The electrical current. To this end selenium, in theory,

The origin of the mechanical televisions of the 1920s and 1930s can be traced to the accidental discoveries of Willoughby Smith. In 1873 Smith, who was an electrical engineer at the time, had been tasked with running and laying underwater cable for telegraphs. To create the circuits required to complete this project Smith experimented with conductive materials that displayed a high value of resistance to electrical current. To this end selenium, in theory, seemed to fit the job perfectly. However, when tested in the field the material gave inconsistent results. After further investigation, Smith discovered that the selenium rods he was using could drastically alter their conductivity when exposed to light. Giving way to the advent of photoelectric cells 1.In the years to come following Smith’s discovery a new technology would emerge that would revolutionize entertainment. In 1883 the American inventor Charles Fritts  created the first working photoelectric cell. Later that same year a German engineer by the name of Paul Nipkow theorized a device which would come to be called the Nipkow disk. While being rotated, this device could recreate an image by measuring the amount of light exposure in an area and then translate it into specific electrical impulses. Though Nipkow did not create the device himself, it was through the advancement of this technology that a path was paved for products such as the mechanical television 2. Though extremely outdated now, in the 1920s and 1930s the newest product to make use of this advancement in technology was the mechanical television. As early as 1920, Scottish inventor John Baird is credited as having used the Nipkow disk in his prototype television 3. However, it was not until 1928 that the first “commercially” available TV’s were sold to the public. By 1934, 42 US stations were in operation. The mechanical television was a revolutionary product and would come to shape the entertainment industry forever 4.