What Is An Ohm

Ohm is the standard scientific unit of electrical resistance. It is named after Georg Simon Ohm, who introduced Ohm’s law.

The law first appeared in the book Die Galvanische Kette, Mathematisch Bearbeitet (“The Galvanic Circuit Investigated Mathematically”) in 1827, where Ohm explains his complete electricity theory.

Ohm’s law

Ohm’s law describes the fundamental result of Ohm’s experiments in 1825 and 1826. Ohm’s work was inspired by the experiments of the conduction of heat performed by Jean-Baptiste Fourier. Ohm’s law states:

“The current in an electrical circuit is directly proportional to the voltage and inversely proportional to the resistance.”

Voltage, current, and resistance

Below are the formulas to calculate the values used in Ohm’s law, where V represents voltage, I represents current, and R represents resistance.

V = I * R

I = V / R

R = V / I

Nikola Tesla, Power terms, SI