Kerala Plus One Question Paper 2025 Electronic System

KERALA BOARD

QUESTION
PAPER
2025
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Kerala Board of Public
Examinations

FY-353
Reg. No. : ......................................

Name : ...........................................

FIRST YEAR HIGHER SECONDARY EXAMINATION, MARCH 2025

Part – III Time : 2 Hours
ELECTRONIC SYSTEMS Cool-off time : 15 Minutes
Maximum : 60 Scores

General Instructions to Candidates :
 There is a ‘Cool-off time’ of 15 minutes in addition to the writing time.
 Use the ‘Cool-off time’ to get familiar with questions and to plan your answers.
 Read questions carefully before answering.
 Read the instructions carefully.
 Calculations, figures and graphs should be shown in the answer sheet itself.
 Malayalam version of the questions is also provided.
 Give equations wherever necessary.
 Electronic devices except non-programmable calculators are not allowed in the
Examination Hall.
 
    15  ‘  ’ .
 ‘  ’    
 .
      .
    .
  , , ,   
.
   .
    .
     
    .

FY-353 1 P.T.O.

Answer all questions from 1 to 4. Each carries 1 score. (4  1 = 4)

1. Two capacitors 12 F and 4 F are connected in series. Its effective capacitance is
_________.

(a) 16 F (b) 3 F

(c) 12 F (d) 4 F

2. The knee voltage of germanium diode is _______.

(a) 0.7 V (b) 1.12 V

(c) 0.3 V (d) 2V

3. Holding current is related to _________ component.

(a) LDR (b) SCR

(c) LED (d) Varactor diode

4. y = A  B is logically equivalent to _________ gate.

(a) AND (b) OR

(c) NOR (d) NAND

Answer any 10 questions from 5 to 16. Each carries 2 scores. (10  2 = 20)

5. Write any two applications in the field of communication.

6. Write the colour codes of the following resistors :

(a) 5.6 k  5% (1)

(b) 10 k  10% (1)

FY-353 2

1  4    . 1  .

(4  1 = 4)

1. 12 F, 4 F      . 
  _________ .

(a) 16 F (b) 3 F
(c) 12 F (d) 4 F

2.    knee voltage _______ .
(a) 0.7 V (b) 1.12 V
(c) 0.3 V (d) 2V

3. Holding current _________  .

(a) LDR (b) SCR
(c) LED (d) Varactor diode

4. y = A  B    _________ .

(a) AND (b) OR
(c) NOR (d) NAND

5  16    10  .
2  . (10  2 = 20)

5.     
 .

6.       :

(a) 5.6 k  5% (1)
(b) 10 k  10% (1)

FY-353 3 P.T.O.

7. What are the factors affecting the inductance of an inductor ?

8. Semiconductors exhibit negative temperature coefficient of resistance. Give reason.

9. (a) What is doping ? (1)

(b) A doped semiconductor is known as __________. (1)

10. You are provided with transistors, resistors and capacitors. Draw a circuit to generate
square wave using these components.

11. What are the requirements of a biasing circuit ?

12. Draw the DC load line and mark the operating point of class B power amplifier.

13. Draw the logic circuit for the Boolean equation y = A B + A B .

14. Define AM.

15. You are supplied with a galvanometer and a resistor. Arrange these components to
make voltmeter.

16. Compare TDM and FDM.

FY-353 4

7.       ?

8.      
.  .

9. (a)    ? (1)

(b)    __________  . (1)

10.  , ,   .
      .

11.     ?

12. DC load line  class B   
.

13. y = A B + A B      .

14. AM .

15.  ,   .  
   .

16. TDM, FDM   .

FY-353 5 P.T.O.

Answer any 8 questions from 17 to 26. Each carries 3 scores. (8  3 = 24)

17. (a) State Kirchhoff’s current law. (1)

(b) Calculate the current I in the given network. (2)

18. A transformer has 1200 turns in primary winding and 300 turns in secondary winding.
Its primary voltage is 240 V and primary current is 2A.

(a) Identify the type of transformer. (1)

(b) Calculate its secondary voltage and current. (2)

19. Explain the breakdown mechanisms in a diode when it is reverse biased.

20. (a) ___________ regulator IC is used to obtain + 12V dc output in regulated power
supply. (1)

(b) Draw the block diagram of DC power supply. (2)

21. Draw the symbol of an NPN transistor. Label all the currents and bias this transistor in
active region.

22. Draw the output characteristics of a transistor in CE configuration and mark different
regions of operation.

FY-353 6

17  26    8  .
3  . (8  3 = 24)

17. (a) Kirchhoff’s current law . (1)

(b)  network I . (2)

18.    1200   300
 .    240 V    2A  .
(a)    . (1)

(b)     . (2)

19.     ,   
  .

20. (a)     + 12V dc  
___________  IC . (1)

(b) DC     . (2)

21.  NPN   .   
    .

22. CE       
   .
FY-353 7 P.T.O.

23. (a) Which biasing circuit is most commonly used to avoid thermal runaway ? (1)

(b) Draw the circuit diagram. (2)

24. (a) The gain of an amplifier is 10. Calculate its output voltage if the input voltage is
2V. (1)

(b) Draw the circuit of an RC coupled amplifier. (2)

25. Draw the symbol of

(a) LED

(b) SCR

(c) Thermistor

26. Implement the following using NOR gate only :

(a) AND gate

(b) OR gate

Answer any 3 questions from 27 to 31. Each carries 4 scores. (3  4 = 12)

27. The PIV of a rectifier is 2 V m,

(a) Identify the rectifier. (1)

(b) Draw the circuit diagram. (2)

(c) Draw its input and output waveform. (1)

FY-353 8

23. (a) Thermal runaway   

   ? (1)

(b)   . (2)

24. (a)    10 .    2V

   . (1)

(b) RC coupled amplifiers   . (2)

25.  .

(a) LED

(b) SCR

(c) Thermistor

26. NOR gate     .

(a) AND gate

(b) OR gate

27  31    3  .
4  . (3  4 = 12)
27.   PIV, 2 Vm .

(a)   . (1)

(b)   . (2)

(c)     . (1)

FY-353 9 P.T.O.

28. (a) State Ohm’s law. (1)

(b) In the circuit given below, find (3)

(i) Total resistance

(ii) Current-I

(iii) Total power

29. (a) Draw the structure of N-channel JFET. (1)

(b) Compare FET and BJT. (3)

30. Simplify using K-map f(A, B, C, D) = m(0, 1, 2, 3, 4, 5, 6, 7, 13, 15)

31. (a) What is a Lissajous pattern ? (1)

(b) Draw the block diagram of a CRO. (3)

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FY-353 10

28. (a) Ohm’s law . (1)

(b)  ,   . (3)

(i) Total resistance

(ii) Current-I

(iii) Total power

29. (a) N-channel JFET   . (1)

(b) FET, BJT   . (3)

30. K-map   f(A, B, C, D) = m(0, 1, 2, 3, 4, 5, 6, 7, 13, 15)

31. (a) Lissajous pattern   ? (1)

(b) CRO    . (3)

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FY-353 11 P.T.O.

FY-353 12