2025100209

B.Tech 2nd Semester Examination, 2025

03 Hours70 marks

Instructions

The marks are indicated in the right-hand margin.
There are NINE questions in this paper.
Attempt FIVE questions in all.
Question No. 1 is compulsory.

Q.1 Choose the correct option / answer the following (Any seven question only):

Ask AI

Q1.1
When a pure semiconductor is heated, its resistance will
a)
Goes up

b)
Remains the same

c)
Goes down

d)
None

Ask AI
Q1.2
The random motion of holes and free electrons due to thermal agitation is called
a)
Diffusion

b)
Ionisation

c)
Pressure

d)
None of these

Ask AI
Q1.3
A zener diode is used as
a)
An amplifier

b)
A rectifier

c)
A voltage regulator

d)
A multivibrator

Ask AI
Q1.4
The ripple factor of a half-wave rectifier is
a)
2

b)
0.48

c)
1.21

d)
None

Ask AI
Q1.5
The number of depletion layers in a transistor is
a)
Four

b)
Two

c)
Three

d)
One

Ask AI
Q1.6
In a transistor, $ I_{C}=100~mA $ and $ I_{E}=100.2~mA $. The value of $ \beta $ is
a)
100

b)
50

c)
1

d)
200

Ask AI
Q1.7
A non inverting closed loop op-amp circuit generally has a gain factor
a)
Less than one

b)
Greater than one

c)
Zero

d)
Equal to one

Ask AI
Q1.8
If ground is applied to the (+) terminal of an inverting op-amp, the (-) terminal will
a)
Not need an input resistor

b)
Be virtual ground

c)
Have high reverse current

d)
Not invert the signal

Ask AI
Q1.9
The binary code of (21.125) is
a)
10101.001

b)
10101.010

c)
10100.001

d)
10100.111

Ask AI
Q1.10
Which of the following gate is a two-level logic gate
a)
OR gate

b)
EXCLUSIVE OR gate

c)
NAND gate

d)
NOT gate

Ask AI

Q.2 Solve both questions :

Ask AI

Q2.1
Explain the working of p-n junction diode and draw its V-I Characteristics.
Ask AI
Q2.2
Draw a neat circuit diagram of bridge rectifier and explain its operation with output waveforms. Derive the average value of current and voltage.
Ask AI

Q.3 Solve both questions :

Ask AI

Q3.1
Explain working principle of Depletion type MOSFET (n-channel). Draw & Explain its characteristics.
Ask AI
Q3.2
Explain the working principle and characteristics of a full-wave rectifier. Derive the expressions for output voltage and ripple factor for a full-wave rectifier.
Ask AI

Q.4 Solve both questions :

Ask AI

Q4.1
Draw the block diagram of Op-Amp and list all the ideal characteristics of op-amp.
Ask AI
Q4.2
Explain the working of op-amp as an Integrator and derive its output equation.
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Q.5 Solve both questions :

Ask AI

Q5.1
Draw the circuit of NPN transistor in common base configuration and discuss its working. Draw input-output characteristic.
Ask AI
Q5.2
Explain the output and transfer characteristics of a JFET. How does the gate-source voltage $ (V_{GS}) $ affect the drain current $ (I_D) $?
Ask AI

Q.6 Solve both questions :

Ask AI

Q6.1
Convert the following:
(i) $ (53.625)_{10} $ to $ (?)_{2} $
(ii) Find the base x if $ (211)_{x}=(152)_{8} $
(iii) Subtract using 1's complement: $ (10111) - (110011) $
(iv) Find the 1's and 2's compliment of $ (010100)_2 $
Ask AI
Q6.2
Discuss the working of basic logic gates: NAND, NOR, XOR. Derive the truth tables and Boolean expressions for each gate.
Ask AI

Q.7 Solve both questions :

Ask AI

Q7.1
Explain the concept of load line analysis in a BJT. Derive the expressions for the load line and operating point. Explain their significance in amplifier design.
Ask AI
Q7.2
Explain the difference between intrinsic and extrinsic semiconductors. How does the addition of impurities affect the electrical properties of semiconductors?
Ask AI

Q.8 Solve both questions :

Ask AI

Q8.1
Discuss the working principle of clipping circuits. What are the different types of clipping circuits?
Ask AI
Q8.2
Explain the concepts of static and dynamic resistance in a diode. Derive expressions for both and discuss their significance in diode operation.
Ask AI

Q.9 Write short notes on any two of the following:

Ask AI

Q9.1
Solar cell
Ask AI
Q9.2
Basic logic gates, their symbols and truth tables
Ask AI
Q9.3
Clipping and Clamping circuits
Ask AI
Q9.4
Transistor biasing techniques
Ask AI

2025V4100209

B.Tech 2nd Semester Examination, 2025

03 Hours70 marks

Instructions

The marks are indicated in the right-hand margin.
There are NINE questions in this paper.
Attempt FIVE questions in all.
Question No. 1 is compulsory.

Q.1 Choose the correct option / answer the following (Any seven question only):

Ask AI

Q1.1
When a pure semiconductor is heated, its resistance will
a)
Goes up

b)
Remains the same

c)
Goes down

d)
None

Ask AI
Q1.2
The random motion of holes and free electrons due to thermal agitation is called
a)
Diffusion

b)
Ionisation

c)
Pressure

d)
None of these

Ask AI
Q1.3
A zener diode is used as
a)
An amplifier

b)
A rectifier

c)
A voltage regulator

d)
A multivibrator

Ask AI
Q1.4
The ripple factor of a half-wave rectifier is
a)
2

b)
0.48

c)
1.21

d)
None

Ask AI
Q1.5
The number of depletion layers in a transistor is
a)
Four

b)
Two

c)
Three

d)
One

Ask AI
Q1.6
In a transistor, $ I_{C}=100~mA $ and $ I_{E}=100.2~mA $. The value of $ \beta $ is
a)
100

b)
50

c)
1

d)
200

Ask AI
Q1.7
A non inverting closed loop op-amp circuit generally has a gain factor
a)
Less than one

b)
Greater than one

c)
Zero

d)
Equal to one

Ask AI
Q1.8
If ground is applied to the (+) terminal of an inverting op-amp, the (-) terminal will
a)
Not need an input resistor

b)
Be virtual ground

c)
Have high reverse current

d)
Not invert the signal

Ask AI
Q1.9
The binary code of (21.125) is
a)
10101.001

b)
10101.010

c)
10100.001

d)
10100.111

Ask AI
Q1.10
Which of the following gate is a two-level logic gate
a)
OR gate

b)
EXCLUSIVE OR gate

c)
NAND gate

d)
NOT gate

Ask AI

Q.2 Solve both questions :

Ask AI

Q2.1
Explain the working of p-n junction diode and draw its V-I Characteristics.
Ask AI
Q2.2
Draw a neat circuit diagram of bridge rectifier and explain its operation with output waveforms. Derive the average value of current and voltage.
Ask AI

Q.3 Solve both questions :

Ask AI

Q3.1
Explain working principle of Depletion type MOSFET (n-channel). Draw & Explain its characteristics.
Ask AI
Q3.2
Explain the working principle and characteristics of a full-wave rectifier. Derive the expressions for output voltage and ripple factor for a full-wave rectifier.
Ask AI

Q.4 Solve both questions :

Ask AI

Q4.1
Draw the block diagram of Op-Amp and list all the ideal characteristics of op-amp.
Ask AI
Q4.2
Explain the working of op-amp as an Integrator and derive its output equation.
Ask AI

Q.5 Solve both questions :

Ask AI

Q5.1
Draw the circuit of NPN transistor in common base configuration and discuss its working. Draw input-output characteristic.
Ask AI
Q5.2
Explain the output and transfer characteristics of a JFET. How does the gate-source voltage $ (V_{GS}) $ affect the drain current $ (I_D) $?
Ask AI

Q.6 Solve both questions :

Ask AI

Q6.1
Convert the following:
(i) $ (53.625)_{10} $ to $ (?)_{2} $
(ii) Find the base x if $ (211)_{x}=(152)_{8} $
(iii) Subtract using 1's complement: $ (10111) - (110011) $
(iv) Find the 1's and 2's compliment of $ (010100)_2 $
Ask AI
Q6.2
Discuss the working of basic logic gates: NAND, NOR, XOR. Derive the truth tables and Boolean expressions for each gate.
Ask AI

Q.7 Solve both questions :

Ask AI

Q7.1
Explain the concept of load line analysis in a BJT. Derive the expressions for the load line and operating point. Explain their significance in amplifier design.
Ask AI
Q7.2
Explain the difference between intrinsic and extrinsic semiconductors. How does the addition of impurities affect the electrical properties of semiconductors?
Ask AI

Q.8 Solve both questions :

Ask AI

Q8.1
Discuss the working principle of clipping circuits. What are the different types of clipping circuits?
Ask AI
Q8.2
Explain the concepts of static and dynamic resistance in a diode. Derive expressions for both and discuss their significance in diode operation.
Ask AI

Q.9 Write short notes on any two of the following:

Ask AI

Q9.1
Solar cell
Ask AI
Q9.2
Basic logic gates, their symbols and truth tables
Ask AI
Q9.3
Clipping and Clamping circuits
Ask AI
Q9.4
Transistor biasing techniques
Ask AI

2023101302

B.Tech. 3rd Semester Examination, 2023

03 Hours70 marks

Instructions

The marks are indicated in the right-hand margin.
There are NINE questions in this paper.
Attempt FIVE questions in all.
Question No. 1 is compulsory.

Section A

Ask AI

Q1
Choose the correct answer of the following (Any seven question only) :

a)
The average value of the full-wave rectified sine wave with period $\pi$ and a peak value of $V_m$ is

a)
$0.707 V_m$

b)
$0.5 V_m$

c)
$0.637 V_m$

d)
$0.318 V_m$

2 marks
b)
The most commonly used transistor configuration for use as a switching device is

a)
Common-base configuration

b)
Common-collector configuration

c)
Collector-emitter shorted configuration

d)
Common-emitter configuration

2 marks
c)
The Gunn diode is made of

a)
Silicon

b)
Germanium

c)
Gallium Arsenide

d)
Selenium

2 marks
d)
If for a silicon N-P-N transistor, the base - to - emitter voltage is 0.7V and the collector - to - base voltage is 0.2V, then the transistor is operating in the

a)
Active region

b)
Saturation region

c)
Reverse active region

d)
Cut-off region

2 marks
e)
What current does $I = Aq(\frac{D_p}{L_p}p_n + \frac{D_n}{L_n}n_p)$ represent in pn junction diode?

a)
Forward current

b)
Diffusion current

c)
Drift current

d)
Reverse saturation current

2 marks
f)
For normal operation of a transistor,

a)
Forward bias the emitter diode and reverse bias the collector diode

b)
Forward bias the emitter diode as well as the collector diode

c)
Reverse bias the emitter diode as well as the collector diode

d)
Reverse bias the emitter diode and forward bias the collector diode

2 marks
g)
Transistor is in saturation when

a)
$I_B = I_C$

b)
$I_B > \frac{I_C}{\beta_{dc}}$

c)
$I_B = 0$

d)
$I_B < \frac{I_C}{\beta_{dc}}$

2 marks
h)
If a differential amplifier has a gain of 20,000 and CMRR = 80 dB, its common mode gain is

a)
2

b)
1

c)
1/2

d)
0

2 marks
i)
An operational amplifier possesses

a)
Very large input resistance and very large output resistance

b)
Very large input resistance and very small output resistance

c)
Very small input resistance and very small output resistance

d)
Very small input resistance and very large output resistance

2 marks
j)
If the input ($V_{in}$) to the circuit is a sine wave, the output will be : [Diagram: A diode circuit taking input $V_{in}$]

a)
Half-wave rectified sine wave

b)
Full-wave rectified sine wave

c)
Triangular wave

d)
Square wave

2 marks
14 marks
Ask AI

Section B

Ask AI

Q2
Answer the following:

a)
With a neat circuit diagram and waveform, explain the working of bridge rectifier.

7 marks
b)
Explain Zener diode as voltage regular with no load.

7 marks
Ask AI
Q3
Answer the following:

a)
Explain the operation of enhancement MOSFET.

7 marks
b)
Draw the DC load line for transistor and identify Q point.

7 marks
Ask AI
Q4
Answer the following:

a)
With a neat circuit diagram, explain the working of wein bridge oscillator using op-Amp.

7 marks
b)
Explain common base input characteristic of BJT.

7 marks
Ask AI
Q5
Answer the following:

a)
An amplifier with open loop voltage gain $A_v = 1000 \pm 100$ is available. It is required to have amplifier whose gain varies by not more than $\pm 0.2\%$ . Find (i) Reverse transmission factor $\beta$ of the feedback network, (ii) Gain with feedback.

7 marks
b)
Define, four basic ways of connection the feedback signal. Such as voltage-series feedback, voltage-shunt feedback, current-series feedback, current-shunt feedback.

7 marks
Ask AI
Q6
Answer the following:

a)
Explain the differences between BJT & FET.

7 marks
b)
Calculate the output voltage $V_o$ of the circuit shown in figure. The input voltages are $V_1 = 2.5V$ and $V_2 = 1V$ . [Diagram: Summing/difference op-amp circuit with $V_1$ to 1k, $V_2$ to 3.3k, non-inverting terminal to 1.5k, and feedback resistor 2.2k.]

7 marks
Ask AI
Q7
Draw and explain pin configuration of 741 OP-Amp.

14 marks
Ask AI
Q8
What is an SCR? Explain its working with switching characteristics.

14 marks
Ask AI
Q9
Write short notes on any two of the following :

a)
Differential amplifier

7 marks
b)
Explain positive half wave rectifier with input and output waveforms

7 marks
c)
Define OP-Amp parameter Gain, CMRR, Slew rate, Input Resistance.

7 marks
d)
Explain inverting amplifier.

7 marks
14 marks
Ask AI

2023104301

B.Tech 3rd Semester Examination, 2023

03 Hours70 marks

Instructions

The marks are indicated in the right-hand margin.
There are NINE questions in this paper.
Attempt FIVE questions in all.
Question No. 1 is compulsory.

Section A

Ask AI

Q1
Answer the following questions (any seven only):

a)
Define Doping.

2 marks
b)
What are the two types of extrinsic semiconductors?

2 marks
c)
Write any two differences between Zener breakdown and Avalanche breakdown.

