Joule heating, also known as resistive, resistance, or Ohmic heating, is the process by which the passage of an electric current through a conductor produces heat.
Joule's first law, also known as the Joule–Lenz law, states that the power of heating generated by an electrical conductor is proportional to the product of its resistance and the square of the current:
P
∝
I
2
R
{\displaystyle P\propto I^{2}R}
Joule heating affects the whole electric conductor, unlike the Peltier effect which transfers heat from one electrical junction to another.