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Solid And Semiconductor
Unit IX: Electronic Devices
Semiconductors; semiconductor diode – I-V characteristics in forward and reverse bias, diode as
a rectifier; I-V characteristics of LED, photodiode, solar cell, and Zener diode; Zener diode as a
voltage regulator. Junction transistor, transistor action, characteristics of a transistor; transistor as
an amplifier (common emitter configuration) and oscillator. Logic gates (OR, AND, NOT,
NAND and NOR). Transistor as a switch.
[1995]
Q.1
Q.2
How does the conductivity of a semiconductor change with temperature?
Draw a p-n junction with reverse bias.
P
R
 
n
_
Q.3
+
Write the truth table of OR gate.
Input
Q.4
100

Output
A
B
Y
0
1
0
1
0
0
1
1
0
1
1
1
Find the truth table of the following gate.
A
Y
B
Q.5
Draw a circuit for p-n junction diode in forward bias. Sketch the voltage versus current
graph for the same.
Q.6
Draw a labeled diagram of full wave rectifier using p-n junction diodes.
[1996]
Q.1
What is the order of energy gap in a semiconductor.
Q.2
Name the logic gate shown in fig. and write its truth table.
A
B
Y
[1997]
Q.1
In the given diagram is the diode D forward or reverse biased?
R

[1998]
Q.1
How does the conductance of a semiconducting material change with rise of temperature?
Q.2
Write the truth table for the combination of gets shown here.



Q.3
Y
Find the truth table of the following gates.
A
A
Y
Y
B
Q.4
What is the function of base region of a transistor. Why this region thin and slightly
doped?
Q.5
What is Zener diode? How can it be used as a voltage regular?
[1999]
Q.1
How does the collector current changes in a junction transistor if the base region has the
larger width?
Q.2
What is an ideal diode? Draw the output wave from across R for the input waveform
given below.
+4v


R



_
0V

-4V
Q.3
Draw a logic circuit diagram showing how a NAND gate can be converted to NOT gate.
Q.4
In the given circuit a voltmeter V is connected across the lamp L. What changes would
occur at lamp L and the voltmeter V if the resistance R is reduced in value. Give reason
for your answer.
V
L
+
_
Q.5
The input resistance of a common emitter amplifier is 2 k and ac current gain is 20. If
the load resistor used is 5, calculate (i) the voltage gain of the amplifier (ii) the
transconductance of the transistor used.
[2000]
Q.1
How does the energy gap in a semiconductor vary, when doped with a pentavalent
impurity?
Q.2
Distinguish between p-type and n-type type semiconductor on the basis of energy band
diagram.
Q.3
The following table gives the output of a two input
logic gate.
(i)
Identify the logic gate and draw its logic
symbol.
(ii)
If the output of this gate is fed as input to a
NOT gate, name the new logic gate so
formed.
A
0
1
0
1
B
0
0
1
1
Y
1
1
1
0
[2001]
Q.1
What is meant by the term doping of an intrinsic semiconductor? How does it affect the
conductivity of a semiconductor?
Q.2
Identify the logic gates marked X and Y in the following fig. Write down the output at Z
when A = 1, B = 1 and A = B = 0.
A
X
B
Y
Z
Q.3
In only one of the circuits given below the lamp L lights. Which circuit is it? Give reason
for your answer.
L
6V
+
_



 R




R

Q.4
+
_ 6V
L
Semiconductor has equal electron and hole concentration of 2  108 / m3. On doping with
a certain impurity, the hole concentration increases to 4  1010 / m3.
(i)
What type of semiconductor is obtained on doping?
(ii)
Calculate the new electron and hole concentration of the semiconductor.
(iii)
How does the energy gap vary with doping.
[2002]
Q.1
How does the width of depletion region of a p-n junction vary if the reverse bias applied
to it is decreased?
Q.2
How does the width of depletion region of a p-n junction vary if the reverse bias applied
to it is increases.
In the given figures, the symbol of logic gate and two input waveforms A and B are
Q.3
shown.
Q.4
(i)
Name the logic gate
(ii)
Write the truth table
(iii)
Give the output wave-form.
A
Y
B
In fig. the circuit symbol of a logic gate and two input waveforms A and B are shown :
(i)
name the logic gate
(ii)
Write its truth table.