2 marks
d)
What materials are used to construct an LED?

2 marks
e)
What is transistor? Give its circuit symbol.

2 marks
f)
Give the relation between $\alpha$ and $\beta$ .

2 marks
g)
Why base made thin in BJT?

2 marks
h)
What are the applications of JFET?

2 marks
i)
What are the differences between JFET and MOSFET?

2 marks
j)
Write Shockley's equation.

2 marks
14 marks
Ask AI

Section B

Ask AI

Q2
Answer the following:

a)
With a neat diagrams explain the working of a PN junction diode in forward bias and reverse bias and plot the V-I characteristics.

7 marks
b)
Explain the switching characteristic of PN junction diode.

7 marks
Ask AI
Q3
Answer the following:

a)
Draw and Explain V-I characteristics of Zener diode.

7 marks
b)
With neat diagram explain the construction and working of LED.

7 marks
Ask AI
Q4
Answer the following:

a)
With a neat sketch explain the operation of CLC (ie $\pi$ section) and LC filter.

7 marks
b)
Describe the working principle of full wave rectifier with centre tapped transformer and derive the expressions for the ripple factor and efficiency.

7 marks
Ask AI
Q5
Answer the following:

a)
Explain the working of NPN and PNP transistor.

7 marks
b)
Draw and explain the input and output characteristics of a transistor in CC configuration.

7 marks
Ask AI
Q6
Answer the following:

a)
Explain Zener Diode as a Voltage Regulator.

7 marks
b)
Explain the working of positive clamping circuit.

7 marks
Ask AI
Q7
Explain the construction, working and operating characteristics of N-Channel JFET's with relevant diagrams.

14 marks
Ask AI
Q8
Describe the kind of operation that takes place in the enhancement mode MOSFET. How does this differ from depletion mode type?

14 marks
Ask AI
Q9
Write Short notes on any two of the following:

a)
Characteristics of an Ideal Operational Amplifier

7 marks
b)
Difference between Inverting and non inverting amplifier

7 marks
c)
Effects of negative feedback in amplifiers

7 marks
d)
Various topologies of feedback amplifier

7 marks
14 marks
Ask AI

2022104301

End Semester Examination - 2022

03 Hours70 marks

Instructions

The marks are indicated in the right-hand margin.
There are NINE questions in this paper.
Attempt FIVE questions in all.
Question No. 1 is compulsory.

Section A

Ask AI

Q1
Choose the correct answer of the following (Any seven question only) :

a)
What is the ripple factor of a half-wave rectifier?

a)
0.31

b)
0.48

c)
0.707

d)
1.21

2 marks
b)
Which of the following is true in construction of a transistor?

a)
The collector dissipates lesser power

b)
The emitter supplies minority carriers

c)
The collector is made physically larger than the emitter region

d)
The collector collects minority charge carries

2 marks
c)
For what kind of amplifications can the active region of the common-emitter configuration be used?

a)
Voltage

b)
Current

c)
Power

d)
All of the above

2 marks
d)
The leakage current in a pn junction is of the order of

a)
A

b)
mA

c)
kA

d)
$\mu A$

2 marks
e)
A zener diode is always .......... connected.

a)
reverse

b)
forward

c)
either reverse or forward

d)
none of the above

2 marks
f)
The effective channel length of MOSFET in saturation decreases with increase in

a)
Gate voltage

b)
Drain voltage

c)
Source voltage

d)
Body voltage

2 marks
g)
A BJT with $\beta = 50$ has base to collector leakage current $I_{CBO}$ of $2.5 \mu A$ . If the transistor is connected in CE configuration, the collector current for $I_B = 0$ is.

a)
$0.05 \mu A$

b)
$0.1275 mA$

c)
$0.157 mA$

d)
$0.516 mA$

2 marks
h)
The threshold voltage of an n-channel enhancement type MOSFET is 0.5 V. When the device is biased at a gate voltage of 3 V, pinch-off would occur at a drain voltage of :

a)
2V

b)
2.5V

c)
3V

d)
1.5V

2 marks
i)
In an op-amp, the input impedance is .......... and the output impedance is .......... .

a)
High, high

b)
Low, low

c)
High, low

d)
Low, high

2 marks
j)
A MOSFET can be operated with .......... .

a)
negative gate voltage only

b)
positive gate voltage only

c)
positive as well as negative gate voltage

d)
None of the above

2 marks
14 marks
Ask AI

Section B

Ask AI

Q2
Answer the following:

a)
Draw the diagram & Explain the working of full-wave rectifier with filter.

7 marks
b)
A half-wave rectifier is used to supply 50V d.c. to a resistive load of $800 \Omega$ . The diode has a resistance of $25 \Omega$ . Calculate the a.c. voltage required.

7 marks
Ask AI
Q3
Answer the following:

a)
Explain the working of current series feedback amplifier with the help of block diagram.

8 marks
b)
Explain about the distortions present in amplifier. List advantages of negative feedback.

6 marks
Ask AI
Q4
Answer the following:

a)
Draw V-I characteristics curves of JFET and mark various regions Explain how FET is voltage controlled device.

8 marks
b)
Draw the block diagram and explain the operation of sweep frequency generator.

6 marks
Ask AI
Q5
Answer the following:

a)
Draw the cross-sectional view of an n-p-n transistor and explain its operation in active region of operation. What are the different current components of the transistor? How can one use a transistor as amplifier?

7 marks
b)
Define $\alpha_{dc}$ and $\beta_{dc}$ . Derive the relationship between $\alpha_{dc}$ and $\beta_{dc}$ . If the base current in a transistor is $30 \mu A$ , when the emitter current is $7.2 mA$ , what are the values of $\alpha_{dc}$ and $\beta_{dc}$ ? Also, calculate the collector current.

7 marks
Ask AI
Q6
Answer the following:

a)
Draw and explain the input and output characteristics of CB configuration. Where can we use the CB configuration in a transistor circuit? Explain with proper justification.

7 marks
b)
Explain the construction and working principle of a photo diode.

7 marks
Ask AI
Q7
Answer the following:

a)
Explain the characteristics of an Ideal Op-Amp.

7 marks
b)
Explain Op-amp as Differentiator and Integrator. Also draw the output Waveforms?

7 marks
Ask AI
Q8
Answer the following:

a)
With a neat diagram explain the working of a PN junction diode in forward bias and reverse bias.

7 marks
b)
Consider a pn junction in equilibrium at room temperature (T=300 K) for which the doping concentrations are $N_A = 10^{18} / \text{cm}^3$ and $N_D = 10^{16} / \text{cm}^3$ and the cross-sectional area $A = 10^{-4} \text{ cm}^2$ . Calculate $p_p, n_{po}, n_n, p_{no}, V_o, W, X_n, X_p$ , and $Q_j$ . Use $n_i = 1.5 \times 10^{10} / \text{cm}^3$ .

7 marks
Ask AI
Q9
Explain the following (attempt any two) :

a)
Voltage divider bias network

7 marks
b)
Clipper and Clamper

7 marks
c)
Drift and Diffusion current

7 marks
14 marks
Ask AI

2020041401

B.Tech 4th Semester Special Exam., 2020 (Old Course)

3 hours70 marks

Instructions

The marks are indicated in the right-hand margin.
There are NINE questions in this paper.
Attempt FIVE questions in all.
Question No. 1 is compulsory.

Section A

Ask AI

Q1
Answer the following questions briefly (any seven) :

a)
Compute the collector current if base current is $60 \mu A$ and current gain is 70.

2 marks
b)
Define ripple as referred to in a rectifier circuit.

2 marks
c)
A Zener diode has how many p-n junctions?

2 marks
d)
Write the formula for total power dissipated by a transistor in terms of voltage and current associated to transistor circuit.

2 marks
e)
What is the value of $V_{BE}$ for a C-E configuration, when a silicon transistor is forward biased?

2 marks
f)
In a base resistor method, if the value of $\beta$ changes by 50, then by what factor collector current will change?

2 marks
g)
In voltage divider bias, $V_{CC} = 25 V$ . $R_1 = 10 k\Omega$ , $R_2 = 2.2 k\Omega$ , $R_C = 3.6 k\Omega$ and $R_E = 1 k\Omega$ . What is the emitter voltage?

2 marks
h)
When drain voltage equals the pinch-off-voltage, then what will happen to drain current if drain voltage increases?

2 marks
i)
At which point in JFET biasing, the JFET is not longer able to control the current?

2 marks
j)
Why is an SCR made of silicon and not germanium?

2 marks
14 marks
Ask AI

Section B

Ask AI

Q2
Answer the following:

a)
Explain Hall effect phenomenon and list out its applications. Quantitatively discuss the use of Hall effect to determine mobility.

7 marks
b)
Define static and dynamic resistances of diode. What are their uses?

7 marks
Ask AI
Q3
Answer the following:

a)
In the circuit given below, the Zener voltage ($V_Z$) = 6 V, knee current ($I_Z$) = 6 mA and maximum power dissipated in Zener diode ($P_{max}$) = 0.4 W. Compute maximum and minimum values of $R_L$ such that $V_o = 11 V$ for the satisfactory operation of this circuit : [Diagram: Zener regulator with source 15V, series resistor $R_s=80\Omega$ , Zener diode $V_Z=6V$ in series with a 5V source, and output voltage $V_o=11V$ across load resistor $R_L$ .]

7 marks
b)
Draw the circuit diagram of full-wave bridge rectifier and give its input and output waveforms. Also derive the expression for the DC current.

7 marks
Ask AI
Q4
Answer the following:

a)
Explain the working of full-wave bridge rectifier with the help of its circuit diagram, input and output waveforms. List the advantages and disadvantages of this rectifier.

7 marks
b)
Define stabilization factors S, S' and S''. Derive the expression of S for fixed bias transistor circuit.

7 marks
Ask AI
Q5
Answer the following:

a)
A transistor amplifier connected in CE mode has $\beta = 80$ and $I_B = 30 \mu A$ . Compute the values of $I_C, I_E$ and $\alpha$ .

7 marks
b)
Explain the working of RC low-pass filter and draw its frequency response. Compute the cut-off frequency if RC circuit consisting of a resistor of $8 k\Omega$ in series with a capacitor of 60 nF.

7 marks
Ask AI
Q6
Answer the following:

a)
Compute the stability factor S for emitter feedback bias circuit. How the stability of Q-point is better in emitter feedback bias compare to fixed bias circuit?

7 marks
b)
Why is an FET known as a unipolar device? How do you compare this device with BJT?

7 marks
Ask AI
Q7
Answer the following:

a)
Data sheet of an EMOSFET specifies the following parameters : $I_{D(on)} = 60 mA$ at $V_{GS} = 7 V$ and $V_T$ , the threshold voltage for EMOSFET is equal to 3 V. Determine the drain current at $V_{GS} = 4 V$ .

7 marks
b)
Explain thermal runaway. Show graphically that thermal runaway cannot take place if the quiescent point is located at $V_{CE} < (1/2) V_{CC}$ .

7 marks
Ask AI
Q8
Answer the following:

a)
An inverting op-amp has $R_f = 120 k\Omega$ and $R_1 = 4 k\Omega$ . Find the voltage gain of the amplifier. Also find the amplifier input resistance, input current and the output voltage, if the Input voltage is 0.2 V. Assume op-amp to be ideal.

7 marks
b)
Discuss a current-series feedback amplifier and compute the expression for transconductance using low-frequency approximate h-model of amplifier with an unbypassed emitter resistance.

7 marks
Ask AI
Q9
Answer the following:

a)
Draw the V-I characteristic of silicon-controlled rectifier (SCR) and explain different parameters of the curve. Explain any two SCR triggering or turn-on methods.

7 marks
b)
Explain the characteristics of an ideal op-amp. Mention two applications of op-amp. Draw the integrator circuit using op-amp.

7 marks
Ask AI

2020101302

B.Tech 3rd Semester Exam., 2020

3 hours70 marks

Instructions

The marks are indicated in the right-hand margin.
There are NINE questions in this paper.
Attempt FIVE questions in all.
Question No. 1 is compulsory.

Q.1 Fill in the blanks/Answer any seven of the following:

Ask AI

Q1.1
In CB configuration, output characteristics may be shown by plot of _______.
Ask AI
Q1.2
The _______ carriers enter the channel region through the _______ terminal and leave the channel through the _______ terminal in JFET.
Ask AI
Q1.3
Mention the advantages of Wien bridge oscillator.
Ask AI
Q1.4
What is reverse leakage current in CE configuration?
Ask AI
Q1.5
How is amplifier different from the oscillator?
Ask AI
Q1.6
Name the breakdown mechanism in the lightly doped P-N junction diode under reverse biased condition.
Ask AI
Q1.7
Draw the V-I characteristics of photodiode.
Ask AI
Q1.8
What is transconductance with reference to JFET?
Ask AI
Q1.9
What is the effect of removing bypass capacitor across the emitter resistor in case of CE amplifier?
Ask AI
Q1.10
What is meant by phase reversal?
Ask AI

Q.2 Solve both questions:

Ask AI

Q2.1
Find the DC voltage, ripple factor and efficiency for the half-wave rectifier given in the circuit. What should be PIV of the diode used? If bridge rectifier is used for same power supply, what will be the value of DC voltage and PIV of diode?

Ask AI
Q2.2
Calculate the range of $I_{L}$ and $R_{L}$ so that $V_{RL}$ being maintained at 10 V and also calculate the value of maximum voltage rating in the circuit with 50V source, 1K series resistor, 10V Zener with $I_{Zmax}$ 32 mA, Variable $R_L$.

Ask AI

Q.3 Solve both questions:

Ask AI

Q3.1
Draw the waveform of output $v_{0}$ and explain the operation of circuit with AC source $v_i$, Resistor R, Parallel clippers with diodes and batteries $V_{R1}$ and $V_{R2}$ where $V_{R1} < V_{R2}$.

Ask AI
Q3.2
Discuss the application of SCR as a power control with the help of circuit diagram.
Ask AI

Q.4 Solve both questions:

Ask AI

Q4.1
For the network given, determine the following parameters using the approximate equivalent model: Voltage gain $A_{v}$, current gain $A_{i}$, input impedance $Z_{i}'$ and $Z_{i}$.

Ask AI
Q4.2
Calculate the value of $R_{1}$ in the biasing circuit so that the Q-point is fixed at $I_{C}=8~mA$ and $V_{CE}=3V$ with $V_{CC} = -9V$, 250$\Omega$ collector resistor, 500$\Omega$ emitter resistor, $\beta=80$.

