Fracarro, from the disk of Nipkow to the digital convergence

The dream of transmitting images, in addition to sounds, has been considered and studied since the distant 1880, and the best results were obtained in 1884 by a disk with a spiral pattern of holes punched through it. This was invented by a German physicist of Russian origins, Paul Gottlieb Nipkow, on 24^th December 1883.When this disk, equipped with lenses in each hole, was spun rapidly, it decomposed the image into lines, starting from the most external hole (which read the upper line) to the most internal one, which identified the lower line. Therefore, the image was transformed into a series of luminous impulses that, striking a battery of photocells, turned themselves into electrical impulses: the principle of mechanical television was created.