[EURCS 301 / EURIT 301]
B.Tech. DEGREE EXAMINATION
III SEMESTER
BASIC ELECTRONICS
(Effective from the admitted batch 2007–08)
(Common for CSE & IT branches)
Time: 3 Hours Max.Marks: 60
------------------------------------------------------------------------------------
Instructions: Each Unit carries 12 marks.
Answer all units choosing one question from each unit.
All parts of the unit must be answered in one place only.
Figures in the right hand margin indicate marks allotted.
-------------------------------------------------------------------------------------------
UNIT-I
1. a) Explain the term conductivity. Derive an expression for
conductivity. 5
b) Sketch the circuit for full-wave rectifier.
Derive the expression for DC current and the DC diode
voltage. 7
OR
2. a) Draw the circuit for a half-wave rectifier. Derive an
expression for DC diode voltage. 6
b) Compare full-wave rectifier with Bridge rectifier. 6
UNIT-II
3. a) Define saturation resistance for a CE transistor. 2
b) Explain thermal instability. 10
OR
4. a) Draw the circuit for self-bias. How this circuit is
improvement over fixed-bias circuit? 6
b) Draw the circuit symbol for a pnp transistor and
indicate the reference directions for current and
reference polarity for voltages. 6
UNIT-III
5. a) Draw the circuit to obtain input and output characteristics
of a CE configuration. 6
b) Draw the approximate hybrid model for CE amplifier.
obtain expressions for input impedance. 6
OR
6. a) Explain the terms large-signal current gain β and small-signal
current gain hfe for CE configuration. 6
b) Draw the approximate hybrid model for CE amplifier. Obtain
expressions for voltage gain. 6
UNIT-IV
7. a) How is FET used as a voltage variable resistance? Explain. 6
b) Explain the operation of depletion MOSFET and
enhancement MOSFET. 6
OR
8. a) Explain the pinch-off voltage. 6
b) Draw the low-frequency small-signal model of FET. 6
UNIT-V
9. a) Explain voltage-shunt feed back amplifier. 6
b) Draw the circuit for Wein-bridge oscillator and explain its
principle of operation. 6
OR
10. a) Using a neat circuit, explain the principle of operation
of RC phase-shift oscillator. 6
b) What are four possible topologies of a feed back amplifier?
Explain briefly. 6
[03-07/IIIS/107]
[EURCS 301 / EURIT 301]
B.Tech. DEGREE EXAMINATION
III SEMESTER
BASIC ELECTRONICS
(Effective from the admitted batch 2007–08)
(Common for CSE & IT branches)
Time: 3 Hours Max.Marks: 60
------------------------------------------------------------------------------------
Instructions: Each Unit carries 12 marks.
Answer all units choosing one question from each unit.
All parts of the unit must be answered in one place only.
Figures in the right hand margin indicate marks allotted.
-------------------------------------------------------------------------------------------
UNIT-I
1. a) Explain the term conductivity. Derive an expression for
conductivity. 5
b) Sketch the circuit for full-wave rectifier.
Derive the expression for DC current and the DC diode
voltage. 7
OR
2. a) Draw the circuit for a half-wave rectifier. Derive an
expression for DC diode voltage. 6
b) Compare full-wave rectifier with Bridge rectifier. 6
UNIT-II
3. a) Define saturation resistance for a CE transistor. 2
b) Explain thermal instability. 10
OR
4. a) Draw the circuit for self-bias. How this circuit is
improvement over fixed-bias circuit? 6
b) Draw the circuit symbol for a pnp transistor and
indicate the reference directions for current and
reference polarity for voltages. 6
UNIT-III
5. a) Draw the circuit to obtain input and output characteristics
of a CE configuration. 6
b) Draw the approximate hybrid model for CE amplifier.
obtain expressions for input impedance. 6
OR
6. a) Explain the terms large-signal current gain β and small-signal
current gain hfe for CE configuration. 6
b) Draw the approximate hybrid model for CE amplifier. Obtain
expressions for voltage gain. 6
UNIT-IV
7. a) How is FET used as a voltage variable resistance? Explain. 6
b) Explain the operation of depletion MOSFET and
enhancement MOSFET. 6
OR
8. a) Explain the pinch-off voltage. 6
b) Draw the low-frequency small-signal model of FET. 6
UNIT-V
9. a) Explain voltage-shunt feed back amplifier. 6
b) Draw the circuit for Wein-bridge oscillator and explain its
principle of operation. 6
OR
10. a) Using a neat circuit, explain the principle of operation
of RC phase-shift oscillator. 6
b) What are four possible topologies of a feed back amplifier?
Explain briefly. 6
[03-07/IIIS/107]
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