Karnataka 2nd PUC Question Bank for Electronics

Government of Karnataka
Department of School Education
(Pre-University)

QUESTION BANK

Contents

Sl. Name of the Chapter Hours Marks Page
No.
no
1 Field Effect Transistor (FET) 04 04 2
2 Transistor Biasing 03 03 4
3 Transistor Amplifiers 14 12 6
4 Feedback in Amplifiers 06 06 11
5 Operational Amplifiers 15 13 14
6 Oscillators 08 07 20
7 Wireless Communications 04 04 24
8 Modulation and Demodulation 15 12 26
9 Power Electronics and its applications 08 06 31
10 Digital Electronics 18 18 34
11 Microcontroller 10 08 39
12 C - Programming 09 06 41
13 Modern Communication Systems 06 06 43
Total 120 105

1

Question Bank
E – Easy, A – Average, D - Difficult
Chapter 1
Field Effect Transistors (FET)
I Choose the correct answer (MCQ):
1. Name a unipolar device. (E)
(a) Diode (b) BJT (c) FET (d) TRIAC
(c) FET
2. Drain characteristics of JFET in Ohmic region is (E)
(a) nonlinear (b) linear (c) exponential (d) constant
(b) linear
3. Unit less parameter of JFET is (E)
(a) Drain resistance (b) Trans-conductance
(c) Amplification factor (d) None of these
(c) Amplification factor
4. The relation between µ, gm and rd in JFET is (D)
𝑔
(a) rd = µ × gm (b) gm = µ × rd (c) µ = gm × rd (d) µ = 𝑟𝑚
𝑑
(c) µ = gm × rd
5. The terminal which controls the flow of charge carriers in a JFET is (E)
(a) Source (b) Drain (c) Emitter (d) Gate
(d) Gate
6. An example for the voltage controlled device is (A)
(a) BJT (b) FET (c) SCR (d) TRIAC
(b) FET
7. FET is a (A)
(a) Current controlled device (b) Voltage controlled device
(c) Bipolar device (d) More noisy device
(b) Voltage controlled device
8. How many junctions are present in JFET? (A)
(a) one (b) two (c) three (d) four
(b) two
9. The number of terminals in FET is (E)
(a) one (b) two (c) three (d) four
(c) three
10. In JFET the ratio of drain to source voltage (VDS) to drain current (ID) for a constant value of
gate to source voltage (VGS) is known as (A)
(a) A.C drain resistance (b) D.C drain resistance
(c) trans-conductance (d) amplification factor
(b) D.C drain resistance
11. Identify the terminals of JFET (A)
(a) cathode, anode and grid (b) emitter, base and collector
(c) source, gate and drain (d) anode, cathode and emitter

2

(c) source, gate and drain
12. In P-channel JFET, the charge carriers are (A)
(a) electrons (b) holes (c) both electrons and holes (d) photon
(b) holes
13. In N-channel JFET, the charge carriers are (A)
(a) electrons (b) holes (c) both electrons and holes (d) none of these
(a) electrons
14. When VGS = 0, then the drain current ID is given by (D)
(a) ID = 0 (b) ID = IDSS (c) ID < IDSS (d) ID > IDSS
(b) ID = IDSS
15. If the reverse bias voltage on the gate of JFET is increased, the width of the conducting channel
(A)
(a) decreases (b) increases (c) remains same (d) none of these
(a) decreases

II Three mark questions (knowledge)
1. What are the functions of drain, source and gate of JFET? (E)
2. Briefly explain the construction of n-channel FET. (E)
3. Briefly explain the working of n-channel JFET with its relevant diagram. (D)
4. Explain the formation of depletion region in JFET due to VGS. (D)
5. What are FET characteristics? Define drain resistance. (E)
6. Draw the drain characteristics of an n-channel JFET and briefly explain the different regions of the
drain characteristics. (A)
7. Define FET parameters. (E)
8. Mention any three advantages of JFET over BJT. (A)
9. Derive the relation µ = rd x gm in JFET. (A)
*****

3

Chapter 2
Bipolar Junction Transistor (BJT) Biasing
Choose the correct answer (MCQ):
1. For faithful amplification the operating point is chosen at the (E)
(a) Centre of the active region (b) Cut off region
(c) Saturation region (d) Inversion region
(a) Centre of the active region
2. The transistor works as an amplifier when the operating lies in (E)
(a) center of active region (b) Cut off region
(c) Saturation region (d) Inversion region
(a) center of active region
3. The most commonly used biasing circuit for the stable operating point is (A)
(a) base bias (b) collector feedback bias
(c) voltage divider bias (d) emitter feedback bias
(c) voltage divider bias
4. The transistor biasing circuit which is independent of β is (A)
(a) base bias (b) collector feedback bias
(c) voltage divider bias (d) emitter feedback bias
(c) voltage divider bias
5. The self-destruction of a transistor due to increase in temperature and hence leakage current
is called (D)
(a) Stabilizer (b) Stabilization
(c) Thermal runaway (d) Stability factor
(c) Thermal runaway
6. Advantage of voltage divider bias is (A)
(a) Q point doesn’t shift (b) offer excellent stabilization
(b) β independent biasing circuit (d) all of these
(d) all of these
7. The operating point is also known as (E)
(a) cut-off point (b) quiescent point (c) saturation point (d) pinch-off point
(b) quiescent point
8. Leakage current depends on (D)
(a) temperature (b) reverse bias voltage
(c) both (a) and (b) (c) none of these
(c) both (a) and (b)
9. In which region does a transistor behaves as a closed switch? (E)
(a) active region (b) cut off region
(c) saturation region (d) inversion region
(c) saturation region
10. The stabilisation of operating point over temperature in voltage divider bias method is
provided by the resistor (A)
(a) 𝑅𝐸 (b) 𝑅𝐶 (c) 𝑅1 (d) 𝑅2
(a) 𝑹𝑬
4

11. ICEO is the flow of transistor leakage current from (E)
(a) collector to emitter with base open
(b) collector to emitter with base closed
(c) emitter to collector with base closed
(d) emitter to collector with base open
(a) collector to emitter with base open
12. The saturation point on the dc load line is (A)
𝑉
(a) 𝑉𝐶𝐸 = 0 , 𝐼𝐶 = 0 (b) 𝑉𝐶𝐸 = 0 , 𝐼𝐶 = 𝑅𝐶𝐶
𝐶
𝑉
(c) 𝑉𝐶𝐸 = 𝑉𝐶𝐶 , 𝐼𝐶 = 0 (d) 𝑉𝐶𝐸 = 𝑉𝐶𝐶 , 𝐼𝐶 = 𝑅𝐶𝐶
𝐶
𝑽𝑪𝑪
(b) 𝑽𝑪𝑬 = 𝟎 , 𝑰𝑪 = 𝑹
𝑪

13. The cut-off point on the dc load line is (A)
𝑉
(a) 𝑉𝐶𝐸 = 0 , 𝐼𝐶 = 0 (b) 𝑉𝐶𝐸 = 0 , 𝐼𝐶 = 𝑅𝐶𝐶
𝐶
𝑉𝐶𝐶
(c) 𝑉𝐶𝐸 = 𝑉𝐶𝐶 , 𝐼𝐶 = 0 (d) 𝑉𝐶𝐸 = 𝑉𝐶𝐶 , 𝐼𝐶 =
𝑅𝐶
(c) 𝑽𝑪𝑬 = 𝑽𝑪𝑪 , 𝑰𝑪 = 𝟎
14. Heat sink is made of (E)
(a) metal (b) plastic (c) wood (d) ceramic
(a) metal
II Two mark questions:
1. Write the expressions for the coordinates of Q point in voltage divider biasing circuit. (A)
2. What are the biasing conditions for a transistor to be used as an amplifier? (E)
3. Mention any two types of transistor biasing methods. (A)
4. Mention two leakage currents in a transistor. (E)
5. Mention the factors on which leakage current depends. (E)
6. What is the need for biasing a transistor? (D)
7. Define Q point. Mention its importance. (D)
8. Discuss about the selection of Q-point. (A)
9. Write the advantages of voltage divider bias circuit. (A)
10. What is thermal runaway? (E)
11. What is heat sink? Why it is used? (E)
12. Sketch the transistor output characteristics in CE mode. Indicate different regions of the
characteristics. (A)
13. Draw the biasing arrangement for npn transistor in CE configuration with two sources. (A)
14. Draw the DC load line on the output characteristics of a CE amplifier. (E)
15. Draw the circuit diagram of a voltage divider bias circuit. (E)
*****

5

Chapter 3
Transistor Amplifiers
I Choose the correct answer (MCQ):
1. An electronic circuit which increases the magnitude of the input signal is known as (E)
(a) rectifier (b) amplifier (c) clamper (d) clipper
(b) amplifier
2. For faithful amplification, transistor is operated in (E)
(a) Cut-off region (b) Saturation region
(c) Active region (d) Inverse region
(c) Active region
3. The phase difference between the input and output waveforms in CB amplifier is (A)
(a) 180⁰ (b) 90⁰ (c) 0⁰ (d) 2700
(c) 0⁰
4. The number of transistors used in two stage CE amplifier is (E)
(a) one (b) two (c) three (d) four
(b) two
5. The transistor amplifier which has current gain less than unity (A)
(a) CE amplifier (b) CB amplifier
(c) CC amplifier (d) Both (a) and (c)
(b) CB amplifier
6. Which transistor amplifier produces the phase difference of 180° between input and output
voltage? (E)
(a) CE amplifier (b) CB amplifier
(c) CC amplifier (d) Emitter follower
(a) CE amplifier
7. The unit of power gain is (D)
(a) volt (b) ampere (c) decibel (d) hertz
(c) decibel
8. Voltage gain in decibel is (D)
(a) 10 log10 Av (b) log10 Av (c) 20 log10 A𝑣 (d) 30 log10 𝑣
(c) 20 𝐥𝐨𝐠 𝟏𝟎 𝐀𝒗
9. Voltage gain of common collector amplifier is (D)
(a) 0 (b) ≅ 1 (c) ∞ (d) none of these
(b) ≅ 𝟏
10. If Am is the voltage gain of transistor amplifier at mid frequency band, then what will be the
voltage gain at cutoff frequencies? (D)
(a) Am/2 (b) Am/√2 (c) 2Am (d) √2Am
(b) Am/√2
11. Buffer amplifier is the alternative name of (A)
(a) CC-amplifier (b) CB-amplifier (c) CE-amplifier (d) inverting amplifier
(a) CC-amplifier
12. Small signal amplifiers are also called as (E)
(a) Voltage amplifiers (b) Power amplifiers
(c) Class B amplifier (d) Class C amplifier
6

(a) Voltage amplifiers
13. Power gain is the product of voltage gain and (E)
(a) current gain (b) resistance (c) frequency (d) impedance
(a) current gain
14. The difference between the two cut-off frequencies in an amplifier is known as (A)
(a) resonance (b) bandwidth (c) band factor (d) quality factor
(b) bandwidth
15. For drawing ac equivalent circuit of a transistor, reduce all the dc sources to zero and (D)
(a) short all the capacitors (b) open all the capacitors
(c) remove all capacitors (d) remove collector resistors
(a) short all the capacitors
16. The power amplifier through which current flows for only half cycle of input signal is (D)
(a) Class A (b) Class B (c) Class C (d) Class AB
(b) Class B
17. Conduction angle for class-B power amplifier is (D)
(a) 60° (b) 180° (c) 270° (d) 360°
(b) 180°
18. Identify the power amplifier in which conduction angle is 360°. (A)
(a) Class AB (b) Class A (c) Class B (d) Class C
(b) Class A
II Fill in the blanks:
1. The circuit which increases the strength of a weak signal is known as ____. (E)
amplifier
2. The process of increasing the magnitude of an input signal is called as _________(E)
amplification
3. Increase in the amplitude of signal without any change in its shape is called as ________(A)
faithful amplification
4. CB amplifier is suitable for _______ applications. (A)
high frequency
5. Current gain in CB amplifier is nearly ________. (E)
unity
6. Phase difference between input and output waveforms in CE amplifier is _________. (E)
180⁰
7. Voltage gain of CE amplifier is ________. (A)
high
8. CC amplifier has the highest ________ gain. (A)
current
9. The alternative name for CC-amplifier is _______. (E)
emitter follower or buffer amplifier
10. CC amplifier is used to match ________ (E)
impedance
11. Buffer has ________ voltage gain. (E)
unity

7

12. The amplifiers which raises the power level of the signal is called as __________. (A)
power amplifiers
13. CE amplifier has __________ power gain. (D)
highest
14. The need of cascading in amplifier system is to increase the __________ of the amplifier. (A)
gain
15. Small signal amplifiers are also called as __________ amplifiers. (E)
voltage
16. Large signal amplifiers are ______ amplifiers. (E)
power
17. The voltage gain over mid-frequency range in an RC coupled amplifier is _________. (D)
constant
III Five mark essay type questions
1. With a circuit diagram describe the working of a CB amplifier and draw its input and output
waveforms. (A)
2. Explain the working of CE amplifier with a circuit diagram using voltage divider bias and draw its
input and output waveforms. (A)
3. Explain the working of CC amplifier with a circuit diagram and draw its input and output
waveforms. (A)
4. Explain with the circuit diagram, the working of two stage Direct coupled CE amplifier. Draw the
frequency response curve. (D)
5. With a circuit diagram explain the working of two stage RC coupled CE amplifier. Draw its
frequency response curve. (D)

IV Five marks numerical:
1. Calculate the voltage gain, input
impedance and output impedance in
the circuit shown. Given β = 100,
VBE = 0.7 V and re’ =26mV/IE. (A)
(Ans: Av = 317, Zin(base) = 1.575 kΩ,
Zo = 5 kΩ)

8

2. For the CE amplifier circuit shown in the
circuit, find (a) DC voltage across 20 kΩ,
(b) IE, (c) re’ (d) Zin(base) (e) Zo.
Given β = 100, VBE = 0.7 V and
re’ = 26mV/IE. (D)
(Ans: V2 = 2V, IE = 1.3 mA, re’ = 20 Ω,
Zin(base) = 2 kΩ, Zo = 3.2 kΩ )

3. For the transistor CE amplifier given
calculate (a) Zo, (b) Zin(base) (c) Av (d)
Ai and (e) AP. Given β = 100,
VBE = 0.7 V and re’ =26mV/IE. (D)
(Ans: Zo = 5 kΩ, Zin (base) = 2 kΩ,
AV = 250, Ai = 100, AP = 25000)

4. In a CE amplifier circuit as shown in
the figure, Calculate (a) re’
(b) Zin (base) (c) Zo d) Ai and e) Av
[Given β = 100, VBE = 0.7] (D)
(Ans: re’ = 7.78 Ω,
Zin(base) = 778 Ω, Zo = 2 kΩ,
Ai = 100, AV = 257)

9

5. For the given CE amplifier circuit
using silicon transistor. Calculate
(i) V2 (Voltage drop across R2)
(ii) IE (iii) re’ (iv) AV (v) Ai
(Given re’ = 26mV/IE,
VBE = 0.7 V and β = 150) (A)
(Ans: V2 = 1.5 V, IE = 1.7 mA,
re’ = 15.29 , Av = 130, Ai = 150)

6. For the CE amplifier circuit given, R1 = 100 kΩ, R2 = 10 kΩ, Rc = 2.2 kΩ, RE = 220 Ω, VCC = 15 V, VBE
= 0.7 V, r’e = 26mV/IE and β = 100, IE = 3.01 mA. Calculate (a) re’ (b) Zo (c) Av (d) Zin(base). (A)
(Ans: re’ = 8.6 Ω, Zo = 2.2 kΩ, AV = 255.8, Zin(base) = 860 Ω)

