The Brief Introduction to TEC

Time : Mar 20 2015Source :analogtechnologies Author : Analog Click :
In 1821, Thomas Seebeck discovered when two conductors with different materials and different temperature are connected, there is current flowing in the loop However, twelve years later, J. C. Peltier discovered an opposite phenomenon, that is ,by deleting a conductor in the loop, the external current can flow through the loop, and then a temperature difference between two connecting points is appeared. This phenomenon came to be known as Peltier Effect. Owing to the limitation of material at that time, the temperature difference in Petier Effect is mostly the thermal resistance produced when large current flows through the materail. Along with the development of material science in recent years, the heating or cooling effect of the connection point becomes more practical, which can be used as heat pumps. In actual application, there's no much difference with the cooling method that is based on fluorine carbon vapor compression refrigeration. There are no moving parts and working fluid in TEC, so it makes refrigeration equipment miniaturization possible.

Basic Operational Principle
Since the Peltier Effect can be linearly controlled by the current, TEC has been used in a large number of applications involving precision temperature control. Temperature sensitive component, TEC, and temperature sensors (thermistors) are integrated in a single module. TEC control requires a power supply with reversible electrical level to provide positive and negative voltage. If you'd like to make this in the single power supply, then H bridge circuit can be utilized. Strong and pulse width modulation (PWM) controls two output voltages, which   change the current flowing through the TEC as well as the current direction. Through constant changing of the current, small sized TEC can control the temperature of all kinds of discrete devices, such as optical fiber laser driver, precision voltage reference, or any other temperature sensitive devices. 
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