Ohm's law means that in the same circuit, the current passing through a certain conductor is directly proportional to the voltage across the conductor and inversely proportional to the resistance of the conductor. This law was proposed by German physicist George Simon Ohm in his paper "Determination of the Law of Conductivity of Metals" published in April 1826. Kohlrausch studied Ohm's law in 1849 using a Dellmann electrometer.
The current is measured by an ammeter and the potential difference is measured by a quadrant potentiometer. According to the measurement results, the current intensity of the conductor is proportional to the potential difference.
With the progress of research on circuits, people gradually realized the importance of Ohm's law, and Ohm's own reputation also greatly improved. In order to commemorate Ohm's contribution to electromagnetism, the physics community named the unit of resistance ohm, represented by the symbol Ω.