(1789-1854) German physicist who studied electricity and discovered the fundamental law that bears his name. The SI unit of electrical resistance, the ohm, is named for him, and the unit of conductance (the inverse of resistance) was formerly called the mho, which is “ohm” spelled backward.
Ohm was born and educated in Erlangen, Bavaria. He worked as a schoolteacher until 1833, when he became professor of physics at the Polytechnic Institute, Nuremberg, moving to Munich University 1849.
Ohm began the work that led him to his law of electricity in 1825. He investigated the amount of electromagnetic force produced in a wire carrying a current, expecting it to decrease with the length of the wire in the circuit. Using a thermocouple because it produced a constant electric current, he employed an electroscope to measure how the tension varied at different points along a conductor to verify his law, and presented his arguments in mathematical form in his great work Die Galvanische Kette 1827.

ETYM So called from the German electrician, German s. Ohm.
Unit of electrical resistance: resistance of circuit in which current of one ampere is produced by one volt.
Si unit (symbol w) of electrical resistance (the property of a substance that restricts the flow of electrons through it).
It was originally defined with reference to the resistance of a column of mercury, but is now taken as the resistance between two points when a potential difference of one volt between them produces a current of one ampere.
The unit of measure for electrical resistance. A resistance of 1 ohm will pass 1 ampere of current when a voltage of 1 volt is applied.
A unit of electrical resistance equal to the resistance between two points on a conductor when a potential difference of one volt between them produces a current of one ampere.