*****

10

Chapter 4
Feedback in Amplifiers
Choose the correct answer (MCQ):
1. Negative feedback is also called (D)
(a) regenerative feedback (b) degenerative feedback
(c) direct feedback (d) forward feedback
(b) degenerative feedback
2. Aβ is called (A)
(a) feedback ratio (b) feedback factor
(c) feedback fraction (d) loop gain
(d) loop gain
3. Negative feedback is used in (E)
(a) amplifiers (b) oscillators (c) both (a) and (b) (d) neither (a) nor (b)
(a) amplifiers
4. The only advantage of positive feedback is (E)
(a) voltage gain increases (b) voltage gain decreases
(c) noise increases (d) distortion increases
(a) voltage gain increases
5. Disadvantage of negative feedback is (E)
(a) Decrease in gain (b) Increase in bandwidth
(c) Increase in the gain stability (d) Reduces noise
(a) Decrease in gain
6. In a voltage-series negative feedback, the closed loop gain of the amplifier is (D)
A A A A
(a) Af = (b) Af = (c) Af = (d) A f =
1−Aβ 1+Aβ Aβ 1−β
𝑨
(𝒃) 𝑨𝒇 =
𝟏 + 𝑨𝜷
7. The gain of an amplifier without any feedback is known as (E)
(a) open-loop gain (b) feedback gain
(c) loop-gain (d) closed-loop gain
(a) open-loop gain
8. The gain of the amplifier with feedback is known as (E)
(a) open-loop gain (b) loop gain
(c) feedback ratio (d) closed-loop gain
(d) closed-loop gain
9. What happens to the input impedance of an amplifier when voltage series negative feedback
is applied? (A)
(a) Remains same (b) Increases (c) Decreases (d) Oscillates
(b) Increases
10. What happens to the voltage gain of an amplifier when voltage series negative feedback is
applied? (A)
(a) Remains same (b) Increases (c) Decreases (d) Oscillates
(c) Decreases
11

11. What happens to the output impedance of an amplifier when voltage series negative
feedback is applied? (A)
(a) Remains same (b) Increases (c) Decreases (d) Oscillates
(c) Decreases
12. Which type of feedback connection increases input impedance? (D)
(a) Series (b) Shunt (c) Both (a) and (b) (d) none of these
(a) Series
13. The negative feedback amplifier which has both input impedance and output impedance low
is (D)
(a) voltage-series (b) current-series (c) voltage-shunt (d) current-shunt
(c) voltage-shunt
14. What happens to the bandwidth of an amplifier when negative feedback is applied? (A)
(a) Remains same (b) Increases (c) Decreases (d) Oscillates
(b) Increases

Three Marks questions:
1. Write the advantages of negative feedback amplifier. (E)
2. Give any three differences between positive feedback and negative feedback. (E)
3. Define the terms open loop gain, closed loop gain and feedback fraction. (E)
4. Mention the types of negative feedback connection in amplifiers. (A)
5. Compare input and output impedance characteristics of four types of feedback connections. (D)
6. Derive an expression for voltage gain of voltage series negative feedback connection. (A)
7. Derive an expression for input impedance of voltage series negative feedback connection. (A)
8. Derive an expression for output impedance of voltage series negative feedback connection. (D)
9. Draw the frequency response curve of an amplifier with and without feedback. Write the
expression for the bandwidth of an amplifier with negative feedback. (D)
Two marks numerical:
1. Calculate the gain of a negative feedback amplifier with an open loop gain A = 250 and feedback
factor β = 0.1. (E) (Ans: 9.65)
2. In a negative feedback amplifier if A = 1000 and β = 0.04, find the gain with feedback. (E)
(Ans: 24.39)
3. An amplifier of gain 500 reduces to 50 after negative feedback. Calculate the feedback fraction.
(A) (Ans: 0.018 or 1.8%)
4. In a negative feedback amplifier Vs = 20 mV, Vi = 15 mV, Vf = 5 mV and Vo = 800 mV. Determine
A, Af and β. (D) (Ans: A = 53.33, Af = 40, β = 0.0625)
5. If an amplifier has a bandwidth of 500 Hz and voltage gain of 100. What will be the new bandwidth
if 6% negative feedback is introduced? (E) (Ans: 3500 kHz)
6. In an amplifier upper cut-off frequency is 1000 kHz and open loop gain is 100. Determine upper
cut-off frequency when 2% negative feedback is introduced. (D) (Ans: 3000 kHz)
7. In an amplifier lower cut-off frequency is 500 Hz and open loop gain is 100. Determine lower cut-
off frequency when 5% negative feedback is introduced. (D) (Ans = 83.3 Hz)

12

8. An amplifier with Zi =1 kΩ has a voltage gain A = 1000. If a negative feedback of β = 0.01 is applied.
Calculate the input impedance of the negative feedback amplifier. (E) (Ans: 11 kΩ)
9. An amplifier with ZO =10 kΩ has a voltage gain A = 500. If a negative feedback of β = 0.01 is applied.
Calculate the output impedance of the negative feedback amplifier. (A) (Ans: 1.66 kΩ)
10. An amplifier has a bandwidth of 220 kHz and voltage gain of 100. Calculate the gain and
bandwidth if β = 0.1 negative feedback is introduced. (D) (Ans: 9.09, 2.42 MHz)
11. An amplifier has an output impedance of 3 kΩ without feedback and 300 Ω with feedback. If the
open loop gain is 180 find the feedback factor. (D) (Ans: 0.05 or 5%)
12. The loop gain Aβ of a negative feedback amplifier is 20. If BW = 10 kHz find the bandwidth of an
amplifier with feedback (BWf). (E) (Ans: 210 kHz)
*****

13

Chapter 5
Operational Amplifier
Choose the correct answer (MCQ):

1. Number of op-amp present in IC 741 (E)
(a) 1 (b) 2 (c) 3 (d) 4
(a) 1
2. Input stage of op-amp consists of (A)
(a) darlington pair (b) Inverting amplifier
(c) differential amplifier (d) emitter follower
(c) differential amplifier
3. Input impedance of ideal op-amp is (E)
(a) few ohm (b) 0 Ω (c) ∞ Ω (d) 10 MΩ
(c) ∞ Ω
4. An ideal op-amp has (E)
(a) Zo = ∞ (b) BW = 0 (c) Zi = ∞ (d) Av = 0
(c) Zi = ∞
5. An ideal op-amp has (A)
(a) Zi = ∞ (b) Zo = 0 (c) BW = ∞ (d) all of these
(d) all of these
6. Output impedance of an ideal Op-Amp is (E)
(a) 0 Ω (b) 100 Ω (c) 1000 Ω (d) ∞ Ω
(a) 0 Ω
7. An op-amp circuit in which the output signal is in-phase with the input signal is known as (E)
(a) non-inverting amplifier (b) inverting amplifier
(c) integrator (d) differentiator
(a) non-inverting amplifier
8. A special case of non inverting amplifier in which Vo = Vi. (A)
(a) Buffer (b) Integrator
(c) Differentiator (d) Logarithmic amplifier
(a) Buffer
9. The voltage gain of an op-amp buffer amplifier is (E)
(a) Zero (b) Unity (c) Infinity (d) 103
(b) Unity
10. By virtual ground concept, voltage at inverting terminal VA is related to voltage at non
inverting terminal VB by the relation (D)
(a) VA ≠ VB (b) VA = VB (c) VA > VB (d) VA < VB
(b) VA = VB
11. Phase difference between the input and output of op-amp inverting amplifier is (A)
(a) 00 (b) 900 (c) 1800 (d) 2700
(c) 1800
12. The rate of change of output voltage in op-amp is known as (A)
(a) CMRR (b) Input impedance (c) Slew rate (d) Bandwidth
(c) Slew rate
14

13. Slew rate is expressed in (A)
(a) V/µS (b) µS /V (c) A/mS (d) Ω/µS
(a) V/µS
14. The voltage gain of an op amp buffer amplifier is (E)
(a) infinity (b) zero (c) unity (d) ∞
(c) unity
15. The ratio of differential mode gain to common mode gain is called as (A)
(a) CMRR (b) Slew rate (c ) offset voltage (d) open loop gain
(a) CMRR
16. The open-loop gain value of an ideal op-amp is (A)
(a) 0 (b) 1 (c) ∞ (d) none of these
(c) ∞
17. The feedback component of op-amp differentiator is (E)
(a) Resistor (b) Capacitor (c) Inductor (d) Diode
(a) Resistor
18. The feedback component used in the op-amp integrator is (E)
(a) Resistor (b) Capacitor (c) Inductor (d) Diode
(b) Capacitor
19. The output of differentiator circuit when input is sine wave (A)
(a) Cosine wave (b) Sine wave (c) Square wave (d) Triangular wave
(a) Cosine wave
20. What is the output of op-amp integrator circuit if sine wave is given to its input? (A)
(a) Sine wave (b) Square wave (c) Cosine wave (d) Triangular wave
(c) Cosine wave
21. An Op-amp integrator converts square wave into (D)
(a) Triangular wave (b) Sine wave (c) Cosine wave (d) Sawtooth wave
(a) Triangular wave
22. Zero crossing detector is an application of (A)
(a) Subtractor (b) Adder (c) Comparator (d) Inverting amplifier
(c) Comparator
23. The active component used in op-amp filter circuit is (E)
(a) Resistor (b) Op-amp (c) Capacitor (d) Inductor
(b) Op-amp
24. An active low pass filter circuit which uses only one RC-section is called as (D)
(a) first order low pass active filter (b) zero order low pass active filter
(c) third order low pass active filter (d) second order low pass filter
(a) first order low pass active filter

Fill in the blanks:
1. A differential amplifier amplifies the _________ between two input signals. (E)
difference
2. IC 741 is a _______ op-amp. (E)
mono
3. Op-amp buffer is used for __________ matching. (E)
impedance
15

4. The rate of change of output voltage is known as _______. (A)
slew rate
5. The CMRR value of an ideal op-amp is ________. (A)
infinity (∞)
6. The output impedance of an ideal op-amp is ________. (E)
zero (0)
7. Op-amp buffer has ________ voltage gain. (E)
unity
8. Inverting amplifier circuit is _______ application of Op-Amp. (E)
linear
9. Op-amp inverting adder is also called as ________ amplifier.
summing
10. Op-amp in an open-loop configuration can be used as a _________. (A)
comparator
11. comparator is the example for the _______application of op-amp. (A)
nonlinear
12. An op-amp differentiator converts sine wave into __________ wave. (A)
cosine
13. The feedback element in an op-amp differentiator is ________. (E)
resistor
14. A zero crossing detector circuit switches its output state every time input crosses _______
level. (E)
zero
15. Zero crossing detector is an application of ________. (E)
comparator
16. An op-amp integrator converts square waves into __________ wave. (D)
triangular
Five marks essay type questions:
1. What is non inverting op-amp? Derive an expression for output voltage of op-amp non inverting
amplifier. (A)
2. What is inverting op-amp? Derive an expression for output voltage and voltage gain of inverting
op-amp. (A)
3. What is an op-amp summing amplifier? Derive an expression for its output voltage. (D)
4. What is an op-amp subtractor? Derive an expression for the output of op-amp subtractor circuit.
(D)
5. What is an op-amp differentiator? Derive an expression for the output of op-amp differentiator
circuit. (D)
6. What is an op-amp integrator? Obtain an expression for the output of op-amp integrator. (D)
Two/three (five) marks numerical:
1. Calculate the output voltage of an inverting amplifier using an input resistance of 2.2 kΩ and
Rf = 6.8 kΩ when the input voltage is 200 mV. (E) (Ans: -618 mV)
2. Calculate the AV of an inverting op-amp, if Rf =18 kΩ and Ri = 12 kΩ.(E) (Ans: -1.5)

16

3. Calculate the output voltage of a non-inverting amplifier using an input resistance of 1.2 kΩ and
Rf =1.8 kΩ when the input voltage is 50 mV. (E) (Ans: 125 mV)
4. The input signals to an adder circuit are 6 mV, -3 mV and 9 mV through resistors of 1.2 kΩ, 1.5 kΩ
and 1.8 kΩ respectively. Find the output voltage if the feedback resistance is 10 kΩ. (D)
(Ans: -80 mV)
5. Design an op-amp adder, if the output voltage Vo = – (0.1 V1 + 0.4 V2 + 0. 02 V3). Assume
Rf = 22 kΩ. (D) (Ans: 220 kΩ, 55 kΩ, 1.1 MΩ)
6. Design an op-amp circuit to realize the output, Vo = - (3V1 + 2V2 + V3). Assume RF = 10 kΩ. Determine
output voltage when V1 = 1 V, V2 = - 2 V and V3 = 2 V. (D)
(Ans: R1 = 3.33 kΩ, R2 = 5 kΩ, R1 = 10 kΩ, Vo = -1V)
7. Find the output voltage for the op-amp circuits given below. (A)

(Ans: Vo1 = 5V and Vo2 = -6V)
8. Calculate the output voltages of Op-amp circuits shown below. Given Vin = 10 mV, V1 = 20 mV
and V2 = 30 mV. (A)

(Ans: Vo1 = 30 mV and Vo2 = -400 mV)
9. Find the output voltages for the op-amp circuits given below. (A)

17

(Ans: Vo1 = -5 V and Vo2 = -3 V)
10. Calculate the output voltages in the given op-amp circuits (A)

(Ans: Vo1 = -9 V and Vo2 = -6 V)
11. Calculate the output voltages in the given op-amp circuits (A)

(Ans: Vo1 = 6 V and Vo2 = -7 V)

12. Calculate output voltages for the op-amp circuits shown below. Given Vi1 = 1 V, Vi2 = 2 V. (E)

(Ans: Vo1 = -2.12 V and Vo2 = 6.87 V)
18

13. Find the output voltage for the op-amp circuits given below. (A)

(Ans: Vo1 = -9.9 V and Vo2 = 5 V)
14. Calculate the output voltage for the circuit shown. (D)

(Ans: 51.99 mV)

15. Calculate the output voltage for the circuit shown. Given V1 = - 2mV, V2 = 4 mV V3 = 8 mV. (A)

(Ans: -10mV)
16. Calculate the cut-off frequency of a first-order low-pass filter for R = 1.2 kΩ and C = 0.047 µF. (E)
(Ans: 2.823 kHz)
17. Calculate the resistance of resistor of a first-order low-pass filter for f = 1.5 kHz and C = 0.022 µF.
(A) (Ans: 4.825 kΩ)
18. Calculate the capacitance of capacitor of a first-order low-pass filter for f = 1.59 kHz and
R = 10 kΩ. (A) (Ans: 10.01 nF)
19. Calculate the cut-off frequency of a first-order high-pass filter for R = 1.2 kΩ and C = 0.01µF. (E)
(Ans: 13.26 kHz)
20. Calculate the resistance of resistor of a first-order high-pass filter for f = 10 kHz and C = 0.022 µF.
(A) (Ans: 723.79 Ω)
21. Calculate the capacitance of capacitor of a first-order high-pass filter for f = 15.9 kHz and R = 10
kΩ. (A) (Ans: 1 nF)
*****

19

Chapter 6
Oscillators
Choose the correct answer (MCQ):

1. An oscillator converts (E)
(a) AC to DC power (b) DC to AC power
(C) DC to DC power (d) none of these
(b) DC to AC power
2. Condition for sustained oscillations is (E)
(a) |Aβ| = 0 (b) |Aβ| = 1 (c) |Aβ| > 1 (d) |Aβ| < 1
(b) |Aβ| = 1
3. A parallel combination of L and C that produces electrical oscillations of any desired frequency is
known as an (A)
(a) tank circuit (b) doubler circuit (c) logic gate (d) clamper circuit
(a) tank circuit
4. Name the oscillator which does not produce phase shift in feedback path (A)
(a) Phase shift oscillator (b) Wein bridge oscillator
(c) Crystal oscillator (d) Hartley oscillator
(b) Wein bridge oscillator
5. Wein bridge oscillator is an example for (E)
(a) LC Oscillator (b) RC Oscillator (c) Crystal Oscillator (d) none of these
(b) RC Oscillator
6. In RC phase shift oscillator three RC sections are used to produce a phase-shift of (E)
(a) 300 (b)1800 (c) 100 (d) 900
0
(b) 180
7. How many RC sections are present in a Phase shift oscillator? (E)
(a) One (b) Two (c) Three (d) Four
(c) Three
8. The most commonly used piezoelectric crystal is (D)
(a) Quartz crystal (b) magnetic crystal
(c) electric crystals (d) tourmaline crystal
(a) Quartz crystal
9. The crystal oscillator works on the principle of (E)
(a) Piezomagnetic effect (b) Piezoelectric effect
(c) Piezostatic effect (d) Piezodynamic effect
(b) Piezoelectric effect
10. The oscillator suitable for generating high frequency signal is (A)
(a) LC oscillators (b) RC oscillators (c) β-oscillator (d) α-oscillator
(a) LC oscillators

