Hall Ticket No Question Paper Code: AEC001
INSTITUTE OF AERONAUTICAL ENGINEERING
(Autonomous)
B.Tech III Semester End Examinations (Regular) December, 2017
Regulation: IARE R16
ELECTRONIC DEVICES AND CIRCUITS
(Common for EEE ECE)
Time: 3 Hours Max Marks: 70
Answer ONE Question from each Unit
All Questions Carry Equal Marks
All parts of the question must be answered in one place only
UNIT I
1. Define a PN Diode. Illustrate the operation of PN diode with V-I characteristics.
A 5 V stabilized power supply is required to be produced from a 12 V DC power supply input
source. The maximum power rating PZ of the Zener diode is 2 W. Using the Zener regulator
circuit calculate: The maximum current flowing through the Zener diode, The minimum value
of the series resistor, Rs, The load current IL if a load resistor of 1 k
is connected across the
Zener diode the Zener current Iz at full load.
2. Derive the current equation for a semiconductor diode with suitable assumptions
Determine the germanium PN junction diode current for the forward bias voltage of 0.2V at
room temperature 24 with reverse saturation current equal to 1.1 mA. Take =1.
UNIT II
3. A half-wave rectifier, having a resistive load of 1000
rectifies an alternating load voltages of
325 V peak value and the diode has a forward resistance of 100
. Calculate
i. Peak, Average and RMS value of current
ii. DC power output
iii. Effiency of the rectifier.
Compare various rectifier filter circuits.
4. Write a short note on
i. Varactor diode
ii. Photo diode
Design a filter for full wave circuit with LC filter to provide an output voltage of 10 V with a
load current of 200 mA and the ripple is limited to 2%.
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UNIT III
5. Draw the symbol of a Unijunction transistor and explain the VI characteristics with its equivalent
circuit.
When the reverse gate voltage of JFET changes from 4.0 to 3.9 the drain current changes
from 1.3 mA to 1.6 mA. Find the value of transconductance.
6. Explain how JFET acts as a voltage variable resistor.
Explain the operation of MOSFET in enhancement mode configuration.
UNIT IV
7. Explain the criteria for fixing the operating point to a transistor.
Calculate the operating point of the self-biased JFET having the supply voltage VDD 20
maximum value of drain current IDSS 10 mA and VGS V at ID 4 mA. Also determine
the values of resistors RD and RS to obtain this bias condition.
8. Explain various bias compensation techniques.
Calculate the value of RS required to self-bias an N-channel JFET with IDSS 40 mA,
VP -10 V and VGSQ V.
UNIT V
9. Illustrate how FET is used as common source Amplifier with a neat figure and explain its features.

Illustrate the FET small signal model with relevant figure of the small signal model of FET in
CS configuration and expressions.
10. With the help of a neat figure showing the small signal low frequency h-parameter model, define
the various h-parameters, provide the h-parameter equivalent circuit for transistor and list
benefits of h-parameters.
A Common Emitter amplifier circuit is drawn by a voltage source of internal impedance
rs 800
and the load impedance is a resistance RL 1000
. The h-parameters are
hie 1 K
hre 2 x hfe 50, hoe= 25 Compute the current gain AI
input resistance RI voltage gain AV and output resistance RO using exact or
approximate analysis.