A thermopile is a device that converts thermal energy into electrical energy. It consists of multiple thermocouples connected in series or parallel, which generate a voltage when there is a temperature difference between their junctions. This makes thermopiles useful for measuring temperature or detecting heat. Thermopiles are commonly used in applications such as infrared thermometers, gas detectors, and temperature sensors. They can efficiently detect heat from objects without direct contact, making them valuable in various industries, including automotive, medical, and environmental monitoring.