What is thermoelectric cooling? Thermoelectric cooling is a way to remove thermal energy from a medium, device or component by applying a voltage of constant polarity to a junction between dissimilar electrical conductors or semiconductors. A thermoelectric cooling system typically employs a matrix of semiconductor pellets sandwiched in between two large electrodes. When a DC voltage source is connected between the electrodes, the negatively-charged side becomes cooler while the positively-charged side becomes warmer. The negative electrode is placed in contact with the component, device or medium to be cooled, while the positive electrode is connected to a heatsink that radiates or dissipates thermal energy into the external environment. Thermoelectric cooling is used in electronic systems and computers to cool sensitive components such as power amplifiers and microprocessors. The technology can also be useful in a satellite or space probe to moderate the extreme temperatures that occur in components on the sunlit side and to warm the components on the dark side. In scientific applications, digital cameras and charge-coupled devices (CCDs) are sometimes cooled using thermoelectric cooling to minimize thermal noise, thereby optimizing the sensitivity and image contrast. In general, thermoelectric cooling is less efficient than compressor-based refrigeration. However, in situations where thermal energy must be transferred away from a solid or liquid on a small scale, a thermoelectric cooling may be more practical and cost-effective than a conventional refrigeration system. Other advantages of the thermoelectric cooling include the absence of moving mechanical parts, physical ruggedness, portability, long operating life and minimal maintenance requirements. A thermoelectric cooling system is also known as a Peltier heat pump