Thermo-Electric Effect is: The effect where electricity is produced by the direct conversion of heat energy into electrical energy is known as Thermo-Electric Effect. Thermo-electric effect is reversible effect. If a circuit contains conductors of different materials and the junction between those conductors are maintained at different temperatures, then electric current are found to flow in the circuit. Three related effects of this kind are found. They are: (1) Seebeck effect (2) Peltier effect (3) Thomson effect.