Ohm's law experiment
Amr Essam Wasfy
Contents
 Introduction
 Objectives
 Equipment
 Steps
 Results
 Comments
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Ohm's law experiment
Amr Essam Wasfy
Introduction
Ohm's law states that the current through
a conductor between two points is directly
proportional to the potential difference or
voltage across the two points, and inversely
proportional to the resistance between them.[1]
The mathematical equation that describes this
relationship is:[2]
Where I is the current through the resistance in
units of amperes, V is the potential difference
measured across the resistance in units of
volts, and R is the resistance of the conductor
in units of ohms. More specifically, Ohm's law
states that the R in this relation is constant,
independent of the current.[3]
The law was named after the German physicist
Georg Ohm, who, in a treatise published in
1827, described measurements of applied
voltage and current through simple electrical
circuits containing various lengths of wire. He
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Ohm's law experiment
Amr Essam Wasfy
presented a slightly more complex equation
than the one above (see History section below)
to explain his experimental results. The above
equation is the modern form of Ohm's law.
Objectives
In this experiment we want to verify
Ohm's law by proving that the relation
between the current in the circuit and the
resistance is a linear relation.
Equipments

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Resistance
Ammeter
Conducting wires
Voltage source
Connections
We will connect the equipments stated as
shown in figure (1)
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Ohm's law experiment
Amr Essam Wasfy
Figure (1)
Steps
 First we have to know the value of the
resistance. There are two ways to know
the value of the resistance the first is to
use the Avommeter to measure the value
of the resistance, the second way is to
use the colors painted on each resistance
to know its value by using the data
shown in figure (2).
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Ohm's law experiment
Amr Essam Wasfy
Figure (2)
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Ohm's law experiment
Amr Essam Wasfy
 Then we will measure the current in the
circuit, it will be zero as we didn't turn on
the voltage source yet.
 Then we will turn on the voltage source
which connected to the circuit shown in
figure (1), we will set it to supply the
circuit with (2v), and we will measure the
current in the circuit.
 We will set the voltage source supply the
circuit with (4,6,8,10v) and we will
measure the current in each case.
 We will note the measures we took an
draw the grave between the voltage and
the current.
 Then we will calculate the slope of the
grave it should equal the value of
resistance we measured in the first step.
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Ohm's law experiment
Amr Essam Wasfy
Results
By measuring
V
I
Slope =
0
0
2
3
R=0.69
4
6
8
10
5.84 8.87 11.73 14.69
=0.66 kΩ
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0.69 kΩ
Ohm's law experiment
Amr Essam Wasfy
Comments
There should be an error between
calculating and measurements when we
measured the resistance it was 0.69 kΩ and
when we calculated it from the grave it
was 0.66 kΩ so the percent of the
error here is 4.3%.
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