezo-electric crystals are employed for oscillator stabilization.
A crystal has the following parameters L 0.33H,C1 0.065pF,C2 1.0pF and
R=5.5KΩ. Determine series resonant frequency and Q factor of the crystal.
14. Compare the merits and demerits of different types of inter stage coupling in amplifiers

What is cross over distortion? Why most power amplifiers used in practice are designed
to operate in class AB stage?
An inverting op-amp with slew rate 0.5V/μsec is shown in the figure. Determine closed
loop voltage gain ii) input impedance of the circuit iii) Maximum operating frequency
C B3C045 Total Pages:4
Page 4 of 4

PART D
Answer any 2 questions. Each question carries 10 marks.
15. Draw the circuit diagram of an astable-multivibrator using 555 timer to generate the
output signal with frequency 2 KHz and duty cycle of 75
What are the advantages and features of instrumentation amplifier? Derive the expression
for output voltage of instrumentation amplifier.
16. Design a Wein bridge oscillator circuit to produce a 100KHz, ± 9Voutput. Design
amplifier to have closed loop gain of 3.
What is the function of precision rectifier circuits? What is the significance of UTP and
LTP in Schmitt trigger circuits?
17. Discuss how logarithmic amplifier is realized with op-amp circuitry.
What is the basic principle of RC oscillators? Design a phase shift oscillator to oscillate
at 500Hz.