(iii)
Give the output waveform
A
Y
B
[2003]
Q.1
Q.2
Q.3
Q.4
Q.5
Q.6
What type of extrinsic semiconductor is formed when
(i)
germanium is doped with indium?
(ii)
Silicon is doped with bismuth?
Give the ratio of number of holes and number of conduction electrons in an intrinsic
semiconductor.
In a semiconductor the concentration of electron is 8  1013 cm-3 and that of holes is 5 
1012 cm-3. Is it a p-type or n-type semiconductor?
Define the terms ‘potential barrier’ and depletion region for a p-n junction diode.
How a p-type semiconductor formed? Name the major charge carriers in it. Draw the
energy level diagram of p-type semiconductor.
Name the gate obtained from the combination of gates sown in fig. Draw the logic
symbol. Give the truth table of the combination.
A
Y
B
(i)
(ii)
[2004]
Q.1
Name the logic gate which can be realized by using p-n junction diode in the given
diagram. Give its logic symbol and write the truth table. Name the gate which will be
obtained by combining with a NOT gate.
Q.2
Draw energy band diagram of a p-type semiconductor.
Q.3
Draw voltage current characteristic of a Zener diode.
Q.4
Draw energy band diagram of n-type semiconductor.
Q.5
As ac input signal of frequency 60 Hz is rectified by a (i) half wave (ii) full wave
rectifier. Draw the output waveform and write the output frequency in each case.
Q.6
Which special type of diode can act as a voltage regulator? Give the symbol of this diode
and draw the general shape of its V-I characteristics.
Q.7
A semiconductor has equal electron and hole concentration 6 108 m-3. On doping with a
certain impurity, electron concentration increases to 8 1012 m-3. Identify the type of
semiconductor after doping.
Q.8
With the help of a diagram, show the biasing of a light emitting diode (LED). Give its
two advantages over conventional incandescent lamps.
Q.9
Name the p-n junction diodes which emit spontaneous radiations when forward biased.
How do we choose the semiconductor, to be used in these diodes, if the emitted radiation,
is to be in the visible region?
Q.10 Draw a circuit diagram to show how a photodiode is biased. Draw its characteristic
curves for two different intensities.
Q.11 Draw a labeled circuit diagram of a common emitter amplifier using p-n-p transistor.
Define the term voltage gain and write an expression for it. Explain how the input and
output voltage are out of phase by 180 fir a common-emitter transistor amplifiers.
Q.12 Draw the circuit diagram of common-emitter amplifier using an npn transistor. Draw the
input and output waveforms of the signal. Write the expression for its voltage gain.
milliampere
Q.13 The V-I characteristic of a silicon diode is given in the figure. Calculate the diode
resistance in forward bias at V = +2V.
80
70
60
50
40
30
20
10
0
Si-diode
1
2
3
Volts
V(Forward bas)
Cut-in voltage
[2005]
Q.1
Distinguish between metals, insulators and semiconductors on the basis of their energy
bands.
Q.2
What are energy bands? How are these formed? Distinguish between a conductor, an
insulator and a semiconductor on the basis of energy band diagram.
Q.3
With the help of a suitable diagram explain the working of transistor as an oscillator.
Q.4
A photodiode is fabricated from a semiconductor with band gap of 2.8 eV. Can it detect a
wavelength of 6000 nm? Justify.
Q.5
A change of 0.2 mA in the base current causes a change of 5 mA in the collector current
for a common emitter amplifier.
(i)
Find the a.c. current gain of the transistor.
(ii)
If the input resistance is 2 k, and its voltage gain is 75, calculate the load resistor
used in the circuit.
[2006]
Q.1
Q.2
Explain how the width of depletion layer in a p-n junction diode changes when the
junction is
(i) forward biased (ii) reverse biased.
What is the function of base region of a transistor. Why is this region made thin and
slightly doped?
[2007]
Q.1
Two semiconductor materials X and Y shown in the given
figure, are made by doping germanium crystal with indium
and a arsenic respectively. The two are joined end-to-end
and connected to a battery as shown.
(i)
Will the junction be forward biased or reverse
biased?
(ii)
Sketch a V- I graph for this arrangement.
X
Y
Q.2
Draw the circuit diagram of a common emitter amplifier using n-p-n transistor. What is
the phase difference between the input signal and output voltage? State two reasons why
a common emitter amplifier is preferred to a common base amplifier.
Q.3
Explain the formation energy band in solids. Draw energy band diagram for (i) a
conductor, (ii) an intrinsic semiconductor.
