Ohm’s Law

Ohm’s Law is a mathematical equation that shows the relationship between electric voltage, current and resistance. Ohm’s Law was named after Bavarian mathematician and physicist Georg Ohm.

Ohm’s Law can be stated as three mathematical equations, all derived from the same principle. In the following equations, V is voltage measured in volts, I is current measured in amperes and R is resistance measured in ohms:

  • V = I x R
  • R = V / I
  • I = V / R

Knowing any two of the values of a circuit, one can determine the third using Ohm’s Law. For example, if a circuit has a current of 2 amperes, and a resistance of 1 ohm, then according to Ohms Law, voltage equals 2 (V = 2 x 1).

Typically, Ohm’s Law is only applied to DC circuits and not AC circuits.

Note well: The letter “E” is sometimes used in representations of Ohm’s Law for voltage instead of “V.”

Webopedia Staff
Webopedia Staff
Since 1995, more than 100 tech experts and researchers have kept Webopedia’s definitions, articles, and study guides up to date. For more information on current editorial staff, please visit our About page.

Related Articles

Human Resources Management System

A Human Resources Management System (HRMS) is a software application that supports many functions of a company's Human Resources department, including benefits administration, payroll,...

How To Defend Yourself Against Identity Theft

Almost every worldwide government agency responsible for identity theft issues will tell you the same thing: The first step to fighting identity theft is...

Infographic

An infographic is a visual representation of information or data. It combines the words information and graphic and includes a collection of imagery, charts,...

Phishing

What is phishing? Phishing is a type of cybercrime in which victims are contacted by email, telephone, or text message by an attacker posing as...

ScalaHosting

ScalaHosting is a leading managed hosting provider that offers secure, scalable, and affordable...

HRIS

Human resources information system (HRIS) solutions help businesses manage multiple facets of their...

Best Managed Service Providers...

In today's business world, managed services are more critical than ever. They can...