20

11. Both positive and negative feedback is employed in (D)
(a) Wein- bridge oscillator (b) RC phase-shift oscillator
(c) Crystal oscillator (d) Collpitt’s oscillator
(a) Wein-bridge oscillator
12. In a Wein bridge oscillator voltage gain of its internal amplifier is (A)
(a) 29 (b) 3 (c) 0 (d) 2
(b) 3
13. Mention the high frequency stability oscillator (A)
(a) Crystal oscillator (b) Hartley oscillator
(c) Wein bridge oscillator (d) Colpitts oscillator
(a) Crystal oscillator
14. In a crystal oscillator, the frequency determining element is (E)
(a) resistor (b) capacitor (c) inductor (d) crystal
(d) crystal
15. The major drawback of LC and RC oscillators is (D)
(a) poor frequency stability (b) good frequency stability
(c) excellent frequency stability (d) none of these
(a) poor frequency stability
Fill in thes blanks:
1. Positive feedback is used in _______(E)
oscillator
2. In an oscillator circuit the feedback signal is in _______ with the input signal. (A)
phase
3. A circuit which generates ac signal without any externally applied input signal is called as an
________ (A)
oscillator
4. An electrical oscillations whose amplitude decreases with time are known as _______
oscillations. (E)
damped
5. The condition A = 1 and overall phase shift to be 00 or 3600 in oscillators is known as
________(E)
Barkhausen criterion
6. Tank circuit produces ________ oscillations (E)
damped
7. LC oscillators are used to produce high _______. (A)
frequencies
8. Hartley oscillator uses ________ feedback. (D)
inductive
9. Colpitts oscillator uses ________ feedback. (D)
capacitive
10. In a RC phase shift oscillator, each RC section provides a phase shift of _______. (A)
600

21

11. Phase shift produced by bridge network in Wein bridge oscillator is _____(A)
𝟎𝟎
12. The oscillator which works on the principle of piezo- electric effect is ____(A)
crystal oscillator

Three mark questions:

1. Explain briefly how the oscillations are produced in a LC tank circuit. (D)
2. What is an oscillator? Mention Barkhausen criterion. (A)
3. Sketch nature of oscillator output waveforms for (a) Aβ > 1, (b) Aβ < 1 and (c) Aβ = 1. (E)
4. Draw the circuit diagram of a Hartley oscillator. Mention the expression for its frequency of
oscillations and feedback ratio β. (E)
5. Draw the circuit diagram of a Colpitts oscillator. Mention the expression for its frequency of
oscillations. (A)
6. Draw the circuit diagram of a RC phase shift oscillator. Write the expression for its frequency of
oscillations. (E)
7. Draw the circuit diagram of a Wein bridge oscillator. Write the expression for its frequency of
oscillations. (A)
8. Compare RC and LC oscillators.
9. What is piezoelectric effect? Draw the circuit diagram of crystal oscillator. (A)
10. Draw the circuit diagram of crystal oscillator. Draw the electrical equivalent circuit of a crystal.
(D)

Two mark numerical:
1. Determine frequency of the tank circuit. Given L = 10 mH and C = 1 µF. (E) (1.59 kHz)
2. A transistor Colpitts oscillator has L = 4 mH, C 1 = 10 nF and C2 = 10 nF. Determine the frequency
of oscillations. (D) (Ans: 35.6 kHz)
3. Determine the frequency of oscillation in a transistor Colpitt’s oscillator. Given L = 10 mH, C eq =
50 𝑛F. (A) (Ans: 7.12 kHz)
4. A Colpitts oscillator circuit is to generate a frequency of 24 kHz. The capacitors used are C 1 = 0.2
µF and C2 = 0.22 µF. Find the value of an inductor used. (Ans: 0.42 mH)
5. Calculate the frequency of oscillations and feedback ratio in a Colpitts oscillator circuit containing
the tank circuit with L = 10 µH, C1 = 0.22 µF and C2 = 0.47µF. (D) (Ans: 130 kHz, 0.46)
6. A Hartley oscillator has L1 = 3 mH, L2 = 5 mH and C = 10 nF. Calculate the frequency of oscillations.
(E) (Ans: 17.8 kHz)
7. A Hartley oscillator having Leq = 1 µH and C = 5 pF. Determine frequency of oscillations. (A)
(Ans: 71.16 MHz)
8. A Hartley oscillator circuit is to generate a frequency of 1200 kHz. If the capacitor in the feedback
network has a value of 220 pF and one of the inductors value is 20 µH, calculate the value of the
other inductor. (D) (Ans: 60.03 µH)
9. Calculate the frequency and feedback ratio of the circuit shown below. (A)
22

(Ans: 79.56 kHz, 0.33)

10. A RC phase shift oscillator uses three identical RC sections in the feedback network. The values of
the components are R = 680 Ω and C = 220 nF. Determine the frequency of oscillation. (A)
(Ans: 434.5 Hz)
11. A RC phase shift oscillator has R1 = R2 = R3 = R = 10 kΩ and C1 = C2 = C3 = C = 0.047 µF. Determine
frequency of oscillations. (E) (Ans: 138.3 Hz)
12. What should be the value of identical capacitors required for a phase shift oscillator to produce a
frequency of 338 Hz, if the identical resistances used is 220 Ω? (Ans: 0.874 µF)
13. The frequency of the phase shift oscillator is 125 Hz. If the value of capacitances C 1 = C2 = C3 =
0.22 µF, calculate the value of R1 = R2 = R3 = R. (E) (Ans: 2.36 kΩ)
14. The frequency of the Wien bridge oscillator is 1.2 kHz. If the resistances R 1 = R2 = R = 820 Ω,
calculate the value of capacitances C1 = C2 = C. (E) (Ans: 0.161 µF)
15. The RC network of Wien bridge oscillator consists of resistors and capacitors of values R 1 = R2 = R
= 270 kΩ and C1 = C2 = C = 470 pF. Determine the frequency of oscillations. (A) (Ans: 1.25 kHz)
16. The frequency of the Wien bridge oscillator is 1.5 kHz. If the capacitance value used is C1 = C2 = C =
0.1 µF, calculate the value of resistance R1 = R2 = R to be used. (A) (Ans: 1.06 kΩ)

*****

23

Chapter 7
Wireless Communications
Choose the correct answer (MCQ):
1. The velocity of an EM wave is (E)
(a) 3 ×106 m/s (b) 3 ×107 m/s (c) 3 ×108 m/s (d) 3 ×109 m/s
(c) 3 ×108 m/s
2. The shortest distance measured between the transmitting antenna and the first receiving
antenna along the earth’s surface after ionospheric propagation is called (A)
(a) skip zone (b) Skip distance (c) radio horizon (d) optical horizon
(b) Skip distance
3. The region on the earth where neither ground wave nor sky wave is present is termed as (E)
(a) skip zone (b) Skip distance (c) radio horizon (d) optical horizon
(a) skip zone
4. Identify the layers of Ionosphere. (E)
(a) D layer (b) E layer (c) F layer (d) All of these
(d) All of these
5. Ground waves are also called (A)
(a) Surface waves (b) space waves
(c) Sky waves (d) Line of sight waves
(a) Surface waves
6. The layer of atmosphere which is responsible for sky wave propagation is (E)
(a) Troposphere (b) Stratosphere (c) Mesosphere (d) Ionosphere
(d) Ionosphere
7. Line of sight waves are also called (A)
(a) Space waves (b) Ground waves (c) Sky waves (d) None of these
(a) Space waves
8. The nearest ionospheric layer to the earth surface during day time is (A)
(a) D layer (b) E layer (c) F1 layer (d) F2 layer
(a) D layer
9. The medium through which the information flows is known as (E)
(a) Source (b) Transmitter (c) Channel (d) Receiver
(c) Channel
10. The Ionosphere layers that is present during both day and night time are (D)
(a) D, E and F (b) D and E (c) only F (d) only D
(c) only F
11. Which layer of the Ionosphere is called Kennelly-Heaviside layer (D)
(a) D layer (b) E layer (c) F1 layer (d) F2 layer
(b) E layer
12. Which layer of the Ionosphere is called Appleton-Barnett layer (D)
(a) D layer (b) E layer (c) F layer (d) none of these
(c) F layer
13. The maximum distance up to which a space wave can reach is called as (D)
(a) skip zone (b) Skip distance (c) radio horizon (d) optical horizon
(c) radio horizon
24

Three mark questions
1. Draw the block diagram of a communication system and explain the function of each block. (D)
2. Define Critical angle, Critical frequency and Skip distance. (E)
3. Define critical frequency, skip zone and noise signal in wireless communication system. (E)
4. Write a short note on ionosphere. (A)
5. Write a note on D layer, E layer and F layer.(A)
6. What are the different types of wave transmission? (E)
7. What is Line of Sight? Differentiate between radio horizon and optical horizon.
(D)
*****

25

Chapter 8
Modulation and Demodulation
Choose the correct answer (MCQ):

1. How many side bands are present in AM? (E)
(a) 1 (b) 2 (c) 3 (d) ∞
(b) 2
2. The maximum transmission efficiency in AM wave is (E)
(a) 25% (b) 33.33% (c) 66.66% (d) 100%
(b) 33.33 %
3. The intermediate frequency in super heterodyne AM radio receiver is (A)
(a) 455 Hz (b) 455 kHz (c) 455 MHz (d) 455 GHz
(b) 455 kHz
4. If the amplitude of the modulating signal is half of the carrier signal, then the modulation
index 𝑚𝑎 is (A)
(a) 0 (b) 0.5 (c) 1 (d) 1.5
(b) 0.5
5. AM wave is distorted when (D)
(a) 𝑚𝑎 = 0 (b) 𝑚𝑎 = 0.5 (c) 𝑚𝑎 = 1.0 (d) 𝑚𝑎 = 1.5
(d) 𝑚𝑎 = 1.5
6. In AM wave, Vmax = 10 V and Vmin = 5 V. Modulation index ma is (A)
(a) 1/3 (b) 2/3 (c) 1/2 (d) 1
(a) 1/3
7. The abbreviation of AGC in radio receiver stands for (A)
(a) Audio Gain Control (b) Abrupt Gain Control
(c) Alternate Gain Control (d) Automatic Gain Control
(d) Automatic Gain Control
8. The permissible modulation index value to obtain maximum power without distortion in an
AM transmitter is (A)
(a) 𝑚𝑎 > 1 (b) 𝑚𝑎 < 1 (c) 𝑚𝑎 = 1 (d) 𝑚𝑎 = 0
(c) 𝑚𝑎 = 1
9. The signal obtained after modulation is called (E)
(a) modulated signal (b) modulating signal
(c) carrier signal (d) none of these
(a) modulated signal
10. Amplitude modulated signal contains (E)
(a) 5 frequency components (b) 2 frequency components
(c) 3 frequency components (d) none of these
(c) 3 frequency components
11. In amplitude modulation, if the modulation index is more than 100% then the output signal
is (D)
(a) undistorted (b) distorted (c) contains no noise (d) none of these
(b) distorted
12. In AM wave, useful power is carried by (A)
(a) sidebands (b) carrier signal (c) guard bands (d) none of these
26

(a) side bands
13. Modulation is done in (E)
(a) radio transmitter (b) radio receiver (c) loud speaker (d) none of these
(a) radio transmitter
14. In a receiver, the ratio of the signal power to the noise power at its output is termed as (A)
(a) signal-to-noise ratio (SNR) (b) resistivity (c) viscosity (d) none of these
(a) signal-to-noise ratio (SNR)
15. Modulation index in FM is denoted by (E)
(a) ma (b) mb (c) mp (d) mf
(d) mf
16. The expression for carrier swing (CS) in FM is (E)
(a) 2∆F (b) ∆F (c) 3∆F (d) 4∆F
(a) 2∆F
17. In frequency modulation, the ratio of the frequency deviation to the frequency of the
modulating signal is termed as (A)
(a) modulation index (b) resolution index
(c) matching index (d) none of these
(a) modulation index
18. The device used for detection (demodulation) is called (A)
(a) detector or demodulator (b) inverter
(c) chopper (d) none of these
(a) detector or demodulator
19. The ability of a receiver to pick up weak signals, and amplify it is termed as (D)
(a) sensitivity (b) resistivity (c) selectivity (d) none of these
(a) sensitivity
20. The minimum length of an antenna for effective communication of RF signals should be (E)
1 1
(a) of wavelength (b) of wavelength
4 2
3 1
(c) 4 of wavelength (d) 8 of wavelength
1
(a) 4 of wavelength

Fill in the blanks:
1. The process of changing some characteristics of carrier signal in accordance with
instantaneous value of the modulating signal is called ________. (E)
modulation
2. In AM, the ratio of amplitude of modulating signal to the amplitude of carrier wave is
called________ (E)
modulation index
3. In amplitude modulation, bandwidth is________ the modulating signal frequency. (A)
twice
4. The ratio of frequency deviation to modulating signal frequency in FM is _______. (A)
modulation index
5. Diode detector is also called as ________ (E)
demodulator
27

6. The process of recovering signal from modulated carrier wave is _____.(A)
demodulation
7. In frequency modulation __________ of the carrier wave remains same. (A)
amplitude
8. Carrier swing is _____________ the frequency deviation in FM. (E)
twice
9. Demodulation is done in _________(A)
radio receiver
10. Modulation in which only the amplitude of carrier wave is varied in accordance with the
instantaneous value of modulating wave is called as ________ modulation. (E)
amplitude
11. Modulation in which only the frequency of carrier wave is varied in accordance with the
instantaneous value of modulating wave is called as _________modulation. (E)
frequency
12. __________ is a measure of ability of a radio receiver to deliver a constant output for a given
period of time. (D)
Stability
13. In AM, when modulation is more than 100%, it is called as _________. (D)
over modulation
14. The ability of a receiver to select a desired station signal and reject all unwanted station
signals is termed as _________. (A)
selectivity
15. In SHD radio receiver, all the incoming frequencies are converted into __________
frequency. (D)
intermediate
Two Mark questions:
1. Mention the different types of modulation. (E)
2. Define Modulation index of an AM wave. Mention sidebands frequencies of AM. (E)
3. Write the expressions for amplitude and frequency of LSB in AM. (E)
4. What is over modulation and why is it not preferred in AM? (A)
5. Mention frequencies and their amplitudes of sidebands. (E)
6. Name the frequency components present in an AM wave? Which component carries
information? (D)
7. Write the expression for instantaneous value of amplitude modulated wave. Write the
expression for ma in terms of Vmax and Vmin. (A)
8. Write the expression for PT in terms of PC. What is the upper limit of ma in AM? (D)
9. Define frequency modulation. Write an expression for instantaneous voltage of FM wave. (E)
10. What is carrier swing? Write an expression for carrier swing of FM. (E)
11. Write the circuit diagram of diode detector. (A)
12. What are the advantages of super heterodyne receiver? (E)
13. What do you mean by AGC? Why is it necessary for a receiver? (A)
14. Mention any two limitations of AM. (E)