Q.4
The output of a 2-input AND gate is fed to a NOT gate. Draw the logic circuit of this
combination of gates and write its truth table.
Q.5
The output of an OR gate is connected to both the inputs of a NAND gate. Draw the logic
circuit of this combination of gates and write its truth table.
Q.6
State the principle of working of p-n diode as a rectifier. Explain with the help of a circuit
diagram, the use of p-n diode as a full wave rectifier. Draw a sketch of the input and
output waveforms.
Q.7
What will be the values of inputs A and B for the Boolean expression ( A  B).( AB)  1 .
Q.8
Draw the symbolic representation of (i) pnp (ii) npn transistor. Why is the base region of
a transistor thin and lightly doped? With a proper circuit diagram show the biasing of pnp
transistor in common base configuration. Explain the movement of charge carriers
through different parts of the transistor in such a configuration and show that IE = IC + IB.
Q.9
Explain with the help of a schematic diagram, the principal and working of light emitting
diode. What criterion is kept in mind while choosing the semiconductor material for such
a device? Write any two advantages of light emitting diode over conventional
incandescent lamps.
[2008]
Q.1
Q.2
Q.3
State the reason, why GaAs is most commonly used in making of a solar cell.
Draw the labeled circuit diagram of common emitter transistor amplifier. Explain clearly
how the input and output signals are in opposite phase.
Or
State briefly the underlying principle of a transistor oscillator. Draw a circuit diagram
showing how the feedback is accomplished by inductive coupling. Explain the oscillator
action.
The inputs A and B are inverted by using two NOT gates and their outputs are fed to the
NOR gate as shown below.
(1)
A
Y
(2)
B
Q.4
Q.5
Q.6
Q.7
Analyse the action of the gates (1) and (2) and identify the logic gate of the complete
circuit so obtained. Give its symbol and the truth table.
State the factor, which controls (i) wavelength of light and (ii) intensity of light, emitted
by a LED.
Which special type of diode can act as a voltage regulator? Give the symbol of this diode
and draw the general shape of its V-I characteristics.
Draw the output waveform at X, using the given inputs A, B for the logic circuit shown
below. Also identify the gate.
The given inputs A and B are fed to 2-inputs NAND gate. Draw the output waveform of
the gate.
A
Inputs
B
t1
t2
t3
t4
t5
t6
Q.8
Two signals A, B as given below, are applied as input to (i) AND (ii) NOR and (iii)
NAND gates. Draw the output wave-form in each case.
V
Input A
t
0
t1
t2
t3
t4
t5
t6
t7
t1
t2
t3
t4
t5
t6
t7
t8
Input B
0
t
t8
[2009]
Q.1
Q.2
Q.3
Give the logic symbol of AND gate.
[1]
Explain with the help of a circuit diagram how a zener diode works as a DC voltage
regulator. Draw its I -V characteristics.
[3]
Give a circuit diagram of a common emitter amplifier using an n-p-n transistor. Draw the
input and output waveforms of the signal. Write the expression for its voltage gain.
[3]
[2010]
Q.1
(i)
(ii)
Identify the logic gates marked P and Q in the given logic circuit.
Write down the output at X for the inputs A = 0, B = 0 and A = 1, B = 1.
[2]
A
Q
P
X
B
Q.2
(a)
Draw the circuit diagrams of a p-n junction diode in (i) forward bias, (ii) reverse
bias. How
are these circuits used to study the V-I characteristics of a silicon
diode? Draw the typical
V-I characteristics.
(b)
What is a light emitting diode (LED)? Mention two important advantages of
LEDs over
conventional lamps.
[5]
OR
(a)
Draw the circuit arrangement for studying the input and output characteristics of
an n-p-n transistor in CE configuration. With the help of these characteristics
define (i) input resistance, (ii) current amplification factor.
(b)
Describe briefly with the help of a circuit diagram how an n-p-n transistor is used
to produce self-sustained oscillations.
[2011]
Q.1
What happens to the width of depletion layer of a p-n junction when it is (i) forward
biased, (ii) reverse biased?
[1]
Q.2
Draw a labelled diagram of a full wave rectifier circuit. State its working principle. Show
the input-output waveforms.
[3]
You are given a circuit below. Write its truth table. Hence, identify the logic operation
carried out
by this circuit. Draw the logic symbol of the gate it corresponds to.
Q.3
[3]
A
X
Z
B
Y
[2012]
Q.1
In the given block diagram of a receiver, identify the boxes labeled as X and Y and write
their functions.
