A Peltier device is a type of thermoelectric cooler that uses electricity to create a temperature difference between its two sides. When a voltage is applied, one side absorbs heat and becomes cold, while the other side releases heat and becomes hot. This effect is known as the Peltier effect, named after the French physicist Jean Charles Athanase Peltier. Peltier devices are commonly used in applications like portable coolers, electronic component cooling, and temperature control in scientific instruments. They are compact, lightweight, and can be powered by a simple electrical source, making them versatile for various cooling needs.