Useful for BSc I year students

1. SRI SAIBABA NATIONAL COLLEGE::ANANATPUR
(Autonomous)
Department of Electronics
B.Sc., Electronics
I Year Practicals
Prepared By
Dr.C.Saritha
Dr.V.Sukanya

2. SSBN DEGREE (Autonomous) COLLEGE
Department of Electronics
B.Sc., I year - List of Experiments
1. Conversion of Basic meter into ohm meter
2. Verification of Kirchoff”s Laws
3. Verification of Thevenin’s and Norton’s theorems
4. Measurement of voltage (ac and dc) and frequency using CRO
5. Verification of Maximum power transfer theorem
6. Frequency response of CR circuit
7. Conversion of basic meter into voltmeter
8. VI characteristics of PN junction diode
9. VI characteristics of Zener diode
10. Zener diode voltage and current regulation characteristics

3. 1. Conversion of Basic meter into ohm meter
Aim:
To convert the given micro ammeter into ohm meter and also to determine the unknown
resistance values by using the ohm meter.
Apparatus:
Battery eliminator (1.5V), micro ammeter (0-200μA), Resistance box (2), multimeter, plug
key, bread board, connecting wires etc.
Circuit diagram:
Model Graph:

4. Tabular Column:
S.No. Resistance in ohms Deflections in divisions
1 500
2 1000
3 1500
4 2000
5 2500
6 3000
7 3500
8 4000
9 4500
10 5000
11 5500
12 6000
13 6500
14 7000
15 7500
16 8000
17 8500
18 9000
19 9500
20 10000
21 R1( )
22 R2( )
23 R3( )
24 R4( )
25 R5( )
Result :

5. The given micro ammeter is converted into ohmmeter and the values of unknown
resistances are determined by using the graph.
S.No. Resistors of different values Resistance in Ω
From From From
colour code multimeter Graph
1 R1(
)
2 R2(
)
3 R3(
)
4 R4(
)
5 R5(
)

6. 2. Verification of Kirchoff”s Laws
Aim :
To verify the kirchoff’s voltage and current laws by arranging simple electric circuits.
Apparatus :
Resistors of different values, Battery eliminator, multimeter, bread board and connecting
wires etc.
General circuit diagrams:
Kirchoff’s Current Law:
Kirchoff’s Voltage Law:

7. Circuit diagram:
Observation Table for Kirchoff’s Voltage Law :
S.No. Input Voltage Voltage Voltage Voltage Total ouput voltage
voltage Vi VAB VBC VCD VDE Vo = VAB + VBC + VCD + VDE
in volts in volts in volts in volts in volts
1 1
2 2
3 3
4 4
5 5
6 6
7 7

8. 8 8
9 9
10 10
Observation Table for Kirchoff’s Current Law :
S.No. V AB V BC V BC VCD V DE V DE I2 + I3 I5 + I6
I1 = I2 = I3 = I4 = I5 = I6 =
R1 R2 R3 R4 R5 R6
in mA in mA
in mA in mA in mA in mA in mA in mA
1
2
3
4
5
6
7
8
9
10
Result :
Kirchoff’s voltage law and Kirchoff’s current law are verified by arranging simple electric
circuit.
S.No. I 1 in mA I 2 + I 3 in mA I4 in mA I 5 + I 6 in mA
1
2
3
4
5
6
7
8
9
10
3. Verification of Thevenin’s and Norton’s theorems
Aim:

9. To state and verify Norton’s theorem and Thevenin’s theorem by using the suitable electric
circuits.
Apparatus :
Resistors 100Ω (2), Resistance Box (1), multimeter, Battery eliminator, voltmeter (0-10V),
milliammeter (0-10mA), bread board and connecting wires etc.
General Circuit :
To find Thevenin’s Resistance :
Observation Table to find Thevenin’s Resistance (Rth):

10. S.No. Resistance in Ω Thevenin’s Resistance Rth in Ω
R1 R2 R3 Experimental Value Theoretical Value
R1R 2
Rth = R3 + in Ω
R1 + R 2
1 100 100 100
2 100 200 100
3 100 300 100
4 100 400 100
5 100 500 100
6 100 600 100
7 100 700 100
8 100 800 100
9 100 900 100
10 100 1000 100
To find Thevenin’s Voltage:
Observation Table to find Thevenin’s Voltage (Vth) :
S.No. Resistance in Ω Thevenin’s Voltage Vth in Volts
R1 R2 R3 Experimental Theoretical Value
Value R2
Vth = ⋅ V in volts
R1 + R 2
1 100 100 100

11. 2 100 200 100
3 100 300 100
4 100 400 100
5 100 500 100
6 100 600 100
7 100 700 100
8 100 800 100
9 100 900 100
10 100 1000 100
To find Norton’s Current ( IN ):
Observation Table to find Norton’s Current ( IN ) :
S.No. Resistance in Ω Norton’s Current IN in mA
R1 R2 R3 Experimental Theoretical Value
Value Vth
IN = in mA
Rth
1 100 100 100
2 100 200 100
3 100 300 100
4 100 400 100
5 100 500 100
6 100 600 100

