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Important questions
Electronic devices(EX304)
UNIT-I
1.
Explain PN junction diode with sketch its diagram.
Explain diode capacitances.
2.
Explain the law of Mass action.
3.
Explain piecewise linear approximation of diode.
4.
What do you mean by drift current and diffusion current in a semiconductor?.
5.
Explain Hall Effect and drive the formula for mobility.
6.
Draw V-I characteristics of Si and Ge diode.
7.
Explain its diff. regions and give comparison of Si & Ge diode
8.
Discuss current component in PN junction and derive current equation of diode.
9.
Write short notes on
(a)Generation and recombination of carriers
(b) Extrinsic and intrinsic semiconductor
10.
Explain the followings
(a) Depletion region (b) Barrier potential
UNIT II
1.
What is rectifier? What are different types of rectifiers?
2.
Explain the combinational clipper circuit with suitable example
3.
What is clamper? Explain with the help of diagram.
4.
Explain sampling gate circuit?
5.
Explain working of Tunnel diode and draw the volt ampere diagram.
6.
Explain Zener diode as a voltage regulator.
7.
Derive efficiency, PIV for FWR ,HWR with suitable diagram
8.
Compare all three types of rectifier .
9.
Explain the zener diode as a peak clipper
10.
Explain the PIN diode in detail.
UNIT III
1.
Define α and β of BJT.
2.
Write down the operation of n-p-n transistor with schematic diagram.
3.
Explain the early effect in BJT with the aid of necessary plots.
4.
Draw the basic structure, circuit symbol and equivalent circuit of UJT. Also explain the
working of it.
5.
Explain the input and output characteristics of CB CE CC configuration of BJT .
6.
Derive the expression for IE and IC for BJT using Ebers-Moll model with proper
necessary diagram.
7.
Draw and explain the input and output characteristics of CB configuration.
8.
Draw and explain the input and output characteristics of CE configuration.
9.
Draw and explain the input and output characteristics of CC configuration.
10.
Write short notes on photo transistor.
UNIT IV
1.
Explain transistor as an amplifier and draw input and output waveform.
2.
What do you understand by load line . Explain it with suitable example.
3.
Explain the q-point and its significances.
4.
What are the criteria for selection of Q-point on load line.
5.
Explain the term stability factor.
6.
Explain Miller capacitance.
7.
Draw and explain the load line of BJT transistor and locate Q-point on it .
8.
Explain voltage divider biasing and find stability factor?
9.
Draw H-parameter model of CB configuration.
10.
Drive the expression for Ai, Av, Zi and Zo with CE configuration of BJT using hparameter.
UNIT V
1.
Define the pinch-off voltage VP.
2.
Compare FET with BJT
3.
Draw the output and transfer characteristics of MOSFET.
4.
Compare between Depletion and enhancement type MOSFET.
5.
Discuss the working and characteristics of Depletion type MOSFET.
6.
Explain the construction and working of N channel JFET.
7.
Draw the transfer and output characteristics of JFET.
8.
Explain the various reasons of operations of MOSFET.
9.
Which region is used for MOSFET to work as a constant current source.
10.
in which region of JFET power dissipation is maximum.
.