Direct current (3) 'Ohm's law'

Ohm's law

In our previous post, we discussed about the resistance. Today we are about to study the Ohm's law.

Whenever electric current flows through a conductor , the following factors are present :

1. The potential difference V across the conductor causing the current to flow.
2. The opposition or resistance R of the conductor which must be overcome.
3. The current I which in the conductor as a result of pressure overcoming the resistance.

The relationship between these three quantities are defined in Ohm's law.

Ohm's law:

The voltage difference across a conductor is directly proportional to the current which goes through it due to the voltage difference , provided the temperature of the conductor does not change.

or

The ratio of potential difference  V between any two points of a conductor to the current I flowing between them is constant, provided the temperature of the conductor does not change.

Mathematically,

V/I = constant

or

V/I = R

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

This can be written as, 

V = IR

This law is applicable to both DC and AC circuits. But it is complicated than DC .

Derived relations from Ohm's law

• Power is given by the product of voltage and current.
  
  
  W = VI
  Using ohm's law we can rewrite this equation as,
  
  
  
  

   W = I²R 

   W = V²/R