Movies have been an important part of popular culture for about 100 years. Though essentially a photographic medium, movies have historically relied heavily on electrical, electronics and computer technologies.
In the era of silent films, cameras and projectors used electric motors to achieve constant film speed. In addition, electric lights were important in both filming and projecting. In the early years in the studios, arc floodlights and Cooper-Hewitt mercury-vapor tubes were most important. From the mid 1920s on, incandescent tungsten bulbs became common, both because brighter incandescent lights were newly available and because they did not produce the noticeable humming that arc lights did. The humming had not been a problem with silent films. After about 1940, tungsten floodlights with reflecting surfaces on the inside of the bulb behind the filament became common.