12. 7 100 700 100
8 100 800 100
9 100 900 100
10 100 1000 100
Result:
Thevenin’s and Norton’s theorems are verified by arranging suitable electrical circuits.
Thevenin’s voltage and Norton’s current are also measured and they are in good agreement
with the calculated values.
4. Measurement of voltage (ac and dc) and frequency using CRO
Aim :
To measure the alternating voltage (AC) , direct voltage (DC) and frequency of the given
AC signal.
Apparatus :
CRO (Cathode Ray Oscilloscope), battery eliminator, AFO (Audio frequency oscillator or
Function generator ), multimeter and connecting wires etc.
Block diagram of CRO :

13. Measurement of Direct Voltage (DC) :
Observation table to measure DC voltage :
S.No. Length of vertical Reading on Measured voltage Actual DC voltage
line in X cm Volts/Div Vo= X.N in volts Vi in volts
Scale (N)
1 0.5
2 1.0
3 1.5
4 2.0
5 2.5
6 3.0

14. Measurement of Alternating Voltage (AC) :
Observation table to measure AC voltage :
S.No. Length of Reading on Peak to Peak RMS Actual
vertical line Volts/Div Peak voltage voltage voltage AC
in X cm Scale (N) VPP=X.N V PP VP voltage Vi
VP = Vrms =
in volts 2 2 in volts
in Volts in volts
1 0.5
2 1.0
3 1.5
4 2.0
5 2.5
6 3.0

15. Measurement of frequency :
Observation table to measure frequency :
S.No. Actual Distance Reading on Time period Measured
frequency between two Time/Div T=X.N msec frequency
in Hz successive Scale (N) 1
f = Hz
T
peaks X in cm
1 50
2 100
3 150
4 200
5 250
6 300
Result :

16. By using CRO the alternating voltage, direct voltage and frequency of the given AC signal
are measured and the resultant values are in good agreement with the calculated values.
5. Verification of Maximum power transfer theorem
Aim :
To state and verify maximum power transfer theorem by arranging simple electric circuit.
Apparatus :
Batteries 1.5V – (2), Resostpr 100Ω –(1), Resistance box – (1), multimeter and connecting
wires etc.
Circuit diagram :

17. Model Graph :
Calculation :
E2
Maximum Power Pmax =
4 RL
Observation Table :

18. S.No. Load Resistance RL in Ω Voltage across the load V L2
Power P = in mW
resistance VL in Volts RL
1 10
2 20
3 30
4 40
5 50
6 60
7 70
8 80
9 90
10 100
11 110
12 120
13 130
14 140
15 150
16 160
17 170
18 180
19 190
20 200
Result :
Maximum power is delivered when load resistance is equal to the internal resistance of the
source.
Maximum power Pmax = ________________
Value of Resistance at maximum power
From graph
Actual value 100Ω

19. 6. Frequency response of CR circuit
Aim :
To study the frequency response of high pass and low pass filters and also to determine the
cutoff frequency by constructing suitable CR circuits.
Apparatus :
Function generator -1, multimeter, capacitors and resistors of suitable values, connecting
wires etc.
Design :
1
Cutoff frequency f 0 = 2ΠR C Where f0 = 100Hz, C=0.1μF
1
Now R = =
2Πf 0 C

20. Circuit diagram for High pass filter :
Model Graph :

21. Observation table for high pass filter : Input voltage Vi = 1V
S.No. Frequency in Hz Output voltage V0
Gain =
V0 in volts Vi
1 20
2 30
3 40
4 50
5 60
6 70
7 80
8 90
9 100
10 200
11 300
12 400
13 500
14 600
15 700
16 800
17 900

22. 18 1000
19 2000
20 3000
21 4000
22 5000
23 6000
24 7000
25 8000
26 9000
27 10000
Design :
1
Cutoff frequency f 0 = 2ΠR C Where f0 = 500Hz, C=0.1μF
1
Now R = =
2Πf 0 C
Circuit diagram for Low pass filter :
Model Graph :

23. Observation table for low pass filter : Input voltage Vi = 1V
S.No. Frequency in Hz Output voltage V0
Gain =
V0 in volts Vi
1 20
2 30
3 40
4 50
5 60
6 70
7 80
8 90
9 100
10 200
11 300
12 400
13 500
14 600
15 700
16 800
17 900
18 1000
19 2000
20 3000
21 4000
22 5000
23 6000
24 7000
25 8000
26 9000

24. 27 10000
Result :
The frequency response of low pass and high pass filters is studied by arranging suitable
CR circuits. Also the cutoff frequencies are found experimentally and are tabulated below.
S.No. Filter type Cutoff frequency in Hz
Theoretical value Experimental value
1 High pass filter 100
2 Low pass filter 500

25. 7. Conversion of basic meter into voltmeter
Aim :
To study the given basic meter into voltmeter of required range by determining its internal
resistance.
Apparatus :
Galvanometer, battery eliminator, keys -2, commutator, resistance box, multimeter,
connecting wires etc.
Circuit diagram 1 :
Formulas :
E
Maximum current I m = where E = 1.2V
R + Rm
R = Resistance for full scale deflection
Rm = Internal resistance of the meter

