This document discusses the thermoelectric effect and its three main phenomena: Seebeck effect, Peltier effect, and Thomson effect. 1. Seebeck effect is the conversion of heat energy into electrical energy via a temperature difference across two dissimilar metals. It produces a thermoelectric current. 2. Peltier effect is the converse of Seebeck effect - it involves the absorption or production of heat when an electric current passes through the junction of two different conductors. 3. Thomson effect refers to the absorption or production of heat when an electric current passes through a single, unequally heated conductor. The key relationships between these effects are also summarized, including how Seebeck effect results