28

15. Represent the principle of amplitude modulation using diagrams. (E)
16. Draw the block diagram of AM transmitter. (D)
Three Mark questions:
1. Briefly explain the need for modulation. (E)
2. Discuss the need for modulation with reference to length of the antenna. (A)
3. Sketch modulating signal, carrier and AM wave. (E)
4. Draw the frequency spectrum of an AM wave. (E)
5. Sketch the waveforms of AM wave for ma = 0.5, ma = 1 and ma = 1.5. (A)
6. What are the characteristics of a good radio receiver? (A)
7. Define Sensitivity, Selectivity, Fidelity characteristics of a radio receiver. (E)
8. Derive an expression for modulation index of an AM wave in terms of Vmax and Vmin. (D)
9. Derive an expression for the total power of AM wave in terms of P C. (A)
10. Sketch modulating signal, carrier wave and modulated wave of FM. (E)
11. Draw the circuit of an AM diode detector. Sketch the waveforms at different stages. (E)
12. Draw the labelled block diagram of SHD AM radio receiver. (D)
Five marks Numerical:
1. A sinusoidal carrier signal of peak amplitude 5 V and frequency 100 kHz is amplitude modulated
by a 5 kHz signal of peak amplitude 3 V. What is the modulation index? Draw the spectrum of
the modulated signal. (E) (Ans: ma = 0.6, Carrier: fC = 100 kHz and VC = 5 V, LSB: fLSB = 95 kHz
and VLSB = 1.5 V, USB: fUSB = 105 kHz and VUSB = 1.5 V)
2. A sinusoidal carrier voltage VC = 80 sin2 π × 105t is amplitude modulated by a sinusoidal voltage
Vm = 32 sin2 π × 103 t. Write the equation of the AM wave and draw the output frequency
spectrum. (A) (Ans: ma = 0.4, Carrier: fC = 100 kHz and VC = 80 V, LSB: fLSB = 99 kHz and VLSB
= 16 V, USB: fUSB = 101 kHz and VUSB = 16 V)
3. A modulating signal 10sin(2πΧ103t) is used to modulate a carrier signal 20sin(2πΧ104t). Find the
(a) modulation index (b) percentage modulation (c) frequencies of the sideband components
(d) bandwidth of the amplitude modulated signal. (A)
(Ans: ma = 0.5, 50%, Carrier: fLSB = 9 kHz, fUSB = 11 kHz, BW = 2 kHz)
4. The carrier current of an AM transmitter is 8 A, it increases to 8.65 A when the carrier is
amplitude modulated. Find the % modulation. Determine the antenna current Ia when the depth
of modulation is 0.75 if carrier current remains same. (A) (Ans: ma = 0.58, Ia = 9.056 A)
5. Determine the power content of the carrier and each of the sidebands for an AM signal having
a percent modulation of 80% and a total power of 2200 W. (E)
(Ans: PC = 1666 W, PLSB = 267 W, PUSB = 267 W)
6. An antenna has an impedance of 50 Ω. A un modulated AM signal produces a current of 4.8 A.
The percentage of modulation is 90. Calculate (a) the carrier power (b) the total power and (c)
sideband power. (E) (Ans: PC = 1152 W, PT = 1618 W, PSB = 466 W)
29

7. The antenna current of an AM transmitter is 8 A when only the carrier signal is transmitted. It
increases to 8.93 A when the carrier signal is modulated by a sinusoidal signal. Find the
modulation index and percentage of modulation. Determine the antenna current when
modulation index is changed to 0.8. (D) (Ans: ma = 0.7, 70 %, It = 9.2 A)
8. A 20 kW carrier wave is amplitude modulated at 70% depth of modulation by a sinusoidal
modulating signal. Calculate (a) Total Power (b) Side band power (c) Power in each sideband.
(D) (Ans: PT = 24.9 kW, PSB = 4.9 kW, PLSB = PUSB = 2.45 kW)

*****

30

Chapter 9
Power Electronics and its applications
Choose the correct answer (MCQ):
1. SCR has (E)
(a) Two Junctions and three layers (b) Three junctions and three layers
(c) Three junctions and four layers (d) Four junctions and three layers
(c) Three junctions and four layers
2. A thyristor is a (E)
(a) controlled power device (b) uncontrolled power device
(c) passive device (d) resistor
(a) controlled power device
3. The control terminal in an SCR is (E)
(a) anode (b) cathode (c) gate (d) base
(c) gate
4. Identify the power device (E)
(a) SCR ( b) TRIAC (c) MOSFET (d) all of these
d) all of these
5. Identify the bidirectional semiconductor controlled device (A)
(a) Power diode (b) Power transistor (c) SCR (d) TRIAC
(d) TRIAC
6. Drift layer of a power diode is also called (A)
(a) Metallization layer (b) Anode terminal
(c) Epitaxial layer (d) substrate layer
(c) Epitaxial layer
7. Impurity atom density of power diode in drift region (i.e. epitaxial layer) is (E)
(a) 1018 / 𝑐𝑚3 (b) 1019 / 𝑐𝑚3 (c) 1017 / 𝑐𝑚3 (d) 1014 / 𝑐𝑚3
(d) 1014 / 𝑐𝑚3
8. The common name of SCR is (E)
(a) TRIAC (b) BJT (c) Thyristor (d) MOSFET
(c) Thyristor
9. A power MOSFET is a (E)
(a) voltage controlled device (b) current controlled device
(c) uncontrolled device (d)None of these
(a) voltage controlled device
10. The branch of electronics which deals with the control and conversion of large amounts of
electrical power with high efficiency is called (A)
(a) Power electronics (b) digital electronics
(c) current electronics (d) none of these
(a) Power electronics
11. SCR is triggered by (D)
(a) current pulse (b) voltage pulse
(c) both voltage and current (d) none of these
(a) current pulse

31

12. The terminals of an SCR are (A)
(a) emitter, base and collector (b) drain, source and gate
(c) anode, cathode and gate (d) none of these
(c) anode, cathode and gate
13. A power MOSFET, in its output characteristics has (D)
(a) cut-off region (b) active region (c) ohmic region (d) all of these
(d) all of these
14. A TRIAC is a (E)
(a) unidirectional switch (b) bidirectional switch
(c) optical switch (d) mechanical switch
(b) bidirectional switch
Two marks questions:
1. Mention any four power devices. (E)
2. Sketch electric field strength of punch through type power diode. (A)
3. Draw two transistor model of a thyristor. (E)
4. Sketch schematic section of a power diode showing impurities atom densities. (A)
5. Draw the VI characteristics of power diode under forward biased condition for two temperatures.
(D)
6. Name the types of power converters. (E)
7. What is meant by a non-punch through in power diode? (E)
8. Sketch the typical V-I characteristics of SCR for different gate currents. (A)
9. What is TRIAC? Give the circuit symbol of TRIAC. (E)
10. Draw the V-I characteristics of TRIAC. (E)
11. Mention the four operating modes of TRIAC. (E)
12. What are the different types of power MOSFET? (E)
13. Sketch the output characteristics of MOSFET. (A)
Three marks numerical:
1. Determine Vdc and Idc of SCR HWR. Given firing angle is 300 and rms voltage of ac input to the
rectifier is 230 V and load is 10 Ω. (E) (Ans: 96.60 V, 9.65 A)
2. Determine Vdc and Idc of SCR FWR. Given firing angle is 00 and rms voltage of ac input to the
rectifier is 230 V and load is 20 Ω. (A) (Ans: 207 V, 10.35 A)
0
3. Determine Vdc and Idc of SCR HWR. Given firing angle is 90 and rms voltage of ac input to the
rectifier is 230 V and load is 20 Ω. (E) (Ans: 51.7 V, 2.58 A)
0
4. Determine Vdc and Idc of SCR FWR. Given firing angle is 60 and peak voltage of ac input to the
rectifier is 230 V and a rheostat load of 25 Ω is connected. (A) (Ans: 155.25 V, 6.21 A)
5. A thyristor is connected in series with a load resistance 50 Ω. The supply voltage is 230 V rms,
50 Hz. The thyristor is triggered at an angle of 30◦ during every positive half cycle. Compute the
(a) average value of load voltage and (b) average value of load current. (D) (Ans: 96.60 V, 1.93 A)

32

6. A half wave rectifier feeds a 15 Ω resistance. The supply voltage is 230 V rms. The firing angle is
π/2. Find (a) average value of load voltage and (b) average value of load current (c) power
delivered to the load. (E) (Ans: 51.76 V, 3.45 A, 178.57 W)
7. A full controlled converter is supplied from a 230 V rms, 50 Hz ac supply for a firing angle of 30◦,
determine the average load voltage consider load as purely resistive. (E) (Ans: 193.20 V)
8. A full wave rectifier has an input voltage of 200 V rms. The load resistance is 100 Ω and firing angle
is 30◦. Find average load voltage and average load current. (E) (Ans: 167.98 V, 1.68 A)

*****

33

Chapter 10
Digital Electronics
Choose the correct answer (MCQ):
1. The logical AND term is also called as (E)
(a) Sum term (b) Product term
(c) Sum of Product (d) Product of Sum
(b) Product term
2. The logical OR term is called (E)
(a) Sum term (b) Product term (c) SOP (d) POS
(a) Sum term
3. Minterm in Boolean expression represents (A)
(a) Sum (OR) term (b) Product (AND) term
(c) Both (a) and (b) (d) None of the above
(b) Product (AND) term
4. Logic expression for the output of XOR gate is (A)
(a) Y = ̅̅̅̅̅
𝐴. 𝐵 (b) Y = A.B (c) Y = A + B (d) Y = 𝐴̅ B + A 𝐵̅
(d) Y = 𝑨̅B+A𝑩 ̅
5. The logic expression for sum in Half adder is (A)
(a) Y = ̅̅̅̅̅
𝐴. 𝐵 (b) Y = A.B (c) Y = A + B (d) Y = 𝐴̅ B + A 𝐵̅
̅ ̅
(d) Y = 𝑨 B + A 𝑩
6. BCD code for (23)10 is (D)
(a) 0001 0111 (b) 0101 0110 (c) 0010 0011 (d) None of these
(c) 0010 0011
7. Excess-3 code of (18)10 is (E)
(a) 0001 1000 (b) 0001 1110 (c) 1000 0001 (d) 0100 1011
(d) 0100 1011
8. Full adder adds (E)
(a) two input bits (b) three input bits
(c) four input bits (d) two input bytes
(b) three input bits
9. Gray code is used in shaft position (D)
(a) decoder (b) multiplexer (c) encoder (d) register
(c) encoder
10. Logic expression for the output of two input XNOR gate is (E)
(a) Y = AB (b) Y = A+B (c) Y = A  B ̅+B
(d) Y = A ̅

(c) Y = A  B
11. Excess-3 code is an example for (D)
(a) Non-weighted code (b) BCD code
(c) ASCII code (d) Weighted code
(a) Non-weighted code

34

12. In a Flip Flop SET condition stands for (E)
(a) Q = 0, 𝑄̅ = 0 (b) Q = 0, 𝑄̅ = 1 (c) Q = 1, 𝑄̅ = 0 (d) Q = 1, 𝑄̅ = 1
̅ =0
(c) Q = 1, 𝑸
13. In a Flip Flop RESET condition stands for (E)
(a) Q = 0, 𝑄̅ = 0 (b) Q = 0, 𝑄̅ = 1 (c) Q = 1, 𝑄̅ = 0 (d) Q = 1, 𝑄̅ = 1
(c) Q = 0, 𝑸 ̅ =1
14. Sum of product equation can be realized by (E)
(a) XOR gates (b) XNOR gates (c) NOR gates (d) NAND gates
(d) NAND gates
15. A group of 2 adjacent cells with 1 in a K-map is called (A)
(a) Pair (b) Quad (c) Octet (d) Double
(a) Pair
16. Identify the non-weighted code. (D)
(a) 2421 (b) 5421 (c) 8421 (d) Gray code
(d) Gray code
17. The number of variables that can be eliminated by a Quad in K-map is (A)
(a) 2 (b) 4 (c) 3 (d) 1
(a) 2
18. Logic circuits in which the output depends upon the present and previous inputs state is called
as (A)
(a) combinational logic circuit (b) sequential logic circuit
(c) random logic circuit (d) none of these
(b) sequential logic circuit
19. When a NOT gate is placed in between S input to R input of SR flip-flop, the resulting flip-flop
is a (A)
(a) SR Latch (b) SR flip-flop (c) D-flip-flop (d) T-flip-flop
(c) D-flip-flop
20. D flip-flop is also known as (E)
(a) T-flip-flop (b) master slave flip-flop
(c) Delay flip-flop (d) J-K flip-flop
(c) Delay flip-flop

Fill in the blanks:
1. Flip-flops are used to store _______. (E)
data
2. Half-adder is a __________circuit. (E)
binary arithmetic
3. Half adder is a _____________ circuit. (E)
combinational
4. A half adder can be realized using one XOR gate and one ________ gate. (A)
AND
5. NAND gate is also known as________ gate. (E)
universal
35

6. Gray code is used to reduce error that occurs in data_________. (D)
transmission
7. Logic gates used to realize other gates are known as __________ gates. (E)
universal
8. Excess-3 code is also known as __________ code. (A)
self-complementary
9. A logic circuit which is used to add two bits is called ________. (E)
half-adder
10. Mapping technique used to simplify the Boolean expression is known as ________(A)
K-map
11. A group whose all 1’s are overlapped (used) by another groups is called a __________ group
(D)
redundant
12. In a__________ logic circuit output depends on only the present inputs, but not on the
previous state of the circuit. (A)
combinational

Two mark questions:
1. Name universal gates. (E)
2. Draw the pin diagram of IC 7400. (E)
3. Draw the pin diagram of IC 7402. (E)
4. Write minterm designation table for three input variables. (D)
5. Realize D flip flop using only NAND gates. (A)
6. Realize XOR gate using basic gates. (E)
7. Realise XNOR gate using basic gates. (E)
8. Draw the logic circuit of a full adder using 3 input X-OR gate and basic gates. (D)
9. Draw the logic circuit of full adder using two half adders and an OR gate. (D)
10. What is half adder? Write its truth table. (A)
11. Realise half adder using XOR and AND gates. (A)
12. Realise half adder using only NAND gates. (A)
13. Realise half subtractor using NAND gates. (A)
14. Write the truth table of full adder. (E)
15. What is a Pair? How many variables can be eliminated by a Pair in the K- map? (E)
16. What is a Quad? How many variables can be eliminated by a quad in the K-map? (E)
17. What is an octet? How many variables can it be eliminated by an octet in the K-map? (E)
18. Distinguish between combinational logic circuits and sequential logic circuits. (D)
19. Draw the logic circuit of a basic NAND latch. (E)
20. Draw the logic circuit of un-clocked SR flip flop using NAND gates. (A)
Three mark questions:
1. Convert (1101)2 into gray code using XOR gates. (E)
2. Convert (1010)G into binary number using XOR gates. (E)
36