Ask AI

Q.5 Solve both questions:

Ask AI

Q5.1
Given a depletion-type MOSFET. In the positive $v_{GS}$ region, does the drain current increase at a significantly higher rate than for negative value? Does the $I_{D}$ curve become more and more vertical with increasing positive values of $V_{GS}$?
Ask AI
Q5.2
Draw V-I characteristic curves of JFET and mark various regions. Explain how FET is voltage-controlled device.
Ask AI

Q.6 Solve both questions:

Ask AI

Q6.1
Explain the working of single-stage common emitter amplifier with the help of circuit diagram. Draw and explain the DC load-line analysis of this amplifier.
Ask AI
Q6.2
A single-stage amplifier has voltage gain of 10 and bandwidth of 1 MHz. Three such stages are cascaded and negative feedback of 10% is applied to the cascade stage. Find out the overall voltage gain and bandwidth of cascade stage with feedback.
Ask AI

Q.7 Solve both questions:

Ask AI

Q7.1
Explain the operation of Colpitts oscillator with the help of circuit diagram.
Ask AI
Q7.2
Draw the block diagram and explain the operation of sweep frequency generator.
Ask AI

Q.8 Solve both questions:

Ask AI

Q8.1
Discuss with the help of circuit diagram, the purpose of providing negative feedback and positive feedback.
Ask AI
Q8.2
Draw the circuit diagram of voltage-shunt feedback amplifier and derive the expression of closed-loop voltage gain using op-amp.
Ask AI

Q.9 Solve both questions:

Ask AI

Q9.1
Explain the operation performed by the circuit with AC $v_{in}$, Resistor $R_1$, Capacitor $C_F$ in feedback, Load $R_L$ and derive the expression of output voltage $v_{0}$.

Ask AI
Q9.2
Op-amp can be used to add the DC voltage (addition operation). Draw the circuit and explain the operation of adder using op-amp in non-inverting mode.
Ask AI

2020V2101302

B.Tech 3rd Semester Exam., 2020 (New Course)

03 Hours70 marks

Instructions

The marks are indicated in the right-hand margin.
There are NINE questions in this paper.
Attempt FIVE questions in all.
Question No. 1 is compulsory.

Q.1 Fill in the blanks/Answer any seven of the following:

Ask AI

Q1.1
In CB configuration, output characteristics may be shown by plot of ______

Ask AI
Q1.2
The carriers enter the channel region through the ______ terminal and leave the channel through the ______ terminal in JFET.

Ask AI
Q1.3
Mention the advantages of Wien bridge oscillator.

Ask AI
Q1.4
What is reverse leakage current in CE configuration?

Ask AI
Q1.5
How is amplifier different from the oscillator?

Ask AI
Q1.6
Name the breakdown mechanism in the lightly doped P-N junction diode under reverse biased condition.

Ask AI
Q1.7
Draw the V-I characteristics of photodiode.

Ask AI
Q1.8
What is transconductance with reference to JFET?

Ask AI
Q1.9
What is the effect of removing bypass capacitor across the emitter resistor in case of CE amplifier?

Ask AI
Q1.10
What is meant by phase reversal?

Ask AI

Q.2 Solve both questions :

Ask AI

Q2.1
Find the DC voltage, ripple factor and efficiency for the half-wave rectifier given in the circuit below: What should be PIV of the diode used? If bridge rectifier is used for same power supply, what will be the value of DC voltage and PIV of diode?

Ask AI
Q2.2
Calculate the range of $I_L$ and $R_L$ so that $V_{RL}$ being maintained at 10 V and also calculate the value of maximum voltage rating in the circuit given below :

Ask AI

Q.3 Solve both questions :

Ask AI

Q3.1
Draw the waveform of output $v_0$ and explain the operation of circuit given below: (Refer to question paper for circuit diagram)

Ask AI
Q3.2
Discuss the application of SCR as a power control with the help of circuit diagram.

Ask AI

Q.4 Solve both questions :

Ask AI

Q4.1
For the network given below, determine the following parameters using the approximate equivalent model. Voltage gain $A_v$ , current gain $A_i$ , input impedance $Z_i'$ and $ Z_i $:

Ask AI
Q4.2
Calculate the value of $R_1$ in the biasing circuit in the figure given below so that the Q-point is fixed at $I_C = 8 \text{ mA}$ and $V_{CE} = 3\text{V}$ :

Ask AI

Q.5 Solve both questions :

Ask AI

Q5.1
Given a deletion-type MOSFET. In the positive $v_{GS}$ region, does the drain current increase at a significantly higher rate than for negative value? Does the $I_D$ curve become more and more vertical with increasing positive values of $v_{GS}$ ?

Ask AI
Q5.2
Draw V-I characteristic curves of JFET and mark various regions. Explain how FET is voltage-controlled device.

Ask AI

Q.6 Solve both questions :

Ask AI

Q6.1
Explain the working of single-stage common emitter amplifier with the help of circuit diagram. Draw and explain the DC load-line analysis of this amplifier.

Ask AI
Q6.2
A single-stage amplifier has voltage gain of 10 and bandwidth of 1 MHz. Three such stages are cascaded and negative feedback of 10% is applied to the cascade stage. Find out the overall voltage gain and bandwidth of cascade stage with feedback.

Ask AI

Q.7 Solve both questions :

Ask AI

Q7.1
Explain the operation of Colpitts oscillator with the help of circuit diagram.

Ask AI
Q7.2
Draw the block diagram and explain the operation of sweep frequency generator.

Ask AI

Q.8 Solve both questions :

Ask AI

Q8.1
Discuss with the help of circuit diagram, the purpose of providing negative feedback and positive feedback.

Ask AI
Q8.2
Draw the circuit diagram of voltage-shunt feedback amplifier and derive the expression of closed-loop voltage gain using op-amp.

Ask AI

Q.9 Solve both questions :

Ask AI

Q9.1
Explain the operation performed by the circuit given below and derive the expression of output voltage $v_0$ :

Ask AI
Q9.2
Op-amp can be used to add the DC voltage (addition operation). Draw the circuit and explain the operation of adder using op-amp in non-inverting mode.

Ask AI

2020V3101302

B.Tech 3rd Semester Exam., 2020 (New Course)

03 Hours70 marks

Instructions

The marks are indicated in the right-hand margin.
There are NINE questions in this paper.
Attempt FIVE questions in all.
Question No. 1 is compulsory.

Q.1 Fill in the blanks/Answer any seven of the following:

Ask AI

Q1.1
In CB configuration, output characteristics may be shown by plot of ______
Ask AI
Q1.2
The carriers enter the channel region through the ______ terminal and leave the channel through the ______ terminal in JFET.
Ask AI
Q1.3
Mention the advantages of Wien bridge oscillator.
Ask AI
Q1.4
What is reverse leakage current in CE configuration?
Ask AI
Q1.5
How is amplifier different from the oscillator?
Ask AI
Q1.6
Name the breakdown mechanism in the lightly doped P-N junction diode under reverse biased condition.
Ask AI
Q1.7
Draw the V-I characteristics of photodiode.
Ask AI
Q1.8
What is transconductance with reference to JFET?
Ask AI
Q1.9
What is the effect of removing bypass capacitor across the emitter resistor in case of CE amplifier?
Ask AI
Q1.10
What is meant by phase reversal?
Ask AI

Q.2 Solve both questions :

Ask AI

Q2.1
Find the DC voltage, ripple factor and efficiency for the half-wave rectifier given in the circuit below: What should be PIV of the diode used? If bridge rectifier is used for same power supply, what will be the value of DC voltage and PIV of diode?

Ask AI
Q2.2
Calculate the range of $ I_L $ and $ R_L $ so that $ V_{RL} $ being maintained at 10 V and also calculate the value of maximum voltage rating in the circuit given below :

Ask AI

Q.3 Solve both questions :

Ask AI

Q3.1
Draw the waveform of output $ v_0 $ and explain the operation of circuit given below: (Refer to question paper for circuit diagram)

Ask AI
Q3.2
Discuss the application of SCR as a power control with the help of circuit diagram.
Ask AI

Q.4 Solve both questions :

Ask AI

Q4.1
For the network given below, determine the following parameters using the approximate equivalent model. Voltage gain $ A_v $, current gain $ A_i $, input impedance $ Z_i' $ and $ Z_i $:

Ask AI
Q4.2
Calculate the value of $ R_1 $ in the biasing circuit in the figure given below so that the Q-point is fixed at $ I_C = 8 \text{ mA} $ and $ V_{CE} = 3\text{V} $:

Ask AI

Q.5 Solve both questions :

Ask AI

Q5.1
Given a deletion-type MOSFET. In the positive $ v_{GS} $ region, does the drain current increase at a significantly higher rate than for negative value? Does the $ I_D $ curve become more and more vertical with increasing positive values of $ v_{GS} $?
Ask AI
Q5.2
Draw V-I characteristic curves of JFET and mark various regions. Explain how FET is voltage-controlled device.
Ask AI

Q.6 Solve both questions :

Ask AI

Q6.1
Explain the working of single-stage common emitter amplifier with the help of circuit diagram. Draw and explain the DC load-line analysis of this amplifier.
Ask AI
Q6.2
A single-stage amplifier has voltage gain of 10 and bandwidth of 1 MHz. Three such stages are cascaded and negative feedback of 10% is applied to the cascade stage. Find out the overall voltage gain and bandwidth of cascade stage with feedback.
Ask AI

Q.7 Solve both questions :

Ask AI

Q7.1
Explain the operation of Colpitts oscillator with the help of circuit diagram.
Ask AI
Q7.2
Draw the block diagram and explain the operation of sweep frequency generator.
Ask AI

Q.8 Solve both questions :

Ask AI

Q8.1
Discuss with the help of circuit diagram, the purpose of providing negative feedback and positive feedback.
Ask AI
Q8.2
Draw the circuit diagram of voltage-shunt feedback amplifier and derive the expression of closed-loop voltage gain using op-amp.
Ask AI

Q.9 Solve both questions :

Ask AI

Q9.1
Explain the operation performed by the circuit given below and derive the expression of output voltage $ v_0 $:

Ask AI
Q9.2
Op-amp can be used to add the DC voltage (addition operation). Draw the circuit and explain the operation of adder using op-amp in non-inverting mode.
Ask AI

2020V4101302

B.Tech 3rd Semester Exam., 2020 (New Course)

03 Hours70 marks

Instructions

The marks are indicated in the right-hand margin.
There are NINE questions in this paper.
Attempt FIVE questions in all.
Question No. 1 is compulsory.

Q.1 Fill in the blanks/Answer any seven of the following:

Ask AI

Q1.1
In CB configuration, output characteristics may be shown by plot of ______

Ask AI
Q1.2
The carriers enter the channel region through the ______ terminal and leave the channel through the ______ terminal in JFET.

Ask AI
Q1.3
Mention the advantages of Wien bridge oscillator.

Ask AI
Q1.4
What is reverse leakage current in CE configuration?

Ask AI
Q1.5
How is amplifier different from the oscillator?

Ask AI
Q1.6
Name the breakdown mechanism in the lightly doped P-N junction diode under reverse biased condition.

Ask AI
Q1.7
Draw the V-I characteristics of photodiode.

Ask AI
Q1.8
What is transconductance with reference to JFET?

Ask AI
Q1.9
What is the effect of removing bypass capacitor across the emitter resistor in case of CE amplifier?

Ask AI
Q1.10
What is meant by phase reversal?

Ask AI

Q.2 Solve both questions :

Ask AI

Q2.1
Find the DC voltage, ripple factor and efficiency for the half-wave rectifier given in the circuit below: What should be PIV of the diode used? If bridge rectifier is used for same power supply, what will be the value of DC voltage and PIV of diode?

Ask AI
Q2.2
Calculate the range of $I_L$ and $R_L$ so that $V_{RL}$ being maintained at 10 V and also calculate the value of maximum voltage rating in the circuit given below :

Ask AI

Q.3 Solve both questions :

Ask AI

Q3.1
Draw the waveform of output $v_0$ and explain the operation of circuit given below: (Refer to question paper for circuit diagram)

Ask AI
Q3.2
Discuss the application of SCR as a power control with the help of circuit diagram.

Ask AI

Q.4 Solve both questions :

Ask AI

Q4.1
For the network given below, determine the following parameters using the approximate equivalent model. Voltage gain $A_v$ , current gain $A_i$ , input impedance $Z_i'$ and $ Z_i $:

Ask AI
Q4.2
Calculate the value of $R_1$ in the biasing circuit in the figure given below so that the Q-point is fixed at $I_C = 8 \text{ mA}$ and $V_{CE} = 3\text{V}$ :

Ask AI

Q.5 Solve both questions :

Ask AI

Q5.1
Given a deletion-type MOSFET. In the positive $v_{GS}$ region, does the drain current increase at a significantly higher rate than for negative value? Does the $I_D$ curve become more and more vertical with increasing positive values of $v_{GS}$ ?

Ask AI
Q5.2
Draw V-I characteristic curves of JFET and mark various regions. Explain how FET is voltage-controlled device.

Ask AI

Q.6 Solve both questions :

Ask AI

Q6.1
Explain the working of single-stage common emitter amplifier with the help of circuit diagram. Draw and explain the DC load-line analysis of this amplifier.

Ask AI
Q6.2
A single-stage amplifier has voltage gain of 10 and bandwidth of 1 MHz. Three such stages are cascaded and negative feedback of 10% is applied to the cascade stage. Find out the overall voltage gain and bandwidth of cascade stage with feedback.

Ask AI

Q.7 Solve both questions :

Ask AI

Q7.1
Explain the operation of Colpitts oscillator with the help of circuit diagram.

Ask AI
Q7.2
Draw the block diagram and explain the operation of sweep frequency generator.

Ask AI

Q.8 Solve both questions :

Ask AI

Q8.1
Discuss with the help of circuit diagram, the purpose of providing negative feedback and positive feedback.

Ask AI
Q8.2
Draw the circuit diagram of voltage-shunt feedback amplifier and derive the expression of closed-loop voltage gain using op-amp.

Ask AI

Q.9 Solve both questions :

Ask AI

Q9.1
Explain the operation performed by the circuit given below and derive the expression of output voltage $v_0$ :

Ask AI
Q9.2
Op-amp can be used to add the DC voltage (addition operation). Draw the circuit and explain the operation of adder using op-amp in non-inverting mode.

