Study Material

1. COURSE SYLLABUS
EC 6304 ELECTRONIC CIRCUITS - I L T P C
3 1 0 4
UNIT I POWER SUPPLIES AND BIASING OF DISCRETE BJT AND MOSFET 9
Rectifiers with filters- DC Load line, operating point, various biasing methods for BJT-
Design -Stability-Bias compensation, Thermal stability, Design of biasing for JFET, Design
of biasing for MOSFET
UNIT II BJT AMPLIFIERS 9
Small signal Analysis of Common Emitter-AC Load line, Voltage swing limitations,
Common collector and common base amplifiers – Differential amplifiers- CMRR-
Darlington Amplifier- Bootstrap technique - Cascaded stages - Cascode Amplifier-Large
signal Amplifiers – Class A , Class B and Class C Power Amplifiers .
UNIT III JFET AND MOSFET AMPLIFIERS 9
Small signal analysis of JFET amplifiers- Small signal Analysis of MOSFET and JFET,
Common source amplifier, Voltage swing limitations, Small signal analysis of MOSFET and
JFET Source follower and Common Gate amplifiers, - BiMOS Cascode amplifier
UNIT IV FREQUENCY ANALYSIS OF BJT AND MOSFET AMPLIFIERS 9
Low frequency and Miller effect, High frequency analysis of CE and MOSFET CS amplifier,
Short circuit current gain, cut off frequency – fα and fß unity gain and Determination of
bandwidth of single stage and multistage amplifiers
UNIT V IC MOSFET AMPLIFIERS 9
IC Amplifiers- IC biasing Current steering circuit using MOSFET- MOSFET current
sources- PMOS and NMOS current sources. Amplifier with active loads - enhancement load,
Depletion load and PMOS and NMOS current sources load- CMOS common source and
source follower- CMOS differential amplifier- CMRR.
TOTAL (L: 45+T: 15): 60 PERIODS
TEXT BOOK:
1. Donald .A. Neamen, Electronic Circuit Analysis and Design –2nd
Edition,Tata Mc Graw
Hill, 2009.
REFERENCES:
1. Adel .S. Sedra, Kenneth C. Smith, “Micro Electronic Circuits”, 6th
Edition, Oxford
University Press, 2010.
2. David A., “Bell Electronic Devices and Circuits”, Oxford Higher Education Press, 5
Edition, 2010
3. Behzad Razavi, “Design of Analog CMOS Integrated Circuits”, Tata Mc Graw Hill, 2007.
4. Paul Gray, Hurst, Lewis, Meyer “Analysis and Design of Analog Integrated Circuits”, 4th
Edition, John Willey & Sons 2005
5. Millman.J. and Halkias C.C, “Integrated Electronics”, Mc Graw Hill, 2001.
6. D.Schilling and C.Belove, “Electronic Circuits”, 3rd
Edition, Mc Graw Hill, 1989.
7. Robert L. Boylestad and Louis Nasheresky, “Electronic Devices and Circuit Theory”, 10th
Edition, Pearson Education / PHI, 2008.

203. B.E/B.TECH DEGREE EXAMINATION NOV/DEC 2016
THIRD SEMESTER
ELECTRONICS AND COMMUNICATION ENGINEERING
EC6304 ELECTRONIC CIRCUITS-I
THIRD SEMESTER
TIME: 3 hours maximum: 100 Marks
Answer all the questions
PART-A (10*2=20 Marks)
1. What is a Q point? Page No 3
2. What is the impact of temperature on drain current of MOSFET?
3. What is an ac load line?
4. Draw the small signal ac equivalent circuit of the BJT? Page No 34
5. What is the impact of including a source resistor in the FET amplifier?
6. Why multi-stage amplifiers are required?
7. What is the reason for reduction in gain at lower and higher frequencies in case of
amplifiers? Page No 114
8. Determine the unity-gain bandwidth of a FET with parameters,Cgd=10fF,Cgs=50fF
and Gm=1.2mA/V.
9. Why active loads are not used with discrete circuits?
10. Define CMRR. Page No 153
PART –B( 5* 13 =65 Marks)
11.(a) Analyze a BJT with a voltage diver bias circuit, and determine the change in
the Q point with a variation in β when the circuit contains an emitter resistor.Let the
biasing resistors be
Rb1=56kΩ,Rb2=12.2kΩ,Rc=2kΩ,Re=0.4kΩ,Vcc=10V,Vbe(on)=0.7V,and β=100.
Or
(b)Consider the Circuit shown below with transistor parameters Idss=12mA,Vp=-
4V,and λ=0.008V-1
.Determine the small signal voltage gain Av=Vo/Vi.