3. Convert Y(A, B, C) = AC+B̅ into canonical SOP form. (A)
4. Convert the Boolean expressions Y = AC + B𝐶̅ into canonical SOP form. (A)
5. Convert the Boolean expression Y = AB + C into canonical SOP form. (A)
6. Convert (E)
(a) (82)10 into BCD
(b) (1010)2 into gray code
(c) (34)10 into excess-3code
7. Convert the Boolean expression Y= A.B + B.C + A.C into its canonical SOP form expression. (D)
8. Convert (1001)2 into gray code using XOR-gates. (E)
9. Convert (1001)Gray into binary using XOR-gates. (E)
10. Find the excess-3 code of (786)10. (E)
Five mark essay type questions:
1. Realize NOT, AND, OR and XOR gates using NAND gates. (E)
2. Realize NOT, OR, AND and XNOR gates using NOR gates. (E)
3. What is full adder? Realize full adder using block diagrams of two half adders and an OR gate.
Write the truth table of full adder. (D)
4. What is a half subtractor? Draw its logic circuit and write its truth table along with the Boolean
expression for difference and borrow. (E)
5. Explain the working of a unclocked RS Flip-Flop using NAND gates. Write its truth table. (A)
6. Explain the working of a clocked RS Flip-Flop using NAND gates. Write its truth table. (A)
7. Why RS flip flop is converted into D flip flop. Explain the working of D Flip-flop with logic circuit
and truth table. (D)
Five marks numerical:
1. Simplify the Boolean expression Y(A,B,C,D) m(1, 4,5,11,14) +d (0,10,15). Draw the NAND gate
equivalent circuit to realize the simplified equation. (A)
2. Simplify the Boolean expression, Y = ∑m (0, 1, 4, 13, 15) + ∑d (2, 5, 7) and then draw the logic
diagram for the simplified expression using basic gates. (E)
3. Simplify the Boolean expression
Y = ∑m (1, 2, 3, 5, 7, 9, 11, 13) + ∑d (0, 10, 15) and then draw the logic diagram for
simplified expression using basic gates. (E)
4. Simplify the Boolean expression Y = Σm (0,2,7,8,10,13) + Σd (5,15) using K-map. Draw the NAND
gate equivalent circuit to realize the simplified equation. (A)
5. Simplify Y = f(A, B, C, D) = ∑m(0, 1, 2, 4, 5, 8, 9, 10, 12, 13) and draw the logic circuit for simplified
expression using NAND gates. (D)
6. Simplify the Boolean expression Y(A, B, C, D) = Σm(4,5,7,9,11,12,13,15) + Σd(1,3,8)
using K-map. Draw the NAND gate equivalent circuit to realize the simplified expression. (A)
7. Simplify the Boolean expression Y = ∑m (0, 2, 4, 8, 10) + ∑d (12, 14) using K-map. Draw the
NAND gate equivalent circuit to realize the simplified expression. (A)

37

8. Simplify the Boolean expression Y = ∑m (4, 5, 7, 9, 11, 12, 13, 15) + ∑d (1, 3, 8) using K-map.
Draw the NAND gate equivalent circuit to realize the simplified expression. (A)
9. Simplify the Boolean expression Y = ∑m (0, 2, 6, 8, 10, 12, 14) + ∑d (4, 9, 13) using K-map. Draw
the NAND gate equivalent circuit to realize the simplified expression. (A)
10. Simplify the Boolean expression Y = ∑m (1, 3, 5, 6, 8, 9, 11, 12) + ∑d (0, 7, 14) using K-map. Draw
the logic circuit using basic gates to realize the simplified expression. (A)
11. Simplify the Boolean expression Y = ∑m (0,2,4,6,8,10,11,12,14,15) + ∑d (9,13) using K-map. Draw
the logic circuit using basic gates to realize the simplified expression. (D)
12. Simplify the Boolean expression Y (A, B, C, D) = ∑m (1,2,3,5,6,7,12) using K-map. Also draw the
logic circuit for the simplified expression using basic gates. (A)
*****

38

Chapter 11
Microcontroller
Choose the correct answer (MCQ):

1. The number of timers present in 8051 microcontroller is (E)
(a) 1 (b) 2 (c) 3 (d) 4
(b) 2
2. 8051 microcontroller is a (E)
(a) 8 bit controller (b) 16 bit controller
(c) 32 bit controller (d) 64 bit controller
(a) 8 bit controller
3. Microcontroller chip contains (A)
(a) RAM (b) ROM (c) Timer (d) All of these
(d) All of these
4. The number of I/O pins (lines) present in 8051 microcontroller is (A)
(a) 16 (b) 24 (c) 32 (d) 40
(c) 32
5. The number of bits of data a register A of 8051 holds is (A)
(a) 64 bits (b) 32 bits (c) 16 bits (d) 8 bits
(d) 8 bits
6. Identify the addressing mode of the instruction MOV A, @R0 (A)
(a) Register (b) Immediate (c) Direct (d) Indirect
(d) Indirect
7. The addressing mode of the instruction MOV A, #43H (A)
(a) Indirect (b) Immediate (c) Register (d) Direct
(b) Immediate
8. Full form of CPU is (E)
(a) Common Perform Unit (b) Central Programming Unit
(c) Central Processing Unit (c) none of these
(c) Central Processing Unit
9. The microcontroller which deals with 8 bit data is known as (E)
(a) 8 bit microcontroller (b) 16 bit microcontroller
(c) 32 bit microcontroller (d) none of these
(a) 8 bit microcontroller
10. ALU performs (D)
(a) Arithmetic operations only (b) logic operations only
(c) Both arithmetic and logical operations (d) none of these
(c) Both arithmetic and logical operations
11. The only two 8051 microcontroller instruction which uses B register are (D)
(a) ADD and SUM (b) MUL and DIV
(c) PUSH and POP (d) none of these
(b) MUL and DIV

39

Two Mark questions:
1. Mention two differences between microprocessor and microcontroller. (A)
2. List the applications of microcontroller. (E)
3. Mention the memory capacity of internal RAM and ROM of 8051 chip. (A)
4. Briefly explain register addressing mode. (A)
5. Mention the features of 8051 microcontrollers. (D)
6. What is an addressing mode? Why is it necessary? (E)
7. Mention any four addressing modes. (E)
8. Mention the addressing modes of 8051 microcontroller. (A)
9. What is register addressing mode? Mention one example. (E)
10. What is direct addressing mode? Mention one example. (E)
11. What is indirect addressing mode? Mention one example (A)
12. What is immediate addressing mode? Mention one example. (E)
13. What are data transfer instructions? Give one example. (E)
14. What are arithmetic instructions? Give one example. (E)
15. Which general purpose registers are used for multiplication and division operations in 8051?
Five marks Programs:
1. Write a ALP to add F1H and 0EH, save the result in register R0. What is the content of R0 after
execution of the program? (E)
2. Write instructions to move 56H into register A, 4EH into register R1, then add them together
and save the result in register R0. What is the content of R0 after execution of the program? (A)
3. Write an assembly language program to add two numbers 1FH and B4H and store the result in R0.
Verify the result by binary addition. (A)
4. Write an assembly language program to subtract 35H from 4AH and save the result into register
R0. Verify the content of R0 after executing the program. (A)
5. Write an assembly language program to subtract 34H from 9AH and save the result into register
R0. What is the content of R0 after execution of the program? (D)
6. Write a program to multiply two 8 bit numbers 06H and 09H. Store the result Lower Byte at R0
and Higher Byte at R1. (E)
7. Write an ALP to multiply 02H and 03H. Store lower order byte in R0 and higher order byte in R1.
(E)
8. Write ALP program to multiply 35H and 45H. In which registers lower byte and higher byte of
results are stored? (A)
9. Write ALP program to divide 3FH by 2 AH. In which registers, quotient and remainder are stored
after execution of the program. (D)
10. Write ALP program to divide EDH by 1EH and store the quotient in R0 and remainder in R1. (E)
*****

40

Chapter 12
C-Programming
Choose the correct answer (MCQ):

1. Size of an integer data in C programming is (E)
(a) 1 byte (b) 2 byte (c) 4 byte (d) 8 byte
(a) 2 byte
2. Size of float data type in C programming is (E)
(a)1 byte (b) 2 bytes (c) 4 bytes (d) 8 bytes
(c) 4 bytes
3. ‘Not equal to’ operator in C programming is (E)
(a) ~ (b) != (c) =! (d) ≠
b) !=
4. If a = 16 and b = 3 then the value of the operation a/b in C programming is (A)
(a) 1 (b) 5 (c) 13 (d) 19
(b) 5
5. If a = 16 and b = 3 then the value of the operation a%b in C programming is (A)
(a) 1 (b) 5 (c) 13 (d) 19
(a) 1
6. The operator ‘&’ in C programming denotes (E)
(a) Bitwise OR (b) Logical OR (c) Bitwise AND (d) Exclusive OR
(c) Bitwise AND
7. What is the meaning of the C operator && (double ampersand)? (E)
(a) Bitwise OR (b) Logical OR (c) Bitwise AND (d) Logical AND
(d) Logical AND
8. The correct C equivalent expression for A = 𝑎+𝑏 . (D)
𝑐
𝑎+𝑏
(a) A = 𝑐 (b) A = (a+b)/c (c) A = (a*b)/c (d) A = (a/b)/c
(b) A = (a+b)/c
9. The number of keywords (reserved words) in C programming language is (E)
(a) 24 (b) 16 (c) 8 (d) 32
(d) 32
10. Identify the header file. (A)
(a) stdio.h (b) conio.h (c) math.h (d) all of these
(d) all of these
11. Basic unit or basic building blocks of a C program are called as (E)
(a) tokens (b) documents (c) files (d) none of these
(a) tokens
12. C operators used for performing comparison are called as (A)
(a) relational operators (b) arithmetic operators
(c) logarithmic operators (d) none of these
(a) relational operators

41

13. The C equivalent expression for 3x2 + 2x +1 is (D)
(a) (3*x*2)*(2*x+1) (b) (3*x*x) + (2*x) +1
(c) (3*x*x+1)+(2*x*1) (d) none of these
(b) (3*x*x) + (2*x) +1

Five marks C programming questions:
1. Write a C program to accept two integer numbers and print whether they are equal or not
equal. (E)
2. Write a C program to accept three integer numbers and print their sum and average. (A)
3. Write a C program to accept the three different integers and print the largest amongst them. (A)
4. Write a C-program to accept radius (in float) and print area of the circle. (D)
5. Write a C-program to accept diameter (in float) and print area of the circle. (D)
6. Write a C program to accept the three different integers and print the smallest amongst them. (A)
*****

42

Chapter: 13
Modern Communication Systems
Choose the correct answer (MCQ):
1. Shapes of the cells in mobile network operation system is (E)
(a) octagonal (b) circular (c) oval (d) hexagonal
(d) hexagonal
2. When a person with cell-phone passes through various cells, the process by which the MTSO
System automatically switches call from one cell to other cell without call interruption is called
(a) cell hand-off (b) call hand-off (c) cell splitting (d) call switching
(b) call hand-off
3. The data range of wi-fi is upto (A)
(a) 100 meters (b) 1 km (c) 2 km (d) 1.2 km
(a) 100 meters
4. Carrier of information in optical fiber communication system is (E)
(a) copper (b) light (c) water (d) aluminium
(b) light
5. Expansion of CDMA is (E)
(a) Code Division Mobile Access (b) Call Division Mobile Access
(c) Code Division Multiple Access (d) Call Division Multiple Access
(c) Code Division Multiple Access
6. Abbreviation of GSM is (E)
(a) General Service for Mobile Communication (b) Global System for Mobile Communication
(c) General System for Mobile Communication (d) Global Service for Mobile Communication
(b) Global System for Mobile Communication
7. What is the standard form of MTSO (E)
(a) Mobile Technology Switching Office (b) Mobile Telephone System Office
(c) Mobile Telephone Switching Office (d) Mobile Telephone Service Office
(c) Mobile Telephone Switching Office
8. A typical downlink frequency in satellite communication system is (A)
(a) 4 Hz (b) 4 kHz (c) 4 MHz (d) 4 GHz
(d) 4 GHz
9. A typical uplink frequency in satellite communication system is (A)
(a) 6 GHz (b) 4 GHz (c) 10 GHz (d) 15 GHz
(a) 6 GHz
10. The signal transmitted from earth to satellite is called (E)
(a) uplink signal (b) sampling signal
(c) damping signal (d) none of these
(a) uplink signal
11. RADAR stands for (D)
(a) RAdio Detection And Ranging (b) RAdio Demodulator And Rectifier
(c) RApid Detector And Radio (d) none of these
(a) RAdio Detection And Ranging

43

12. Transponder acts as (A)
(a) the receiver (b) frequency changer
(c) the transmitter (d) all of these
(d) all of these
Two marks questions:
1. Mention any two advantages of digital cell phone system. (A)
2. Mention any two types of protocols used in computer networks. (A)
3. What is a transponder and Mention its main function. (E)
4. Mention the important techniques used for Bluetooth operation. (D)
5. What is Wi-Fi? Briefly explain its operation. (E)
6. Explain what is meant by cell splitting. (E)
7. Distinguish between uplink and downlink signals. (D)
8. List the functions of a transponder. (E)
9. Draw the block diagram of an optical fiber communication system. (A)
Three marks questions:
1. Explain briefly satellite communication system. (E)
2. Mention the advantages of cell phone systems. (A)
3. Mention the advantages and uses of Wi-Fi. (A)
4. Mention few applications of satellites. (E)
5. Mention few applications of optical fiber communication. (E)
6. What is RADAR? Mention its two applications. (E)
7. Draw the block diagram of a RADAR system. (A)
8. Draw the block diagram of satellite transponder. (A)
9. Mention the additional features of the latest 3G and 4G cell phone systems. (D)
10. With a diagram explain the function of each block of a satellite communication system. (D)
11. Mention few applications of Bluetooth. (E)
12. Give a comparison of Bluetooth and Wi-Fi. (E)
*****

44

Registration No: 40
40
A2 – 2024
Subject
Code 40
ELECTRONICS
Time : 3 Hours 15 Minutes] [Total No. of Questions: 48] [Max. Marks : 70

Instructions :
1. For PART – A questions, only the first written answers will be considered for evaluation.
2. PART – D consists of two sections. Section – I is of essay type questions, Section – II
is of problems.
3. For questions having diagrams, alternate questions are given at the end of the
question paper, in a separate section for visually-challenged students.
4. Truth Table and circuit diagram must be drawn wherever necessary.
5. Solve the problems with necessary formulae.

PART – A
I. Select the correct answer from the choices given: (15 × 1 = 15)
1) Unitless parameter of JFET is
a) Transconductance b) Amplification factor
c) Drain resistance d) Trans resistance

2) The most commonly used biasing circuit for stable operating point is
a) Emitter feedback bias b) Fixed bias
c) Collector-to-base feedback bias d) Voltage divider bias

3) For faithful amplification, transistor is operated in
a) Cut-off region b) Saturation region
c) Active region d) Inverse region

4) Negative feedback is used in
a) Oscillator b) Amplifier
c) Digital circuit d) Gates

40 ELECTRONICS P.T.O. 1

40 Electronics 03-2024.indd 1 15-04-2024 11:33:10

40

5) In op-amp, ratio of ∆Vo to ∆t is
a) CMRR b) Input impedance
c) Slew rate d) Bandwidth

6) The feedback component used in the op-amp integrator is
a) Resistor b) Capacitor
c) Inductor d) Diode

7) Crystal oscillator works on the principle of
a) Piezomagnetic effect b) Piezostatic effect
c) Piezodynamic effect d) Piezoelectric effect

8) Ground waves are also called
a) Surface waves b) Space waves
c) Sky waves d) Line-of-sight waves

9) Modulation index in FM is denoted by
a) ma b) mb
c) mp d) mf

10) Drift layer of power diode is also called
a) Metalization layer b) Anode terminal
c) Epitaxial layer d) Substrate layer

11) The logical OR term is called
a) Sum term b) Product term
c) SOP d) POS

12) 8421 BCD code for (36)10 is
a) 00111001 b) 11000011
c) 00110110 d) 11110000

2

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40

13) Microcontroller chip contains
a) RAM b) ROM
c) Timer d) All of these

14) Size of integer data type in C-Program is
a) 8 byte b) 16 byte
c) 32 byte d) 2 byte

15) Downlink frequency in satellite communication system is
a) 4 GHz b) 4 KHz
c) 4 MHz d) 4 Hz

II. Fill in the blanks by choosing appropriate answer from those given in the bracket: 
 (5 × 1 = 5)
[ a) Heat sink b) Power c) Voltage d) Half adder e) Op-amp f) Demodulation]

16) FET is a _____ controlled device.

17) ______ is used to protect the transistor from overheating.

18) Large signal amplifiers are ______ amplifiers.

19) The process of recovering signal from modulated carrier wave is _____.

20) Logic circuit which performs binary addition of only two bits is called _____.

PART – B

III. Answer any five questions: (5 × 2 = 10)

21) Mention two leakage currents in a transistor.

Ω. If voltage series negative feedback is
22) An amplifier has Av = 100 and Zi = 10KΩ
applied with β = 0.01, calculate Zif.