[2]
Q.2
Q.3
Describe briefly with the help of a circuit diagram, how the flow of current carriers in a
p-n-p transistor is regulated with emitter-base junction forward biased and base collector
junction reverse biased.
[2]
(a)
Describe briefly, with the help of a diagram, the role of the two important
processes involved in the formation of a p-n junction.
(b)
Name the device which is used as a voltage regulator. Draw the necessary circuit
diagram and explain its working.
OR
(a)
Explain briefly the principle on which a transistor amplifier works as an
oscillator. Draw the necessary circuit diagram and explain its working.
.
(b)
Identify the equivalent gate for the following circuit and write its truth table.
[5]
[2013]
Q.1
The graph shown in the figure represents a plot of current versus voltage for a given
semiconductor. Identify the region, if any, over which the semiconductor has a negative
resistance.
Q.2
In the circuit shown in the figure, identify the equivalent gate of the circuit and make its
truth table.
Q.3
Draw typical output characteristics of an n-p-n transistor in CE configuration. Show how
these characteristics can be used to determine output resistance.
Q.4
Draw V- I characteristics of a p-n junction diode. Answer the following questions, giving
reasons:
(i)
Why is the current under reverse bias almost independent of the applied potential
upto a critical voltage?
(ii)
Why does the reverse current show a sudden increase at the critical voltage?
Name any semiconductor device which operates under the reverse bias in the
breakdown region.
[2014]
Q.1
Explain with the help of a circuit diagram, the working of a p-n junction diode as a half
wave rectifier.
Q.2
Draw a circuit diagram of n-p-n transistor amplifier in CE configuration. Under what
condition does the transistor act as an amplifier?
Q.3
Write any two distinguishing feature between conductors, semiconductors and insulators
on the basis of energy band diagrams.
SAMPLE PAPER
Q.1
Q.2
The ratios of number density of free electrons to holes (ne / nh), for two different materials
‘A’ and ‘B’, are equal to one and less than one respectively? Name the type of
semiconductor to which ‘A’ and ‘B’ belong? Draw energy level diagram for ‘A’ and ‘B’?
Two signals ‘A’ and ‘B’ shown in the given figure are used as two inputs of (i) AND
gate, (ii) NOR gate and (iii) NAND gate. Obtain the output in each of the three cases.
A
O
1
2
3
4
5
6
7
3
4
5
6
7
8
B
1
Q.3
Q.4
Q.5
2
Explain, by drawing a circuit diagram, how an AND gate can be released in practice
using P –N junction diodes?
Given the value of the threshold voltage for a
(i) silicon diode
(ii) germanium diode
Name the device that converts changes in intensity of illumination into changes in
electric current? Give three applications of this device?
A given p –n function is biased in two different ways as shown in the figure. identify the
type of biasing used in each case. What is the effect of these biasing on the barrier
potential across the given p –n junction?
-1V
+2 V
-3 V
(a)
(b)
Q.6
The output of an unregulated de power supply needs to the regulated. Name the devices
that can be used for this purpose and draw the relevant circuit diagram?
For the transistor circuit shown here, identify the
(i)
type of transistor used and
Ic
(ii)
biasing configuration employed.
Q.7
_
+
A
C
+
+
VCE
E
R2
_
-
VBE
Collector current (IC) in mA
The output characteristics of the transistor, for this biasing configuration are as shown
12.5
Base Current (Ib)
60A
50A
10
40A
30A
7.5
0 0.5 1
1.5 2
2.5
3
3.5
4
Collector to emitter voltage (VCE) in volts
Use these graphs to estimate the value of the current amplification factor for the transistor
for
VCK = 3V?
Q.8 Identify the logic gates 1 and 2 in the logic circuit given below? Also write the truth table
for the final output for all possible combinations of the inputs ‘A’ and ‘B’?
1
Q.9
R1
B
V
VBE
+
mA
2
What is rectification? With the help of a labelled circuit diagram, explain full wave
rectification using junction diodes?
Q.10 With a proper circuit diagram, show the biasing of a N-P-N transistor. Explain the
movement of charge carriers through different parts of this transistor. Hence show that
Q.11
Q.12
Q.13
Q.14
Q.15
Q.16
Q.17
Ia = Ib + Ic?
A transistor is being used as a common emitter amplifier. What is the value of phase
difference? If any, between the collector-emitter voltage and the input signal?