Ask AI

2020V6101302

B.Tech 3rd Semester Exam., 2020 (New Course)

03 Hours70 marks

Instructions

The marks are indicated in the right-hand margin.
There are NINE questions in this paper.
Attempt FIVE questions in all.
Question No. 1 is compulsory.

Q.1 Fill in the blanks/Answer any seven of the following:

Ask AI

Q1.1
In CB configuration, output characteristics may be shown by plot of ______

Ask AI
Q1.2
The carriers enter the channel region through the ______ terminal and leave the channel through the ______ terminal in JFET.

Ask AI
Q1.3
Mention the advantages of Wien bridge oscillator.

Ask AI
Q1.4
What is reverse leakage current in CE configuration?

Ask AI
Q1.5
How is amplifier different from the oscillator?

Ask AI
Q1.6
Name the breakdown mechanism in the lightly doped P-N junction diode under reverse biased condition.

Ask AI
Q1.7
Draw the V-I characteristics of photodiode.

Ask AI
Q1.8
What is transconductance with reference to JFET?

Ask AI
Q1.9
What is the effect of removing bypass capacitor across the emitter resistor in case of CE amplifier?

Ask AI
Q1.10
What is meant by phase reversal?

Ask AI

Q.2 Solve both questions :

Ask AI

Q2.1
Find the DC voltage, ripple factor and efficiency for the half-wave rectifier given in the circuit below: What should be PIV of the diode used? If bridge rectifier is used for same power supply, what will be the value of DC voltage and PIV of diode?

Ask AI
Q2.2
Calculate the range of $I_L$ and $R_L$ so that $V_{RL}$ being maintained at 10 V and also calculate the value of maximum voltage rating in the circuit given below :

Ask AI

Q.3 Solve both questions :

Ask AI

Q3.1
Draw the waveform of output $v_0$ and explain the operation of circuit given below: (Refer to question paper for circuit diagram)

Ask AI
Q3.2
Discuss the application of SCR as a power control with the help of circuit diagram.

Ask AI

Q.4 Solve both questions :

Ask AI

Q4.1
For the network given below, determine the following parameters using the approximate equivalent model. Voltage gain $A_v$ , current gain $A_i$ , input impedance $Z_i'$ and $ Z_i $:

Ask AI
Q4.2
Calculate the value of $R_1$ in the biasing circuit in the figure given below so that the Q-point is fixed at $I_C = 8 \text{ mA}$ and $V_{CE} = 3\text{V}$ :

Ask AI

Q.5 Solve both questions :

Ask AI

Q5.1
Given a deletion-type MOSFET. In the positive $v_{GS}$ region, does the drain current increase at a significantly higher rate than for negative value? Does the $I_D$ curve become more and more vertical with increasing positive values of $v_{GS}$ ?

Ask AI
Q5.2
Draw V-I characteristic curves of JFET and mark various regions. Explain how FET is voltage-controlled device.

Ask AI

Q.6 Solve both questions :

Ask AI

Q6.1
Explain the working of single-stage common emitter amplifier with the help of circuit diagram. Draw and explain the DC load-line analysis of this amplifier.

Ask AI
Q6.2
A single-stage amplifier has voltage gain of 10 and bandwidth of 1 MHz. Three such stages are cascaded and negative feedback of 10% is applied to the cascade stage. Find out the overall voltage gain and bandwidth of cascade stage with feedback.

Ask AI

Q.7 Solve both questions :

Ask AI

Q7.1
Explain the operation of Colpitts oscillator with the help of circuit diagram.

Ask AI
Q7.2
Draw the block diagram and explain the operation of sweep frequency generator.

Ask AI

Q.8 Solve both questions :

Ask AI

Q8.1
Discuss with the help of circuit diagram, the purpose of providing negative feedback and positive feedback.

Ask AI
Q8.2
Draw the circuit diagram of voltage-shunt feedback amplifier and derive the expression of closed-loop voltage gain using op-amp.

Ask AI

Q.9 Solve both questions :

Ask AI

Q9.1
Explain the operation performed by the circuit given below and derive the expression of output voltage $v_0$ :

Ask AI
Q9.2
Op-amp can be used to add the DC voltage (addition operation). Draw the circuit and explain the operation of adder using op-amp in non-inverting mode.

Ask AI

2020V7101302

B.Tech 3rd Semester Exam., 2020

3 hours70 marks

Instructions

The marks are indicated in the right-hand margin.
There are NINE questions in this paper.
Attempt FIVE questions in all.
Question No. 1 is compulsory.

Q.1 Fill in the blanks/Answer any seven of the following:

Ask AI

Q1.1
In CB configuration, output characteristics may be shown by plot of _______.
Ask AI
Q1.2
The _______ carriers enter the channel region through the _______ terminal and leave the channel through the _______ terminal in JFET.
Ask AI
Q1.3
Mention the advantages of Wien bridge oscillator.
Ask AI
Q1.4
What is reverse leakage current in CE configuration?
Ask AI
Q1.5
How is amplifier different from the oscillator?
Ask AI
Q1.6
Name the breakdown mechanism in the lightly doped P-N junction diode under reverse biased condition.
Ask AI
Q1.7
Draw the V-I characteristics of photodiode.
Ask AI
Q1.8
What is transconductance with reference to JFET?
Ask AI
Q1.9
What is the effect of removing bypass capacitor across the emitter resistor in case of CE amplifier?
Ask AI
Q1.10
What is meant by phase reversal?
Ask AI

Q.2 Solve both questions:

Ask AI

Q2.1
Find the DC voltage, ripple factor and efficiency for the half-wave rectifier given in the circuit. What should be PIV of the diode used? If bridge rectifier is used for same power supply, what will be the value of DC voltage and PIV of diode?

Ask AI
Q2.2
Calculate the range of $I_{L}$ and $R_{L}$ so that $V_{RL}$ being maintained at 10 V and also calculate the value of maximum voltage rating in the circuit with 50V source, 1K series resistor, 10V Zener with $I_{Zmax}$ 32 mA, Variable $R_L$.

Ask AI

Q.3 Solve both questions:

Ask AI

Q3.1
Draw the waveform of output $v_{0}$ and explain the operation of circuit with AC source $v_i$, Resistor R, Parallel clippers with diodes and batteries $V_{R1}$ and $V_{R2}$ where $V_{R1} < V_{R2}$.

Ask AI
Q3.2
Discuss the application of SCR as a power control with the help of circuit diagram.
Ask AI

Q.4 Solve both questions:

Ask AI

Q4.1
For the network given, determine the following parameters using the approximate equivalent model: Voltage gain $A_{v}$, current gain $A_{i}$, input impedance $Z_{i}'$ and $Z_{i}$.

Ask AI
Q4.2
Calculate the value of $R_{1}$ in the biasing circuit so that the Q-point is fixed at $I_{C}=8~mA$ and $V_{CE}=3V$ with $V_{CC} = -9V$, 250$\Omega$ collector resistor, 500$\Omega$ emitter resistor, $\beta=80$.

Ask AI

Q.5 Solve both questions:

Ask AI

Q5.1
Given a depletion-type MOSFET. In the positive $v_{GS}$ region, does the drain current increase at a significantly higher rate than for negative value? Does the $I_{D}$ curve become more and more vertical with increasing positive values of $V_{GS}$?
Ask AI
Q5.2
Draw V-I characteristic curves of JFET and mark various regions. Explain how FET is voltage-controlled device.
Ask AI

Q.6 Solve both questions:

Ask AI

Q6.1
Explain the working of single-stage common emitter amplifier with the help of circuit diagram. Draw and explain the DC load-line analysis of this amplifier.
Ask AI
Q6.2
A single-stage amplifier has voltage gain of 10 and bandwidth of 1 MHz. Three such stages are cascaded and negative feedback of 10% is applied to the cascade stage. Find out the overall voltage gain and bandwidth of cascade stage with feedback.
Ask AI

Q.7 Solve both questions:

Ask AI

Q7.1
Explain the operation of Colpitts oscillator with the help of circuit diagram.
Ask AI
Q7.2
Draw the block diagram and explain the operation of sweep frequency generator.
Ask AI

Q.8 Solve both questions:

Ask AI

Q8.1
Discuss with the help of circuit diagram, the purpose of providing negative feedback and positive feedback.
Ask AI
Q8.2
Draw the circuit diagram of voltage-shunt feedback amplifier and derive the expression of closed-loop voltage gain using op-amp.
Ask AI

Q.9 Solve both questions:

Ask AI

Q9.1
Explain the operation performed by the circuit with AC $v_{in}$, Resistor $R_1$, Capacitor $C_F$ in feedback, Load $R_L$ and derive the expression of output voltage $v_{0}$.

Ask AI
Q9.2
Op-amp can be used to add the DC voltage (addition operation). Draw the circuit and explain the operation of adder using op-amp in non-inverting mode.
Ask AI

2020V8101302

B.Tech 3rd Semester Exam., 2020 (New Course)

03 Hours70 marks

Instructions

The marks are indicated in the right-hand margin.
There are NINE questions in this paper.
Attempt FIVE questions in all.
Question No. 1 is compulsory.

Q.1 Fill in the blanks/Answer any seven of the following:

Ask AI

Q1.1
In CB configuration, output characteristics may be shown by plot of ______
Ask AI
Q1.2
The carriers enter the channel region through the ______ terminal and leave the channel through the ______ terminal in JFET.
Ask AI
Q1.3
Mention the advantages of Wien bridge oscillator.
Ask AI
Q1.4
What is reverse leakage current in CE configuration?
Ask AI
Q1.5
How is amplifier different from the oscillator?
Ask AI
Q1.6
Name the breakdown mechanism in the lightly doped P-N junction diode under reverse biased condition.
Ask AI
Q1.7
Draw the V-I characteristics of photodiode.
Ask AI
Q1.8
What is transconductance with reference to JFET?
Ask AI
Q1.9
What is the effect of removing bypass capacitor across the emitter resistor in case of CE amplifier?
Ask AI
Q1.10
What is meant by phase reversal?
Ask AI

Q.2 Solve both questions :

Ask AI

Q2.1
Find the DC voltage, ripple factor and efficiency for the half-wave rectifier given in the circuit below: What should be PIV of the diode used? If bridge rectifier is used for same power supply, what will be the value of DC voltage and PIV of diode?

Ask AI
Q2.2
Calculate the range of $ I_L $ and $ R_L $ so that $ V_{RL} $ being maintained at 10 V and also calculate the value of maximum voltage rating in the circuit given below :

Ask AI

Q.3 Solve both questions :

Ask AI

Q3.1
Draw the waveform of output $ v_0 $ and explain the operation of circuit given below: (Refer to question paper for circuit diagram)

Ask AI
Q3.2
Discuss the application of SCR as a power control with the help of circuit diagram.
Ask AI

Q.4 Solve both questions :

Ask AI

Q4.1
For the network given below, determine the following parameters using the approximate equivalent model. Voltage gain $ A_v $, current gain $ A_i $, input impedance $ Z_i' $ and $ Z_i $:

Ask AI
Q4.2
Calculate the value of $ R_1 $ in the biasing circuit in the figure given below so that the Q-point is fixed at $ I_C = 8 \text{ mA} $ and $ V_{CE} = 3\text{V} $:

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Q.5 Solve both questions :

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Q5.1
Given a deletion-type MOSFET. In the positive $ v_{GS} $ region, does the drain current increase at a significantly higher rate than for negative value? Does the $ I_D $ curve become more and more vertical with increasing positive values of $ v_{GS} $?
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Q5.2
Draw V-I characteristic curves of JFET and mark various regions. Explain how FET is voltage-controlled device.
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Q.6 Solve both questions :

Ask AI

Q6.1
Explain the working of single-stage common emitter amplifier with the help of circuit diagram. Draw and explain the DC load-line analysis of this amplifier.
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Q6.2
A single-stage amplifier has voltage gain of 10 and bandwidth of 1 MHz. Three such stages are cascaded and negative feedback of 10% is applied to the cascade stage. Find out the overall voltage gain and bandwidth of cascade stage with feedback.
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Q.7 Solve both questions :

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Q7.1
Explain the operation of Colpitts oscillator with the help of circuit diagram.
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Q7.2
Draw the block diagram and explain the operation of sweep frequency generator.
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Q.8 Solve both questions :

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Q8.1
Discuss with the help of circuit diagram, the purpose of providing negative feedback and positive feedback.
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Q8.2
Draw the circuit diagram of voltage-shunt feedback amplifier and derive the expression of closed-loop voltage gain using op-amp.
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Q.9 Solve both questions :

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Q9.1
Explain the operation performed by the circuit given below and derive the expression of output voltage $ v_0 $:

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Q9.2
Op-amp can be used to add the DC voltage (addition operation). Draw the circuit and explain the operation of adder using op-amp in non-inverting mode.
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2020104301

B.Tech 3rd Semester Exam., 2020 (New Course)

3 hours70 marks

Instructions

The marks are indicated in the right-hand margin.
There are NINE questions in this paper.
Attempt FIVE questions in all.
Question No. 1 is compulsory.