23) Write the steps to draw DC equivalent circuit of CE transistor amplifier.

24) In Wein bridge oscillator, f = 75 Hz and C = 0.22 µF. Calculate the value of resistance.

25) Name any two power converters.

P.T.O. 3

40 Electronics 03-2024.indd 3 15-04-2024 11:33:10

40

26) Realize XOR gate using NAND gates.

27) Name any two addressing modes in microcontroller.

28) Name any two operators in C-program.

29) Draw the block diagram of satellite transponder.

PART – C

IV. Answer any five questions: (5 × 3 = 15)

30) Explain the construction of n-channel JFET.

31) Mention the types of negative feedback connection in amplifiers.

32) Compare RC oscillator and LC oscillator.

ηF. Calculate the resonant
33) In Hartley oscillator, L1 = 10 mH, L2 = 90 mH and C = 1η
frequency of oscillator.

34) Define critical frequency, skip zone and skip distance in wireless communication
system.

35) Draw the frequency spectrum of AM wave and also write the expression for
bandwidth.

Ω.
36) In SCR-HWR, firing angle is 90°, rms voltage of ac input is 230V and load is 10Ω
Evaluate Vdc and Idc.

37) Convert Y(A, B, C) = AB + BC into Canonical SOP form.

38) Expand RADAR. Mention its applications.

PART – D (Section – I)

V. Answer any three questions: (3 × 5 = 15)

39) With a circuit diagram, explain the working of CB amplifier. Draw input and output
waveform.

40) Derive an expression for output voltage and voltage gain in inverting op-amp.

4

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40

41) Derive an expression for instantaneous voltage of AM wave.

42) Explain the working of D Flip-flop with logic circuit and truth table.

43) Write an ALP to multiply 02H and 03H. Store lower order byte in R0 and higher
order byte in R1.

44) Write a C program to find largest of three different integer numbers.

PART – D (Section – II)

VI. Answer any two questions: (2 × 5 = 10)
26mV
45) For CE amplifier circuit shown in figure β = 100, VBE = 0.7V, re' = .Ω
IE
Calculate
Ω
a) Voltage across 20KΩ
b) Emitter current, IE
c) re'
d) Zin(base)
e) Ai



P.T.O. 5

40 Electronics 03-2024.indd 5 15-04-2024 11:33:10

40

46) Calculate the output voltages in the given op-amp circuits:

a)

b)

(3+2)

47) A sinusoidal carrier voltage νc = 80sin (2ππ × 105) t is amplitude modulated by
a sinusoidal voltage νm = 32sin (2π π × 103) t. Determine a) Modulation index
b) Modulating signal frequency c) Carrier signal frequency d) LSB frequency and
e) USB frequency.

48) Simplify the boolean expression y(A, B, C, D) = Σm (0, 1, 5, 7, 15) + d (2, 4, 13) using
K-map. Draw the logic circuit diagram for simplified expression using only basic
gates.

6

40 Electronics 03-2024.indd 6 15-04-2024 11:33:10

40

PART – E
(Visually-challenged Students Only)

Ω, R2 = 20KΩ
45) In single stage CE amplifier, R1 = 80KΩ Ω, Rc = 1KΩ
Ω, RE = 0.1KΩ
Ω,
26mV
Vcc = 10V, VBE = 0.7V, β = 100, re' = .Ω
IE
Calculate

Ω
a) Voltage across 20KΩ

b) Emitter current, IE

c) re'

d) Zin(base)

e) Ai

Ω, R2 = 2KΩ
46) a) An op-amp adder is given with R1 = 5KΩ Ω, Rf = 10KΩ
Ω V1 = 2V and
V2 = 1V. Evaluate the output voltage.

Ω, R1 = 10KΩ
b) An op-amp non-inverting amplifier is given with Rf = 20KΩ Ω, and
Vin = –2V. Determine the output voltage. (3+2)

____________

P.T.O. 7

40 Electronics 03-2024.indd 7 15-04-2024 11:33:10

40 Electronics 03-2024.indd 8 15-04-2024 11:33:10

Registration No: 40
40
A3 – 2024
Subject
Code 40
ELECTRONICS
Time : 3 Hours 15 Minutes] [Total No. of Questions: 48] [Max. Marks : 70
Instructions :
1. For PART – A questions, only the first written answers will be considered for evaluation.
PART – D consists of two Sections Section – I is of essay type questions, Section – II
2. 
is of problems.
3. For questions having diagrams, alternate questions are given at the end of the
question paper, in a separate section for Visually-Challenged Students.
4. Circuit diagrams and truth tables must be drawn wherever necessary.
5. Solve problems with relevant formulae.

PART – A
I. Select the correct answer from the choices given: (15 × 1 = 15)
1) The terminal which controls the flow of charge carrier in a JFET is
a) Source b) Drain
c) Gate d) Emitter

2) The operating point in a transistor is also called as
a) Pinch-off point b) Cut-off point
c) Quiescent point d) Saturation point

3) The transistor amplifier which has current gain less than unity
a) CE amplifier b) CB amplifier
c) CC amplifier d) Both a and c

4) What happens to the bandwidth of an amplifier if voltage series negative feedback
is applied?
a) Remains same b) Increases
c) Decreases d) Oscillates

40 ELECTRONICS P.T.O. 1

40

5) The rate of change of output voltage in op-amp is known as
a) CMRR
b) Slew rate
c) Input impedance
d) Output impedance

6) The output of differentiator circuit when input is sine wave
a) Cosine wave
b) Sine wave
c) Square wave
d) Triangular wave

7) Total number of RC sections present in phase shift oscillator
a) One b) Two
c) Three d) Four

8) 
Which of the following is the nearest ionospheric layer to the earth surface
during daytime?
a) D Layer b) E Layer
c) F1 Layer d) F2 Layer

9) Number of Sidebands in AM
a) FOUR b) ONE
c) THREE d) TWO

10) A thyristor is a
a) Controlled device
b) Uncontrolled device
c) Passive device
d) Resistor

2

40

11) Excess-3 code is an example for
a) Non-weighted code
b) ASCII code
c) Weighted code
d) Non-self complementary code

12) The logical OR term is called
a) Product term b) Sum term
c) Sum of product d) Product of sum

13) 8051 microcontroller is a
a) 32 bit controller b) 64 bit controller
c) 16 bit controller d) 8 bit controller

14) The number of keywords in C programming language is
a) 24 b) 16
c) 8 d) 32

15) Carrier of information in optical fibre communication is
a) Water b) Light
c) Copper d) Silicon

II. Fill in the blanks by choosing appropriate answer from those given in the bracket. 
 (5 × 1 = 5)
[ a) Emitter follower b) Radio receiver c) Minority d) Data e) High f) Op-amp]

16) The switching speed of FET is ________.

17) In a transistor the leakage current is due to ________ charge carriers.

18) CC amplifier is also called as _________.

19) Demodulation is done in __________.

20) Flip-flops are used to store __________.

P.T.O. 3

40

PART – B

III. Answer any five questions: (5 × 2 = 10)

21) Mention any two types of transistor biasing circuits.

22) Write the steps to draw AC equivalent circuit of CE transistor amplifier.

23) In an amplifier Z0 = 6kΩ, A = 100. Find Zof when β = 0.02 in voltage series negative
feedback amplifier.

24) Determine the frequency of Wein bridge oscillator having R1 = R2 = R = 20 kΩ and
C1 = C2 = C = 100nF.

25) Name any two types of power converters.

26) What is Half adder? Write its truth table.

27) Write any two features of 8051 microcontroller.

28) Mention any two control statements in C-programming.

29) Compare Wi-Fi and Bluetooth.

PART – C

IV. Answer any five questions: (5 × 3 = 15)

30) Obtain the relation between FET parameters.

31) Define the terms:
(a) Open-loop gain
(b) Closed-loop gain and
(c) Feedback factor.

32) Draw the circuit diagram of Hartley oscillator. Write the expression for its frequency
of oscillations.

33) In a Colpitts oscillator, f = 20kHz and Ceq = 10nF. Determine inductor value.

4

40

34) Draw the block diagram of communication system and explain each block.

35) Mention the characteristics of good Radio receiver.

36) Calculate Vdc and Idc of SCR full wave rectifier. The firing angle is 0°, rms voltage of

ac input to the rectifier is 230V and load is 20Ω.

37) Convert the Boolean expression Y (A, B, C) = AC + AC into SOP form.

38) List the additional features of 3G and 4G cell mobile system.

PART – D

(Section – I)

V. Answer any three questions: (3 × 5 = 15)

39) With circuit diagram explain the working of two-stage direct coupled CE amplifier.

Draw its frequency response curve.

40) Derive an expression for output voltage of Op-Amp non-inverting amplifier.

41) Derive an expression for modulating index for AM in terms of Vmax and Vmin.

42) Realize NOT, AND, OR and XNOR gates using NOR gate.

43) Write an assembly language program to subtract 34H from 9AH and save the result

into register R0. What is the content of R0 after execution of the program?

44) Write a C-program to find sum and average of four integer numbers.

P.T.O. 5

40

PART – D
(Section – II)

VI. Answer any two questions: (2 × 5 = 10)

45) In a CE amplifier circuit as shown in the figure below,
Calculate
a)
b) Zin (base)
c) Z0
d) Ai and
e) Av
26mV
[Given IE = 1.65 mA, β = 100, VBE = 0.7 V, = ]
IE

Ce

6

Ce Ce

40

46) a) Calculate output voltage (VO).

b) Calculate output voltage (VO).

47) AM transmitter, with carrier power of 10kW, is modulated to a depth of 50%.
Find a) Total power
   b) Sideband power.

48) Simplify the given Boolean expression using K-map.
Y (A, B, C, D) = Σm (5, 9, 12, 13, 15) + Σd (7, 8). Draw the logic circuit using basic gates
for simplified expression.

P.T.O. 7

40

PART – E
[For Visually-Challenged Students Only]

45) In single stage CE transistor amplifier, R1 = 90kΩ, R2 = 22kΩ, RC = 5kΩ, RE = 1kΩ,
26mV
VCC = 12V, VBE = 0.7V, β = 100, = .Ω, IE = 1.65 mA.
IE
Calculate

a)

b) Zin (base)

c) Z0

d) Ai and

e) AV.

46) a) 
An op-amp non-inverting amplifier is given with Rf = 500kΩ, Rin = 250kΩ
and Vin = 2V. Calculate the output voltage.

b) An op-amp adder is given with R1 = 200kΩ, R2 = 300kΩ, Rf = 600kΩ V1 = 1V,
V2 = 2V. Evaluate output voltage. (2 + 3)

____________

8

£ÉÆÃAzÀt ¸ÀASÉå :
Registration No. :

X1 – 2025
«µÀAiÀÄ ¸ÀAPÉÃvÀ /
40 (NS)
Subject Code

J¯ÉPÁÖç¤Pïì («zÀÄå£Áä£À «eÕÁ£À) / ELECTRONICS
[¸ÀªÀÄAiÀÄ: 3 UÀAmÉUÀ¼ÀÄ] [MlÄÖ ¥Àæ±ÉßUÀ¼À ¸ÀASÉå : 45] [UÀjµÀ× CAPÀUÀ¼ÀÄ : 70]
[Time : 3 Hours] [Total No. of questions : 45] [Max. Marks : 70]

Instructions : 1) For Part – A questions, only the first written answer will be
considered for evaluation.
2) Part – D consists of two sections. Section – I is of essay
type questions and Section – II is of problems.
3) Circuit diagram and truth tables must be drawn wherever
necessary.
4) Solve the problems with necessary formulae.
5) For the questions having diagrams, alternate questions are
given at the end of the question paper in separate section
for visually challenged students.

PART – A

I. Select the correct answer from the choices given : (15 × 1 = 15)

1) An example for the voltage controlled device is
a) BJT b) FET
c) SCR d) TRIAC

P.T.O.

40 (NS) -2-

2) The operating point is also called as
a) Quiescent point b) Cutoff point
c) Saturation point d) Breakdown point

3) Conduction angle for class-B power amplifier is
a) 60° b) 180°
c) 270° d) 360°

4) What happens to voltage gain of an amplifier, when negative feedback is
applied?
a) Increases b) Decreases
c) Remains same d) Oscillates

5) The rate of change of output voltage in op-amp is known as
a) Input offset voltage b) CMRR
c) Output offset voltage d) Slew rate

6) The active component used in op-amp filter circuit is
a) Resistor b) Op-amp
c) Capacitor d) Inductor

7) Name the high frequency stability oscillator
a) Colpitts oscillator b) Hartley oscillator
c) Wein bridge oscillator d) Crystal oscillator

8) The layer of ionosphere which remains during both day and night time is
a) F Layer b) E Layer
c) D Layer d) Troposphere

-3- 40 (NS)

9) The intermediate frequency in AM radio receiver is
a) 455 Hz b) 455 KHz
c) 455 MHz d) 455 GHz

10) The common name of SCR is
a) Diode b) TRIAC
c) MOSFET d) Thyristor

11) 8421 BCD code for (59)10 is
a) 0101 1010 b) 0110 1001
c) 0101 1001 d) 1001 0101

12) In a flip-flop, SET condition stands for
a) Q = 0, Q = 0 b) Q = 0, Q = 1
c) Q = 1, Q = 0 d) Q = 1, Q = 1

13) How many timers are present in 8051 microcontroller?
a) 1 b) 2
c) 3 d) 4

14) ‘Not equal to’ operator in C programming is
a) ~ b) ≠
c) =! d) !=

15) Expansion of CDMA is
a) Code Division Mobile Access
b) Call Division Mobile Access
c) Code Division Multiple Access
d) Call Division Multiple Access

40 (NS) -4-

II. Fill in the blanks by choosing appropriate answer from the bracket : (5 × 1 = 5)

[ a) combinational b) damped c) twice d) comparator e) thermal f) highest ]

16) CE amplifier has _____________ power gain.

17) Zero crossing detector is an application of _____________.

18) Tank circuit produces _____________ oscillations.

19) Carrier swing is _____________ the frequency deviation in FM.

20) Half adder is a _____________ circuit.

PART – B

III. Answer any five questions : (5 × 2 = 10)

21) Mention any two types of transistor biasing circuits.

22) In an amplifier bandwidth is 1 MHz and β = 0.01. Determine bandwidth
when negative feedback is introduced. Given A = 100.

23) A transistor colpitts oscillator is provided with L = 10 μ H and C eq = 1nF .
Determine frequency of oscillations.

24) Write the expression for PT in terms of PC . What is the upper limit of ma
in AM?

25) Name the four types of power converters.

26) Draw the logic circuit of a full adder using 3 - input X-OR gate and basic
gates.

27) Distinguish between ROM and RAM.

28) Write a note on Wifi.

-5- 40 (NS)

PART – C
IV. Answer any five questions : (5 × 3 = 15)

29) Mention the differences between FET and BJT.

30) Derive an expression for input impedance of voltage series negative
feedback amplifier.

31) Sketch nature of oscillator output waveform for a) Aβ > 1 b) Aβ < 1
c) Aβ = 1

32) What is noise signal? Differentiate between radio horizon and optical
horizon.

33) Draw the circuit diagram of diode detector. Sketch the waveforms at
different stages.

34) Determine Vdc and Idc of SCR HWR. Given firing angle is 60°, rms
voltage to the rectifier is 230 V and a load of 20 Ω is connected.

35) Convert (1010)2 into gray code using X-OR gate.

36) Write any three uses of fiber optic communication.

PART – D (Section I)
V. Answer any three questions : (3 × 5 = 15)
37) Explain working of CC amplifier. Draw input and output waveforms.
38) Derive an expression for the output voltage of an op-amp summing
amplifier.
39) Realize NOT, AND, OR and XOR gates using NAND gates.
40) Write ALP program to divide 3 FH by 2 AH. In which registers, quotient
and remainder are stored after execution of the program.
41) Write a C program to accept two integer number and print whether they
are equal or not equal.

