A thermoelectric cooler, (TEC), is a solid-state device that operate on the Peltier effect and acts as a heat pump when voltage is applied to the junction between two dissimilar materials. An array of p- and n- type semiconductor elements, (ex. bismuth telluride), is typically soldered between two ceramic plates, (ex aluminum oxide). TECs are often used in electronics to cool computer processors and in high-end CCDs to reduce thermal noise.