Ohm’s Law Calculator


What is Ohm’s Law?

Ohm’s Law is a fundamental principle in the field of electrical engineering and electronics, defining the relationship between voltage, current, and resistance in an electrical circuit. It states that the current through a conductor between two points is directly proportional to the voltage across the two points. This relationship is expressed with the simple equation I = V/R, where I represents the current in amperes (A), V represents the voltage in volts (V), and R represents the resistance in ohms (Ω).

Understanding Ohm’s Law is crucial for engineers and technicians as it applies to almost all basic circuits and electronic components. It helps in designing circuits, analyzing electrical problems, and understanding how changes in a circuit affect the current flow and voltage. The law is named after Georg Simon Ohm, a German physicist who first formulated this relationship in 1827.

Ohm’s Law is not just a theoretical concept but a practical tool used in various applications. From simple tasks like determining the correct resistor to use in a circuit to complex electrical network analyses in power systems, Ohm’s Law serves as a cornerstone of electrical engineering principles.

“Ohm’s Law Pie chart”, by Wizard346, licensed under Creative Commons. Source: Wikipedia

Frequently Asked Questions

  1. What are the applications of Ohm’s Law? Ohm’s Law is widely used in electrical engineering and electronics to design and analyze circuits. It’s fundamental in calculating the right values for components in circuits, such as resistors, and understanding the behavior of electronic devices.
  2. Does Ohm’s Law apply to all materials? Ohm’s Law applies to ohmic materials, which are materials that have a constant resistance over a range of voltages. However, some materials, known as non-ohmic, do not follow Ohm’s Law as their resistance changes with voltage or temperature.
  3. How is Ohm’s Law useful in everyday life? In everyday life, Ohm’s Law is used in various electronic devices. For instance, it helps in determining the power requirements and battery life of gadgets and can be used to troubleshoot electrical appliances.
  4. Can Ohm’s Law be used for AC circuits? Ohm’s Law can be applied to AC circuits, but it’s more complex due to the presence of capacitance and inductance, which cause phase differences between current and voltage. In such cases, the concept of impedance is used instead of just resistance.
  5. Is there a limitation to using Ohm’s Law? Ohm’s Law is less effective in semiconductor materials, where current and voltage do not have a linear relationship. Additionally, at very high frequencies, parasitic capacitance and inductance can affect the law’s applicability.


Ohm’s Law is a key concept in electrical engineering, offering a simple yet powerful tool for understanding and designing electrical circuits. Its versatility makes it applicable in various technologies and industries, from household electronics to large-scale power systems. While there are limitations and cases where Ohm’s Law does not apply, its fundamental principles remain a cornerstone of electrical theory and practice. For engineering enthusiasts and professionals alike, a solid grasp of Ohm’s Law is essential for successful circuit design and analysis. Whether you are a student, hobbyist, or seasoned engineer, Ohm’s Law continues to be an invaluable part of your electrical engineering toolkit.