Section A

Ask AI

Q1
Choose the correct option of the following (any seven) :
a)
Which of the following expressions represents the correct formula for the density of electrons occupying the donor level?

a)
$n_d = N_d - N_d^+$

b)
$n_d = N_d - N_d^-$

c)
$n_d = N_d + N_d^+$

d)
$n_d = N_d + N_d^-$

2 marks
b)
What is the ripple factor of a half-wave rectifier?

a)
0.31

b)
0.48

c)
0.707

d)
1.21

2 marks
c)
Which of the following is true about the resistance of a Zener diode?

a)
It has an incremental resistance

b)
It has dynamic resistance

c)
The value of the resistance is the inverse of the slope of the i-v characteristics of the Zener diode

d)
All of the above

2 marks
d)
Which of the following is true in construction of a transistor?

a)
The collector dissipates lesser power

b)
The emitter supplies minority carriers

c)
The collector is made physically larger than the emitter region

d)
The collector collects minority charge carriers

2 marks
e)
Consider the following statements : A clamper circuit

adds or subtracts a d.c. voltage to a waveform

does not change the waveform

amplifies the waveform Which are correct?

a)
1, 2

b)
1, 3

c)
1, 2, 3

d)
2, 3

e)
None of the above
2 marks
f)
For what kind of amplifications can the active region of the common-emitter configuration be used?

a)
Voltage

b)
Current

c)
Power

d)
All of the above

2 marks
g)
How does the FET operate before the pinch-off region with small value of drain-to-source voltage in accordance to the control of drain-to-source resistance by the bias voltage?

a)
As a voltage controlled resistor

b)
As a voltage dependent resistor

c)
As a voltage variable resistor

d)
All of the above

2 marks
h)
A junction FET can operate in

a)
depletion mode only

b)
enhancement mode only

c)
depletion and enhancement modes

d)
neither depletion nor enhancement mode

2 marks
i)
Which of the following is not a property of an ideal operational amplifier?

a)
Zero input impedance

b)
Infinite bandwidth

c)
Infinite open-loop gain

d)
Zero common-mode gain or conversely infinite common mode-rejection

2 marks
j)
Which among the following is the major responsible reason for the cause of 'slew rate'?

a)
Current limiting

b)
Saturation of internal stages due to application of high frequency and amplitude signal

c)
Both (i) and (ii)

d)
None of the above

2 marks
14 marks
Ask AI

Section B

Ask AI

Q2
Answer the following:

a)
Draw potential energy diagrams for a forward as well as a reverse-biased p-n junction and explain the flow of currents in both the cases.

7 marks
b)
The p-silicon has resistivity of $100 \Omega \text{ cm}$ . The other parameters for silicon are : Intrinsic carrier density, $n_i = 10^{10} \text{ cm}^{-3}$ , Hole mobility, $\mu_p = 500 \text{ cm}^2 / \text{v.s}$ and Electron mobility, $\mu_n = 1200 \text{ cm}^2 / \text{v.s}$ . Calculate the number of electrons for every 5000 million holes in the semiconductor.

7 marks
Ask AI
Q3
Answer the following:

a)
Determine $v_o$ and the required PIV rating of each diode for the configuration of the following figure : [Diagram: Bridge rectifier circuit with input sine wave (peak 100V), ideal diodes, and load resistor $R_L = 2.2 k\Omega$]. In addition, determine the maximum current through each diode.

7 marks
b)
The circuit shown below uses a 9V Zener diode. If the load resistance $R_L$ is equal to $1.5 k\Omega$ and the d.c. source equals 24V, find the maximum value of resistor R required to maintain a constant voltage of 9V across the load. [Diagram: Zener diode circuit with source $V_s=24V$ , series resistor R, and parallel combination of Zener $V_Z=9V$ and load $R_L=1.5k\Omega$ .]

7 marks
Ask AI
Q4
Answer the following:

a)
Draw the cross-sectional view of an n-p-n transistor and explain its operation in active region of operation. What are the different current components of the transistor? How can one use a transistor as amplifier?

7 marks
b)
Define $\alpha_{dc}$ and $\beta_{dc}$ . Derive the relationship between $\alpha_{dc}$ and $\beta_{dc}$ . If the base current in a transistor is $30 \mu A$ , when the emitter current is $7.2 mA$ , what are the values of $\alpha_{dc}$ and $\beta_{dc}$ ? Also, calculate the collector current.

7 marks
Ask AI
Q5
Answer the following:

a)
Draw and explain the input and output characteristics of CB configuration. Where can we use the CB configuration in a transistor circuit? Explain with proper justification.

7 marks
b)
Design a collector to base bias circuit shown in the figure below for the specified conditions : $V_{CC} = 15V, V_{CE} = 5V, I_C = 5mA, \beta = 150$ . [Diagram: Collector-to-base bias circuit configuration.]

7 marks
Ask AI
Q6
Answer the following:

a)
Draw the structure of JFET and discuss its working. What is pinch-off voltage? How to get its value experimentally?

7 marks
b)
For the voltage-divider configuration of the figure shown below, determine : (i) $I_{DQ}$ and $V_{GSQ}$ , (ii) $V_D$ and $V_S$ . [Diagram: JFET voltage divider bias circuit. $V_{DD}=24V, R_1=10 M\Omega, R_2=6.8 M\Omega, R_D=2.2 k\Omega, R_S=0.75 k\Omega$ . JFET parameters: $V_{GS(Th)}=-3V, I_{D(on)}=5mA, V_{GS(on)}=-6V$ .]

7 marks
Ask AI
Q7
Answer the following:

a)
Define an ideal operational amplifier. Draw the approximate block diagram of an OPAMP giving various stages of the amplifier.

7 marks
b)
Find the output voltage of the following OPAMP circuit : [Diagram: Inverting OPAMP circuit with non-inverting terminal grounded through 2k, inverting terminal connected to 12V via 2k, and feedback resistor 10k.]

7 marks
Ask AI
Q8
Answer the following:

a)
Draw the gain-frequency response of an RC coupled amplifier. Discuss fall in gain at very low and at very high frequencies.

7 marks
b)
Common emitter (CE) amplifier shown in the figure has voltage gain of 150 when $R_E=0$ . Stability is brought through negative feedback by adding resistor $R_E$ . Calculate the value of resistor $R_E$ using feedback concepts so that final voltage gain ($= A_{FB}$) is equal to 100. [Diagram: CE amplifier circuit with voltage divider bias $R_1=100k, R_2=100k, R_C=5k, V_{CC}=+15V$ and unbypassed emitter resistor $R_E$ .]

7 marks
Ask AI
Q9
Answer the following:

a)
Explain the construction and working principle of a photo diode (PD).

7 marks
b)
Explain the construction and working principle of an SCR. Write the applications utilizing SCR.

7 marks
Ask AI

2020ESC-202 (101302)

B.Tech 3rd Semester Special Exam., 2020

03 Hours70 marks

Instructions

The marks are indicated in the right-hand margin.
There are NINE questions in this paper.
Attempt FIVE questions in all.
Question No. 1 is compulsory.

Q.1 Answer/Fill in the blanks/Write true or false (any seven):

Ask AI

Q1.1
Why is filter required to be added after rectifier circuit?
Ask AI
Q1.2
What is the application of voltage regulator?
Ask AI
Q1.3
DC value of pure AC waveform is ______.
Ask AI
Q1.4
Which of the transistor currents is always the largest?
Ask AI
Q1.5
What is the source of leakage current in a transistor?
Ask AI
Q1.6
What is the major difference between a bipolar and a unipolar device?
Ask AI
Q1.7
Give the advantage of negative feedback in amplifier.
Ask AI
Q1.8
BUT amplifier changes the frequency and shape of the signal.
Ask AI
Q1.9
CMMR for ideal operational amplifier is ______.
Ask AI
Q1.10
Slew rate for ideal operational amplifier is ______.
Ask AI

Q.2 Solve both questions :

Ask AI

Q2.1
Draw volt-ampere characteristics of a Zener diode. What is meant by the knee voltage in the curve?
Ask AI
Q2.2
Describe in detail the avalanche breakdown mechanism in a diode.
Ask AI

Q.3 Solve both questions :

Ask AI

Q3.1
Explain the principle of operation of LED with the help of diagram.
Ask AI
Q3.2
Derive the expression for $ I_C $ in terms of $ I_E $ and $ \alpha_{dc} $ for a common-base BUT configuration. For a given $ \alpha_{dc} $ of 0.998, determine $ I_C $, if $ I_E = 4 \, \text{mA} $.
Ask AI

Q.4 Solve both questions :

Ask AI

Q4.1
Define the stability factor. What does smaller stability factor indicate?
Ask AI
Q4.2
Derive the expression for stability factor for voltage divider bias (self-bias) circuit.
Ask AI

Q.5 Solve both questions :

Ask AI

Q5.1
Explain the construction and characteristics of FET.
Ask AI
Q5.2
Draw and explain h-parameter small signal model for BJT.
Ask AI

Q.6 Solve both questions :

Ask AI

Q6.1
Explain the working of common emitter amplifier with the help of circuit diagram.
Ask AI
Q6.2
What are the roles of coupling and bypass capacitors? Explain in detail.
Ask AI

Q.7 Solve both questions :

Ask AI

Q7.1
Describe the RC phase-shift oscillator with circuit diagram.
Ask AI
Q7.2
Explain the working of high-frequency LC oscillator with the help of circuit diagram.
Ask AI

Q.8 Solve both questions :

Ask AI

Q8.1
Explain the working of voltage series feedback amplifier with the help of block diagram.
Ask AI
Q8.2
Design an integrator using op-amp and explain its working.
Ask AI

Q.9 Solve both questions :

Ask AI

Q9.1
Write the circuit diagram of differential amplifier configurations and explain its working.
Ask AI
Q9.2
Explain about CMRR, slew rate and concept of virtual ground.
Ask AI

2020SPECIALESC-202 (101302)

B.Tech 3rd Semester Special Exam., 2020 (New Course)

03 Hours70 marks

Instructions

The marks are indicated in the right-hand margin.
There are NINE questions in this paper.
Attempt FIVE questions in all.
Question No. 1 is compulsory.

Q.1 Answer/Fill in the blanks/Write true or false (any seven):

Ask AI

Q1.1
Why is filter required to be added after rectifier circuit?
Ask AI
Q1.2
What is the application of voltage regulator?
Ask AI
Q1.3
DC value of pure AC waveform is ______
Ask AI
Q1.4
Which of the transistor currents is always the largest?
Ask AI
Q1.5
What is the source of leakage current in a transistor?
Ask AI
Q1.6
What is the major difference between a bipolar and a unipolar device?
Ask AI
Q1.7
Give the advantage of negative feedback in amplifier
Ask AI
Q1.8
BJT amplifier changes the frequency and shape of the signal. (True/False)
Ask AI
Q1.9
CMMR for ideal operational amplifier is ______
Ask AI
Q1.10
Slew rate for ideal operational amplifier is ______
Ask AI

Q.2 Solve both questions :

Ask AI

Q2.1
Draw volt-ampere characteristics of a Zener diode. What is meant by the knee voltage in the curve?
Ask AI
Q2.2
Describe in detail the avalanche breakdown mechanism in a diode.
Ask AI

Q.3 Solve both questions :

Ask AI

Q3.1
Explain the principle of operation of LED with the help of diagram.
Ask AI
Q3.2
Derive the expression for $ I_C $ in terms of $ I_E $ and $ \alpha_d $ for a common-base BJT configuration. For a given $ \alpha_d $ of 0.998, determine $ I_C $ if $ I_E = 4 \text{ mA} $.
Ask AI

Q.4 Solve both questions :

Ask AI

Q4.1
Define the stability factor. What does smaller stability factor indicate?
Ask AI
Q4.2
Derive the expression for stability factor for voltage divider bias (self-bias) circuit.
Ask AI

Q.5 Solve both questions :

Ask AI

Q5.1
Explain the construction and characteristics of FET.
Ask AI
Q5.2
Draw and explain h-parameter small signal model for BJT.
Ask AI

Q.6 Solve both questions :

Ask AI

Q6.1
Explain the working of common emitter amplifier with the help of circuit diagram.
Ask AI
Q6.2
What are the roles of coupling and bypass capacitors? Explain in detail.
Ask AI

Q.7 Solve both questions :

Ask AI

Q7.1
Describe the RC phase-shift oscillator with circuit diagram.
Ask AI
Q7.2
Explain the working of high-frequency LC oscillator with the help of circuit diagram.
Ask AI

Q.8 Solve both questions :

Ask AI

Q8.1
Explain the working of voltage series feedback amplifier with the help of block diagram.
Ask AI
Q8.2
Design an integrator using op-amp and explain its working.
Ask AI

Q.9 Solve both questions :

Ask AI

Q9.1
Write the circuit diagram of differential amplifier configurations and explain its working.
Ask AI
Q9.2
Explain about CMRR, slew rate and concept of virtual ground.
Ask AI

2019041401

B.Tech 4th Semester Exam., 2019

3 hours70 marks

Instructions

The marks are indicated in the right-hand margin.
There are NINE questions in this paper.
Attempt FIVE questions in all.
Question No. 1 is compulsory.

Section A

Ask AI

Q1
Answer the following questions briefly (any seven) :

a)
If doping level in a crystal diode is increased, what will happen to the width of depletion layer?

b)
How does Zener diode behave in the breakdown region?

c)
At which voltage avalanche occurs in a diode?

d)
If the maximum DC current rating of diodes in bridge rectifier is 2A, then what is the maximum DC load current?

e)
A half-wave rectifier has an input voltage of 240 V r.m.s. If the step-down transformer has a turns ratio of 8 : 1, what is the peak load voltage? Ignore diode drop.

f)
If $V_{CC} = +20 \text{ V}$ , voltage-divider resistor $R_1$ is $5 \text{ k\Omega}$ and $R_2$ is $2 \text{ k\Omega}$ , what is the base bias voltage?

g)
When does thermal runaway occur?

h)
With the E-MOSFET, what is the value of drain current when gate input voltage is zero?

i)
What is the bandwidth of an ideal operational amplifier?

j)
If gate current is increased, then what will happen to anode-cathode voltage at which SCR closes?

14 marks
Ask AI

Section B

Ask AI

Q2
Answer the following:

a)
Differentiate between ideal and practical voltage sources. Give their graphical representations and convert $20 \text{ V}$ voltage source with its series resistance of $10 \text{ \Omega}$ into its equivalent current source.

7 marks
b)
Derive continuity equation for carrier concentration in body of a semiconductor.

7 marks
Ask AI
Q3
Answer the following:

a)
Derive the expressions for (i) $I_{rms}$ , (ii) $I_{dc}$ , (iii) ripple factor and (iv) efficiency of rectification; in case of full-wave rectifier.

6 marks
b)
Draw a sketch to show various currents in an N-P-N transistor and derive the relationship between various components.

8 marks
Ask AI
Q4
Answer the following:

a)
A 4 : 1 transformer supplies a bridge rectifier that is driving a load of 400 ohms. If the transformer input is $230 \text{ V}/50 \text{ Hz}$ supply, calculate the d.c. output voltage, P-I-V and the output frequency. Assume the rectifier diodes to be ideal.

7 marks
b)
Draw diode I-V characteristics, discuss its temperature dependence and obtain the expression for diode dynamic resistance.

7 marks
Ask AI
Q5
Answer the following:

a)
Using a common collector N-P-N transistor configuration, derive the expressions for voltage gain and current gain.