40 (NS) -6-

PART – D (Section II)

VI. Answer any two questions : (2 × 5 = 10)

42) For the given CE amplifier circuit using silicon transistor.
Calculate

(i) V2 (Voltage drop across R 2 )

(ii) IE

(iii) re′

(iv) AV

(v) Ai

26 mV
Given re′ = , VBE = 0.7 V and β = 150 .
IE

-7- 40 (NS)

43) Calculate output voltages for the op-amp circuits shown below. Given
Vi 1 = 1 V , Vi 2 = 2 V . (2 + 3)

a)

b)

40 (NS) -8-

44) A sinusoidal carrier voltage v c = 60 sin 2π × 10 5 t is modulated by a
sinusoidal voltage v m = 30 sin 2π × 10 3 t .

(a) Draw the frequency spectrum of AM

(b) Calculate bandwidth.

45) Simplify the Boolean expression
Y(A, B, C, D) =  m(1, 4, 5, 11, 14) +  d(0, 10, 15)
Draw the NAND gate equivalent circuit to realize the simplified equation.

PART – E

(For Visually Challenged Students Only)

42) For the CE amplifier circuit using silicon transistor R1 = 45 kΩ , R 2 = 5 kΩ ,
26 mV
R C = 2 kΩ , R E = 470 Ω , VCC = +15 V , β = 150 , VBE = 0.7 V , re′ =
IE

Calculate
(i) V2 (Voltage drop across R 2 )

(ii) IE

(iii) re′

(iv) A V

(v) Ai (5)

43) a) An op-amp inverting amplifier is provided with R i 1 = 4.7 kΩ ,
R f 1 = 10 kΩ , V1 = 1 V . Determine output voltage V01 . (2)

b) An op-amp non-inverting amplifier is provided with R i 2 = 8.2 kΩ ,
R f 2 = 20 kΩ , V2 = 2 V . Determine output voltage V02 . (3)

—————

Registration No: 40
40
H2 – 2025
Subject
Code 40
ELECTRONICS
Time : 3 Hours 00 Minutes] [Total No. of Questions: 45] [Max. Marks : 70
Instructions :
1. For PART – A questions, only the first written answers will be considered for evaluation.
2. 
PART – D consists of two Sections: Section – I is of essay type questions and
Section – II is of problems.
3. Circuit diagrams and truth tables must be drawn wherever necessary.
4. Solve the problems with necessary formulae.
5. For questions having diagrams, alternate questions are given at the end of the
question paper in a separate section for Visually-Challenged Students.

PART – A
I. Select the correct answer from the choices given. (15 × 1 = 15)
1) The terminal which controls flow of charge carrier through channel in JFET is
a) Gate b) Drain
c) Source d) Emitter

2) The biasing circuit which provides excellent stabilization is
a) Fixed bias b) Collector to base feedback bias
c) Emitter feedback bias d) Voltage divider bias

3) The phase shift between input voltage and output voltage of CB amplifier is
a) 0° b) 80°
c) 90° d) 180°

4) What happens to output impedance of an amplifier when voltage-series negative
feedback is applied?
a) Increases b) Decreases
c) Oscillates d) Reduced to zero

40 ELECTRONICS P.T.O. 1
S-20

40 Electronics 04-2025.indd 1 16-04-2025 12:16:32

40

5) The feedback component in op-amp differentiator is

a) Capacitor b) Resistor

c) Inductor d) Diode

6) Input impedance of ideal op-amp is

a) few ohm b) 0 Ω

c) ∞ Ω Ω
d) 10 MΩ

7) Crystal Oscillator works on the principle of

a) Piezomagnetic effect

b) Electroluminance effect

c) Resonance effect

d) Piezoelectric effect

8) The nearest ionospheric layer to the earth surface during daytime is

a) E layer b) D layer

c) F1 layer d) F2 layer

9) In AM wave, Vmax = 10V and Vmin = 5V. Modulation index ma is

1 2
a) b)
3 3

1
c) d) 1
2

10) Drift layer of power diode is also called as

a) Metalization layer

b) Substrate layer

c) Source layer

d) Epitaxial layer

2

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40

11) Non-weighted code is
a) 8421 code b) 2421 code
c) 5421 code d) Gray code

12) In a flip-flop, RESET state is
a) Q = 0, Q = 0 b) Q = 1, Q = 0
c) Q = 1, Q = 1 d) Q = 0, Q = 1

13) 8051 microcontroller is a
a) 64 bit microcontroller b) 16 bit microcontroller
c) 8 bit microcontroller d) 32 bit microcontroller

14) Number of keywords in C program language is
a) 32 b) 64
c) 320 d) 8

15) Carrier of information in optical fiber communication system is
a) Water b) Light
c) Copper d) Silicon

II. Fill in the blanks by choosing an appropriate answer from those given in the bracket. 
 (5 × 1 = 5)
b = 1 c) Modulation index d) Voltage e) Ab
[a) Race around condition b) Ab b > 1
f) Summing amplifier]

16) Small signal amplifiers are also called as _____ amplifiers.

17) Op-amp inverting adder is also called as ______.

18) Condition for sustained oscillation is ________.

19) Ratio of frequency deviation to modulating signal frequency in FM is _______.

20) ________ is the disadvantage of JK flip-flop.

P.T.O. 3

40 Electronics 04-2025.indd 3 16-04-2025 12:16:32

40

PART – B

III. Answer any five questions: (5 × 2 = 10)

21) Name two leakage currents in a transistor.

22) In an amplifier, voltage gain is 100, output impedance is 5 KΩ. If voltage-series
negative feedback is applied with β = 0.02, then evaluate the value of output
impedance with feedback.

23) In RC phase shift oscillator, frequency of oscillation is 120Hz and R = 220 Ω. Evaluate
capacitance value.

24) Draw the block diagram of AM transmitter.

25) Draw two transistor model of SCR.

26) What is half adder? Write its truth table.

27) Mention the memory capacity of internal RAM and ROM of 8051 microcontroller.

28) Compare Wi-fi and Bluetooth.

PART – C

IV. Answer any five questions. (5 × 3 = 15)

29) Obtain the relation between µ, gm and rd in JFET.

30) Derive the expression for voltage gain in voltage-series negative feedback amplifier.

31) Distinguish between LC oscillator and RC oscillator.

32) Define critical frequency, skip distance and noise signal in radio communication.

33) Sketch the waveforms for modulating signal, carrier signal and AM wave.

34) Determine Vdc and Idc of SCR full wave rectifier. Given firing angle is 60°, load
resistance is 25Ω and applied AC voltage Vrms = 230V.

35) Obtain canonical expression for y (A, B, C) = A + BC in SOP form.

36) List the additional features of 3G and 4G cell phone system.

4

40 Electronics 04-2025.indd 4 16-04-2025 12:16:32

40

PART – D
(Section – I)

V. Answer any three questions. (3 × 5 = 15)

37) Explain the working of single stage CE transistor amplifier. Draw input and output
waveforms.

38) Derive an expression for an output voltage and voltage gain in op-amp inverting
amplifier.

39) Realize AND, OR, NOT and XNOR gate using NOR gates.

40) 
Write an assembly language program (ALP) to add 23H and 54H using
microcontroller 8051. Store the result in register R0. Verify the result.

41) Write a C program to accept the three different integers and print the largest among
them.

PART – D
(Section – II)

VI. Answer any two questions. (2 × 5 = 10)

Ω, R2 = 10 KΩ,
42) IN CE transistor amplifier, R1 = 100 KΩ, Ω, RC = 2.2 KΩ,
Ω, RE = 220 Ω,
26 mV
Vcc = +15 V, β = 100, VBE = 0.7 V and =
IE

Evaluate
a) Voltage across resistor R2
b) Emitter current IE

c) Emitter junction resistance


d) Input impedance Zin (base)

e) Current gain Ai

P.T.O. 5

40 Electronics 04-2025.indd 5 16-04-2025 12:16:32

40

43) Determine the output voltages in op-amp 1 for V1 = 1 V, V2 = –1V and op-amp 2
for Vin = 1 V.  (3 + 2)

Ω
100 kΩ

Rf
R1
V1 = 1v Ω
25 kΩ
– V01
1
V2 = –1v +
Ω
25 kΩ
R2 op – amp 1

Ω
100 kΩ
R3

Rf
Ω
50 kΩ

Rin
Ω
10 kΩ
– V02
2
+
Vin = 1v
op – amp 2

44) The carrier current of an AM transmitter is 8A and total current is 8.65A. Find the
percentage modulation. Determine the antenna current It , when the depth of modulation
is 0.75 and carrier current remains same. (IC = 8A).

45) Using K-map, simplify the Boolean expression.
y (A, B, C, D) = Σm(1,3,5,6,15) + Σd (7,8,14).
Realize simplified expression using basic gates.

6

40 Electronics 04-2025.indd 6 16-04-2025 12:16:33

40

PART – E
[For Visually-Challenged Students Only]

43) a) In an op-amp subtractor R1 = R2 = 25 KΩΩ (Input resistors), feedback resistor,
Ω and R3 = 100 KΩ.
Rf = 100 KΩ Ω. Input voltage V1 = 1V, V2 = –1V. Find the output
voltage.

Ω; Input resistor
b) In an op-amp non-inverting amplifier, feedback resistor Rf = 50 KΩ;
Ω and input voltage Vin = 1V. Determine the output voltage.
Rin = 10 KΩ (3 + 2)

_____________

P.T.O. 7

40 Electronics 04-2025.indd 7 16-04-2025 12:16:33

40 Electronics 04-2025.indd 8 16-04-2025 12:16:33

Registration No: 40
40
LX – 2025
Subject
Code 40
ELECTRONICS
Time : 3 Hours 00 Minutes] [Total No. of Questions: 45] [Max. Marks : 70
Instructions :
1. For PART – A questions, only the first written answers will be considered for evaluation.
2. 
PART–D consists of two Sections: Section – I is of essay type questions and
Section – II is of problems.
3. Circuit diagrams and truth tables must be drawn wherever necessary.
4. Solve the problems with necessary formulae.
5. For questions having diagrams, alternate questions are given at the end of the
question paper in a separate section for Visually-Challenged Students.

PART – A
I. Select the correct answer from the choices given: (15 × 1 = 15)
1) JFET is a
a) Current controlled device b) Voltage controlled device
c) Bipolar device d) More noisy device

2) The self destruction of a transistor is known as
a) Stabilizer b) Stabilization
c) Thermal runaway d) Stability factor

3) Which transistor amplifier produces the phase difference of 180° between input
and output voltage?
a) CE amplifier b) CB amplifier
c) CC amplifier d) Both (a) and (b)

4) The gain of an amplifier without feedback is known as
a) Closed loop gain b) Feedback gain
c) Open loop gain d) Loop gain

40 ELECTRONICS P.T.O. 1
S-17

40

5) The voltage gain of an op-amp buffer amplifier is

a) Zero b) Unity

c) Infinity d) 103

6) An Op-amp integrator converts square wave into

a) Triangular wave b) Sine wave

c) Cosine wave d) Sawtooth wave

7) In Wein bridge oscillator, the frequency determining components are

a) L and R b) L and C

c) R, L and C d) R and C

8) Ground waves are also known as

a) Space waves b) Surface waves

c) Line of sight waves d) Sky waves

9) The expression for carrier swing (CS) in FM is

a) 2∆F b) ∆F

c) 3∆F d) 4∆F

10) A SCR has

a) One layer

b) Two layers

c) Three layers

d) Four layers

2

40

11) Gray code is used in shaft position
a) Register b) Decoder
c) Multiplexer d) Encoder

12) Minterm in Boolean expression represents
a) Sum (OR) term b) Product (AND) term
c) Both (a) and (b) d) None of the above

13) The data bits in register A of 8051 microcontroller is
a) 16 bits b) 8 bits
c) 32 bits d) 64 bits

14) Size of an integer in C programming is
a) 1 byte b) 2 bytes
c) 5 bytes d) 8 bytes

15) Expansion of MTSO is
a) Mobile Technology Switching Office
b) Mobile Telephone System Office
c) Mobile Telephone Switching Office
d) Mobile Technology System Office

II. Fill in the blanks by choosing an appropriate answer from the bracket:  (5 × 1 = 5)
[(a) Selectivity (b) AND (c) Gain (d) Crystal Oscillator (e) Comparator (f) OR]

16) The need of cascading in amplifier system is to increase the ________ of the
amplifier.

17) ________ is the example for the nonlinear application of op-amp.

18) The oscillator which works on the principle of Piezo-electric effect is ________.

19) The ability of a radio receiver to select a desired station signal and reject all
unwanted station signals is termed as ________.

20) A half adder can be realized using one XOR gate and one ________ gate.

P.T.O. 3

40

PART – B

III. Answer any FIVE questions: (5 × 2 = 10)

21) Define Q-point. Mention its significance.

22) An amplifier with Z0 = 5KΩ has a voltage gain A = 100 and β = 0.02. Find the output
impedance with negative feedback.

23) Determine the frequency of the tank circuit. Given L = 10 µH and C= 1 µF.

24) Mention any two needs for modulation.

25) Sketch schematic cross-section of power diode.

26) Distinguish between combinational logic circuits and sequential logic circuits.

27) Write any four features of 8051 microcontroller.

28) Draw the block diagram of fiber optic communication system.

PART – C

IV. Answer any FIVE questions: (5 × 3 = 15)
29) Explain the working of n-channel JFET.
30) Derive an expression for the voltage gain of an amplifier with negative feedback.
31) Draw the circuit diagram of Colpitt's oscillator. Write the expression for its frequency
of oscillations.
32) Define the following terms with respect to ionospheric propagation.
(a) Critical angle
(b) Critical frequency
(c) Skip distance.
33) Derive an expression for the total power of AM wave in terms of Pc.
34) Determine Vdc and Idc of SCRHWR. Given firing angle is 60° and rms voltage
of ac input to the rectifier is 230V and load is 10Ω.
35) Convert Y = AB + C into canonical SOP form.
36) Explain in brief satellite communication system.

4

40

PART – D
(Section – I)

V. Answer any THREE questions: (3 × 5 = 15)
37) With a circuit diagram, explain the working of CB amplifier and draw its input and
output waveforms.
38) Derive an expression for the output voltage of op-amp adder circuit.
39) Explain the working of a clocked RS flip-flop using NAND gates. Write its truth
table.
40) Write an assembly language program (ALP) to subtract 32H from 48H and save the
result into register R0. Verify the content of R0 after executing the program.
41) Write a C-program to accept radius and print area of the circle.
(Section – II)
VI. Answer any TWO questions: (2 × 5 = 10)
42) For the CE amplifier circuit shown in the fig. calculate
i) DC voltage across 5KΩ   ii) IE  iii) re'  iv) AV  v) Z0
26mv
Given VBE= 0.7V, re' = and β = 100
IE

+ 20V

RC
R1 Ω
45KΩ
Ω
10KΩ
C2

C1

RL
Ω
10KΩ Vout
R2 Ω
5KΩ
20 RE
Ω
1KΩ
mV CE

P.T.O. 5

40

43) Find the output voltage for the op-amp circuits given below.
Ω
10 KΩ

RF
Ω
1.5 KΩ + VCC
– 2
Vin = 1.5V Ri VOI
+

– VEE

a

Ω
10 KΩ

RF
V1 = 0.5v Ω
1 KΩ
– + VCC
R1
V02
Ω
1 KΩ
+ 3
V2 = 1v R2 – VEE

R3 Ω
10 KΩ

b

44) A modulating signal 10 sin (2 π × 103) t is used to amplitude modulate a carrier
signal of 20 sin (2 π × 104) t. Find the

(a) Modulation index.

(b) Frequencies of the sideband components and their amplitudes.

(c) Draw the frequency spectrum.

45) Simplify the Boolean expression:

Y = Σ m (1, 3, 4, 5, 7, 9, 15) + Σ d (0, 11, 13, 14) and then draw the logic diagram for the

simplified expression using NAND gates only.

