Reactors for the Roxy: Evolution of AC Stage Lighting [History]

The introduction of ac services to the "theater districts" of large cities during the early 20th century allowed for the adoption of reactancetype dimmers to control incandescent stage lighting, in place of the hopelessly inefficient resistance dimmers (rheostats) that previously had to be used with dc services. Then, in a relatively short time, reactance dimmers were combined with vacuum tubes to create the first truly electronic type of lamp dimmer, which allowed for a much greater flexibility of control that was not improved upon until the introduction of computer-type stage lighting consoles during the latter part of the century.