7 marks
b)
Design the voltage divider bias circuit to operate from $20 \text{ V}$ supply. The bias conditions are $V_{CE} = 5 \text{ V}, V_E = 7 \text{ V}$ and $I_C = 5 \text{ mA}$ .

7 marks
Ask AI
Q6
Answer the following:

a)
A collector to base circuit has $V_{CB} = 30 \text{ V}, R_B = 200 \text{ k\Omega}, R_C = 4 \text{ k\Omega}$ and $V_{CE} = 20 \text{ V}$ . Calculate $h_{FE}$ and determine $V_{CE}$ when a new transistor is replaced having $h_{FE} = 150$ .

7 marks
b)
Draw two-dimensional structure of n-channel MOSFET. Explain its working.

7 marks
Ask AI
Q7
Answer the following:

a)
An n-channel FET is utilized by amplifier shown in figure for which $V_p = -3.0 \text{ V}$ and $I_{DSS} = 2 \text{ mA}$ . It is desired to bias the circuit at $I_D = 1 \text{ mA}$ , using $V_{DD} = 26 \text{ V}$ . Assume $r_d \gg R_d$ . Find (i) $V_{GS}$ , (ii) $g_m$ and (iii) $R_S$ .

[Diagram: Self-bias JFET amplifier circuit with $R_G, R_D, R_S$ and bypass capacitor $C_S$ , coupling capacitor $C_c$ .]

7 marks
b)
Explain the working of BJT voltage divider bias circuit. Derive the expression for Q-point ($I_{CQ}, V_{CEQ}$) in terms of circuit parameters.

7 marks
Ask AI
Q8
Answer the following:

a)
Explain a voltage-series feedback amplifier with suitable example.

7 marks
b)
Using an op-amp, explain the circuits for a voltage gain amplifier (with least components) and current to voltage converter.

7 marks
Ask AI
Q9
Answer the following:

a)
Explain the working principle of unijunction transistor (UJT).

7 marks
b)
Describe the structure, symbol and operation of SCR with the help of suitable diagrams.

7 marks
Ask AI

2019101302

B.Tech 3rd Semester Exam., 2019 (New Course)

3 hours70 marks

Instructions

The marks are indicated in the right-hand margin.
There are NINE questions in this paper.
Attempt FIVE questions in all.
Question No. 1 is compulsory.

Section A

Ask AI

Q1
Answer any seven of the following questions :

a)
Clipper and clamper are the applications of ________.

b)
Give one application of Zener diode.

c)
SCR is bistable device. (State True or False)

d)
Which of the transistor currents is always the largest?

e)
Sketch the common-base BJT transistor configuration (for n-p-n and p-n-p).

f)
Why is coupling capacitor used in common-emitter amplifier?

g)
Which BJT amplifier configuration has unity voltage gain?

h)
Which BJT amplifier configuration has unity current gain?

i)
Define conversion efficiency.

j)
What is the highest efficiency of class A direct coupled amplifier?

14 marks
Ask AI

Section B

Ask AI

Q2
Answer the following:

a)
For the series connected diode configuration as given below in the figure, determine $V_D, V_R$ and $I_D$ :

[Diagram: Series circuit with 8V source, Si diode (marked $+V_D-$), and resistor $R$ (marked $+V_R-$).]

7 marks
b)
Draw the diagram and explain the working of a full-wave rectifier with filter.

7 marks
Ask AI
Q3
Answer the following:

a)
Explain the working and applications of photodiode.

7 marks
b)
Explain the construction, operation and characteristics of SCR.

7 marks
Ask AI
Q4
Answer the following:

a)
Explain the working of common-collector amplifier as a voltage buffer.

7 marks
b)
Compute and explain common-emitter amplifier operating point and load line.

7 marks
Ask AI
Q5
Answer the following:

a)
Compare between depletion type MOSFET and enhancement type MOSFET.

7 marks
b)
Explain the working of common-base amplifier as a current buffer.

7 marks
Ask AI
Q6
Answer the following:

a)
Explain about the distortions present in amplifier. List the advantages of negative feedback.

6 marks
b)
Explain the working of current series feedback amplifier with the help of block diagram.

8 marks
Ask AI
Q7
Answer the following:

a)
Describe the working of Wien bridge oscillator circuit.

8 marks
b)
Design the R-C elements of a Wien bridge oscillator, when it operates at $f_0 = 10 \text{ kHz}$ .

6 marks
Ask AI
Q8
Answer the following:

a)
Explain the working of a non-sinusoidal type of oscillator with the help of its circuit diagram.

7 marks
b)
Write and explain two applications of differential amplifier with the help of circuit diagrams.

7 marks
Ask AI
Q9
Answer the following:

a)
Write the properties of ideal operational amplifier.

7 marks
b)
Draw the pin configuration of 741 op-amp IC and explain its working.

7 marks
Ask AI

2018041401

B.Tech 4th Semester Examination, 2018

3 hours70 marks

Instructions

The marks are indicated in the right-hand margin.
There are NINE questions in this paper.
Attempt FIVE questions in all.
Question No. 1 is compulsory.

Section A

Ask AI

Q1
Choose the correct answer of the following (any seven) :

a)
When checking a diode, low resistance readings both ways indicate the diode is

a)
open

b)
satisfactory

c)
faulty

d)
not the problem

b)
Which of the following is the correct relationship between $I_B$ and $I_E$ ?

a)
$I_B = \beta I_E$

b)
$I_B = I_E$

c)
$I_B = (\beta + 1) I_E$

d)
$I_E = (\beta + 1) I_B$

c)
If a $169.7 \text{ V}$ half-wave peak has an average voltage of $54 \text{ V}$ , what is the average of two full-wave peaks?

a)
$119.9 \text{ V}$

b)
$108.0 \text{ V}$

c)
$115.7 \text{ V}$

d)
$339.4 \text{ V}$

d)
The Q-point on a load line may be used to determine

a)
$V_C$

b)
$V_{CC}$

c)
$V_B$

d)
$I_C$

e)
For the BJT to operate in the active (linear) region, the base-emitter junction must be ________-biased and the base-collector junction must be ________-biased.

a)
forward, forward

b)
forward, reverse

c)
reverse, reverse

d)
reverse, forward

f)
What is the level of drain current $I_D$ for gate-to-source voltages $V_{GS}$ less than (more negative than) the pinch-off level?

a)
Zero ampere

b)
$I_{DSS}$

c)
Negative value

d)
Undefined

g)
How much times reverse saturation current will increase, if temperature increases $15^\circ\text{C}$ ?

a)
2.52

b)
4.62

c)
4.12

d)
2.82

h)
The total discharge time for the capacitor in a clamper having $C = 0.01 \text{ \mu F}$ and $R = 500 \text{ k\Omega}$ is

a)
$5 \text{ ms}$

b)
$25 \text{ ms}$

c)
$2.5 \text{ ms}$

d)
$50 \text{ ms}$

i)
How many op-amps are required to implement the equation $V_0 = V_1$ ?

a)
2

b)
3

c)
4

d)
1

j)
A non-inverting closed-loop op-amp circuit generally has a gain factor

a)
less than one

b)
greater than one

c)
of zero

d)
equal to one

14 marks
Ask AI

Section B

Ask AI

Q2
Answer the following:

a)
Differentiate between an ideal and a practical voltage source. Give their graphical representations and convert $10 \text{ V}$ voltage source with its series resistance of $2 \text{ \Omega}$ into its equivalent current source.

7 marks
b)
Explain the working of a shunt capacitor filter and derive an approximate expression for ripple factor in half-wave rectifier with shunt capacitor filter.

7 marks
Ask AI
Q3
Answer the following:

a)
Compare the differences between JFET and MOSFET and also prove that the transconductance $g_m$ of a JFET is given by $g_m = \frac{2}{|V_p|} \sqrt{I_{DS} I_{DSS}}$

9 marks
b)
Explain the UJT as a relaxation oscillator.

5 marks
Ask AI
Q4
Answer the following:

a)
Explain Zener and avalanche breakdown in semiconductors.

6 marks
b)
Define $\alpha$ and $\beta$ of a transistor. Also derive the relationship between them.

8 marks
Ask AI
Q5
Answer the following:

a)
Sketch the output characteristics for N-channel JFET with gate-source shorted (i.e., $V_{GS} = 0$). How are ohmic, pinch off and breakdown regions created?

8 marks
b)
Explain the basic structure and working of a P-channel JFET.

6 marks
Ask AI
Q6
Answer the following:

a)
Compare the characteristics of CB, CE and CC configurations of a transistor. Draw the circuit of a common-collector transistor configuration and explain its operation. Also derive the relation between $\gamma$ and $\alpha$ current amplification factors.

8 marks
b)
A collector to base circuit has $V_{CB} = 24 \text{ V}, R_B = 180 \text{ k\Omega}, R_C = 3.3 \text{ k\Omega}$ and $V_{CE} = 10 \text{ V}$ . Calculate $h_{FE}$ and determine $V_{CE}$ when a new transistor is replaced having $h_{FE} = 120$ .

6 marks
Ask AI
Q7
Answer the following:

a)
An inverting op-amp has $R_f = 100 \text{ k\Omega}$ and $R_1 = 2 \text{ k\Omega}$ . Find the voltage gain of the amplifier. Also find the amplifier input resistance, input current and the output voltage if the input voltage is $0.1 \text{ V}$ . Assume op-amp to be ideal.

8 marks
b)
Explain the working of an op-amp as an integrator circuit.

6 marks
Ask AI
Q8
Answer the following:

a)
Explain a voltage-shunt feedback amplifier with suitable example.

8 marks
b)
In a transistor circuit, load resistance is $5 \text{ k\Omega}$ and quiescent current is $1.2 \text{ mA}$ . Determine the operating point when the battery voltage $V_{CC} = 12 \text{ V}$ . How will the Q-point change when the load resistance is changed from $5 \text{ k\Omega}$ to $7.5 \text{ k\Omega}$ ?

6 marks
Ask AI
Q9
Answer the following:

a)
Describe the structure, symbol and operation of SCR with the help of suitable diagrams.

7 marks
b)
In an N-type semiconductor, the Fermi level lies $0.3 \text{ eV}$ below the conduction band at $27^\circ\text{C}$ . If the temperature is increased to $55^\circ\text{C}$ , find the new position of the Fermi level.

7 marks
Ask AI

2017041301

B.Tech 3rd Semester Examination, 2017

3 hours70 marks

Instructions

The marks are indicated in the right-hand margin.
There are NINE questions in this paper.
Attempt FIVE questions in all.
Question No. 1 is compulsory.

Questions

Ask AI

Q1
Answer the following questions (any seven) :

a)
State the most important SCR parameters for high-current devices.

2 marks
b)
State Fermi energy level ($E_F$) of an intrinsic semiconductor.

2 marks
c)
Define base width modulation.

2 marks
d)
Differentiate between drift current and diffusion current.

2 marks
e)
Define avalanche multiplication.

2 marks
f)
Define peak point current of a UJT.

2 marks
g)
State the definition of threshold voltage of a MOSFET.

2 marks
h)
Define CMRR of an op-amp.

2 marks
i)
State the applications of photodiode.

2 marks
j)
Why are PIV of bridge and centre-tapped full-wave rectifier not same?

2 marks
14 marks
Ask AI
Q2
Answer the following questions:

a)
Accurately analyze the collector-to-base bias circuit is shown in figure 1 to determine the $I_B, I_C$ and $V_{CE}$ , when (i) $\beta = 50$; (ii) $\beta = 200$ . Assume $V_{BE} = 0.7\text{ V}$ . [Diagram Fig. 1: Voltage divider bias circuit with $V_{CC}=18\text{V}, R_{B1}=33\text{ k}\Omega, R_{B2}=12\text{ k}\Omega, R_C=1.2\text{ k}\Omega, R_E=1\text{ k}\Omega$]

8 marks
b)
With the help of a neat diagram, explain the input and output characteristics of common-collector (CC) configuration.

6 marks
14 marks
Ask AI
Q3
Answer the following questions:

a)
With the help of band and bond models, explain both N-type and P-type extrinsic silicons.

8 marks
b)
A silicon p-n diode has a doping of $N_D = 8 \times 10^{15} \text{ cm}^{-3}$ and $N_A = 2 \times 10^{16} \text{ cm}^{-3}$ (for Si: $n_i = 1.5 \times 10^{10} \text{ cm}^{-3}, \epsilon_r = 11.9$). (i) Determine the depletion width in the n-region. (ii) Determine the built-in potential at $300\text{ K}$ . (iii) Calculate the depletion width when it biased to $0.5\text{ V}$ .

6 marks
14 marks
Ask AI
Q4
What do you mean by rectification? Explain the working of a half-wave rectifier circuit with resistive load. With sinusoidal input, derive the expressions for the following :

a)
Average output voltage and current

4 marks
b)
RMS load current and voltage

4 marks
c)
Form factor and ripple factor

4 marks
d)
Efficiency

2 marks
14 marks
Ask AI
Q5
Answer the following questions:

a)
Draw the circuit of a UJT relaxation oscillator with provision for frequency adjustment and spike waveform. Show all waveforms, and explain the circuit operation.

8 marks
b)
Draw the circuit diagram to show how an SCR can be triggered by the application of a pulse to gate terminal. Sketch the circuit waveforms and explain its operation.

6 marks
14 marks
Ask AI
Q6
Answer the following questions:

a)
Explain the construction and characteristics of n-channel JFET.

8 marks
b)
The FET circuit is shown in figure 2 has $R_1 = 3.5\text{ M}\Omega, R_2 = 1.5\text{ M}\Omega, R_s = 2\text{ k}\Omega, R_L = 20\text{ k}\Omega, r_d = 40\text{ k}\Omega$ and $g_m = 2.5\text{ mA/V}$ . Find its input impedance and output impedance and voltage gain. [Diagram Fig. 2: JFET amplifier with voltage divider bias ($R_1, R_2$), source resistor ($R_S$), and load ($R_L$)]

6 marks
14 marks
Ask AI
Q7
Answer the following questions:

a)
Given $I_E = 2.5\text{ mA}, h_{fe} = 140, h_{oe} = 20\text{ }\mu\text{s}$ and $h_{ob} = 0.5\text{ }\mu\text{s}$ , determine (i) the common-emitter hybrid equivalent circuit; (ii) the common-base $r_e$-model.

8 marks
b)
Compare the advantages and disadvantages of biasing schemes in BJT.