6

40

PART – E

[For Visually-Challenged Students Only]

42) In a single stage CE amplifier, R1 = 45 kΩ, R2 = 5 kΩ, Rc= 10 kΩ, RE= 1 kΩ and
26 mv
VCC = 20 V. Given VBE = 0.7 V, re' = and β = 100. 5
IE
Calculate

i) DC voltage across 5 kΩ

ii) Emitter current IE

iii) Emitter resistance re'


iv) Voltage gain AV

v) Output impedance Z0

43) a) An op-amp inverting amplifier with Ri = 1.5 kΩ, RF = 10 kΩ and Vin = 1.5v.

Determine the output voltage V01.2

b) An op-amp subtractor circuit with R1= 1 kΩ, R2 = 1 kΩ, R3 = 10 kΩ, RF = 10 kΩ,

V1 = 0.5 V and V2 = 1 V. Determine the output voltage V02.3

_____________

P.T.O. 7

Joár ±ÜÅÍæ°WÜÙÜ ÓÜíTæ : 45 ] Sl. No. :
Total No. of Questions : 45 ]

®æãàí¨Ü~ ÓÜíTæ :
Registration No. :

ËÐÜ¿á ÓÜíPæàñÜ /
Subject Code 40
˨Üá®ݾ®ÜÍÝÓÜŒ / ELECTRONICS
ÓÜÊÜá¿á : 3 WÜípæWÜÙÜá ] [ WÜÄÐÜu AíPÜWÜÙÜá : 70
Time : 3 Hours ] [ Max. Marks : 70

Instructions :

i) For Part-A questions, only the answers written first will be considered for
evaluation.

ii) Part-D consists of two sections. Section-I is of essay type questions,
Section-II is of problems.

iii) Circuit diagrams and truth tables must be drawn wherever necessary.

iv) Solve the problems with necessary formulae.

v) For questions having diagrams, alternate questions are given at the end of
the question paper, in separate part for Visually Challenged Students.

PART – A

I. Select the correct answer from the choices given : 15 × 1 = 15

1. The unitless parameter of JFET is
a) rd b) gm

c) µ d) g mo

2517 M1-2025 1 of 8

Code No. 40

2. For faithful amplification, the operating point is chosen at the

a) Centre of load line b) Cut-off region

c) Saturation region d) Inversion region

3. Identify the power amplifier in which conduction angle is 360°.

a) Class AB b) Class A

c) Class B d) Class C

4. Disadvantage of negative feedback is

a) Decrease in gain

b) Increase in bandwidth

c) Increase in the gain stability

d) Reduces noise

5. An ideal op-amp has
a) Zo = ∞ b) BW = 0

c) Zi = ∞ d) A=0

6. Zero crossing detector is an application of

a) Subtractor b) Adder

c) Comparator d) Inverting amplifier

7. The condition for sustained oscillations is

a) | Aβ | = 0 b) | Aβ | < 1

c) | Aβ | > 1 d) | Aβ | = 1

8. Ground waves are also called as

a) Line of sight waves b) Surface waves

c) Sky waves d) Space waves

2517 2 of 8

Code No. 40

9. The number of sidebands present in AM wave is

a) 1 b) 3

c) 2 d) ∞

10. Identify bidirectional conducting power device.

a) Triac b) SCR

c) Power diode d) Power transistor

11. The excess 3 code of 23(10) is

a) 10101010 b) 01010110

c) 11110000 d) 11100101

12. The logic expression for sum in Half adder is

a) A⊕ B b) A+B

c) A⊕ B d) AB

13. The number of I/O pins present in 8051 microcontroller is

a) 24 b) 16

c) 14 d) 32

14. The operator "&&" in C programming denotes

a) Bitwise OR b) Logical AND

c) Bitwise AND d) Logical OR

2517 3 of 8

Code No. 40

15. Abbreviation of GSM is

a) General Service for Mobile Communication

b) Global System for Mobile Communication

c) General System for Mobile Communication

d) Global Service for Mobile Communication

II. Fill in the blanks by choosing appropriate answer from those given in the

brackets : 5 ×1 = 5

[ (a) Unity (b) FM (c) Colpitts oscillator (d) Low (e) Universal (f) Crystal

oscillator ]

16. CC amplifier has ................... output impedance.

17. Op-amp buffer has .................. voltage gain.

18. ................... works on the principle of piezoelectric effect.

19. In .................... amplitude of carrier remains same.

20. ...................... gates are used to realise other logic gates.

PART – B

III. Answer any five questions : 5 × 2 = 10

21. What is heat sink ? Mention its importance.

22. Find the gain of negative feedback amplifier with an open loop gain

A = 200 and feedback factor β = 0·1.
23. A Wienbridge oscillator has R1 = R2 = 2 ⋅ 2 kΩ and C1 = C 2 = 0 ·1 µF.

Determine the frequency of oscillations.

2517 4 of 8

Code No. 40

24. Define modulation index ma of AM. Write the expression for ma in

terms of Vmax and Vmin in AM wave.

25. List any four power devices.

26. Draw the pin diagram of IC 7400.

27. Write any four addressing modes used in 8051 microcontroller.

28. Mention the important techniques used in Bluetooth communication.

PART – C

IV. Answer any five questions : 5 × 3 = 15

29. Write the function of Source, Drain and Gate terminals of JFET.

30. Give any three differences between positive feedback and negative

feedback.

31. Draw the circuit diagram of Colpitts oscillator. Write the expression

for its frequency of oscillations.

32. Write a note on ionosphere.

33. Draw the labelled block diagram of AM superheterodyne Radio

receiver.
34. Find Vdc and I dc of SCR FWR, given firing angle is 90° and rms voltage

of ac input to the rectifier is 230 volts and load is 20 Ω.
35. a) Convert ( 1101 ) gray code to binary using X-OR gates.

b) Convert given expression into canonical SOP form.

Y ( A, B ) = A B + B 2+1

36. Write any three uses of satellites.

2517 5 of 8

Code No. 40

PART – D
( Section – I )
V. Answer any three questions : 3 × 5 = 15
37. With circuit diagram explain the working of common base amplifier.
Also draw its input and output waveforms.
38. Draw the circuit diagram of Op-amp differentiator and derive an
expression for the output voltage.
39. Explain the working of a clocked SR flipflop using NAND gates.
40. Write assembly language program (ALP) to subtract 23H from 5FH
and save the result into register R1. Verify the content of R1 after
executing the program.
41. Write a C program to accept four integer numbers and print their sum
and average.

( Section – II )
VI. Answer any two questions : 2 × 5 = 10

42. For the CE amplifier circuit given below, find (i) V2 ( voltage across R2 )
/

(ii) I E (iii) re (iv) A v and (v) A p .
/

26 mV
Given re = , VBE = 0 ⋅ 7 V & β = 100.
IE

2517 6 of 8

Code No. 40

43. For the op-amp circuits given below, find output voltages Vo and
1
Vo .
2

a)

b) 3+2

44. An AM transmitter has carrier of 12 kilowatt power and has

percentage modulation 100%.

Find i) Total power

ii) Sideband power

iii) Power in each sideband.

45. Simplify the Boolean expression Y ( A, B,C, D ) = ∑m( 3,6,7,10,11,13,14,15)
+ ∑ d ( 2, 9 )

using K map. Realise the simplified expression using basic gates.

2517 7 of 8

Code No. 40

PART – E

( For Visually Challenged Students only )
42. A transistor CE amplifier is given with Vcc = + 12 V, R1 = 100 k Ω ,
R2 = 20 k Ω , RE = 1 k Ω , Rc = 3 ⋅ 2 k Ω , VBE = 0 ⋅ 7 V, β = 100 and
/

26 mV
re = .
IE

Calculate i) V2 ( Voltage across R2 )

ii) IE
/

iii) re

iv) Av & A p . 5

43. a) An op-amp adder circuit is given with R1 = 2 k Ω , R2 = 1 k Ω ,
R f = 3kΩ , V1 = 1 volt., V2 = 0 ⋅ 5 volt. Evaluate output voltage
Vo .
1

b) An op-amp non-inverting amplifier is given with vi = 1 V,
R1 = 5 kΩ , R f = 20 kΩ . Evaluate the output voltage VO .
2

3+2

2517 8 of 8

Registration No: 40

E 1 – 2025
Subject
Code 40
ELECTRONICS
Time : 3 Hours 00 Minutes] [Total No. of Questions: 45] [Max. Marks : 70

Instructions :
1. For PART – A questions, only the first written answers will be considered for evaluation.
2. 
PART – D consists of two Sections: Section – I is of essay type questions, Section – II
is of problems.
3. Circuit diagrams and truth tables must be drawn wherever necessary.
4. Solve the problems with necessary formulae.
5. For questions having diagrams, alternate questions are given at the end of the
question paper in a separate section for Visually-Challenged Students.

PART – A
I. Select the correct answer from the choices given: (15 × 1 = 15)
1) The relation between µ, gm and rd in JFET is
a) rd = µ × gm b) µ = rd × gm
c) gm = µ × rd d) µ = rd + gm

2) In which region does a transistor behave as an open switch?
a) Cutoff region b) Active region
c) Saturation region d) Inverse region

3) The transistor amplifier which has the current gain less than unity is
a) Common Emitter b) Common Collector
c) Common Base d) Common Source

4) The gain of the amplifier with feedback is known as
a) open-loop gain b) loop gain
c) feedback ratio d) closed-loop gain

40 ELECTRONICS P.T.O. 1
D11-S30

40 Electronics 01-2025.indd 1 06-02-2025 12:22:49

40

5) Output impedance of an ideal Op-Amp is

a) 0 b) 100

c) 1000 d) ∞

6) The feedback component of Op-Amp differentiator is

a) Diode b) Capacitor

c) Inductor d) Resistor

7) The crystal oscillator works on the principle of

a) Magnetic effect b) Electro-magnetic effect

c) Piezo electric effect d) Both (a) and (b)

8) The nearest ionospheric layer to the earth surface during daytime is

a) F1 layer b) F2 layer

c) D layer d) E layer

9) In frequency modulation, the ratio of frequency deviation to the frequency of

modulating signal is termed as

a) carrier frequency b) modulation index

c) carrier swing d) deviation ratio

10) Drift layer of power diode is also called as

a) substrate layer b) active layer

c) epitaxial layer d) depletion layer

2

40 Electronics 01-2025.indd 2 06-02-2025 12:22:49

40

11) Logic expression for the sum output of Half adder is

a) AB + AB b) AB + AB

c) A B + AB d) AB + AB

12) Excess-3 code of (15)10 is

a) 0100 1000 b) 0110 1000

c) 1000 0110 d) 0111 1001

13) 8051 microcontroller is a

a) 8 bit controller b) 16 bit controller

c) 32 bit controller d) 64 bit controller

14) The operator (&) in C-programing denotes

a) Bitwise OR b) Logical AND

c) Bitwise AND d) Exclusive OR

15) A typical uplink frequency in satellite communication is

a) 6 GHz b) 6 MHz

c) 6 KHz d) 4 GHz

II. Fill in the blanks by choosing an appropriate answer from those given in the bracket. 
 (5 × 1 = 5)

[ a) linear b) data c) twice d) buffer e) frequency f) biasing]

16) Common collector amplifier is also called as _______ amplifier.

17) Inverting amplifier circuit is _______ application of Op-Amp.

18) LC oscillators are used to produce high _______ oscillations.

19) In amplitude modulation, bandwidth is _______ the modulating signal frequency.

20) Flip-Flops are used to store _______.

P.T.O. 3

40 Electronics 01-2025.indd 3 06-02-2025 12:22:49

40

PART – B

III. Answer any five questions: (5 × 2 = 10)

21) Mention any two types of transistor biasing circuits.

22) An amplifier with Zi = 1 KΩ has a voltage gain A = 1000. If a negative feedback of
β = 0.01 is applied to it, determine the input impedance of feedback amplifier.

µF.
23) An RC phase shift oscillator has R1 = R2 = R3 = R = 4.7 KΩ and C1 = C2 = C3 = C = 0.047µ
Determine the frequency of oscillations.

24) Draw the block diagram of AM transmitter.

25) Sketch the electric field strength of punchthrough type reverse biased power
diode.

26) Draw the logic circuit of full adder using two half adders and an OR gate.

27) Mention any four addressing modes.

28) Write the advantages of cellphone system.

PART – C

IV. Answer any five questions: (5 × 3 = 15)

29) Explain the construction of n-channel JFET.

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

31) Draw the circuit diagram of Hartley oscillator. Write the expression for its frequency
of oscillations.

32) Draw the block diagram of communication system and explain the functions of
each block.

4

40 Electronics 01-2025.indd 4 06-02-2025 12:22:49

40

33) Define selectivity, sensitivity and fidelity of a radio receiver.

34) Determine Vdc and Idc of SCRFWR. Given firing angle is 90° and rms voltage

of ac input to the rectifier is 230 v and load is 10Ω.

35) Convert Y = AB + C into canonical SOP form.

36) Write any three applications of fiber optic communication.

PART – D

(Section – I)

V. Answer any three questions: (3 × 5 = 15)

37) With a circuit diagram, explain the working of two-stage direct-coupled CE amplifier.

38) Derive an expression for the output voltage of Op-Amp non-inverting amplifier.

39) Realize NOT, OR, AND and X-NOR gates using NOR gates.

40) Write an Assembly Language Program to add E2H and 1CH. Save the result in R0.

What is the content of R0 after the execution of program?

41) Write a C-program to accept the three different integers and print the largest

among them.

P.T.O. 5

40 Electronics 01-2025.indd 5 06-02-2025 12:22:49

40

PART – D

(Section – II)

VI. Answer any two questions: (2 × 5 = 10)

42) For the CE amplifier circuit shown in fig, find

Ω resistor
a) Voltage across 10 KΩ

b) I E

c) γe1

d) Z o


e) A v
26mV
Given VBE = 0.7V, γe1 = , β= 100
IE

Vcc = 20V

RC
5k Ω
R1 100k Ω
C2
V0

C1

RL 5k Ω
Ω
10kΩ
Vi
R2 RE Ω
1kΩ
CE

43) Design an Op-Amp circuit to realize the output Vo = – (2V1+ 3V2 + V3). Assume

Rf = 10 KΩ. Determine the output voltage when V1 = –2V, V2 = 1V and V3 = 2V.

6

40 Electronics 01-2025.indd 6 06-02-2025 12:22:50

40

44) A 50 kW carrier wave is amplitude modulated at 50% depth of modulation by a
sinusoidal modulating signal. Calculate
i) Total power
ii) Sideband power
iii) Power in each sideband.
45) Simplify the given Boolean expression using K-map.
Y = f (A, B, C, D) = Σm (1, 3, 6, 7, 9, 13, 14, 15) + Σd (5, 11).
Draw the logic circuit for the simplified expression using basic gates.

PART – E
[For Visually-Challenged Students Only]

42) In a single stage CE transistor amplifier, R1 = 100 kΩ, R2 = 10 kΩ, RC = RL = 5 kΩ, RE = 1 kΩ,
26mV
VCC = 20 V, β = 100, VBE = 0.7 V, and γe1 =
IE
Calculate

Ω resistor
a) Voltage across 10kΩ

b) I E

c) γe1

d) Z0

e) A V.

___________

P.T.O. 7

40 Electronics 01-2025.indd 7 06-02-2025 12:22:50

40

8

40 Electronics 01-2025.indd 8 06-02-2025 12:22:50

Study Materials
Notes

Model Papers Class 6 Notes

Sample Papers Class 7 Notes
Half Yearly Sample Papers Class 8 Notes

Class 9 Notes
Important Resources
Class 10 Notes
Periodic Table
Class 11 Notes
Writing Skills / Formats

Maps of India / World Class 12 Notes

Books and Solutions

NCERT Books
NCERT Book Solutions
HC Verma Chapter Wise Solutions
RD Sharma Solutions
CGBSE Solutions