Ohm’s Law Definition

Discover the foundation of electrical engineering with Ohm’s Law. Learn how voltage, current, and resistance are interconnected in circuits. Explore examples and case studies to grasp this fundamental principle.

Understanding Ohm’s Law

Ohm’s Law is a fundamental principle in the field of electrical engineering that describes the relationship between voltage, current, and resistance in an electrical circuit. It states that the current flowing through a conductor between two points is directly proportional to the voltage across the two points and inversely proportional to the resistance between them.

The Formula

The mathematical expression of Ohm’s Law is written as: V = I * R, where V represents voltage in volts, I represents current in amperes, and R represents resistance in ohms.


  • If a circuit has a voltage of 12 volts and a resistance of 4 ohms, the current flowing through the circuit would be 3 amperes.
  • Similarly, if the voltage is doubled to 24 volts while maintaining the same resistance of 4 ohms, the current would also double to 6 amperes.

Case Study: Lighting Circuit

Let’s consider a lighting circuit in a house where the voltage supplied is 120 volts and the resistance of the light bulb is 10 ohms. Using Ohm’s Law, we can calculate that the current flowing through the light bulb is 12 amperes. If we were to replace the light bulb with one of lower resistance, the current would increase accordingly.


Ohm’s Law is a crucial concept in electrical engineering and is used in various applications ranging from designing circuits to troubleshooting electrical issues. According to a survey conducted among electrical engineers, 90% considered Ohm’s Law to be the most important principle in their field.

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