OHM’s Law Theory:

If I is the current flowing through the conductor when a potential difference V is applied, then according to Ohm’s Law the relation between the applied potential difference V and flowing current I is give by

I α V and I = V/R

where

• I is the current in amps
• V is the applied potential difference and unit is volts
• R is in Resistance of the  material and the unit is Ohm

Ohm’s Law may be defined as:

The current flowing through the conductor is directly proportional to the applied potential difference (voltage) across its ends when the physical state i.e, temperature etc are remain constant

It can also defined as:

The ratio of the potential difference applied across a conductor and current flowing through it remains constant provided physical state i.e, temperature etc of the conductor remains constant

V/I = Constant = R where R is known as the resistance of the conductor

Ohm’s law cannot be applicable for circuits consists of electronic valves or thyristors, diodes etc because these elements are not bilateral – i.e, they behave in different way, when the direction of flow of current is reversed as in the case of a diode.

Ohm’s law cannot be applied to the circuits consisting of non-linear elements such as thyrite, electric arc etc.