6 marks
14 marks
Ask AI
Q8
Answer the following questions:

a)
Draw the circuit diagram of a practical voltage series feedback amplifier and derive the expressions for input resistance, output resistance, voltage gain and current gain.

8 marks
b)
Explain the operation and characteristics of photodiode.

6 marks
14 marks
Ask AI
Q9
Answer the following questions:

a)
Explain the summing and differential amplifiers using op-amp with derivation of output voltage.

8 marks
b)
Calculate the output voltages $V_2$ and $V_3$ in the circuit of the following figure 3 : [Diagram Fig. 3: Two-stage op-amp circuit. First stage is non-inverting ($R_f=20\text{k}\Omega, R_1=10\text{k}\Omega$), second stage is inverting ($R_{f2}=200\text{k}\Omega, R_{i2}=200\text{k}\Omega$)]

6 marks
14 marks
Ask AI

2017041401

B.Tech 4th Semester Examination, 2017

3 hours70 marks

Instructions

There are Nine Questions in this Paper. All questions carry equal marks.
Attempt Five questions in all.
Question No. 1 is Compulsory.
The marks are indicated in the right-hand margin.

Section A

Ask AI

Q1
Choose the correct alternatives for any seven of the following;

a)
The junction capacitance of a linearly graded junction varies with the applied reverse voltage (V) as

a)
V

b)
$V^{-1/3}$

c)
$V^{-1/2}$

d)
$V^{-1/4}$

b)
Reverse saturation current in a silicon PN junction diode is doubled for every

a)
$10^\circ\text{C}$ increase in temperature

b)
$5^\circ\text{C}$ increase in temperature

c)
$2^\circ\text{C}$ increase in temperature

d)
$1^\circ\text{C}$ increase in temperature

c)
A rectifier is used to

a)
convert ac to dc

b)
convert dc to ac

c)
convert high voltage to low voltage

d)
convert low voltage to high voltage

d)
Polarity of dc output voltage of a half wave rectifier can be reversed by reversing

a)
transformer primary

b)
the diode

c)
transformer secondary

d)
none of these

e)
When a transistor operates in active region, it behaves as

a)
a closed switch

b)
an open switch

c)
an amplifier

d)
none of these

f)
If the Q-point of a transistor lies at ________, the negative part of input signal is clipped at output.

a)
near saturation point

b)
near cut-off point

c)
middle of active region

d)
anywhere of the load line

g)
Trans-conductance of JFET is measured in

a)
mhos or siemens

b)
ohms

c)
volts

d)
amperes

h)
The threshold voltage of an enhancement pMOS transistor is

a)
less than zero volt

b)
equal to zero volt

c)
greater than zero volt

d)
none of these

i)
In a common-emitter amplifier, the unbiased emitter resistance provides

a)
voltage-series feedback

b)
voltage-shunt feedback

c)
current-series feedback

d)
current-shunt feedback

j)
An ideal OP-AMP has

a)
infinite voltage gain

b)
zero output impedance

c)
infinite signal bandwidth

d)
all of these

14 marks
Ask AI

Section B

Ask AI

Q2
Answer the following:

a)
What is a forward biased and reverse biased diode? How is the width of the space charge region and barrier height affected in forward biased and reversed diode?

8 marks
b)
What is the relation between current and voltage in a PN junction diode? Explain each term involved in that relation. The reverse saturation current of a silicon PN junction diode is $10 \text{ \mu A}$ at the temperature $300 \text{ K}$ . Determine the forward bias voltage to be applied across the PN junction to obtain a current of about $100 \text{ mA}$ .

6 marks
Ask AI
Q3
Answer the following:

a)
Explain depletion layer capacitance and diffusion capacitance of a PN junction diode in detail. How do these capacitances vary with respect to applied bias voltage across a silicon PN-junction diode?

7 marks
b)
A silicon has a doping density of acceptors $N_A = 4 \times 10^{18} / \text{ cm}^3$ in the P-type region and a doping density of donors $N_D = 3 \times 10^{15} / \text{ cm}^3$ in the N-type region. Assume $n_i = 2.5 \times 10^{10} / \text{ cm}^3$ at room temperature of $300 \text{ K}$ and the dielectric constant of silicon as $11.7$ . Determine the built in potential and the total space charge (depletion layer) width at $300 \text{ K}$ .

7 marks
Ask AI
Q4
Answer the following:

a)
What is ripple factor? Why ripple factor is so important in power supply? Derive the expression of ripple factor of a full wave rectifier using centre-tap transformer.

8 marks
b)
A single phase full wave rectifier circuit consists of four diodes, a $250 \text{ \Omega}$ load resistance and it is fed from a $15\text{V}, 50 \text{ Hz}$ ac power supply. The forward resistance of each diode is $25 \text{ \Omega}$ . Determine the dc output voltage, dc load current and efficiency.

6 marks
Ask AI
Q5
Answer the following:

a)
What is a bipolar junction transistor (BJT)? Why are these transistors called bipolar devices? What are the different configuration of BJT?

6 marks
b)
Derive the relation between $\alpha$ and $\beta$ of a BJT.

4 marks
c)
The collector current of a transistor is $100 \text{ mA}$ and is $\beta$ is $75$ . Calculate the value of base current and emitter current.

4 marks
Ask AI
Q6
Answer the following:

a)
What are the different types of biasing? Derive the expression for stability factor of self bias circuit.

8 marks
b)
A voltage divider bias circuit of a BJT is shown in Fig.-1 below. Determine the emitter current and collector-to-emitter voltage. Calculate the collector potential Vc. Assume $V_{BE} = 0.65$ and $\beta = 75$ .

[Diagram: Figure-1 - Voltage divider bias circuit of N-P-N transistor. $V_{CC}=18\text{V}, R_1=10\text{k}\Omega, R_2=9.5\text{k}\Omega, R_C=1.5\Omega, R_E=4.5\text{k}\Omega, V_{BE}=0.65, \beta=75$]

6 marks
Ask AI
Q7
Answer the following:

a)
Discuss the construction and working principle of a P-channel enhancement type MOSFET with diagrams and draw the device characteristics.

8 marks
b)
In an N-channel JFET, $I_{DSS}=12 \text{ mA}, V_p=-6 \text{ V}$ . Find the minimum value of $V_{DS}$ for pinch off operation. Determine the value of drain current at $V_{GS}=-3 \text{V}$ .

6 marks
Ask AI
Q8
Answer the following:

a)
Draw the circuit diagram of an integrator using opamp and explain its operation. If a square wave voltage signal is applied at the input of an integrator then draw its out in same time scale of input signal.

9 marks
b)
Draw the circuit diagram of a non-inverting summing amplifier using opamp and determine the output voltage.

5 marks
Ask AI
Q9
Write short notes on the following:

a)
Photo diode

7 marks
b)
Unijunction Transistor

7 marks
Ask AI

2016041301

B.Tech 3rd Semester Examination, 2016

3 hours70 marks

Instructions

There are Nine Questions in this Paper.
Attempt Five questions in all.
Question No. 1 is Compulsory.
The marks are indicated in the right hand margin.

Questions

Ask AI

Q1
Answer the following questions:

a)
Difference between BJT and MOSFET.

2 marks
b)
Define thermal run way.

2 marks
c)
Difference between depletion mode and enhancement mode MOSFET.

2 marks
d)
List the most important SCR parameters for low-current devices.

2 marks
e)
Emitter saturation voltage of UJT.

2 marks
f)
List the most important parameters of operational amplifier and their typical values.

2 marks
g)
Define the Pinch-off voltage JFET.

2 marks
h)
Define flat-band voltage.

2 marks
i)
State the applications of light emitting diode.

2 marks
j)
Why the BJT dimensions of Emitter, Base and Collector of are not same?

2 marks
14 marks
Ask AI
Q2
Answer the following questions:

a)
Derive and explain an intrinsic carrier concentration ($n_i$) of a semiconductor.

6 marks
b)
Explain the operation and characteristics of light emitting diode.

8 marks
14 marks
Ask AI
Q3
Answer the following questions:

a)
For the circuit shown in Figure 1, determine (i) d.c. output voltage (ii) rectification efficiency (iii) peak inverse voltage (iv) output frequency [Diagram: Center-tapped transformer with 10:1 ratio, 220V 50Hz input, bridge rectifier with four diodes, 250 ohm load resistor]

8 marks
b)
Explain the operation of $p^+-n$ silicon diode at equilibrium condition. Also derive the expression for the following : (i) Maximum electric field ($E_{max}$) (ii) Depletion width (W) (iii) Built-in potential ($V_{bi}$)

6 marks
14 marks
Ask AI
Q4
Answer the following questions:

a)
Accurately analyze the collector-to-base bias circuit is shown in Figure 2 to determine the $I_B, I_C$ and $V_{CE}$ when (i) $\beta=50$ and (ii) $\beta=200$ Assume $V_{BE} = 0.7\text{ V}$ . [Diagram: Collector-to-base bias circuit with $V_{CC}=18\text{V}, R_C=2.2\text{ k}\Omega, R_B=270\text{ k}\Omega$]

8 marks
b)
Sketch typical BJT common-emitter input and output characteristics. Explain the shapes of the characteristics.

6 marks
14 marks
Ask AI
Q5
Answer the following questions:

a)
Draw the two biasing circuits for JFET and explain.

8 marks
b)
Derive the gain expression of an integrator and a differentiator using op-amp.

6 marks
14 marks
Ask AI
Q6
Answer the following questions:

a)
Explain the basic operation and characteristics of n-channel depletion type MOSFET.

8 marks
b)
Sketch a $180^\circ$ phase control for an SCR. Draw the load waveform and explain the circuit operation.

6 marks
14 marks
Ask AI
Q7
Answer the following questions:

a)
Draw Sketches to show the basic construction and equivalent circuit of a unijunction transistor (UJT). Briefly explain the device operation.

8 marks
b)
Design a clamper to perform the function shown in the Figure 3 shown below. [Diagram: Input pulse $\pm 20\text{V}$ , output pulse $30\text{V}$ to $-10\text{V}$ , Design block with input $V_{in}$ and output $V_{out}$]

6 marks
14 marks
Ask AI
Q8
Answer the following questions:

a)
Briefly explain the small signal model of JFET.

6 marks
b)
An integrator using op-amp has following component values. $R_i = 1\text{ k}\Omega, R_f = 100\text{ k}\Omega$ and $C_f = 0.1\text{ }\mu\text{F}$ . A $1\text{ kHz}$ square wave applied to integrator. The amplifier uses $\pm 15\text{ V}$ supply and output saturates at $\pm 14\text{V}$ if input alternates between $\pm 5\text{ V}$ then. (i) Determine the maximum change in output (ii) Determine the maximum slew rate.

8 marks
14 marks
Ask AI
Q9
Answer the following questions:

a)
Define the gate power dissipation and explain its importance in SCR.

7 marks
b)
Explain the operation of centre tapped full wave rectifier. And calculate the rms load current and voltage for a sinusoidal input.

7 marks
14 marks
Ask AI

2016041401

B.Tech 4th Semester Examination, 2016

3 hours70 marks

Instructions

The marks are indicated in the right-hand margin.
There are NINE questions in this paper.
Attempt FIVE questions in all.
Question No. 1 is compulsory.

Questions

Ask AI

Q1
Choose the correct alternatives for any seven of the following :

a)
The width of depletion layer of a P-N junction diode is (i) independent of applied voltage (ii) increased with applied reverse bias voltage (iii) increased with applied forward bias voltage (iv) increased with doping

b)
A diffusion current flows through a P-N junction just after its formation due to (i) minority carriers (ii) majority carriers (iii) forward bias (iv) reverse bias

c)
A half-wave rectifier is equivalent to a (i) clipping circuit (ii) clamper circuit (iii) clamper circuit with negative bias (iv) clamper circuit with positive bias

d)
In an LC filter, the ripple factor (i) increases with load current (ii) increases with load resistance (iii) remains constant with load resistance (iv) decreases with load current

e)
If collector-base junction is reverse biased and the emitter-base junction is forward biased, the transistor operates at (i) saturation region (ii) cut-off region (iii) active region (iv) All of the above

f)
If the Q point of a transistor lies at ________, the positive part of input signal is clipped at output. (i) near saturation point (ii) near cut-off point (iii) middle of active region (iv) anywhere of the load line

g)
The input impedance of a JFET is in the range of (i) above $1\text{ M}\Omega$ (ii) $200\text{ k}\Omega$ (iii) $2\text{ k}\Omega$ (iv) $200\text{ }\Omega$

h)
The threshold voltage of an enhancement NMOS transistor is (i) less than zero volt (ii) equal to zero volt (iii) greater than zero volt (iv) None of the above

i)
Which topology of feedback amplifier has very high input and output impedances? (i) Voltage series feedback (ii) Voltage shunt feedback (iii) Current series feedback (iv) Current shunt feedback

j)
An ideal OP-AMP has (i) infinite input impedance (ii) zero output impedance (iii) infinite voltage gain (iv) All of the above

14 marks
Ask AI
Q2
Answer the following questions:

a)
Draw the energy-band diagram of an open-circuited P-N junction diode and derive the expression for contact difference potential across this open-circuited P-N junction diode.

9 marks
b)
At the room temperature of $300\text{ K}$ , the resistivities of the N-type region and P-type region of a germanium P-N junction are $6.5\text{ ohm-cm}$ and $4.5\text{ ohm-cm}$ respectively. Determine the contact potential and potential energy barrier at $300\text{ K}$ . Assume— $n_i = 2.5 \times 10^{13}\text{ /cm}^3$ , $\mu_n = 2000\text{ cm}^2\text{ /Vs}$ , $\mu_p = 900\text{ cm}^2\text{ /Vs}$ .

5 marks
14 marks
Ask AI
Q3
Answer the following questions:

a)
Explain how the process of avalanche breakdown occurs in P-N junction. How is it different from Zener breakdown?

7 marks
b)
Draw the circuit of a Zener diode shunt-regulated power supply. In this regulated power supply, required output voltage across load resistance $R_L$ is $10\text{ V}$ with load current $I_L = 50\text{ mA}$ . Input d.c. voltage varies from $20\text{ V}$ to $30\text{ V}$ . Determine the maximum and minimum Zener currents. [Consider $P_z(\text{max}) = 1000\text{ mW}$]

7 marks
14 marks
Ask AI
Q4
Answer the following questions:

a)
What is transformer utilization factor? Derive the transformer utilization factor of a half-wave rectifier circuit. Discuss the difference between the half-wave and full-wave rectifier circuits.

