A charge-coupled device is a type of electronic image sensor used to detect and record light energy by converting incident photons into corresponding electrical charges. The foundational operational principle involves arranging light-sensitive material into an array of discrete potential wells, or pixels, where incoming light generates an electron-hole pair. These generated charges are then stored within their respective wells. The key characteristic of the technology is the method by which these stored charges are sequentially read out; they are physically shifted, or "coupled," across the array to a final output register. This coupled transfer allows for high signal sensitivity, reduced noise, and the accurate reconstruction of a digital image data set based on the measured electrical signal strength from each pixel.