Seebeck Effect and Seebeck Coefficient Explained

This article defines the Seebeck Effect and Seebeck Coefficient. It also presents the formula for calculating the Seebeck Coefficient and provides values for common materials such as silicon and carbon.

Seebeck Effect

As we know, a thermocouple is made of two different types of wires composed of different materials. The conversion of heat energy into electrical energy at the junction of these dissimilar wires is known as the Seebeck Effect.

Thermopile structure and mathematical equation

Seebeck Coefficient

The voltage output of a thermopile in response to a temperature difference across the material is known as the thermoelectric coefficient, or Seebeck Coefficient. It is measured in volts per kelvin (V/K) or mV/K.

Seebeck Coefficient Formula

The Seebeck coefficient can be calculated using the following formula:

Vout=NS(TxTREF)V_{out} = N \cdot S \cdot (T_x - T_{REF})

Where:

  • VoutV_{out} is the output voltage
  • NN is the number of thermocouples used in the thermopile
  • SS is the Seebeck coefficient
  • TxT_x is the temperature at the measurement junction
  • TREFT_{REF} is the temperature at the reference junction

The table below shows the Seebeck coefficient in µV/K relative to platinum for various materials.

Material TypeSeebeck Coefficient (µV/K)
Silicon440
Germanium330
Copper, Silver, Gold6.5
Cadmium, Tungsten7.5
Lead4.0
Aluminium3.5
Carbon3.0
Mercury0.6