Why does the conductivity of a semiconductor increase with rise in temperature?
Draw the logic symbol and the truth table of an OR–gate. Describe its realization with
circuit diagram using semiconductor diodes?
Differentiate between n- type and p- type semiconductor on the basis of energy band
diagrams. Explain the process of condition in both types of materials?
Which type of extrinsic semiconductor is formed when
(i)
Germinium is doped with indium.
(ii)
Silicon is doped with bismuth.
The forbidden energy gap in semiconductors, insulators and metals are Es, EI, and Em
respectively. Arrange these in descending order? The band gap is silicon is 1.12 eV.
What is the maximum wavelength of light that can be emitted by it?
For the digital circuit given below, write the truth table showing the outputs ‘Y1’ , ‘Y2’
and ‘Y3’ for all possible inputs at ‘A’ and ‘B’?
A
B
Y1
Y2
Y3
Q.18 A radioactive nucleus decays by emitting a particle. How will the proton–neutron
ratio of the daughter nucleus change as compared to the parent nucleus?
Q.19 What do the acronyms LASER and LED stand for? Name the factor, which determines
(i) frequency (ii) intensity of light emitted by LED? State the basis difference between the
light emitted by LASER and LED?
Q.20 Explain the formation of the depletion layer and the barrier potential in a ‘p-n’ junction
diode. Also explain with the help of a circuit diagram, its use as a full wave rectifier.
Draw the input on the corresponding output voltage time waveforms?
Q.21 Draw the energy level diagrams for (i) n–type & (ii) p-type semiconductors. Mark the
donor and acceptor levels in the diagrams?
Q.22 With the help of a block diagram, explain the concept of feedback used in an oscillator.
Explain by drawing a circuit diagram, the working of a transistor as an oscillator?
Q.23 Draw the logic symbol and write the truth table of AND gate. With the help of a circuit
diagram describe the realisation of AND gate using semiconductor diodes.
Q.24 With the help of a circuit diagram explain the use of n-p-n transistor as an amplifier in
common emitter configuration. What is the phase relationship?
Q.25 How is a sample of an n-type semiconductor electrically neutral though it has an excess
of negative charge carriers?
Q.26 How is the band gap, Eg, of a photo diode related to the maximum wavelength, m, that
can be detected by it?
Q.27 A student has to study the input and output characteristics of a n-p-n silicon transister in
the Common Emitter configuration. What kind of a circuit arrangement should she use
for this purpose?
Draw the typical shape of input characteristics likely to be obtained by her. What do we
understand by the cut off, active and saturation states of the transistor? In which of these
states does the transistor not remain when being used as a switch?
OR
Input signals A and B are applied to the input terminals of
the ‘dotted box’ set-up shown here. Let Y be the final
output signal from the box.
Draw the wave forms of the signals labelled as C1 and C2
within the box, giving (in brief) the reasons for getting
these wave forms. Hence draw the wave form of the final
output signal Y. Give reasons for your choice.
What can we state (in words) as the relation between the
final output signal Y and the input signals A and B ?
Q.28 Zener diodes have higher dopant densities as compared to ordinary p-n junction diodes.
How does it affect the
(i)
Width of the depletion layer?
(ii)
Junction field?
Q.29 Using a suitable combination from a NOR, an OR and a NOT gate, draw circuits to
obtain the truth table given below:
Q.30 Draw the transfer characteristics of a base biased transistor in its common emitter
configuration. Explain briefly the meaning of the term ‘active region’ in these
characteristics. For what practical use, do we use the transistor in this ‘active region’?
Q.31 Draw a circuit diagram of a common emitter amplifier using n-p-n transistor? Write an
expression for the current gain. Show input and output voltages graphically and explain
the phase relation between them?
Q.32 The graph, shown here, represents the V-I characteristics of a device. Identify the region,
if
any,
over
which
this
device
has
a
negative
resistance.
[1]
Q.33 For the circuit shown here, find the current flowing through the 1 resistor. Assume that
the two diodes, D1 and D2, are ideal diodes.
[2]
Q.34 Define the terms ‘depletion layer’ and ‘barrier potential’ for a P-N junction diode. How
does an increase in the doping concentration affect the width of the depletion region?
Draw the circuit of a full wave rectifier. Explain its working.
OR
Why is the base region of a transistor kept thin and lightly doped?
