The Peltier effect is a thermoelectric phenomenon where heat is absorbed or released when an electric current flows through a junction of two different conductors or semiconductors. This effect is named after the French physicist Jean Charles Athanase Peltier, who discovered it in 1834. It is commonly used in thermoelectric coolers, which can transfer heat from one side to another, creating a temperature difference. In practical applications, the Peltier effect allows for efficient cooling in devices like portable refrigerators and electronic components. By applying a voltage across a thermoelectric module, one side becomes cold while the other side heats up, enabling temperature control without moving parts.