Download edc imp questions 2015

Section-I
1. a) what is modified Hall coefficient. Derive the expression for hall voltage
b) What are the applications for Hall voltage?
2. Draw the energy band diagram of i) conductor ii) semi conductor iii) insulator and discuss
the nature of their conductivities.
3. Explain about drift and diffusion currents in semiconductors.
4***. Derive continuity equation (OR) Derive an expression for continuity equation
5. Explain about Fermi levels in intrinsic and extrinsic semiconductors.( OR) Derive an
expression for Femi level in Intrinsic ,Extrinsic semiconductors with neat sketch
6. Define the following terms:
a) Mobility and conductivity b) generation and recombination rate
c) Mass action law
d) Law of junctions
Section-II
1* (a) Explain the volt ampere (V-I)characteristics of PN diode.
(b) Explain the temperature dependence of VI characteristics.
(c)What are general specifications of p-n junction diode?
(OR)
Explain the working of PN diode with energy band diagram
2***. Derive an expression for diode current equation
3. (a) Derive the expression for the barrier potential V0 at the junction of a P-N diode
*(b) Explain the situation for the occurrence of the phenomenon of Avalanche breakdown
and Zener break down in semiconductor diodes and discusses the consequences.
(c) Draw the equivalent, circuit of a Semiconductor diode and briefly explain how the
diode acts as a switch.
4***(a) Explain the concept of Transition capacitance CT of an p-n junction diode. Derive the
Expression for transition capacitance CT of a diode. How it varies w.r.t to applied voltage
(b) Derive an expression for diffusion capacitance of a diode. How it varies w.r.t to applied
voltage
5*. Explain qualitatively the V-I characteristics of a tunnel diode
6. Explain the working of the following electronic devices in brief
(a) LED b) Varactor diode
c) PIN diode OR Photo diode
7. Explain the working of Zener diode as voltage regulator
8. Explain different current components present in a diode (or)
Explain the following terms
a) Cutin voltage
b) break down voltage
c) Leakage current, reverse bias current d) forward bias current
Section-III
1. *Derive the ripple factor of Pi- Filter with neat sketch.
2. a ) Why do we need filters in a power supply under what condition we shall prater or
use a
capacitor filter?
b)* What is the function of a bleeder resistor?
c) Describe the terms capacitor input filter and inductor input filter
3. Derive ripple factor of a capacitor filter
4. Discuss the operation of HW rectifier with and without capacitor filter.
5. Define the terms as referred to FWR circuit:
i. PIV ii. Average d.c. roltage iii. RMS current iv. Ripple factor.
6. Determine:
(a) DC output voltage, (b) PIV (c) Rectification efficiency of the given circuit as
shown in figure
7.* Explain and compare working of
a) Half wave rectifier with and without filter
b) Full wave rectifier with and without filter
c) Bridge rectifier with and without filter
(OR ) Compare FWR with center tap and Bridge rectifier.
Section-4* (Read all questions)
1. Explain the input, and output characteristics of BJT in CB configuration.
2. (a) Explain active region, saturation region and cut-off region in transistor characteristics.
(b) Differentiate between NPN and PNP transistors.
(c) Explain the input and output characteristics of the transistor in CC configuration with
diagrams. What is the Inference from these characteristics?
3. (a) What are the different configurations of BJT?
(b) Derive the relation between α and β.
4. (a) With the help of a neat diagram show different. Current components in a transistor
(b) Why is CE configuration is most widely used’?
5. a) Explain the phenomenon of Base width modulation in Transistor operation and discuss
its influence on Base current in a Common Base operated Transistor.
*b) Draw the output characteristics of a Common Base operated Transistor and discuss the
role of ‘Early Effect’ on the CB Transistor output characteristics.
6. Define the following terms a) emitter injection efficiency b) transport factor
7. Compare CB, CE, CC configurations.
section-5(Read all questions)
1. (a) Draw a diagram showing the structural details of UJT device.
(b) Draw a diagram showing the equivalent circuit. of an Uni junction Transistor.
(c) Define intrinsic stand-off ratio from the equivalent circuit of UJT device
2. (a) Why we call FET as a voltage controlled device?
(b) Write about the broad classification of FET.
3. With a neat sketch explain the drain source characteristics & transfer characteristics of
enhancement ONLY type MOSFET.
4. (a) Draw the circuit and explain the drain and gate characteristics of a JFET in C. S.
configuration.
(b) Give the parameter values and specifications of a JFET.
5. Draw the basic structure of a SCR. and explain its characteristics.
Section-6
*1.(a) Define the three stability factors?
(b) Calculate the values of the resistors in a fixed bias circuit using the following
specifications. ICQ=9.2mA.
VceQ=4.4V. hfe=1115, Vbe=O.7V and Vcc=9v.
**2. What is the need for biasing? Explain the types of biasing with neat circuit diagrams?
3. (a) Discuss the phenomena of thermal runaway
(b) What is meant by bias stabilization?
4. Derive the expression for stability factors S, S’, S’’.
**5. Explain transistor in self bias OR potential divider bias, fixed bias
6. Draw the Transistor biasing circuit using Collector-to-base bias arrangement. Explain the
concept of providing proper bias for the Transistor to act as amplifying device
Section-7
1. Draw the small signal hybrid model of CE amplifier and derive the expressions for its Ai,
Ao, Ri and Ro.
2. For the CC amplifier the transistor parameters are hic = 1500, hfe = -80 hoc = 2 x lO5
mho hrc = 1 Calculate input impedance Zi,Voltage gain AV, and output impedance R0.
3. (a) What are the hybrid or h parameters?. Why are they so called?
(b) Draw the hybrid parameter equivalent circuit for an n-p--n common emitter transistor
and briefly explain.
4. Draw the circuit diagram of small signal CE amplifier circuit and give its equivalent hybrid
model. What is the role of Cc and Ce.
5. From the CE Transistor h-parameter equivalent circuit derive the expressions for
calculating Voltage arid current gains of Transistor amplifier circuits.
* mark indicates compulsory read questions