Draw the circuit diagram of the ‘set-up’ used to study the characteristics of a npn
transistor in its common emitter configuration. Sketch the typical (i) Input characteristics
and (ii) Output characteristics for this transistor configuration.
How can the output characteristics be used to calculate the ‘current gain’ of the
transistor?
Q.35 Draw the input waveforms for three different inputs if the output waveform from the
given logic Gate is as follows.
Or
Two car garages have a common gate which needs to open automatically when a car
enters either of the garages or car enters both. Design a truth table, logic symbol and
hence Boolean expression for a circuit that resembles this situation using diodes.
Q.36 (a)
Why Si and Ga As are preferred materials for solar cells? Draw V-I
Characteristics of Zener
diode. How a Zener diode can act as voltage regulator?
(b)
In a p-n junction diode, the current I can be expressed as I = I0 exp { (eV/2KB T)1
}where I0 is called reverse saturation current, V is the voltage across the diode
and is positive for forward bias and negative for reverse bias, I is current through
the diode, KB is Boltzmann constant (8.6 x 10-5 eV/K) and T is the absolute
temperature. If for a given diode I0 = 5 x 10-12 A and T =300K, then
(i)
(ii)
10 A [5]
What will be the forward current at a forward voltage of 0.6 V?
What will be the dynamic resistance if forward current at 0.7 V is 14.3 x
-7
OR
(a)
Define trans- conductance of a transistor.
(b)
Show by circuit diagram, how a transistor work as a feed back oscillator. Also
give collector and emitter current variation graph due to inductive coupling
(c)
Two amplifiers are connected one after the other in series (cascaded)
The first amplifier has a voltage gain of 10 and second has a voltage-gain of 20. If
the input signal is 0.01V, calculate the output voltage of the ac signal.
Q.37 Draw the logic symbol of a 2-input NOR gate. Write down its truth table.
OR
Draw a labelled circuit diagram of n-p-n transistor amplifier in CE–configuration.
Q.38 With the help of circuit diagram of an npn transistor in common emitter mode, explain its
use as an amplifier.
Draw the output versus input voltage curve and mark the region in which the transistor is
used a (i) switch, and (ii) amplifier.
OR
Draw forward and reverse characteristic curves of a PN junction diode.
Explain briefly with the help of a circuit diagram, how a PN junction diode works as a
full wave rectifier. If frequency of input ac signal is ‘f’ what is the frequency of output.
Q.39 Why is a photodiode operated in reverse bias mode? Figure shows reverse bias current,
under different illumination intensities I1, I2, I3, for a given photodiode. Arrange the
intensities I1, I2, I3 and I4 in decreasing order of magnitude.
Q.40 Draw the output wave form at X, using the given inputs A, B for the logic circuit shown
below. Also identify the (equivalent) gate.
Q.41 An a.c. signal is fed into two circuits X and Y and the corresponding output in the two
cases have the waveform shown below. Name the circuits X and Y. Also draw their
detailed circuit diagrams.
OR
The transfer characteristic of a base biased transistor in CE configuration is as shown.
Name the region corresponding to the values (i) 0 to V, (ii) V1 to V2 (iii) greater than V2
of the input voltage applied to the transistor.
Identify the voltage range that should not be used if the transistor has to work as a switch.
What is the practical use of transistor, when it is operated in this voltage range? Name the
source that result in a higher energy of the output of a transistor operated in this range?
Q.42 Inputs A & B are applied to the logic gate set up as shown below. Complete the truth
table given below, and name the equivalent gate formed by this ‘set-up.’
Q.43 The set up, shown below, can produce an a-c output without any external input signal.
Identify the components X and Y of this set up. Draw the circuit diagram for this set up
and briefly describe its working.
OR
Explain the formation of the depletion region for a P-N Junction. How does the width of
this region change when the junction is
(i)
(ii)
Forward biased, and (ii) reverse based.
How does an increase in the doping concentration affect the width of the depletion
region?
Q.44 A certain n-p-n transistor has the common emitter output characteristics as shown
(a)
(b)
find the emitter current at V = 10 V and Ib = 60 A
find  at this point.
Q.45 For the given combination of gates, Find the values of outputs Y1 and Y2 in the table
given below. Identify the gates G1 and G2.
Q.46 The figure below shows the V-I characteristics of a semiconductor device.
(i)
Identify the semiconductor device used here.
(ii)
Draw the circuit diagram to obtain the given characteristics of this diode.
(iii)
Briefly explain how this device is used as voltage regulator.