9 marks
b)
The turn ratio of the transformer used in single-phase full-wave rectifier circuit is $20:1$ . The primary of transformer is connected to $230\text{ V}$ and $50\text{ Hz}$ a.c. supply. Determine the peak inverse voltage of each diode and output frequency. Assume all diodes are ideal.

5 marks
14 marks
Ask AI
Q5
Answer the following questions:

a)
Draw the circuit diagram of an N-P-N junction transistor CE configuration and describe the static input and output characteristics. Also define active, saturation and cut-off regions and saturation resistance in CE configuration.

6 marks
b)
Derive the relation between $\alpha$ and $\beta$ of a BJT.

4 marks
c)
A BJT has a base current $I_B = 150\text{ }\mu\text{A}$ , $I_{CO} = 10\text{ }\mu\text{A}$ and $\alpha = 0.98$ . Calculate the collector current and emitter current.

4 marks
14 marks
Ask AI
Q6
Answer the following questions:

a)
What do you mean by biasing? Why is it required? Define stability factors for biasing. What are the factors on which stability of biasing depends?

8 marks
b)
The voltage divider bias circuit of N-P-N transistor is shown in figure below. Calculate the values of $R_1$ and $R_C$ when collector current is $1\text{ mA}$ and collector to emitter voltage is $2.6\text{ V}$ . Assume $V_{BE} = 0.65\text{ V}$ and $\beta = 100$ . [Diagram: Voltage divider bias with $V_{CC}=6\text{V}, R_1, R_2=10\text{k}\Omega, R_C, R_E=350\text{ }\Omega$]

6 marks
14 marks
Ask AI
Q7
Answer the following questions:

a)
Discuss the construction and working principle of an N-channel enhancement-type MOSFET with diagrams and draw the device characteristics.

8 marks
b)
In an N-channel JFET, $I_{DSS} = 12\text{ mA}$ and $V_P = -8\text{ V}$ and $g_{mo} = 4000\text{ }\mu\text{s}$ . Determine the drain current and transconductance at $V_{GS} = -5\text{ V}$ .

6 marks
14 marks
Ask AI
Q8
Answer the following questions:

a)
Draw the circuit diagram of a differentiator using OP-AMP and explain its operation. If a square-wave voltage signal is applied at the input of a differentiator, then draw its out in same timescale of input signal.

9 marks
b)
Draw the circuit diagram of an inverting summing amplifier using OP-AMP and determine the output voltage.

5 marks
14 marks
Ask AI
Q9
Write short notes on the following:

a)
Light-emitting diode

7 marks
b)
Silicon-controlled rectifier

7 marks
14 marks
Ask AI

2015041301

B.Tech 3rd Semester Exam., 2015

3 hours70 marks

Instructions

(i) The marks are indicated in the right-hand margin.
(ii) There are NINE questions in this paper.
(iii) Attempt FIVE questions in all.
(iv) Question No. 1 is compulsory.

Questions

Ask AI

Q1
Answer the following questions:

a)
Why is silicon preferred over germanium in making of semiconductor devices?

b)
What do you understand by transition capacitance of a diode?

c)
Why we cannot measure the barrier potential of a diode using voltmeter?

d)
Explain one disadvantage of bridge rectifier.

e)
Capacitor filter is not suited for heavy loads. Why?

14 marks
Ask AI
Q2
Answer the following questions:

a)
Derive and explain an intrinsic carrier concentration ($n_i$) of a semiconductor.

6 marks
b)
Explain the operation and characteristics of light emitting diode.

8 marks
14 marks
Ask AI
Q3
Answer the following questions:

a)
For the circuit shown in Figure 1, determine (i) d.c. output voltage (ii) rectification efficiency (iii) peak inverse voltage (iv) output frequency

8 marks
b)
Explain the operation of p-n silicon diode at equilibrium condition. Also derive the expression for the following: (i) Maximum electric field ($E_{max}$) (ii) Depletion width (W) (iii) Built-in potential ($V_{bi}$)

6 marks
14 marks
Ask AI
Q4
Answer the following questions:

a)
Accurately analyze the collector-to-base bias circuit is shown in Figure 2 to determine the $I_B$ , $I_C$ and $V_{CE}$ when (i) $\beta = 50$ and (ii) $\beta = 200$ . Assume $V_{BE} = 0.7$ V.

8 marks
b)
Sketch typical BJT common-emitter input and output characteristics. Explain the shapes of the characteristics.

6 marks
14 marks
Ask AI
Q5
Answer the following questions:

a)
Draw the two biasing circuits for JFET and explain.

8 marks
b)
Derive the gain expression of an integrator and a differentiator using op-amp.

6 marks
14 marks
Ask AI
Q6
Answer the following questions:

a)
Explain the basic operation and characteristics of n-channel depletion type MOSFET.

8 marks
b)
Sketch a $180^\circ$ phase control for an SCR. Draw the load waveform and explain the circuit operation.

6 marks
14 marks
Ask AI
Q7
Answer the following questions:

a)
Draw Sketches to show the basic construction and equivalent circuit of a unijunction transistor (UJT). Briefly explain the device operation.

8 marks
b)
Design a clamper to perform the function shown in the Figure 3 shown below.

6 marks
14 marks
Ask AI
Q8
Answer the following questions:

a)
Briefly explain the small signal model of JFET.

6 marks
b)
An integrator using op-amp has following component values: $R_i = 1\text{ k}\Omega, R_f = 100\text{ k}\Omega$ and $C_f = 0.1\text{ }\mu\text{F}$ . A $1\text{ kHz}$ square wave applied to integrator. The amplifier uses $\pm 15\text{ V}$ supply and output saturates at $\pm 14\text{ V}$ if input alternates between $\pm 5\text{ V}$ then: (i) Determine the maximum change in output (ii) Determine the maximum slew rate.

8 marks
14 marks
Ask AI
Q9
Answer the following questions:

a)
Define the gate power dissipation and explain its importance in SCR.

7 marks
b)
Explain the operation of centre tapped full wave rectifier. And calculate the rms load current and voltage for a sinusoidal input.

7 marks
14 marks
Ask AI

2015041401

B.Tech 4th Semester Exam., 2015

3 hours70 marks

Instructions

(i) The marks are indicated in the right-hand margin.
(ii) There are NINE questions in this paper.
(iii) Attempt FIVE questions in all.
(iv) Question No. 1 is compulsory.

Questions

Ask AI

Q1
Choose the correct option of any seven of the following:

a)
The mobility of an electron in a conductor is expressed in terms of

a)
$\text{cm}^2/\text{V-s}$

b)
$\text{cm}/\text{V-s}$

c)
$\text{cm}^2/\text{V}$

d)
$\text{cm}^2/\text{s}$

b)
Current flow in a semiconductor depends on the phenomenon of

a)
drift

b)
diffusion

c)
recombination

d)
All of the above

c)
A certain amount of --- still flows when diode is under reverse biased condition.

a)
reverse bias current

b)
reverse saturation current

c)
reverse diode current

d)
diode off current

d)
Bridge rectifiers are preferred because

a)
they require small transformer

b)
they have less PIV

c)
they need small transformer and also have less PIV

d)
they have low ripple factor

e)
Transistor is

a)
current-controlled current device

b)
current-controlled voltage device

c)
voltage-controlled current device

d)
voltage-controlled voltage device

f)
In a JFET, drain current is maximum when $V_{GS}$ is

a)
zero

b)
negative

c)
positive

d)
equal to $V_P$

g)
Input impedance of FET is

a)
low

b)
high

c)
medium

d)
None of the above

h)
Which of the following will not decrease as a result of introduction of feedback?

a)
Instability

b)
Bandwidth

c)
Overall gain

d)
Distortion

i)
In a common-emitter amplifier, the unbypassed emitter resistance provides

a)
voltage shunt feedback

b)
current series feedback

c)
positive voltage feedback

d)
positive current feedback

j)
LEDs are fabricated from

a)
silicon

b)
germanium

c)
silicon or germanium

d)
gallium arsenide

14 marks
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Q2
Answer the following questions:

a)
What is the concentration of holes in Si crystals having donor concentration of $1.4 \times 10^{24} / \text{ m}^3$ , when the intrinsic carrier concentration is $1.4 \times 10^{18} / \text{ m}^3$ ? Find the ratio of electrons to holes concentration.

6 marks
b)
Draw the V-I characteristic of Si and Ge diode on the same axis and explain.

8 marks
14 marks
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Q3
Answer the following questions:

a)
Explain the working of centre-tapped full-wave rectifier.

6 marks
b)
For the circuit of Fig. 1, determine the range of $R_L$ and $I_L$ that will result in $V_{R_L}$ being maintained at $10\text{ V}$ .

8 marks
14 marks
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Q4
Answer the following questions:

a)
Derive the relation between $\alpha$ and $\beta$ of BJT.

5 marks
b)
Describe the working of NPN transistor and explain the input and output characteristics of common-emitter amplifier.

9 marks
14 marks
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Q5
Answer the following questions:

a)
Find $I_C$ and $V_{CE}$ for the circuit shown in Fig. 2 for the BJT whose $\beta = 80$ .

6 marks
b)
Draw and explain potential divider biasing circuit.

8 marks
14 marks
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Q6
Answer the following questions:

a)
List the advantages and disadvantages of FET over BJT.

5 marks
b)
Explain the working of JFET along with its transfer and output characteristics.

9 marks
14 marks
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Q7
Answer the following questions:

a)
What are the advantages of negative feedback in amplifiers? Explain them.

6 marks
b)
Draw the circuit diagram of voltage series feedback amplifier and derive the expression for input and output impedances.

8 marks
14 marks
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Q8
Answer the following questions:

a)
Name six important parameters of an operational amplifier. What are their ideal values and practical values?

6 marks
b)
Describe the working of OPAMP as an integrator and an inverter.

8 marks
14 marks
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Q9
Write notes on the following:

a)
SCR

7 marks
b)
LED

7 marks
14 marks
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2013041301

B.Tech 3rd Semester Exam., 2013

3 hours70 marks

Instructions

The marks are indicated in the right-hand margin.
There are NINE questions in this paper.
Attempt FIVE questions in all.
Question No. 1 is compulsory.

Questions

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Q1
Choose the correct alternative of the following (any seven):

a)
When a step-input is given to an op-amp integrator, the output will be (i) a ramp (ii) a sinusoidal wave (iii) a rectangular wave (iv) a triangular wave with d.c. bias

b)
In a JFET, at pinch-off voltage applied on the gate (i) the drain current becomes almost zero (ii) the drain current begins to decrease (iii) the drain current is almost at saturation value (iv) the drain to source voltage is close to zero volt

c)
The value of ripple factor of a half-wave rectifier without filter is approximately (i) 1.2 (ii) 0.2 (iii) 2.2 (iv) 2.0

d)
In the voltage regulator shown in Fig. 1, if the current through the load decreases [Diagram: Zener voltage regulator with series resistor R1, Zener diode D, and load resistor RL] (i) the current through R1 will increase (ii) the current through R1 will decrease (iii) Zener diode current will increase (iv) Zener diode current will decrease

e)
The lowest output impedance is obtained in case of BJT amplifiers for (i) CB configuration (ii) CE configuration (iii) CC configuration (iv) CE with $R_E$ configuration

f)
What is the peak current through the resistor in the circuit shown in Fig. 2 assuming the diode to be ideal? [Diagram: AC source 12sin(omega t) in series with 1k ohm resistor, a diode, and a 4V battery opposing the source] (i) 4 mA (ii) 8 mA (iii) 12 mA (iv) 16 mA

14 marks
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Q2
Answer the following questions:

a)
Explain how the process of avalanche breakdown occurs in a P-N junction diode. How is it different from Zener breakdown?

b)
A silicon diode has a saturation current of $5\text{ }\mu\text{A}$ at room temperature of $300\text{ K}$ . Determine its value at $400\text{ K}$ .

14 marks
14 marks
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Q3
Answer the following questions:

a)
For the circuit shown in Fig. 3 below: [Diagram: Zener regulator with $R_s=20\text{ }\Omega, V_z=18\text{ V}, R_L=200\text{ }\Omega$ . Input $V_{in}$ can vary from $20\text{ V}$ to $30\text{ V}$] Find— (i) the minimum and maximum currents in Zener diode; (ii) the minimum and maximum power dissipated in the diode.

b)
Draw the voltage doubler circuit. Sketch input and output waveforms and explain the circuit operation.

14 marks
14 marks
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Q4
Answer the following questions:

a)
A simple full-wave bridge rectifier circuit has an input voltage of $240\text{ V}$ a.c. r.m.s. Assume the diodes to be ideal. Find the output d.c. current, d.c. voltage, r.m.s. values of output currents and voltages. Assume load resistance to be $10\text{ k}\Omega$ .

b)
Explain $\alpha$ and $\beta$ factors of transistors. Derive the expressions for them and state their meanings.

14 marks
14 marks
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Q5
Answer the following questions:

a)
In a self-biased CE amplifier, $R_C = 5\text{ k}\Omega, R_2 = 9\text{ k}\Omega, R_1 = 81\text{ k}\Omega, \beta = 50$ and $R_E = 810\text{ }\Omega$ . Compute the stability factor.

b)
What is operating point? Explain its physical significance with proper example.

14 marks
14 marks
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Q6
Answer the following questions:

a)
State the advantages of FET over BJT.

b)
Derive an expression for the gain of negative voltage feedback amplifier.

14 marks
14 marks
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Q7
Answer the following questions:

a)
What is clamping circuit? With neat diagram, explain different types of clampers.

b)
Sketch $V_{out}$ for the network shown in Fig. 4 below. [Diagram: Input square wave $\pm 20\text{V}$ applied to circuit with capacitor C, ideal diode D with $5\text{V}$ bias, and resistor R]

14 marks
14 marks
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Q8
Answer the following questions:

a)
Compute the voltage gain and power gain of the amplifier circuit shown in Fig. 5 below: [Diagram: Op-amp amplifier with $1\text{ M}\Omega$ feedback resistor and $1\text{ M}\Omega$ input resistor]

b)
Explain the turn-off mechanism of SCR.

14 marks
14 marks
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Q9
Write short notes on the following:

a)
UJT

b)
Pi filter

c)
Light-emitting diode (LED)

d)
Integrator

14 marks
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