AL-Turath University College

Medical Instrumentation Technical Engineering

Report about (Ohm's Law)

14-3-2024
Introduction
Ohm’s law is the fundamental law of Electrical Engineering. It relates the current flowing
through any resistor to the voltage applied to its ends. According to the statement: The current
flowing through a constant resistor is directly proportional to the voltage applied to its
ends. This article presents the complete Ohm’s law Lab report and various questions regarding
the lab. The latter portion simplifies the law for beginners by delineating the absolute basic
concepts for beginners.
Ohm's Law is a formula used to calculate the relationship between voltage, current and
resistance in an electrical circuit.
To students of electronics, Ohm's Law (E = IR) is as fundamentally important as Einstein's
Relativity equation (E = mc²) is to physicists.
E=IxR
When spelled out, it means voltage = current x resistance, or volts = amps x ohms, or V = A x
Ω.
If two of these values are known, technicians can reconfigure Ohm's Law to calculate the third.
Just modify the pyramid as follows:

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The same equation can also be expressed in another form: :

• V: It is the electric potential difference between the two ends of the metal carrier
(resistance) and is measured in a unit called volts, denoted by (V).

• I: It is the intensity of the electric current passing through the carrier and is measured in
a unit called amperes, denoted by the symbol (A).

• R: It is the carrier's resistance to current and is measured in a unit called ohms, denoted
by the symbol (Ω)

Quantum mechanics theories show that current depends on the electric field. Thus, the
Draud model (in English:D rude) can be used to explain Ohm's law. The Drode model
treats electrons (or any charge carriers) as if they were balls moving (colliding) between the ions
that make up the composition of the material. These electrons accelerate against the direction of
the electric field applied to the material. These electrons collide with the ions of the material, and
with each collision the electrons deflect at high speeds, resulting in a mass movement of electrons
in a direction opposite to the direction of the electric field.

Importance of Ohm's Law Ohm's law

is used in all branches of electrical and electronic sciences and anywhere electric current flows,
as it is used to find many calculations related to all forms of electrical and electronic circuits, such
as:[4] Calculation of the value of resistors. Determine the strength of the current flow through the
circuit. Measure the voltage applied through the conductor. Calculating the value of resistors helps
to control the electrical circuit and control the flow rate of current through it by adding resistors to
reduce flow or reduce resistors to increase the amount of flow, while determining the flow strength
helps to ensure that the circuit provides sufficient electrical power or not

Factors affecting Ohm's law

There are several factors that affect the electrical resistance of a conductor in Ohm's law, which
are as follows:

➢ Conductor length: Long wires have greater resistance, meaning that the resistance of the
conductor is directly proportional to the length of the conductor; if the length of the
conductor is doubled, the resistance doubles, and if the length of the conductor is halved,
the resistance is halved.

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 ➢ Conductor cross-sectional area: The resistance of the electrical conductor is inversely
proportional to the cross-sectional area of the conductor, that is, thick diameter wires have
less resistance than wires with thin diameters, so the resistance of the conductor doubles
when the cross-sectional area of the conductor decreases, and the resistance decreases
when the cross-sectional area of the conductor increases.
➢ The nature of the conductor material: The resistance of a conductor depends on the type
of material it is made of, for example; the resistance of a copper conductor is lower than
that of a steel conductor.
➢ Conductor temperature: The resistance of the conductor is directly proportional to its
temperature, when the conductor is heated and its temperature is raised, its resistance
increases, and when its temperature decreases, its resistance decreases.

Ohm's law is one of the most important laws of physics used in the applications of electronic and
electrical circuits, through which it is possible to know and measure resistors across circuits and
determine electrical energy and voltage, and the value of resistance depends on the length of the
conductor, the material it is made of, its cross-sectional area andtemperature.

Applications of Ohm's Law

1- Fan regulator

We can control the speed of the fans in our homes by moving the regulator.The current flowing
through the fan is controlled by regulating the resistance through the regulator. A circular handle
can be rotated on the component to achieve variable resistance on the output terminals. For any
specific value of the input, we can calculate the resistance, current and therefore the energy
flowing through Ohm's law.

2- Electric heaters

Electric heaters are common devices used in winter all over the world. The heaters have a metal
coil with high resistance that allows a certain amount of current to pass through them to provide
the required heat. Also, the energy that must be supplied to heaters is calculated according to this
law"pw=I. V".

3- Boilers and electric irons

The electric kettle and irons have a lot of resistors. Resistors limit the amount of current flowing
through them to provide the required amount of heat. The size of the resistors used in them is
determined using Ohm's law.

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5- Chargers

Mobile phone and laptop chargers use a DC power supply in the process. The DC power supply
provides a variable output voltage based on the resistance and the overall work is controlled by
Ohm's law.

6- Electrical switches

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No electric current passes unless the circuit is closed and this is the basis of the work of the
switch, when the circuit is opened, the power is cut off and when it is connected, the electric
current passes.