Verification of OHM’s law
By: Engr.Irshad Rahim Memon

Objective of this practical is to verify that
voltage applied to a closed resistive path is
equal to the product of current flowing
through and resistance of that path
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
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
Few resistors
bread board
multimeter
variable DC power supply
connecting wires etc
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
Ohm’s law states that current through a
closed resistive path is directly proportional
to applied voltage, where resistance of path is
kept constant.
Ohm experimentally determined that if the
voltage across resistor is increased, current
through resistor will also increase as shown
in figure 01.
Figure 01: Ohm law for constant resistance (a) less voltage,
less current (b) more voltage, more current

Ohm also determined if voltage is kept
constant then less resistance results in more
current and more resistance results in less
current as shown in figure 02

Figure 02: Ohm law for constant voltage (a)
less resistance, more current (b) more
resistance, less current

Ohm also determined if voltage is kept
constant then less resistance results in more
current and more resistance results in less
current as shown in figure 02.

Ohm’s law can be formulated as follows:

Connect a variable voltage source, a resistor
and an ammeter in series as shown in figure
03(a) to verify direct relationship between
voltage and current as shown in figure 03(c)

Verification of Ohm’s law for constant resistance
(a) circuit (b) different values of current for
different values of voltage (c) graphical relation
between voltage and current

Also connect a variable resistor, a voltage
source and an ammeter in series as shown in
figure 04(a) to verify inverse relationship
between resistance and current as shown in
figure 04(c)

It is observed that current varies directly with
applied voltage where resistance is kept
constant. It is also observed that current
varies inversely with resistance where applied
voltage is kept constant.

Fill the missing quantity in the table 01 with
the help of Ohm’s law.
S.No
R (Ohm) I (Ampere) V (volt)
Example
1K
1
5M
2
100
3
2
2K
100
50
0.05 m
1
Verification of Kirchhoff’s Voltage Law (KVL)
By: Engr.Irshad Rahim Memon

Objective of this practical is to verify KVL.
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


Few resistors
bread board
multimeter
variable DC power supply
connecting wires etc

Kirchhoff’s voltage law states that “sum of all
the voltage drops around a single closed path
in a circuit is equal to the total source voltage
in that loop” or it can also be defined as “The
algebraic sum of all the voltages (both source
and drop) around a single closed path is
equal to zero” as shown in figure 01.

Figure 01: Demonstration of KVL

KVL may be formulated as follows.
Vs=V1+V2+V3+…+Vn or
Vs-V1-V2-V3-…-Vn=0

For the verification of KVL, a simple series
resistive circuit like shown in figure 01 should
be prepared.


KVL is verified
KVL law is verified for series circuit of three
resistors of known values connected in series.
Results are given in table 01.
S.No
Vs
VR1
VR2
VR3
Vs= VR1 +VR2 +VR3
example
10Volt
2 Volt
3 Volt
5 Volt
10 Volt=2+3+5 Volt
1
5Volt
2
3
15volt
20volt
Verification of Kirchhoff’s Current Law (KCL)
By: Engr.Irshad Rahim Memon

Objective of this practical is to verify KCL.





Few resistors
bread board
multimeter
variable DC power supply
connecting wires etc

Kirchhoff’s current law states that “Algebraic
sum of all currents entering and leaving a
node is equal to zero” as demonstrated in
figure 01.

Figure 01: Demonstration of KCL

For the verification of KCL, a simple parallel
resistive circuit like shown in figure 02 should
be prepared.

Figure 02: Verification of KCL

KCL law is verified for parallel circuit of three
resistors of known values connected in
parallel. Results are given in table 01.
S.No
Itotal
example
1Amp
1
0.5 Amp
2
0.25 Amp
3
0.1 Amp
IR1
IR2
IR3
Itotal = IR1 +IR2 +IR3
0.5 Amp
0.3 Amp
0.2 Amp
1Amp=0.5+0.3+0.2 Amp