- on Education & Information
- Published in issue 11/2004 on page 0
Easy processing with the MAX6675
Design engineers like to use thermoelements when it comes to probing around in really wide temperature ranges. Modern integrated circuits are available that act as sensor interfaces to a microcontroller.The operation of thermoelements is based on the Seebeck effect: a temperature difference across a wire causes movement of free electrons. The amount of charge displacement is dependent on the electrical properties of the wire.As illustrated in Figure 1, thermal energy is applied to electrons normally moving inside a crystal grid structure. The applied energy causes the electrons to move faster and eventually diffuse from the hot to the cold end. There they slow down again, releasing their energy. As electrons concentrate at the cold end, a negative electrode is formed relative to the hot end. At the same time an electrical field is established maintaining a dynamic balance between the electrons.