26. V
Series Resistance Rs = − Rm where V= Range of voltmeter
Im
Im = maximum current
Rm = Internal resistance of the meter
Observation table 1: To find internal resistance
Resistance in resistance
S.No. Resistance in R for full scale Deflection in box for half scale
deflection in ohms galvanometer in deflection in ohms
divisions
Left Right Mean Left Right Left Right Mean
1 50 50
2 40 40
3 30 30
E
Maximum current I m = where E = 1.2V
R + Rm
V
Series resistance Rs = − Rm
Im

27. Circuit diagram 2 :
Observation table 2:
S.No. Resistance in Ω Voltage measured with Calculated voltage Voltage measured
converted meter V = E.
Q
Volts with multimeter
P +Q
in volts
P Q Deflections Voltage
in division in volts
1 1000 50 5
2 1000 40 4
3 1000 30 3
4 1000 20 2
5 1000 10 1
Result :
The given basic meter is connected into voltmeter of range = _________
The internal resistance of the meter Rm =___________
The maximum current passing through the meter Im = __________________
The series resistance require to convert given basic meter into voltmeter is Rs = _________

28. 8. VI characteristics of PN junction diode
Aim :
i) To study the VI characteristics of PN junction diode in forward and reverse bias
conditions.
ii) To determine the resistance of diode in both forward and reverse bias.
iii) To find threshold voltage of the diode.
Apparatus :
PN junction diode, Battery eliminator, resistance box, resistor 100Ω, voltmeters (0-1V,
0-10V), milliammeter (0-10mA), milliammeter (0-1mA), connecting wires, multimeter etc.

29. Circuit diagram for forward bias :
Observation Table 1:
S.No. Input voltage Voltage across the diode Current through the diode
Vi in volts Vd in volts Id in mA
1 0.1
2 0.2
3 0.3
4 0.4
5 0.5
6 0.6
7 0.7
8 0.8
9 0.9
10 1.0

30. Circuit diagram for reverse bias :
Observation Table 2:
S.No. Input voltage Voltage across the diode Current through the diode
Vi in volts Vd in volts Id in mA
1 1
2 2
3 3
4 4
5 5
6 6
7 7
8 8
9 9
10 10

31. Model graph :
Result :
The characteristics of the given diode are studied both in forward and reverse bias
conditions. Also, the forward resistance and threshold voltage are determined from the
graph and they are tabulated below.
Parameter Experimental value Theoretical value
Resistance in forward bias, ≈ 100 Ω
Rf in Ω
Resistance in reverse bias, ≈∞
Rr in Ω
Threshold voltage VT in ≈ (0.3 – 0.4)
volts
9. VI characteristics of Zener diode

32. Aim :
To study the VI characteristics of zener diode in forward and reverse bias conditions and
also to determine its threshold and breakdown voltages.
Apparatus :
zener diode, Battery eliminator, resistance box, resistor 100Ω, voltmeters (0-1V, 0-10V),
milliammeter (0-10mA), connecting wires, multimeter etc.
Circuit diagram for forward bias :

33. Observation Table 1:
S.No. Input voltage Voltage across the diode Current through the diode
Vi in volts Vd in volts Id in mA
1 0.1
2 0.2
3 0.3
4 0.4
5 0.5
6 0.6
7 0.7
8 0.8
9 0.9
10 1.0
Circuit diagram for reverse bias :

34. Observation Table 2:
S.No. Input voltage Voltage across the diode Current through the diode
Vi in volts Vd in volts Id in mA
1 1
2 2
3 3
4 4
5 5
6 6
7 7
8 8
9 9
10 10
Model graph :

35. Result :
The characteristics of the given diode are studied both in forward and reverse bias
conditions. Also, the forward resistance and threshold voltage are determined from the
graph and they are tabulated below.
Parameter Experimental value Theoretical value
Resistance in forward bias, ≈ 100 Ω
Rf in Ω
Resistance in reverse bias, ≈∞
Rr in Ω
Threshold voltage VT in ≈ (0.3 – 0.4)
volts

36. 10. Zener diode voltage and current regulation
characteristics
Aim: To study the voltage and current regulation characteristics of a zener diode.
Apparatus: Zener diode, battery eliminator, voltmeter (0-10V), milliammeter (0-20mA),
bread board, connecting wires etc.
Circuit diagram for voltage regulation :
Observation Table :
S.No. Input voltage Vi in volts Output voltage Vo in volts
1 1
2 2
3 3
4 4
5 5
6 6
7 7
8 8
9 9
10 10
Model graph :

37. Circuit diagram for Current regulation :
Observation Table:
S.No. Current through the zener Output voltage Vo in volts
diode IL in mA
1 1
2 2
3 3
4 4
5 5
6 6
7 7
8 8
9 9
10 10
11 11
12 12

38. 13 13
14 14
15 15
16 16
17 17
18 18
19 19
20 20
Model graph:
Result:
The voltage and current regulation characteristics of a given zener diode are studied and
the graphs are plotted.