204. 12.(a)Analyze a basic common base amplifier circuit and derive the expressions for
its small signal voltage gain current gain input impedance and output impedance.
Page No 46
Or
(b)With neat diagram, explain the operation and advantages of Darlington pair circuit.
Also analyze its small signal voltage gain and input impedance Page No 60
13(a)Determine the small signal voltage gain of a multistage cascade circuit shown in
the figure below.The transistor parameters are
Kn1=0.5mA/V2
,Kn2=0.2mA/V2
,Vtn1=Vtn2=1.2V and λ1=λ2=0.The quiescent drain
currents are Id1=0.2mA and Id2=0.5mA.
(b)(i)Draw the circuit of a basic commom source amplifier with voltage divider bias
and derive the expressions for voltage gain,input impedance and output impedance
using small signal model. Page No 104
(ii) Determine the voltage gain of the circuit,assuming the following parameters
Vdd=3.3V,Rd=10kΩ,Rg1=140KΩ,Rg1=140kΩ,Rg2=60KΩ,and Rsi=4KΩ.The
transistor parameters are Vtn=0.4V,Kn=0.5mA/V2
and λ=0.002V-1
14.(a) Derive the expression for cut-off frequency of a BJT. Page no 117
Or
(b)Construct the high frequency equivalent circuit of a MOSFET from its geometry
and derive the expression for short circuit current gain in the common source
configuration Page No 142

205. 15(a).Draw and explain the operation of a simple MOSFET amplifier with active load
and derive its voltage gain using small signal equivalent circuit. Page No 161
Or
(b)With necessary diagram,explain the operation of a CMOS differential
amplifier.Using small signal analysis,determine the expression for its voltage gain.
Page No 170
PART –C (1*15= 15 Marks)
16 (a)Design the Circuit given below such that Idq=100µA,Vsdq=3V, and
Vrs=0.8V.note that Vrs is the voltage across the source resistor Rs.The value of the
larger bias resistor either R1 or R2 is to be 200kΩ.Transistor parameters values are
Kp=100µA/V2
and Vtp=-0.4V.The Conduction parameters,Kp may vary by ±5
percent.
(b)Design the cascade circuit shown below to meet the following
specifications:Vce1=Vce2=2.5V,Vre=0.7V,Ic1=Ic2=1mA,and Ir1=Ir2=Ir3=0.10mA

207. QUESTION PAPER 71727
B.E/B.TECH DEGREE EXAMINATION APRIL/MAY 2017
THIRD SEMESTER
ELECTRONICS AND COMMUNICATION ENGINEERING
EC6304 ELECTRONIC CIRCUITS-I
THIRD SEMESTER
TIME: 3 hours maximum: 100 Marks
Answer all the questions
PART-A (10*2=20 Marks)
1. List out the three stability factor Page No1
2. Find out the collector and base current of circuit given in Fig 2 hfe=80, VBE(ON)=0.7V
3. State Millers theorem Page No 34
4. Draw the small signal equivalent of CB Configuration Page No 37
5. What are the features of BIMOS cascade amplifier? Page No 84
6. What is the use of source bypass capacitor in CS amplifier?
7. Define rise time .Give the relationship between bandwidth and rise time
8. Sketch hybrid π equivalent of the BJT
9. State the advantages of current steering circuit
10. Define active load and list the types of active load
PART –B( 5* 13 =65 Marks)
11 (a) Derive the stability factors for voltage divider bias circuit and give reason why it is
advantageous than fixed bias circuit . Page No 7 (13)
Or
(b) (i) Draw a circuit which uses a diode to compensate for changes in Ico . Explain how
stabilization achieved in the circuit Page No 17 (8)
(ii) Briefly explain the reason for keeping the operating point of a transistor as fixed (5)
12 (a) Draw the a.c equivalent circuit of CE Amplifier with voltage divider bias and derive
the expression for current gain, voltage gain , Input impedance , output admittance and
overall current gain Page No 39 (13)
Or
(b) Explain the operation of cascade amplifier and derive Voltage gain, overall input
resistance overall current gain and output impedance (13)
13 (a) Derive gain, input and output impedance of common source JFET amplifier with neat
diagram and equivalent circuit Page No 87 (13)
Or
(b) Draw a common gate MOSFET amplifier and derive for Av,Ai and Ri using small signal
equivalent circuit Page No 104 (13)

208. 14 (a) Determine the low frequency response of the amplifier circuit shown in fig 14 (a)
given data’s
Rs=680Ω, R1=68 KΩ, R2=22KΩ, VCE=10V, C1=C2=0.1𝜇F, CE=10𝜇F, RC=2.2KΩ,RL=10KΩ,
=100, hie=rπ=1.1k
Or
(b) Derive expressions for short circuit current gain of common emitter amplifier at High
frequency. Define alpha cut-off frequency, beta cut-off frequency and transition frequency
and derive their values in terms of circuit parameters Page No 129 (13)
15 (a) Explain the operation of MOS differential amplifier with active load and derive for
CMRR. Page No 161 (13)
Or
(b) (i) What is an IC biasing ? Explain in detail about the MOSFET uses as a constant current
source. (8)
(ii) With the analysis, explain about MOSFET current steering circuit Page No 155 (5)
PART –C (1*15= 15 Marks)
16 (a) Find the Midband gain AMand upper 3 - dB frequency Fh of a CS amplifier fed with a
signal source having an internal resistance Rsig =100 KΩ. The amplifier has RG = 4.7MΩ,
RD=RL=15KΩ ,gm=1 mA/V, ro=150KΩ, Cgs=1pF and Cgd=0.4pF (15)
Or
(b) Calculate the input –output resistance of emitter follower circuit shown in Fig 16 (b) .
Assume Rs=0.5 kΩ, rπ =3.28 KΩ,β=100 and ro=100KΩ.