Original Source Models
From the 1825 “The New London Mechanics’ Register and Magazine of Science and the Useful Arts,” displaying Seebeck’s thermoelectric device of Bismuth and Antimony.
These models below depict the Seebeck Effect. When the junction between the bismuth (the bottom plate) and copper (the top plate) is heated, a steady current will flow as long as the heat gradient is maintained. The current is measured by the angle of deflection of the compass needle.