In 1826, Ohm, following a number of experiments, stated that the amount of current in a circuit is directly proportional to the difference in potential difference (voltage), or "pressure" of the current, and inversely proportional to the resistance. [1]
Ohm, in these experiments, drawing inspiration from
Fourier on heat conduction, after testing with voltaic piles, he switched to a bismuth copper thermocouple, as shown, wherein he measured the current passing through the copper strip, with one junction dipped in ice and the other in boiling water (
Ѻ), and then added test wires of varying length, diameter, and material to complete the circuit:
In 1827, Ohm, in his
The Galvanic Circuit Investigated Mathematically, based on his research on a
Volta-style electrochemical cell, stated that electromotive force acting between the extremities of any part of a circuit is the product of the strength of the current, and the resistance of that part of the circuit.
This finding has since come to be known as “Ohm's law” (
Ѻ), defined as follows:
where V is the voltage, R is the resistance, and I is the current.
Quotes | ByThe following are quotes by Ohm:
“The force of the current in a galvanic circuit is directly as the sum of all the tensions, and inversely as the entire reduced length of the circuit.”
— Georg Ohm (1827), The Galvanic Circuit Investigated Mathematically (pg. 36) (Ѻ)
References1. Kirby, Richard. (1956).
Engineering in History (co-authors: Sidney Withington, Arthur Darling, Frederick Kilgour) (pg. 333). Courier, 1990.
In 