Ohm’s Law

Ohm’s Law:

This law applies to electric to electric conduction through good conductors and may be stated as follows :

The ratio of potential difference (V) between any two points on a conductor to the current (I)

flowing between them, is constant, provided the temperature of the conductor does not change.

In Words V/I = Constant or V/I = R

where R is the resistance of the conductor between the two points considered.

Put in another way, it simply means that provided R is kept constant, current is directly proportional to the potential difference across the ends of a conductor. However, this linear relationship between V and I does not apply to all non-metallic conductors.

For example, for silicon carbide, the relationship is given by V = KIm where K and m are constants and m is less than unity. It also does not apply to non-linear devices such as Zener diodes and voltage-regulator (VR) tubes.