What exactly is ohm's law and why is it significant

What exactly is ohm’s law and why is it significant?


There is a statistically significant relationship between current, voltage, and resistance. Georg Simon Ohm discovered the law in the year 1827. Georg Ohm, a German scientist, conducted numerous experiments in an attempt to establish a relationship between the three. There were no meters as we know them now in the days when he was doing his studies. After much effort in his second attempt, however, he succeeded in formulating what we now know as Ohm’s Law. In today’s blog on education, we will discuss what exactly is ohm’s law and why is it significant. Among the most significant and fundamental principles controlling electrical and electronic circuits is Ohm’s Law.

Key variables addressed by Ohm’s Law:

QuantitySymbols for Ohm’s LawMeasurement unitFunction in circuits
VoltageEVolt (V)Pressure in volts (V) that causes electron flow
CurrentIAmpere (A)Electron flow rate
ResistanceROhm (Ω)Greek letter omega represents flow regulator

If the first two variables are accessible, a linear device connects current, voltage, and resistance to determine the third quantity. Almost every branch of electrical and electronic study employs Ohm’s Law. It can be used to determine the value of resistors needed in circuits, as well as the current flowing in a circuit where the voltage can be observed and measured across a known resistor, but it can also be used to calculate a variety of other parameters in all types of electrical and electronic circuits, and in fact anywhere current flows.

Ohm’s Law (E = IR) is as basic to electronics students as Einstein’s Relativity equation (E = mc²) is to physicists.

Image: Ohm’s Law

Ohm’s Law Triangle

To remember the formula, draw a triangle with one side horizontal and a peek at the top, similar to a pyramid. The Ohm’s law triangle is another name for this.

The letter V appears in the top corner of the Ohms law triangle, the letter I appears in the left corner, and the letter R appears in the right-hand bottom corner.

Cover up the unknown quantity with the triangle and then compute it from the other two. Multiply them if they’re in a straight line; divide them if they are on top of each other. In other words, to calculate current, divide the voltage by the resistance, i.e. V/R, and so on. Consider the following diagram.

Image: Ohm’s Law Triangle

Circuit science at the most fundamental level

Atoms are the building blocks of all matter. This also includes circuits. Subatomic particles make up an atom:

  • Protons are the fundamental building blocks of the universe (with a positive electrical charge)
  • Neutrons are the fundamental building blocks of matter (no charge)
  • Electrons are the fundamental building blocks of all matter (negatively charged)

The nucleus’ connection to electrons in the outer shell holds atoms together. Voltage affects the components of atoms in a circuit, causing them to rearrange and create a potential difference. When mutually attracted loose electrons travel toward protons, an electron flow is formed. The term “resistance” refers to any substance in the circuit that prevents this flow.

Significance of Ohm’s Law

Ohm’s Law can be used to verify the static values of circuit elements, current levels, voltage sources, and voltage dips. If test equipment discovers an elevated current measurement, for example, it could indicate that resistance has reduced or voltage has raised, resulting in a high-voltage situation. This could suggest a problem with the supply or the circuit.

A lower-than-normal current measurement in a direct current (dc) circuit could indicate that the voltage has dropped or the circuit resistance has risen. Poor or weak connections, rusting, or broken parts are all possible reasons for higher resistance.

Loads in a circuit draw electrical current. Tiny electrical devices, laptops, home appliances, are all examples of loads. The majority of these components, however, have a label or informational sticker attached to them. These nameplates feature several reference numbers as well as safety certification.

To understand conventional voltage and current values, professional electricians consult nametags on pieces of equipment. If technicians discover that standard values do not register on their electronic multimeters or clamp meters during testing, they can utilize Ohm’s Law to establish which part of the circuit is failing and, as a result, find out where the problem resides.

Some Examples of Ohms Law calculations

Determine how much current will flow through a 500-ohm resistor when a 10-volt power source is connected. The current is the unknown component in the Ohms Law triangle, whereas the voltage and resistance are the known variables. Divide the voltage by the resistance to calculate the current.

I = V/R = 10/500 = 0.02A = 20mA

Ohm’s Law can also be used to find the resistance in a similar way if the current and voltage is known. Consider a 10-volt system with a current of 0.1 amps. According to Ohm’s Law triangle, it can be seen that:

R = V/I = 10/0.1 = 100Ω

If the resistance and current are known, another method is to compute the voltage expected across the resistance. Consider a current of 0.1 amps running across a distance of 250 meters. Voltage can be calculated using the below equation:

V = I*R = 0.1*250 = 25 volts


In a nutshell, Ohm’s law is one of the most fundamental principles in electrical engineering. The law, however, states that the current through a resistor is directly proportional to the voltage across the resistor and inversely proportional to the resistance of the resistor. This law is important because it allows us to calculate the current through a circuit, or the voltage across a resistor, given only two of the three values. Even though engineers took some time to start incorporating Ohm’s law in their designs, it is now considered one of the most fundamental in all of electrical engineering.

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