What is Ohm’s Law?

Ohm's Law is one of the most fundamental principles in electrical engineering and physics. It describes the relationship between three key electrical quantities: Voltage (V), Current (I), and Resistance (R). Formulated by German physicist Georg Simon Ohm in 1827, the law states that the current passing through a conductor between two points is directly proportional to the voltage across the two points and inversely proportional to the resistance.

The Ohm’s Law Formula

Depending on which variable you are trying to find, the formula can be rearranged in three ways:

• Voltage (V) = I × R: To find Volts, multiply Current by Resistance.
• Current (I) = V / R: To find Amps, divide Voltage by Resistance.
• Resistance (R) = V / I: To find Ohms, divide Voltage by Current.

How to Use This Calculator with Steps

Our Ohm’s law calculator is designed to provide not just the answer, but the mathematical process behind it. To use this tool, simply input two known values into the respective fields (Voltage, Current, or Resistance) and leave the third field blank. Click the "Calculate" button, and the tool will instantly solve for the missing variable. The "Steps" section will break down the formula used and show the substitution of values, making it an excellent resource for students and hobbyists.

FAQs about Electrical Circuits

Q: What are the units of measurement?
A: Voltage is measured in Volts (V), Current in Amperes (A), and Resistance in Ohms (Ω).

Q: Why is Ohm's Law important?
A: It allows engineers to determine the correct component sizes needed for a circuit to prevent damage, ensure efficiency, and troubleshoot electrical failures.

Q: Does Ohm's Law apply to all materials?
A: It primarily applies to "ohmic" materials like copper and aluminum. Some components, like diodes and transistors, are non-ohmic and do not follow a linear relationship.