A new solid state power regulator circuit for vapor lamp excitation

For many years, high pressure mercury lamps, so familiar to all of us as street lights, stadium lights, or manufacturing shop lights, have been operated with series inductive ballasts. Recently, however, new types of lamps having characteristics different from those of the common mercury vapor lamp have been developed, requiring new families of inductive ballasts. To eliminate the problem of providing a different ballast for each lamp, and to provide improved ballast performance, a hybrid solid-state circuit has been developed which will operate all of the presently available lamps. This circuit, called a Quadmaster Ballast, includes a series inductor and an AC switch, together with circuitry which causes the AC switch to be triggered at the proper time to regulate lamp power. All of the presently available 400 watt street lamps (mercury, metal halide and sodium) can be operated by simply installing the lamp into the fixture.