Thomas Johann Seebeck was a German physicist and inventor, born on April 18, 1770. He is best known for discovering the Seebeck effect, which describes how a voltage is generated in a circuit made of two different metals when there is a temperature difference between them. This principle is fundamental in thermoelectric devices. Seebeck's work laid the groundwork for the field of thermoelectrics, influencing various applications, including thermocouples and power generation systems. He contributed significantly to the understanding of electricity and heat, and his discoveries continue to impact modern technology and energy solutions.