How do p-type and n-type semiconductor legs work together in a thermoelectric generator?

In a thermoelectric power generator, p-type and n-type semiconductor legs work together to convert a temperature differential into electric power by utilizing the Seebeck effect.

These legs are typically arranged in pairs, connected thermally in parallel between a heat source and a heat sink, and electrically in series. When a temperature difference ($\Delta T$) is applied across the legs, the Seebeck effect generates a voltage ($V_{\alpha }=\alpha \Delta T$). When an electrical load is connected to the circuit, this voltage drives an electric current through the system.1

The efficiency of this process is influenced by two competing factors within the legs:
* Thermal conduction: Heat flows from the source to the sink through the legs, which is determined by the material's thermal conductivity and the leg dimensions.1
* Ohmic heating: Electrical resistance within the legs generates heat, which dissipates some of the produced power.1

Designers optimize these devices by balancing these factors, often using long, thin legs to manage the trade-off between thermal conduction and electrical resistance.1